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A TREATISE ON CHEMISTEY.

TOL in. — PART I.

TREATISE ON CHEMISTRY.

H. E. ^SCOE F.R.S. and C. SCHORLEMMER F.R.S.

PROFR«IK>Rll or f'HFMIflTRY IN THF. VICTORIA UNIVKRfllTY, OWKNS COLLROC, MAKCHBtTKR.

VOLUME III.
THE CHEMISTRY OF THE HYDROCARBONS AND THEIR DERIVATIVES,

ORGANIC CHEMISTRY.

PART I.

''Chymia, alicu Alchemia et Spagirica, est ara corpora vel mixta, vel eompoiita^
irZ aggregala etiam in privcipia mm resoJrevdi, a\U ex principiis in talia
combinandi"^BTABh, 1723.

I^onbon :
MACMILLAN AND CO.

1881.

[ The Jtight of Translation and Jttprodvdion is PMcrved,]

• •

• • •

• • • •

I/>KD011 :

R. Clay, Sous, and Taylor,

BREAD STREET HILL.

\ '.I

CONTENTS.

HfSTOIlICAL iNTRoDltTION

Early Ideas on Organic Chemistry
Lavoisier's Researclies
Ik^rzelius' Investigations
C*onipound Radicals .
Dumas* Theory of Substitutions .
Dumas' Theory of Chemical Types
isolation of the Radicals . . .
Theories of Types and Radic^als .
Gerhardt's Theory of Types
Williamson's Views
Theory of Mixed Types
Definitions of Organic Chemistry
Hvdrocarhons and their Derivatives
Homologous Series

PA«»K

3
5

9
11
15
16
19
22
24
27
30
33
37
39

ILTIMATE Organic Analysis.

Livoisier^s Method of Analysis .
Saussure, Th^nard, and Berthollet's Method
Gay-Lussac and Thenard's Method
Berzelius' Metho<l ....

Liebig's Method

Gas Combustion Furnaces .

Combustion in Current of Oxygen

Combustion of Nitrogenous Bodies

Combustion of Bodies containing Sulphur

Organic Analysis by means of Platinum

Determination of Nitrogen .

Will and Varrentrapp's Method .

Li«-big's Relative Method .

Bunsen's Relative Method .

Dumas' Absolute Method

Simpson's Method

Determination of Chlorine, Bromine, and lodin;

Determination of Sulphur .

Determination of Phosphorus

Determination of other Elements

Determination of Oxygen .

40
41
43
43
45
48

501 1 1

CONTENTS,

Catxjulation of Analyses
Percentage Composition
Oaloulation of Formula*

PAOR

80
80
82

Drtermination of VAi'oru Density
Dumas* Method ....
Gay-Lu8sae*8 Method .
Hofmann's Method
Victor Meyer's Methods

84
84
87
89
94

Dbtermination of Moleculab Formula
Empirical and Rational Fonnulae
Constitutional Formulae
Saturated and Non-Saturated Compounds

103
112
114
117

Isomerism

. 119

Classification of the Carbon Compounds .

. 128

Hydeocarbons of the Paraffin Series
Constitution of the Paraffins
Preparation of the Paraffins
Application of the Paraffins
Origin of Petroleum .
American Oil-wells

130
135
136
140
142
145

Fractional Distillation
DifltilUtion of Mixtures

147
153

The Compounds of the Monad Alcohol Radicals
Alcohols and Ethereal Salts, nature of
Haloid and Simple and Mixed Ethers .
Sulphine Compounds and Snlphoniu Acids
Compound Ammonias
Hydrazine Compounds
Cyanides of Alcohol Radicals
Cyanates and Isocvanates .
Compound Ureas, or Carbamides, &c.
Nit ro- Paraffins ....
Compounds of Alcohol Radicals with Metals

154
154
155
158
159
161
162
163
165
167
168

The Alcohols and their Derivatives
Primary Alcohols and Fatty Acids
Primary Alcohols ....

Aldehydes ......

Haloid Com]K>unds of tlie Acid Radicals
Ethereal Salts, or Com|K)nnd Ethers .

169
169
171
172
173
174

CONTENTS.

vii

PAGE

Auhydrides, or Oxides of the Acid Radicals 176

Tbio- Anhydrides, or Sulphides of the Acid Radicals . .176

Amides 177

Substitution-Products of the Fatty Acids 178

Synthesis of the Primaiit Alcohols and the FAriY Acidh . .179

Liebeu and Rossi's Method 180

Fraukland and Duppa's Method 180

Se«-oni)ary Alcohols and Ketoneh

182

Teutiauy Au'oholh

186

The Methyl Guoir

Metlinne, or Methyl Hydride
Methyl Alcohol ....
Methyl Oxide, or Di-Methyl Ether
Ethereal Salts of Methyl .
Sulphur Compounds of Methyl .
Selenium Compounds of Methyl
Tellurium Compounds of Methyl
Nitrogen Bases of Methyl .
Cyanogen Compounds of Methyl
^itro-Compounds of Methyl
Phosphorus Compounds of Methyl
Ancnic Compounds of Methyl
Compounds of Methyl with Antimony
(.'ompounds of Methyl with Boron
Compounds of Methyl with Silicon
Metallic Compounds of Methyl .
Other Derivatives of Methyl

190
190
194
200
202
212
216
217
218
224
227
229
2^4
243
244
245
245
253

Thk Formyl Groui"
Formic Aldehyde
Formi(? Acid
Tlie Foniiatcs

Thk Ethyl Group

Ethane

Ethvl Alcohol

-Ucoholometr}*

Ethyl Ether, or Ethyl Oxi^le
The Ethereal Salts of Ethyl, or Ethyl Comiwund
Sulphur Compounds of Ethyl
Compounds of Ethyl and Selenium
Compounds of Ethyl and Tellurium .
Nitrogen Bases of JSthyl ....
Cyanogen Comi)ounds of Ethyl .
Kthylated Ureas

Ethers

266
266
269
274

279
279
282
301
323
842
379
397
899
401
413
419

Vlll

C'< »NTKNTS.

Ktlivl Sl*mu•u^bll/i^^o^ ....
Ktliyliitod lliio-Ureas ....
Nitn)-Com|iouii«l« of Ethyl .
rikusphorufl Hasps of Ethyl
Arst'iiii- Coiiipouuds of Ethyl
Aiitiuiony Coinpouiids of Ethyl .
Bisniutli Cnmpouiuls of Ethyl
Horoii i\)inpoun(l8 of Ethyl
SiluMtiironipouiKls of Ethyl
Coitipoundrt of Ethyl with the Mt'talis .
Acotyl CoinpoiiinN ....
.Voi-tic AcM .....

Till' Atrtato.-?, or th«' Salts and Elhri> nf A«
Oxidos of Aeetvl ....

Haloid Conipouiids of Acetyl
Sulphur Coiiipouinls of Acetyl
Nitm^iMi Compounds of Acetyl .
Acptoiiitril ami its Derivatives
Siih»titiition-l*ro<lm-ts of Acetic Arid .

VllC

\ci.l

VMiK

. 421

. 422

. 423

. 431

. 440

. 443

. 447

. 448

. 45(1

. 45.1

. 473

. 483

. 496

. 509

. 513

. 515

517

. 521

. 533

• oMIiilNPS Ci«MAlNINH TllKKE Al»».Ms «iF OaRUuN, or. JIIR TUOI'VI.

<;k«h r

rriniary Propyl Alcohol ......

I'ropionic AKlehydc and IVopioniv Acid
StM'omLry Tn'tpyl AIi*ohoI .....

Aceti^ni-. or Hiinetlivl Kef on. ...

548
548
556
563

< I -Mil 'I'M'.* Ci»NTAiMNii Fun; Atoms of TARnnN, hm thk RrXYL Oinn r 576

Normal Hiilanc and iN iV-rivativts .577

riiir.iiy Butyl CoiMiHiuiils . fiSil

Si. .iTi.l.iry r»iitvH'i>niiHmu«ls .".Sl

!-»i»*MU.inc and it"* Piriv.itivo'S fi^S

TriiiMiy l-^!iut\I L'l'iiiimuud- 5S3

Ttrti.iiy Butyl roiiii>«ninds 5S6

Th- rmtyri- A id-i 59»^

N.v.;::yry! Cotiiihvjti.U 597

• . V!-.; \: - < iNLviMN.. Five Aii-mn i.f i'Ar.n«'S. im; mr. Prsrvi Kic-ri-
N«rv \\ r. iitiT:- iTid i!-i l»i ri\ itivi"* ...

I* •!" T.T.u.- a:ii i*" Pt r;\iitiv»"i
r-.i .\'.r.>'. Ti ■::.!■« ■U'..'i "
!*•:: i: !.-.:*. v". M,:J. n.* .\:..i i*^ 1 »• i;\ if;\. -
Th- r- v: •• • T V '.".ri ■ Ail-.

M'2
003

rtll
617
•*17

• . V. • \;.- t. N. vn:n"- >'.\ Aii'M-s i-F < .VKr.ns. «■!; iiii lUwi «;»;.•;! rt25

!»•■ . \ iti" a:. : •'•. Iv ::v i*i\. - t\:\i

>!■ !li\ .-I'-.'.^.v'. M '".ir.. .•, i i:- 1». ii\ »-.\t- *y:M

CONTENTS.

Tetrametliyl Ethane and its Derivatives
Triniethyl-Ethyl Methane and its Derivatives
The Hexoic or Caproic Acids •

Pai;e
631
633
634

Compounds Contaimxo Seven Atoms of Carbon, or the Heprvr.

Geoup 631)

. 639

. 643

. 644

. 646

Normal Heptane and its Derivatives
laoiheptane and its Derivatives .
Triethvl Methane and its Derivatives
The Heptoic Acids

CoMPorjcDs CojrrAiN'iNG Eight Atoms of Carbon, or the Octyl Group 650

Normal Octyl Componnds 650

Tetraniethvl Butane and its Derivatives 654

TertLiry Octyl Compounds 655

Hexiuethy] Ethane 656

The Octoic Acids 656

roMPCtuvDs Containing Nine Atoms of Carbon, or the Nonyl Groit 658
The Nonoic Acids 059

CoMPorNiiS Containing Tejt Atoms of Carbon, or the Decatyl Giujui* 662
The Capric, or Decatoic Acids 664

OiMP<»rND» C<»NTAININC ElE\'EN AtOMS OF CaRBON, OR THE HeNDECATYL

Group 665

f'**MP*^r\j»< C«iNTAiNiNf; Twelve Atoms of Carbon, ou thk I)<u»f.(atyl

Geoup GH7

♦ "Ml y yvs Containing Thirteen Atoms of Cakiu>n, oii tiik Tuiuk-

'•%tyl Gnnup 669

^•'Ui-rsv'y Containing Fourteen Atoms of CAnnoN, ok the Tetra-

i.F/; An- L Group 669

*-%:^'sifit Containing Fifteen Atoms of Caijwjn, ok the Penta-

iiecattl Group 670

.. Containing Sixteen Atoms of CAKimx, oi: the Hec-

r* ATVL Group 671

X CONTENTS.

PAue

Compounds Containing Seventeen Atomk of Carbon .... 677

Compounds Containing Eighteen Atoms of Carbon .... 678

Co-MPOUNDS Containing from Nineteen to Twenty-four Atoms of

Carbon 681

The Waxes 681

Cioneral Properties of the Fatty Acid.s 684

Soap 688

A TREATISE ON CHEMISTRY.

ORGANIC CHEMISTRY,

vol- ffl «

OEGANIO CHEMISTBY,

OR THE CHEMISTRY OF THE HYDROCARBONS AND THEIR

DERIVATIVES.

HISTORICAL INTRODUCTION.

z Many of the most important chemical facts known to the
ancients have their place in the Organic portion of our science.
Thus, for example, the only acid with which the ancients were
acquainted was an organic substance, viz., vinegar or dilute
acetic acid, and the name of this body and the idea of acidity
were expressed by closely related words, of 09, acetus, vinegar ;
and o^v^i acidus, acid.^

Again, the first reagent of any kind which we find described
is also an organic body, namely the extract of gall-nuts with
which, as Pliny states, the ancients were accustomed to ascer-
tain whether verdigris was adulterated with green vitriol.

The first rude attempts at distillation were also made with
an organic body, viz., turpentine ; whilst the first salts which
were artificially prepared were organic ones, being those ob-
tained by the action of vinegar on the alkalis. The mode
of preparing soap by the action of fats upon the alkalis was
also known in early times. In addition to a knowledge of
the fets and oils, the ancients were acquainted with various
resins, and colouring matters, as well as with sugar and gum.
They likewise understood the preparation of wine from
grape-juice, and certain nations, especially the Egyptians,
Gauls and Germans, were accustomed to prepare beer from
nialted grain.

1 See YoL ii. part i. p. 32.

B 2

HISTORICAL INTKODUCTION.

As the direction in which the science first developed itself
was that of alchemy^ the object of which was the conversion of
the baser metals into gold and silver, it is natural that attention
was in the first place paid rather to the properties of mineral
substances than to those of organic bodies^ Nevertheless im-
provements in general chemical processes, especially that of
distillation, gradually led to the discovery of definite organic
compounds such as spirit of wine {aqua vita:) and certain of the
essential oils. The action of heat upon bodies when air is ex-
cluded was also studied in early times. Thus the products of the
dry distillation, as we now term this process, of bodies such as
cream of tartar were investigated, and the action of acids upon
spirits of wine and other organic substances was likewise examined.

Later on, towards the sixteenth century, the cultivators of
this science, as we have seen,^ exhibited activity mainly in two
directions, in the first place in the prosecution of the branch
science of metallurgy, and secondly, in the development of iatro-
chemistry. In these branches, and especially in the latter, it
was, however, the inorganic division of the science which made
the most rapid strides, because, in opposition to the practice of
the old school, the use of metallic preparations as medicines
was largely introduced. At the same time the study of organic
compounds, and especially of the active principles of organic
bodies, was not entirely neglected. Thus during this period
benzoic acid, succinic acid, wood-vinegar, milk-sugar, and various
ethers were discovered.

In the succeeding epoch, when the true function of chemistry
had become fully recognised, inorganic comix)unds still claimed
the more immediate attention of chemists, not only because
they arc more stable than organic bodies, but also because in
the latter case it had not as yet proved possible, as it had
in tho case of inorganic bodies, to determine their composition
by synthesis as well as by analysis.

a From this period it is that wc may date a distinct separation
of mineral chemistry from that portion of the science which is
concerned \\ii\\ the study of substances formed in vegetable
and animal organisms. For a long time chemical compounds
were groupttl together according to their jihysical properties,
and the common names at present in use for many substances
remind one of this bygone classification. Thus, for instance,
olivo oil and other vegetable and animal oils were placed

* Vol. i. p. 8, "lliHtorical lutroductiou.*'

EARLY IDEAS ON ORGANIC CHEMISTRY. 5

together with oil of vitriol and with oleum tartari (deliquesced
carbonate of potash). Alcohol again (spirit of wine) was classed
with stannic chloride (fuming spirit of Libavius), with ammonia
(spirit of hartshorn), and with nitric acid (spirit of nitre), &c.
Common butter wa« placed in the same group as antimony
trichloride (butter of antimony) and other semi-solid metallic
chlorides. Colourless solid bodies which were soluble in water,
and possessed a peculiar taste were all classed together as salts,
even sugar being placed in this group.

3 In the year 1675 Nicolas Lemery published his Cours de
Chf/mic, In this work the aim of chemistry is defined to be
a knowledge of the various substances "qui se rencontrent
dans un mixte," understanding by this term all growing
or increasing natural products. Lemery distinguished these
bf>lies as mineral, vegetable, and animal products. In the first
group he placed the metals, minerals, earths, and stones ; in the
second, plants, resins, the different kinds of gums, fungi, fniits,
acids, juices, flowers, mosses, manna, and honey; and under
the third head he described the various parts of animal bodies.

Although L(5mery*s system of classification was generally
accepted, the founders of the phlogistic theory endeavoured to
show that the observed diflferences depended on a variation in
the composition of the bodies classed under each head. Thus
Becher in 1669 had argued that the same elements occur in
the three natural kingdoms, but thut they are combined together
in a simpler manner in mineral substances than they are in
vegetable and Animal bodies. Stahl, on the other hand, asserted
in 1702, that in vegetable as well as in animal substances the
watery and combustible principles predominate, and that these
make their appearance when such an organic substance is heated
out of contact with air, water and combustible charcoal being
formed.

At this time, as well as during the preceding period, the
investigation of organic compounds was carried on mainly with a
view either to the preparation of medicines, or to the improve-
ment of technical processes, such as that of dyeing. Only
towards the close of the phlogistic period did organic chemistry
begin to make real progress, and it is from this time forward
that the scientific investigation of organic bodies can be said
to have commenced.

4 The early ideas of van Helmont and afterwards of Stahl,
that all organic substances can be resolved by the action of

HISTORICAL INTRODUCTION.

heat into their ultimate constituents, viz., aqueous and com-
bustible principles, were successfully combated by Boyle, who,
in the Sceptical Chemist (1661), proved that this is not the case,
inasmuch as the application of heat leads to diflferent results
according as air is permitted to have access or not, and that the
various residues thus obtained in no way merit a uniform de-
signation. The general reception of Boyle's views was slow but
sure. Still it was not until Lavoisier's discovery in 1775 of the
composition of carbon dioxide, and Cavendish's determination
of that of water, that the fact of the existence of carbon and
hydrogen in alcohol was ascertained (1784).

5 Amongst the early organic researches of a truly scientific
character those of Scheele deserve the first mention, for he
either discovered nearly all the most important vegetable
acids, or suggested methods for their discrimination. Thus,
he showed that the acid from lemons differs from that from
grapes, whilst that contained in apples differs again from
both of these. He proved that a fourth distinct acid is
found in wood -sorrel, and pointed out that this can be
obtained artificially by heating sugar with nitric acid. Ho
likewise obtained gallic acid from gall-nuts, uric acid from
urine, and lactic acid from sour cow's milk. By the oxidation
of milk-sugar he prepared mucic acid, a substance altogether
different from the acid obtained from cane-sugar. In the pre-
paration of these and other acids Scheele employed methods
many of which are in use at the present day. Scheele also
showed that fatty oils and the solid fats contain the common
principle glycerin, termed by him the sweet spirit of oils. This,
ho says, is connected with sugar not only on account of its sweet
taste, but also because, like sugar, it is oxidized to oxalic acid
by nitric acid.

Scheeles friend Bergman also assisted the progress of
organic chemistry, whilst Rouelle who distinguished himself
by researches on tho hitherto neglected division of animal
chemistry, discovered urea and hippuric acid.

6 Investigations such as these drew general attention to
the subject of organic chemistry, and Lavoisier having estab-
lished the true principle upon which the process of com-
bustion depends, turned his mind to this interesting branch
of the science, and ascertained the ultimate composition of
certain organic compounds. He came to the conclusion that
vegetable bodies are chiefly composed of carbon, hydrogen, and

LAVOISIER'S RESEARCHES.

oxygen, whilst the compounds of the animal kingdom contain
in addition to these elements, nitrogen and not unfrequently
pliosphorus.^

The Lavoisierian system of chemistry was essentially the
chemistry of oxygen and its compounds, and hence attention
was naturally directed to the question whether a given com-
pound is capable of combining, like an element, with oxygen,
or whether it was already combined with this element. To
that portion of a substance which combines with oxygen,
Lavoisier, at the suggestion of Guyton de Morveau, gave the
name of la base or le radical. This might either be an elemen-
tary substance, such as carbon, " le radical de Tacide carbonique,"
or a compound, such as, '* le radical oxalique, tartarique," &c.

Respecting the difference between organic and inorganic
compounds, he states that the oxidizableor acid-forming radicals
of the mineral kingdom are. almost always simple ; those of the
vegetable and especially of the animal kingdom are however
generally composed of two substances, carbon and hydrogen,
and these frequently contain nitrogen as well, and some-
times phosphorus.*

The observation that the elements can form different oxides
led to the supposition that this might likewise be the case
with organic radicals. Thus for example sugar was considered
to be a neutral oxide, "d*un radical hydro-carboneux," whilst
oxalic acid was supposed to be its higher oxide.

Amongst his more important investigations in the domain of
organic chemistry Lavoisier's research on fermentation deserves
especially to be mentioned, not only because he was the first
to point out that sugar is decomposed into carbonic acid and
alcohol, but especially because, in connection with this particular
reaction, he for the first time enunciated the principle which
underlies the whole of our science, viz., that the weight of the
products of any chemical change is equal to the sum of the
weights of the materials taking part in that change, and hence
that all chemical decompositions may be expressed by equations,
the truth of which can be ascertained by the analysis of the
original compound, and controlled by that of the products of
decomposition.

On this point Lavoisier's own words may be quoted : " We
may consider the substances submitted to fermentation and the

* Lavoisier's Elements of ChemUtry (1787), Kerr's Translation, pp. 17S, 174.

* Ibid, p. 261.

8 niSTOniCAL INTRODUCTION.

products resulting from that operation as forming an algebraic
equation ; and, by successively supposing each of the elements in
this equation unknown, we can calculate their values in succes-
sion, and then verify our experiments by calculation and our
calculations by experiment, reciprocally. I have often success-
fully employed this method for correcting the first results of my
experiments, and so to direct me in the proper road for repeating
them to advantage." ^

It must, however, be especially borne in mind that Lavoisier
did not distinguish organic chemistry as a special branch of tho
science; still less did he, as has been stated, define this portion
of chemistry as the chemistry of compound radicals.^ Thus for
example he arranged all the acids together, dividing them like
Lemery into mineral, vegetable, and animal. His more im-
mediate followers also adopted this course, and it was at that
time only occasionally that we find organic bodies classed
together in a group.

7 By degrees, as substances common to both the animal and
the vegetable world were discovered, the distinction between
animal and vegetable chemistry disappeared, and the consequent
fusion, widening the area covered by the general term organic,
gradually led to a distinct separation into Inorganic and Organic
chemistry. At the same time no exact limit could be said
to exist between these two divisions of tho science. One
reason for this was that several compounds were found to exist
which from their origin must be considered as organic, but which
yielded on analysis results proving tliat they exactly obey the
laws of constant and multiple proportion, laws supposed at that
time to apply only to compounds bcl-^nging to the mineral king-
dom. In the majority of instances, on the other hand, organic
bodies appeared not to obey these laws.

8 For the purpose of obtaining more satisfactory informa-
tion on this question, Berzelius, in 1814, proposed to investigate
the composition of such substances more accurately than had
hitherto been done. That this was much needed is clear when
we remember that Proust, so late as 1803, stated that acetic
acid contained nitrogen, and that Dalton changed his formula
for alcohol from 2 C -f H 4- O in 1803, to 3 C 4- H in 1810.

With this view Berzelius improved the processes of organic
analysis, and then ascertained that all organic compounds,

* Layoisier, Elements, p. 107.

' Kopp, Entwickclung dcr Lhcmic in dcr naiercm Zcit, p. 521.

THE INVESTIGATIONS OF BERZELIUa

although in most cases possessing a somewhat complicated
composition, obey the laws of constant and multiple pro-
portions applicable to inorganic compounds. Agreeing with
the views of Lavoisier, Berzelius explained the difference
existing between these two great divisions by stating that
whilst in inorganic nature every oxidized compound contains
a simple radical, organic bodies consist of oxides of compound
radicals. In the case of vegetable substances the radical usually
consists of carbon and hydrogen, whilst in the case of animal
substances it consists of carbon, hydrogen, and nitrogen.*

9 Berzelius, however, did not experimentally investigate these
compound radicals, although the discovery of cyanogen by
Gay-Lussac in 1815 served as an excellent example of the
existence of such a series of bodies. The cyanogen com-
pounds were, however, at that time almost invariably placed
amongst inorganic bodies, for, as has been stated, the limit
between inorganic and organic chemistry was not clearly defined.
Thus Gmelin in 1817, in the first edition of his great handbook,
states that a clear distinction ought to be made between the
two classes of compounds, but that this distinction can be more
readily felt than strictly defined. He laid down that Inorganic
compounds are characterised by their binary constitution, the
most simple consisting of compounds of two elements, a basic
oxide or an acid (that is what we now term an acid-forming
oxide), which can again unite to form a binary compound of a
higher order, namely, a salt. Organic bodies, on the other hand,
are at least ternary compounds, or are composed of three simple
substances, generally united together in less simple proportions
than is the case in inorganic bodies. Accordingly, Gmelin
describes marsh gas, defiant gas, cyanogen, &c., in the inorganic
portion of his handbook. He likewise adds that organic com-
pounds cannot, like inorganic compounds, be artificially built up
from their elements.

About the same time Berzelius again enforced this distinction
between inorganic and organic bodies, asserting, like Gmelin,
that the first could, whilst the latter could not, bo artificially
produced. He assumed that in living structures the elements
obey totally different laws from those which regulate the form-
ation of compounds belonging to the inanimate world. Thus
ia the Introduction to his TraitS ^ he says : " Dans la nature

1 Berzeliws Lehrbueh, 2te Atifl. 1817, vii. 6ii.
« Ibid, French edition, 1840. v. i>. 1.

10 HISTORICAL INTRODUCTION.

vivante les (Elements paraissent obeir k des lois tout autres
que dans la nature inorganique ; les produita (j[ui resultent
de Taction reciproque do ces <51^ments, diflf^rent done de ceux
que nous priJsente la nature inorganique." Organic bodies were
thus believed to be the special product of the so-called vital
force. He admits that the bodies occurring in nature may be
converted into oth^r organic compounds by chemical decom-
positions, but none can be built up from their elements.

10 In the year 1828 came Wohler's memorable discovery of
the artificial formation of urea. Cyanate of ammonia, which was
considered to be a truly inorganic compound, is easily converted
without change of composition into urea, a product of animal
life. This first artificial production of a body hitherto only pro-
duced within the animal organism was however incomplete, for
up to that time the cyanogen compounds had not been prepared
from their elements. Again, this formation remained for a long
time the only one of its kind, and the belief in the existence of
a peculiar vital force still retained a firm footing. Besides, it
was believed that urea, a substance so easily decomposed
into carbon dioxide and ammonia, and moreover only ex-
creted by the animal bcxly, must be looked upon as standing
half way between organic and inorganic compounds, and it
was thought that it would still remain impossible to pre-
pare artificially any of the other more complicated organic
substances.

At the present day the belief in a special vital force has
ceased to encumber scientific progress. We now know that the
same laws of combination regulate the formation of chemical
compounds both in animate and in inanimate nature. So soon
as the constitution of any product of the organic worJd has
been satisfactorily ascertained we look forward with confidence
to its artificial j)reparation.

11 A modification of the early theory concerning the com-
position of organic compounds, by which they were supposed to
consist of the aqueous and the combustible principles, and to
which allusion has boon made, took place in 1815, inconsequence
of the experiments of Gay-Lussac, who found that the weight of
a volume of alcohol vapour is ec^ual to the sum of the weights
of one volume of aqueous vapour and one of olefiant gas ; one
volume of other va|>our being equal to one volume of the fii'st
and two of the latter constituent. At the same time Robiquet
lUid Colin hu<l shown that hydrochloric ether (ethyl chloride)

COMPOUND RADICALS. 11

may be considered to be a compound of hydrochloric acid
with defiant gas.

Founded upon this observation Dumas and BoulJay^ pro-
posed a theory according to which many derivatives of alcohol
may be considered to be compounds in which olofiant gas is
contained, in the same way as ammonia is present in the
ammoniacal salts. Berzelius,^ who was originally opposed
to this view, adopted it at a later period, and proposed that
the name iEtherin should be given to olefiant gas, C^S^. The
following table is taken from Dumas and Boullay's memoir,
the formulae being however altered in accordance with the
modem atomic weights:

llydrochlorate of bicarburctted Amniouia hydrocliloride, NH„ IICl.

hydrogen, CjH4, HCl.
Nitrite of bicarburctted hydrogen, Ammonia nitrite, NH3, HNO,.

Csll4, HNO,.
Sulphate of bicarburctted hydrogen, Acid ammonia 8ulx)liate, NHg, II^SO^.

Alcohol, C3H4, H.jO. Aqueous Ammonia, NH3, 11^0.

tther, (C,HJa, H^O.

Not only did they apply this system of classification to other
derivatives of alcohol but they attempted to extend their theory
to all organic compounds. Although it was found possible to
arrange a certain number of organic bodies according to this
system, the aetherin theory did not command general recogni-
tion, partly because a large number of organic bodies could not
thus be classed, and partly because, in many instances, facts were
against the theory. Thus, for example, although alcohol could
be converted into ether or olefiant gas by the withdrawal of
the elements of water, it was not possible to obtain this or
any of the other a;therin compounds by the juxtaposition of
their supposed proximate constituents, such a synthesis being
possible in the case of the ammoniacal salts.

12 The classical research of Liebig and Wohler' on the
radical of benzoic acid published in 1832 was welcomed by
Berzelius as the dawn of a new era.

In this celebrated investigation the authors proved that bitter-
almond oil, benzoic acid, and a number of compounds obtained
from these, may all be supposed to contain a group of atoms
or, as they expressed it, *' zusammengesetzter Grundstoff," or

^ Ann, Chim, Phj/s, xxxvii. 15. • yinn, Pharm. iii. 286,

» Ana, Plmrm. iii. 249, 282.

12 HISTORICAL INTRODUCTION.

compound radical, to which they gave the name benzoyl, tlie
termination " yl " being derived from the Greek vXrj, matter.

It has been already stated that Berzelius, like Lavoisier, con-
sidered that organic compounds containing oxygen must be
looked upon as the oxides of hydrocarbon radicals. The radical
benzoyl, C^H^O, however, contains oxygen, and hence the pre-
dominating influence which this element had hitherto been
supposed to exert from this time forward ceased, and oxygen
was placed on a footing of equality with the other elements.

The radical theory was now enlarged both by Berzelius and
Liebig, although neither of them agreed in the special views which
the other advocated. Whilst both opposed the aitherin theory,
according to which alcohol and ether must be considered to
be compounds of olefiant gas and water, Berzelius considered
the above compounds as oxides of two diflferent radicals, whereas
Liebig^ in a memoir, properly deemed another pillar of the
radical theory, showed that both compounds contain the same
radical for which he proposed the name of dhi/l. Accord-
ing to his view ether is the oxide, and alcohol the hydrate of
this oxide. The compounds obtained by the action of acids
en alcohol he considered to be saline compounds of the base
ethyl oxide. A similar constitution was ascribed to the other
alcohols and their derivatives, so that each contains a radical
which plays a part similar to that played by potassium or any
other metal in its salts. It is interesting to remember that so
long ago as the year 1834 Liebig asserted that it would probably
be found possible to isolate these radicals by the decomposition
of their chlorides or iodides.

Alcohols on oxidation yield monobasic acids ; methyl alcohol,
or wood-spirit, yields formic acid, CHjO,, ethyl alcohol, or
spirit of wine, being similarly converted into acetic acid, CaH^Oy
The analogy between these acids and monobasic benzoic acid
was not far to seek, and thus the existence in these acids of
the oxygenated radicals CHO and CgHjO was assumed.

Berzelius, however, took exception to this view and asserted
that benzoyl, although in many respects acting like a simple
body, must be regarded as the oxide of the body C^Hj. Like
other oxides benzoyl can unite with more oxygen to form an
acid. Hence formic acid contains the radical formyl, CH, and
acetic acid the radical acetyl, C^Hj. Liebig afterwards adopted
this view, finding that by this means it became possible to group

* Ayin, Pharm, ix. 1.

VIEWS OF DUMAS AND LIEBIG. 13

a large number of compounds round a common centre. Thus
he supposed that vinyl chloride (monochlorethene), CgHgCl,
discovered by Regnault, may be looked upon as acetyl chloride,
and that aldehyde, CgH^O, (which he prepared about this time),
as well as acetic acid may be regarded as the hydrates of two
distinct acetyl oxides.^ In a similar way he considered chloro-
form (which he had also just discovered) to be the chloride of
formyl, assuming that it stands to formic acid in the same
relation as phosphorus trichloride does to phosphorous acid.

In 1837 Dumas adopted these ideas and in his own name,
as well as in that of Liebig, explained the formation of so
large a number of naturally occurring organic compounds from
so small a number of elements, by the fact that these unite
together and give rise to various radicals which sometimes play
the part of chlorine and oxygen, and sometimes that of a
metal. Radicals such as cyanogen, ethyl, benzoyl, &c., may be
said to constitute the elementary bodies of organic chemistry,
their elementary components being only recognised when the
organic nature of the compound is entirely destroyed.

The discovery and isolation of these radicals was the task
which Dumas and Liebig in conjunction with their younger
colleagues set themselves to perform.^

13 The essential idea of the chemical constitution of organic
compounds conceived by Berzelius was a dualistic electro-
cliemical one, analogous to that which he upheld in inorganic
chemistry, the difference being that organic radicals play a
part similar to that played by the elements in the inorganic
portion of the science. According to him the radicals are
divided, like the elements, into electro-positive or base-
forming, and electro-negative or acid-forming radicals. In the
former division are classed metals, hydrogen, and the alcohol
radicals; in the latter the elements of the chlorine group,
oxygen, benzoyl, &c.

" By the comparison of the behaviour of inorganic with that
of organic compounds," says Liebig,^ *'we are led to recognise

* In order to understand the a\)OYe relations it must be borne in mind that the
tquiraUrU weights, ir=l, 0=8, (7=6. &c., were then employed in place of the
atomic weights which we now nsc. We thus have the formulae : water, HO ;
ether, C4//5O ; alcohol, C^H^O, HO ; aldehyde, GJI^O, HO ; acetic acid,
f.\H^O^ HO; chloroform, C^HCl^ ; formic acid, C^H^O, HO, In the sequel the
luc of these old equivalent weights will be indicated by the symbols of the
clemeuts being printed in italics.

» Compl. Rend, v. 567, ' Aniu Pliarm. xxv. 3.

14 IirSTORICAL INTRODUCTION.

the existence of certain component parts which do not undergo
alteration in a series of compounds, and can be replaced by
elementary bodies; of component parts which combine with
elements to form compounds in which the elements can be
replaced by others ; of component parts, therefore, which take
the position of simple bodies and play the part of elements.
In this way the idea of compound radicals has arisen.

Hence, we term cyanogen a i*adical — (1) because it is an
unchanging constituent in a series of compounds ; (2) because
it may be replaced in these compounds by simple bodies ; and
(3) because in its compounds with elementary bodies these
latter can be set free and replaced by their equivalents of other
simple bodies. Of these three conditions, at least two must be
fulfilled if the radical is to be considered as a true one.

This definition of a compound radical is fully accepted at
the present day.

14 The new era welcomed by Berzelius thus appeareil to
open brightly, but these hopes were apparently not destined
to be realized, for whilst Liebig and Berzelius continued to
uphold their new views, the latter, indeed, defining organic
chemistry as the chemistry of compound radicals,^ Dumas put
forth ideas which appeared to him to be inconsistent with the
radical theory. Much difficulty had been experienced in ex-
plaining, according to the radical theory, a large group of
bodies, examined especially by the French chemists, and ob-
tained by the action of chlorine on organic compounds. It
had been noticed that in this reaction hydrogen is expelled,
chlorine entering into combination, and this in equivalent
quantities, one atom of chlorine being taken up for every atom
of hydrogen which the body loses. These observations attracted
but little attention until the year 1834, when Dumas found that
hydrogen in oil of turpentine can be replaced atom for atom
by chlorine, thus :

CioH„ + CI, = CioHijCl + HCl.

He considered that these facts are based upon a law of nature,
to express which he suggested the name of Metalepsy ^
(/LicTciXiy^tv, an exchange). By the study of these phenomena
Dumas arrived at his empirical law of subatitutians,^ namely :
(1) If the hydrogen contained in a hydrogenized body be

^ Jiandbuch Org, Chem. 1843, 1. ' Mem. Acad, Scienc. xv. 548.

• Joitrn. de, Pharm. mai, 1834.

THEORY OF SUBSTITUTIONS. 15

withdrawn by the action of chlorine, bromine, iodine or oxygen,
for every atom of the first, one atom of the elements of the
chlorine group or half an atom of oxygen is substituted.^

(2) If the compound contain oxygen the same law holds good.

(3) If, however, the body contain water, the hydrogen of
the water is first removed without substitution, and then the
remaining hydrogen is substituted as in case No. 1.

This last statement was necessary because alcohol, which
was considered to be a hydrate of ethylene, CgH^H^O, is con-
verted by chlorine into chloral, C2HCI3O. These rules are
known as Dumas' theory of substitutions.

15 Laurent, amongst the younger chemists, especially devoted
himself to the advancement of this subject. He found that the
replacement of hydrogen by its equivalent of chlorine does not
always take place, particularly in the case of oxygenated bodies,
and that for this reason Dumas' third rule is incorrect He
also showed that in those cases in which substitution atom for
atom takes place the physical and chemical properties of the
substitution-product resemble those of the original body.
Hence, he says, the chlorine takes up the position vacated by
the hydrogen atom. In the new compound chlorine plays the
part which hydrogen does in the original body.*

Dumas did not support this view. He sta,tes that his theory
i.s purely empirical, and when Berzelius urged, against him
instead of against Laurent, that he entirely ignored the electro-
chemical difference between hydrogen and chlorine, Dumas
replies that Berzelius attributes to him a view, namely, that
the chlorine takes the actual place of the hydrogen, diamet-
rically opposed to that which he has always held. He adds,
moreover, that he will not hold himself responsible for
alterations which Laurent had made in his theory.

Ill subsequent years the researches of Laurent, Regnault,
and Malaguti, added a large number of substitution-products
to those which were already known, and Dumas himself dis-
covered trichloracetic acid, an instance in which, more than in
any other, the substitution-product exhibits analogy with the
original substance, go that at last Dumas not only adopted
Laurent's views but expanded them considerably.

x6 Before we proceed to the further consideration of the
progress made in this direction it becomes necessary to mention

* Dumas at that time employed the now QniFersally adopted atomic weight for
ozTgi^u. ■ Ann, Chim, Phys, [2], Ivi. 140.

16 HISTORICAL INTUODUCTIOy.

a theory of chemical constitution brought forward by Laurent
in 1836. This theory, termed the micleus theory, has indeed
never been generally adopted, although Gmelin made use of
it in his handbook with certain alterations, as a foundation
for a classification of organic compounds.

According to this theory each organic compound contains a
group of atoms termed a nucleus or germ. Primary nuclei
consist of carbon and hydrogen, and in these the hydrogen
may be replaced by other elements or by groups of atoms. In
this case derivative-^ or secondary-nuclei are produced, and
these exhibit both in composition and in chemical properties a
striking analogy to the primary nuclei. Other atoms may
be attached to this nucleus, or they may quite surround it, and
>vhen these are removed the primary nucleus makes its ap-
pearance. Laurent ftirther assumed that organic compounds
always contain an even number of atoms, and hence the
formula) which he adopts are frequently double of those which
are now employed.

17 In the year 1839,^ Dumas developed the substitution
theory to a theory of chemical types, the principles of which he
thus enunciated : —

(1) The elements of a compound body can, in many
instances, be replaced, either by other elements in equiva-
lents, or by compound bodies which are capable of playing
the part of simple ones.

(2) When such a substitution takes place in equivalent pro-
portions, the body which is formed by such a substitution re-
tains its clumical type, and the element which has entered into
the compound plays the same 2^<^^^ ^s the element which has
been withdrawn.

In addition to the chemical types, in which Dumas included
the following,

CjH^Oj Acetic acid

CjHjClOj, Chloracetic acid

CjH^O Aldehyde

C2HCI3O Chloral

{
i

{CHCI3 Chloroform
CHBrj Bromofomi
CHI3 Iodoform,

' Conqtlcs Rcadus, viii. Ci»y.

DUMAS' VIEWS. 17

he adopted Regoault's suggestioa respecting tlie existence
of molecular or mechanical types, according to which, two
substances belong to the same type when substitution has
taken place, provided that the number of elementary atoms
remains constant. Under this he included compounds which con-
tain the same number of atoms but possess different properties,
such, for instance, as alcohol and acetic acid.

Dumas pointed out, moreover, that the properties of a com-
pound depend rather upon the arrangement of its parts than upon
their special nature. He compared chemical compounds to a
solar system of which the constituent parts are held together
by their mutual attractions. The system remains the same if
the atom of one element be replaced by that of another.

As the best proof of the truth of his ideas, Dumas laid
weight upon the fact that acetic acid, CJIfij^^ and trichloracetic
acid, C^HCl^O^t possess the closest resemblance in chemical
properties.

Berzelius, who, as we have seen, opposed the theory of
substitutions, pointed out the dissimilarity between the two
I odies and insisted on the fact that their essential properties
are distinctly different. He considered acetic acid as a hydrated
oxide of a hydrocarbon-radical termed acetyl, CJI^, whereas
trichloracetic acid is a copulated compound of oxalic acid and
chloride of carbon :

Acetic acid . . , C ^11.^,0^ + HO.
Trichloracetic acid . • CJOI^ + C^O^ + HO.

The constitution of other substitution-products wa:^ viewed by
Berzelius in a similar light, although for this purpose he was
obliged to double and sometimes to treble the simplest formula)
of many compounds, and thus so to complicate the subject
that his theory was not generally accepted.

i8 Liebig opposed the views of Berzelius, which he said
depended on a number of considerations which have no
foundation in fact. He pointed out that even in inorganic
chemistry the metal in permanganic acid can be replaced by
chlorine without altering the form of the substance, although no
two substances are more unlike than chlorine and manganese.
Facts like these, he says, must simply be accepted. If manganese
can be replaced by chlorine, why should a similar replacement
of hydrogen appear incredible ? ^

In another place* Liebig remarked that Berzelius was the first

* Ann, PJiamu xxxi. 119 (Lot note). • Ann, Pharm, xxxii. 72 (foot note).
VOL. III. C

1« HISTORICAL INTRODUCTION.

to adopt the view that organic acids, ethers, and so forth, are
the oxides of compound radicals, and he admits that this
view ilhimined many a dark chapter in organic chemistry.
The analogy which Berzelius first pointed out between
organic and inorganic compounds ought however, he con-
tinues, not to be cairied on beyond a certain point, for if
the principles of inorganic chemistry be consequently followed
out in organic chemistry, the eflfect is rather that of com-
plication than of simplification.

At the same time Liebig did not hesitate to attack the French
chemists,* who went too for for him, and when Dumas assumed
that the carbon in organic substances could be replaced, he
turned tipon him, and in a satirical vein, in a letter dated from
Paris, and signed {anglice) S. Windier,^ relates how not only all
the hydrogen and all the metal in acetate of manganese has
been substituted atom by atom for chlorine, but how at last
even the carbon has been in like manner replaced, and that
the final product, although consisting of nothing but chlorine,
possessed the chief characteristic properties of the original salt !

19 Facts bearing out the truth of the law of substitutions,
so far at any rate as the replacement of hydrogen is con-
cerned, rapidly increased ; but a still more important discovery
was that of reverse substitutions, that is, the production of
the original body from the substitution- product.

In 1842 Melscns showed that by the action of potassium
amalgam trichloracetic acid can bo converted into acetic
acid. Such observations did not however convince Berzelius,
who now looked upon acetic acid as an oxalic acid copulated
with methyl, CJI^-^-C^O^-^- UO ; explaining in the same way
the constitution of other compounds capable of undergoing sub-
stitution, lie supposed that all these contained a group con-
sisting of carbon and hydrogen, and termed by him the cojmla,
in which the hydrogen is replaced by chlorine, etc.

In 1845 Hofniann discovered the chlorinated anilines,* and,
as Liebig in a note to this important investigation expressed
his conviction in the truth of the newer views more strongly
than before, Berzelius replied that all organic bases must be
regarded as copulated ammonias. Aniline is the compound
C,^//^ + y^^H, and chloraniline is C^^II^Cl + XH^ Both contain
ammonia as a basic constituent. The composition of the
copula is a matter of indifference.

* Ann. Pharm. xxiv. 1. • Ann, Chtm, Pharm. xxxiii. 303,

* Ann. CKtm. Phaim. liii. 8 ; Chem, Soc, Mem, ii. 200.

ISOLATION OF THE RADICALS. 19

In the assumption of the copula, the dispute \vith Laurent
as to whether chlorine could replace hydrogen and fulfil its
functions had been overlooked. That which was held to be
absurd was at once accepted as a simple and clear expression
of fact. Berzelius however continued in opposition. His
formulae gradually became more and more complicated, and he
was compelled to adopt more and more doubtful hypothescr
Thus, for example, he represented dichlorformic ether, a com-
pound obtained by Malaguti by acting with chlorine on ethyl
formate, as being copulated of anhydrous formic acid, formyl
chloride, anhydrous acetic acid, and acetyl chloride, giving it the
formula 2C^IO^-\-C^Cl^-v2 C^ff^O^ + C^H^Cl^ ; whilst now,
according to the new atomic weights, the formula is written
C3H4CI0O,. We need not, therefore, be surprised to find that
after Berzelius s death the supporters of his views experienced
great diflSculty in rebuilding the radicals from the copula*.

20 The railical theory had meanwhile received most valuable
support from Bunsen's classical researches on the cacodyl com-
pounds. He showed that these contain a common group of atoms,
cacodyl (afterwards called arsendi methyl, (CH3)2As,) a body
which exactly acts as a metal, and can exist in the free state.^
Soon afterwards Kolbe and Frankland succeeded in preparing
from the compounds of the alcohol radicals the hydrocarbons
which, according to their empirical formulae, must be con-
si dererl as the free radicals. The isolation of the alcohol
radicals as well as of cacodyl was naturally welcomed by the
followers of the radical theory, inasmuch as it placed that
which had hitherto only been a hypothesis in the I'ank of
known facts.

The question formerly much discussed respecting the pos^-
sibiiity of the existence of a radical containing oxygen was
again taken up. Berzelius had denied the possibility of the
existence of such a body, and in 1843 he argued that this view
is as incorrect as that which assumes sulphurous acid (sulphur
dioxide) to be the radical of sulphuric acid, or manganese
peroxide to be that of manganic acid. He adds : " an oxide
cannot be a radical ; the very definition of the word radical is
that it is a body which combined with oxygen forms an oxide."
But as soon as the upholders of the radical theory adopted
the theory of substitutions they were obliged to admit that
the electro-negative element, chlorine, is capable of taking the
place of electro-positive hydrogen without any great alteration

» Ann, Ckem, Pkarm. xlii. 14 ; IWH. Mag, [3] xx. 313, 382. ^95.

(• 2

20 UISTOIUCAL IXTRODUCTION.

occurring in the nature and properties of the compound ; and
when this had been once admitted, the possibility that oxygen
may also replace hydrogen could no longer be denied.

21 The further development of the doctrine of substitutions
and of the theory of types led to a clearer understanding
of the terms equivalent, atom, and molecule.

In this direction the development of the theory of polybasic
acids had an especial value. It has been already remarked
(Vol. ii. p. 35) that according to the dualistic view the neutral
or normal salts of the oxyacids must be regarded as compounds
of a basic oxide with an acid, or rather with an acid-forming
oxide, whilst the acid salts must be considered to be com-
pounds of a neutral salt Nvith a hydrated acid. Hence in
those days the following formulae were in vogue :

Hydrated sulphuric acid 110,80^
Neutral sulphate of potash KO.SO^
Acid sulphate of potash KO.SO^ + RO,SO^

According to these formula} the acid salt contains twice as much
acid as the normal or neutral salt.

Phosphoric acid and citric acid formed, however, exceptions
to this rule, for these were considered as tribasic acids, and their
formula.' as well as those of their salts are not divisible by
three :

I'iionpliotir A<'i<l. Arid SaltR. Kcntral Salts.

POt, VIO, PO^, 2HO, AafK P<\. UO. 2NaO. PO^. ZSaO,

Citrir \iM\.
C„//,0,j. :j//a C'„//bO,„ 2//0. KaO. C\^U^O^^, IIO. 2XaO. C^^fin- 3AaO.

According to Berzelius the only reason for considering an acid
to be iK)lybaHic is that its formula is not thus divisible.^

AfUT the publication of (iraham's classical investigations on
the various modifications of phosphoric acid and its salts, Liebig-
iti IS.'JS pn^iKKsetl his theory of polybasic acids founded upon a
romphite investigJition of the salts of a number of organic
acids. He showed that many organic acids resemble phos-
phoric and citric acids inasmuch as one equivalent of these
ciin take up from one to three equivalents of a base, Siicli
acids he considered to be polybasic, even if their formulae were
clivisibie. And he considered the capability of forming certain
double wilts to l>e the special characteristic of this class of acids.

» Krkulc, Lchrb, i. 80. « Ann. Phann. xxvi. 1,1.

LAURENT AND GERHARDT. 21

Tlio theory of polybasic acids was further developed by
Laurent and Gerhardt, the latter pointing out that the property
of forming two or more ethers was peculiar to these bodies.
Whilst Laurent added that the same holds good for their
amides. Both of these investigators, whose names will always
be honourably associated in the history of the science, laboured
incessantly to combat the views concerning the constitution of
chemical compounds which they deemed incorrect, and to
replace them by others which are more in harmony with
ascertained facts.

22 The interesting speculations of Lau ent and Gerhardt
concerning the relative magnitudes of the atom and mole-
cule went far to settle our views on these pjints, and the
arguments which they made use of for this purpose hold good
at the present day.

Laurent founded his conclusions csixicially on chemical
analogies, and upon the similarity observed in coiTesponding
chemical reactions. Thus, for instance, he showed that a mole-'
cule of chlorine must consist of two atoms, inasmuch as when
it acts upon organic compounds either two, four, or six atoms,
and never one, three, or five atoms take part in the reaction.
He came to the same conclusion by comparing the action of
chlorine with that of cyanogen chloride, benzoyl chloride, and
similar compounds. All these substances exhibit strictly
analogous metamorphoses, pointing to the conclusion that if
the molecule of these chlorides consists of two parts, the same
must also hold good in the case of chlorine itself.

Gerhardt, on the other hand, starting from Avogadro's law,
was led to a clear comprehension of the idea of an atom as
being the smallest portion of an element which is contained
in the molecule of any one of its compounds.

The labours cf these two great investigators met, however,
with but slight consideration during their lifetime. Laurent died
early, and even Gerhardt only lived long enough to enjoy tho
partial recognition of their views which soon afterwards became
general. When Gerhardt first proposed the doubling of the
atomic weights, or rather of the equivalent weights, then in
use, for oxygen, sulphur, and carbon, Berzelius did not think
tlie proposal worthy even of mention in his Jahresbericht.

For the purpose of obtaining a sound experimental basis for
their theoretical views Laurent and Gerhardt published many
valuable experimental investigations. Little consideration
was, however, paid to these results when they were correct.

22 HISTORICAL INTRODUCTION.

and when (as was sometimes the case) they were incoiTect,
they were criticised with no sparing hand. Whilst recog-
nising their great power of arranging facts from a general
l)oint of view, we must admit that they frequently made
assertions which rested more on a theoretical than an experi-
mental basis, and hence their views were frequently criticised,
especially by Liebig ^ as unscientific. Uninfluenced, however,
by these attempts to discredit their work, and fully convinced
of the truth of their ideas, they returned Liebig's sarcasm
with interest.

23 In looking back on these discussions we seem to enter a
bygone age. Berzelius endeavoured to throw ridicule on the exist-
ence of oxygenated radicals by saying that sulphur dioxide may
as truly be considered as the radical of sulphuric acid. At the
present day we actually adopt this view, considering this acid as
a compound of sulphur dioxide (sulphuryl) with the semi-
molecule of hydrogen [x?roxide (livdroxyl), for both of these groups
of atoms fulfil the conditions which Liebig defined as charac-
teristic of a compound radical.

The employment of empirical, or unitary formulne as they
were called, in opposition to dualistic, was a step in the right
direction ; for every compound consisting of more than two
elements is now considered as a chemical whole, and not as mado
tip of several constituents. The unitary system also clearly point;
out the general analogies of similar substances, and enables
the facts to be brought into direct comparison, instead of viewing
the constitution by the deceitful mirror of inherited hypotheses.-

Certain groups of substances can thus be considered from
the same i»oint of view, and their comjwsition indicated by
general formula) such as CmHnOc, the adoption of which led
to the taunt that Liiurent and Gerhardt were creating a sort
of chemical algebra. Tlie use of such formulae, however,
soon proved that the mutual relations of various compounds
could not be thus so clearly exhibited as by the formulae of
the radical theory. Accordingly Laurent and Gerhardt made use
of the so-called synoptical formula;, in which the group of atoms
remaining behind in a number of chemical metamorphoses was
written in a separate iM)sition from the other constituents, or
sometimes marked by a separate sign, the method of represen-
tation at one time falli^ig into the radical and at another time
into the nucleus theorv.

24 TTnpi»rtant j)rogress was next made by the amalgama-

* Ann. Chci, Vluii'tti. IviL 03, 3S*», ami hiii. 227. * Kckule, L^hrh, i. 84.

THEORIES OF TYPES AND RADICALS. 23

tion of the two theories of types and radicals. Dumas had
already pointed out that hydrogen can not only be replaced
by elements such as chlorine, but also by certain groups
of atoms, stich as NOg; and that these may be desig-
nated as compound radicals. Gerhardt revived this view in
1839, but not exactly in the sense of the radical theory, ac-
cording to which theory the radicals are closed groups of atoms
and form the proximate constituents of compouuds. Here,
however, it must be noticed that Liebig ^ had already pointed
out that a radical is not to.be considered as an unalterable
quantity, and that it was not necessary that the existence of
the radical must precede the formation of an organic compound.
Gerhardt did not assume that a substitution must occur when
an element is replaced by a compound body, but rather that a
combination of the two residues takes place to form a chemical
unit, and not a copulated compound. The group of atoms which
can be assumed to be a radical was termed " le rest " or " le
restant." Then came his "thtSorie des residus" according to
which such a residue possesses indeed the composition of a
compound radical, but is not contained as such in the com-
pound. Thus, for instance, the radical theory considers ethyl
nitrate as nitrate of ethyl oxide, and the formula is written, with
equivalent weights, CJIfi,NO^\ this ether is obtained by the
action of nitric acid on alcohol :

CJdfi -^ HNO3 = an^NOg 4- H,0.

According to Gerhardt the reaction which here takes place is
that the one compound gives up an atom of hydrogen, and the
other the group or residue OH, and that these unite together
to form water, whilst the two other residues form the chemical
unit, ethyl nitrate.

Gerliardt's theory of residues soon replaced the radicals of
the old theory, and their assumption in the new theory of
types brought about the union of the two theories. This was
more especially effected by the discovery of the compound
ammonias made by Wurtz* in 1849. Liebig* had foreseen
the possible existence of such compounds, inasmuch as he pre-
dicted that by uniting the alcohol radical with amidogen, ^Hj,
compounds would be obtained possessing the characteristic
properties of ammonias. Wurtz also assumed a corresponding

^ Ann, Ph/inn, xiv. 166 ; xvm. 323,

« ftympfes n^ndua, A out. 13, 1S49 ; Plill. ^fyg. [^] \x\v. 34.

3 HandwdrUrb. i. 698.

24 HISTORICAL IXTRODUCTION.

constitution of these compounds, and he wrote the formula
ethylamine (ethyliaque) C^HyNH^. Still, this iiiay be also
considered, according to Berzelius's views, as a copulated am-
monia, CaH^ + ^Hy Indeed Hofmann,* in his investigations
on aniline, originally adopted this view, although he soon dis-
covered facts which rendered it untenable. He showed that
ethylamine is a substituted ammonia, (C^H^H^X, inasmuch as
the second and third atom of hydrogen can also be replaced by
the alcohol radical, and the compounds thus obtained still
retain their characters as ammonias^

25 The discovery of the compound ammonias may certainly
be regarded as the foundation of our present theory. From
this time forwanl organic compounds have been arranged on
the tif^s of certain simple inorganic bodies. Thus, for instance,
it was assumed that in ammonia the hydrogen could be not
only replaced atom for atom by metals (Laurent), but also by
compound radicals.

In 18.30 Williamson* showed, in an analogous way, that
the alcohols and ethers may bo considered to be built up on the
type of water. When in one molecule of the latter one atom of
hydrogen is replaced by an alcohol radioed an alcohol is obtained.
By the replacement of the second an ether is formed. This view
he further exi^anded, inasmuch as he represented acetic acid as
water in which an atom of hydrogen was replaced by the group
CjHj^O, for which he proposed the name of oxygen-ethyl, or
othyl, in order to distinguish it from tho word acetyl, already
given by Berzelius to a radical containing no oxygen. At the
same time he pointed out that by the replacement of the second
atom of hydrogen by an oxygenated radical, compounds must be
obtained which stand in the same relation to the fatty acids as
ether does to alcohol These bodies, the anhydrous acids, or
anhydrides, were 80c»n afterwards discovered by Gerhardt*

For many yeai-s after this, chemists were accustomed to class
organic compounds on the type of simple inorganic substances
and thus arose Oerhardt's well-known tlieory of types, accord-
ing to which the organic compounds of ascertained constitution
may all be classed under four types : (1) that of hydrogen ;
(2) that of hydrcxihloric acid ; (3) that of water, and (4) that of
ammonia. Accordingly, we have the following :

> Quart. Joum. Chem, Soc. i, 23.1, ii. 334.

- Hn'fixh Assw'iation Ilrporh, IbjO, part ii. p. G.'i ; Chcm, Soc, Joum. (1852),
ir, 22l«.
" (Juarl. Joum. Chem. Hoc. v. 127 ; Ann. Chim. Phys. fa], xzxvii. 285.

GERHARDTS TYPES.

CI 91

WWW K^WW wVW tCffiV

• 1-4

CM
W

• ■-4

o
o

O
OO

P
PS

•c

CI CI

'C
o

26 HISTORICAL INTRODUCTION.

The organic bromides and iodides are of course classed iu the
second division, whilst many sulphur compounds are found in
the third, and bodies containing phosphorus and arsenic are
arranged in the fourth class. This system was further de-
veloped by the classification of many inorganic bodies, such as
the oxyacids which are ranged under the type of water.

26 A further advance in the theory of types was made by its
application to the classification of poly basic acids, such as suU
phuric acid. In the memoir already referred to, Williamson had
placed this acid under the double water type, inasmuch, as he
assumed, that it might be considered as two molecules of water
joined together by the replacement of two atoms of hydrogen by
a group of atoms, whilst a monobasic acid belongs to the typo
of one molecule of water. In a similar way the other dibasic
acids and their salts may be arranged :

Type.

Acetic Aci<l.

Nitric Acid.

S}o

CAo^o

KG, ) Q

Type

Sulphuric Acid.

Succinic Acid.

H j. 0

11 [^

Williamson^ then showed in 1854 that chloroform may be
considered as the trichloride of the radical CH. When it is
heated with sodium ethylate, CoH^.ONa, it yields tribasic formic
ether, CH(OCoH5)3, and this belongs to the type of three mole-
cules of water exactly as chloroform is classed under the type of
three molecules of hydrochloric acid :

Tyjie. Chloroform, Tvi>c. Tribasic formic ether.

CII

3H01 CH. CI, 3Hp

i^u}"-

This view of the constitution of chemical compounds was
further developed by Odling,^ and applied by him to a large
number of organic as well as inorganic compounds. They were
then adopted by Gerhardt in 185G, and published in his Treatise
on Organic Chemistry.*

27 As the possibility of the replacement of several hydrogen
atoms by a radical was first observed in the case of polybasic

* Pi'oc, Iloif. S'X, vii. l.^."). ' Qimrf. Jovi-n, Chun, Ak*. vii, 1.

* Ti-niii f'/thrt, Ot'tj. iv. 6^1, &c.

WILLIAMSON'S VIEWS. 27

acids, the radicals themselves were termed in the first cacs
polybasic, and this expression was afterwards changed to poly-
atomic radicals. This latter term is, however, not wholly free
from objection, and at present the proposal of Erlenmeyer to
employ the word polyvalent is generally adopted.^

The theory of polyvalent radicals soon received valuable sup-
port from Berthelot's investigation of glycerin and its deriva-
tives, the constitution of these compounds being first clearly
pointed out by Wurtz. Indeed this chemist must be considered
to be one of the originators of the new theory of types, not
only on account of the above-mentioned views, but especially
by his valuable discoveries of the glycols or divalent alcohols.

According to this theory, as we have seen, the radicals are not
to be considered as closed groups of atoms, or even as bodies
capable of isolation, but rather as the residues of molecules
which remain unaltered throughout a certain number of reac-
tions. Gerhardt first pointed out that most chemical decom-
positions may be regarded as double substitutions, and he added
that if the substances which exchange their positions in such
a reaction are compound bodies instead of being elementary
ones, they are then termed radicals.

28 These typical formulae were not intended to indicate the
arrangement of the atoms ; they were in no sense constitutional
formulae, but were formulae of decomposition used by common
consent, and expressing a certain immber of reactions. One
of these compounds may, therefore, be represented on various
types.

Thus, for instance, methyl ether, C^H^O, was usually supposed
to belong to the water type, but it may also belong to the fourth
type of marsh gas, which Kekule added to Gerhard t's three
original tj'pes. Under this latter assumption it would consist
of two molecules of marsh gas held together by one atom of
dyad oxygen :

Type.

> Ix)thar Meyer, Moil Thcor. dcr C/icmtc, 3rd Ed. p. 140.

28 HISTOUICAL INTRODUCTION.

By replacing the hydrogen in ammonia by methyl, methyl-
amine, CH^N, is produced ; this may be regarded as a substi-
tuted ammonia, but it may also be looked upon as marsh gas in
which hydrogen has been replaced by the monad group, NH, ;
and lastly, it may be represented as having been formed by the
union of two monad residues, and hence may be classed in the
type of hydrogen ; thus :

aUl C^'S INH.

1h n«

NHj

defiant gas combines with bromine to form ethylene di-
broniide, CgH^Bro. In this the bromine can be replaced by
hydroxyl when ethylene alcohol (ethyl glycol) is formed. These
two compounds may be typically regarded as follows :

Ethylene dibromidc ^^^*| C2H4}bJ

Ethylene alcohol ^^* | O., C,H, | ^^

By the action of hydrochloric acid on the latter body the
liydroxyl is first replaced by chlorine when ethylene chlor-
hydrate is formed, and this, on oxidation, yields monochloracetic
acid.

29 Hence ethylene chlorhydrate may be considered as a
chlorinated ethyl alcohol. It may, therefore, be regarded on the
mixed types of water and hydrochloric acid, the two molecules
being united by tlie replacement of one atom of hydrogen in
each by the dyad radical CgH^ (formula No. 1). Or we may
consider it to bo a compound of ethylene with chlorine and
liydroxyl ; or again it may be represented on the type of water
(formula No. 2), or on the mixed tjpc of hydrochloric acid and
water (formula No. 3).

(1.) (2.) (3.)

HJO

(Oft ' Hf

When clilorapctic acid, also obtaiuetl bv the action of chlorine
on acetic acid, is treated with ammonia, amidacetic acid,

inxED -nTEa »

CjHjNHjO,, is formed. This, like the componnds from which
it is produced, ia moDobasic. It presents, however, certain

analogies ivith the compound ammonias just as chloracetic acid
ciliibitB properties analogous to those of ethyl chloride, and
licnce the formulae of these compounds may be written in
different ways :

{1) (21 (S) (1) (5)

CI)

acij '-'"'** (OH lip cii ^'"'^in

Ami.lflMtic f, H (, ( NH, C,H,(SH.)0

„,.;.( <'5"i'^i mi II

The first of these formulae point out that these compounds
contain the dyad radical CjHjO^. The second and third
formulae show that we have to do with substitution-products
of acetic acid. These may be regarded as compounds of a
monad radical, inasmuch as amidacetic acid is formed from
chloracetic acid, one atom of chlorine btiiip; nplaced by tho
monad-amido group. The fourth series of foniiiiliB constructed
on the mixed type of water and hydrochloric acid, indicate the
water-ammonia type; whiUt in the fifth case amidacetic acid
J3 represented as a compound nmmonia. Which of those for-
mulae is to be preferred depends upon which of the relations of
the compounds it is especially desiitd to lay weight. It in usual
to choose those by which the mere important reactions are most
clearly represented,

30 In 1838 Gerhardt pointed out that by the action of
sulphuric acid on various compounds bodies are formed in
which the characteristic properties of the constituents are not
reproduced. In order to distinguish combinations of this kind
from ordinary compounds, he termed them copulated compounds.
The original views thus propounded by him were afterwards
considerably enlarged and modified by Berzelius, who, although
he at first ridiculed Oerhardt's idea of copulated compounds,
afterwards, as we have seen, adopted the name. With the
notion of these copulated compounds that of copulated radicals
is intimately connected.

According to this view many radicals are supposed to be
made up of several simpler radicals. Thus, lor instance, many

80 HISTORICAL INTRODUCTION

monobasic acids which belong to the type of water may bo
written, first of all, according to the water t}'pe :

Type. Formic Acid. Acetic Aciii Propionic Acid.

g}0 C«g|0 C,H,OJo CH^Oj^j

But these compounds are frequently found to decompose in
such a way that the group carbonyl, CO, is liberated as COj,
together, in the case of formic acid, with liydrogen, and, in the
case of the others, with an alcohol radical. The radicals of these
acids may, therefore, be looked upon as containing carbonyl, and
either hydrogen or an alcohol radical. This is represented in
the following formulae :

Fonnic Acid. Acetic Acid. Propionic Acid.

H.COI0 CH,C01|.o C,H,COjo

The employment of the intermediate types led to the re-
presentation of these acids together with other compounds, as
containing copulated radicals thus :

Formic Acid. Acetic Acid. Propionic Acid.

HI CH3 ) C,Hj )

CO f CO j CO [

h}o h[o h}<^

The followers of Berzelius, especially Frankland and Kolbe,*
considered these acids as conjugate compounds, but as these
chemists did nut recognise any oxygenated radicals, they looked
upon acetic acid as the hydrate of a compound of oxygen
with acetyl containing methyl and carbon, and they expressed
the constitution of acetic acid by the formula HO, (C^^C^^O^
without admitting the new atomic weights.^

The development of the theory of types played an important
part in the history of the science. Instead of supporting the
view of the unalterability of the radicals, it led to the notion
that the residue consists of groups of atoms which, in a certain
series of metamorphoses, remain unaltered, whilst under other
circumstances they may undergo change. It also threw a new

' Chem. Soc. Mem. iii. 890.

* The reader will lind a fuU account of the new theory of typos as well as of
copuhited radicalri in Kckule'a Lehrhuch der organiachtn Chcmie, and in his
memoir *'on the so-called co[>uIated compoauds and the theory of polyatoinio
radicals." — Ann, Chem, PJiarm, civ. 129.

DEFINITIOXS OP ORGANIC CHEMISTRY. 81

light upon facts in other directions, explaining certain analogies
and diflferences, and thus rendering possible a general view
respecting the behaviour of the atoms in compounds.^

31 Before however we can enter into this question we must
refer to another point and once more look back to the time
when Williamson applied the theory of types to inorganic com-
pounds, and showed that the existence of compound radicals
must be assumed in these just as much as in organic substances;

Even before this tin.e many salts, such as those of ammonium
and those of uranyl, had been considered to contain compound
radicals, but the number had then so largely increased that
organic chemistry could not be correctly defined to be the
chemistry of compound radicals.

All the organic compounds formed in nature contain carbon
and hydrogen. Most contain oxygen as well, and many nitrogen.
According to the older views it was, however, supposed that
the hydrogen was, in many compounds, as, for instance, in oxalic
acid, combined with oxygen to form water. Thus carbon was
in some cases found to be the only remaining constituent, and
this fact was pointed out by Gerhardt, in 184G.

Hence, organic chemistry was defined as the chemistry of
the carbon compounds, as well as that of the radicals con-
taining carbon. According to this definition, however, many
compounds of this element must be considered to belong to
organic chemistry although they are not formed from the bodies
of vegetables or animals and occur in the mineral kingdom.
Such bodies are carbon dioxide and marsh gas. This difii-
cuity of classification has been avoided in various ways. Thus,
Gmelin * in his Handbook says : " Carbon is the only element
which is essential to organic compounds ; every one of the
other elements may be absent from particular compounds, but
no compound which in all its relations deserves the name of
organic is destitute of carbon. ... If we were to regard as
organic, those carbon compounds which have hitherto been
classed amongst inorganic substances, namely carbonic oxide,
carbonic acid, sulphide of carbon, phosgene, cast-iron, &c., we
might define organic compounds simply as the compounds of
carion. But organic compounds are still further distinguished
by containing more than one atom of carbon. . . . Htnce
the term organic cowfounds includes all primary compounds

* Lothar Meyer, 3fo<L Theor, dcr Chemie, 8rd Ed. p. 150.

* Uandbool; vii. 4 aud 5.

32 HISTORICAL INTRODrCTIOX.

containing mere than one atom of carbon. By primarr com-
pounds we mean such as are not, like bi-carbonate of potash,
made up of other compounds."

In order to understand this definition it must be remem-
bered that in those davs, the atomic weight of carbon was
supposed to be only half as great as that which is at present
assigned to it, and this remark applies also to oxygen, sulphur,
and seyeral other elements. Thus the followini;^ formulae were
then employetl : carbonic oxide, CO ; carbonic acid, CO^ ;
phosgene gas, COCl ; and carbon disulphide, CS^; whilst to
the organic compounds of most simple constitution, the follow-
ing formulae were assigned: methyl alcohol, CJIJ[)^\ fonnic
acid, CM/J^ ; hydrocyanic acid, CJIX\ cidoroform, CJSCl^

As soon, however, as it appeared that the atomic weights of
the above elements must be doubled, and that the molecule
of carbon dioxide or carbon disulphide contained exactly the
same number of atoms of carbon as one molecule of methyl
alcohol or of formic acid, either Gmelin's definition could no
longer hold goo^l, or the latter compounds must be considered
to belong to inorganic chemistry, or, in the third place, the oxides
and the sulphide of carbon must be considered to be oiganic
compounds.

On this question Kekul^ remarks : " We must come to
the conclusion tliat the chemical compounds of the vegetable
and animal kingdom contain the same elements as those of
inanimate nature. We know that in both cases the same laws
of combination liold good, and hence that no difterences exist
between organic and inorganic compounds, either in their com-
ponent materials, in the forces which hold these materials
together, or in the number and the mode of grouping of their
atoms. Wo notice continuous series of chemical compounds
whose single members, especially when only those which lie
close together, arc compared, exhibit strong analogy, and be-
tween which no natural division is perceptible. If, however,
for tho sake of perspicuity a lino of demarcation is to be
drawn, we must remember that this boundary is an empirical
rather than a natural one, and may be traced at any point
which SiH'ms most desirable. If we wish to express by
organic chemistry that which is usually considered under
tho name, we shall do best to include all carbon com-
pounds. Wo, therefore, define organic chemistry as the che-
mistry of the carbon compounds, and we do not set up any

DEFINITIONS OF ORGANIC CHEMISTRY. 33

opposition between inorganic and organic bodies. That to
which the old name of organic chemistry has been given, and
which we express by the more distinctive term of the chemistry
of the carbon compounds, is merely a special portion of pure
chemistry, considered apart from the other portion only because
the large number and the peculiar importance of the carbon
compounds renders their special consideration necessary."^

Other chemists have expressed themselves in a similar way.
Thus Butlerow states that a division of the kind is needed both
in the interest of the student as well as in that of the scientific
investigator. The carbon compounds exhibit certain peculiari-
ties in consequence of which their investigation demands special
methods, which are not necessary in the case of the other ele-
ments.* Another reason for treating the carbon compounds
separately is the enormous mass of material which presents
itself for investigation, so that although such a division is an
artificial one, it is one which is extremely useful.*

32 The distinction between these classes of carbon compounds
is, however, one which up to the present time has never been
carried out in every detail. Thus, no chemist has ever thought
it advisable to omit such substances as the oxides and the sul-
phide of carbon from the inorganic portion of his work, or
to class substances like carbonate of lime, or spathic iron-ore,
or even cast-iron, under the head of organic compounds. Hence
we find a description of the oxides of carbon, of carbon disul-
phide, and of their various derivatives, generally placed in
the divisions both of inorganic and of organic chemistry. In
the same way the cyanogen compounds are frequently de-
scribed both in inorganic and in organic treatises. The ex-
planation being, that these bodies contain only one atom of
carbon, and that they are in many respects analogous to
the compounds of the elementary bodies. Wood-spirit and
formic acid, on the other hand, which also only contain one
atom of carbon in the molecule, are never considered as inor-
ganic compounds, for they are closely connected with alcohol,
acetic acid, and other bodies containing a larger number of
carbon atoms, whose peculiar properties orginally led to the
distinction between the two great branches of pure chemistry.

33 This peculiarity depends upon the fact that they are

* Lehrbueh d, org. Chemie, i. 11.

* Butlerow, Lekrb, d, org, CTiem, 5.

' Erlenmeyer, Lehrb. d, org. Chem, p, 5,

VOL. ni. D

34 HISTORICAL INTRODUCTION.

carbon compounds, for carbon possesses properties by which
it is distinguished from all other elements. In the first place
we have to remember that hydrogen is found in all organic
bodies in addition to carbon; in most others oxygen occurs;
and in many nitrogen is also contained. Others again consist
of carbon, hydrogen, and nitrogen only.

The number of these bodies is enormously large. Carbon yields
more compounds than all the other elements taken together.
Moreover, the number of atoms contained in the molecule may be
very considerable. Thus, for instance, oil of turpentine consists
of carbon and hydrogen, and contains 26 atoms ; cane-sugar,
which in addition contains oxygen, contains 45 ; and stearin,
also an oxygenated body, contains 173 atoms.

Kekul^,^ who first pointed out that carbon is a tetrad element,
showed at the same time that the existence of so large a number
of carbon compounds may be explained by the fact that the
atoms of this element have the power of combining one with
another. A similar view was also put forward shortly afterwards
by A. S. Couper.^

The atoms of other polyvalent elements, such as oxygen, sul-
phur, &c., are indeed found to combine with one another, but
the number which can be thus connected together is in their
case a very limited one. With carbon, however, such a limit
to the power of combination has not yet been reached. A large
number of its atoms are capable of uniting to form a chain
which in many reactions behaves as if it were a chemical unit.

Still more clearly however is carbon distinguished from all
the other elements by the fact that in such a chain of atoms
all the free combining units can he saturated hy hydrogen. Hence
the existence of a large number of hydrocarbons becomes pos-
sible. These are all volatile, whilst amongst the hydrogen
compounds of the other elements only those of the chlorine,
oxygen, nitrogen, boron, and silicon groups are volatile, and in
the case of each of these (with the exception of phosphorus)
only one hydride is known.

The hydrocarbons are however not only the simplest, but at
the same time, on theoretical grounds, the most important,
compounds of this element, especially because all the other
compounds may be derived from these by the replacement
of hydrogen by other elements. In the organic compounds

* Ann. Ch(m. Pharm, civ. 129 ; cvi. 129; Lehrhuch, i. 161.
« i'AjY. Maff. [4], xvi. 104.

DEFINITION OF ORGANIC CHEMISTRY ADOPTED. 36

occurring in nature we usually find a portion of the hydrogen
replaced by oxygen or by nitrogen, or by both of these elements.
Some few are found to contain sulphur. All the elements
may be made to combine with carbon compounds, but it is only
in a few instances that all the hydrogen in the hydrocarbon
can be replaced by another element. This explains the feet
which has already been mentioned, that by far the larger pro-
portion of carbon compounds contain hydrogen, or a residue of
the hydrocarbon from which they all are derived.

34 Hence we may define that portion of our science which
is usually denoted as organic chemistry as being the chemistry
of tJie hydrocarbons and their derivatives. The characteristic
nature of this definition is seen from the fact that, when the
general chemical constitution of a carbon compound has been
nghtly ascertained, it can be converted into the corresponding
hydrocarbon, or, inversely, it may be prepared from this latter
compound.

In employing this definition, we do not draw any distinctive
line between organic and inorganic chemistry, for the simpler
carbon compounds which have already been described in the
inorganic portion of this work, such as carbon dioxide, carbon
oxychloride, sulphide of carbon, hydrocyanic acid, &c., all of
which contain one atom of carbon, may be looked upon as direct
derivatives of a hydrocarbon, namely, marsh gas, CH^. From
this they can all be prepared, and into this they can all be
converted. When this gas is burnt in the air, water and
carbon dioxide are formed, the monad hydrogen being replaced
by dyad oxygen. Marsh gas can also be directly converted
into carbon disulphide, and when the vapour of the latter
body is passed together with sulphuretted hydrogen over red-
hot metallic copper, the sulphur is substituted by hydrogen,
and the hydrocarbon, marsh gas, is formed. If this latter
compound be treated with chlorine, the first product which is
obtained is methyl chloride, CH3CI, and when this is heated
with caustic potash, wood-spirit, or methyl alcohol, CH^O, is
obtained :

CH3CI + KOH = CH3.OH + KCl.

When this alcohol is oxidised, formic acid is produced, two
atoms of hydrogen being replaced by one atom of oxygen. By
the further action of chlorine on methyl chloride the successive

1) 2

36 HISTORICAL INTRODUCTION.

replacement of all the hydrogen by chlorine takes place, the
last product but one being chloroform, CHCI3 ; and if this sub-
stance be heated with ammonia, hydrocyanic acid is obtained,
three atoms of chlorine being replaced by one atom of triad
nitrogen :

CHCI3 + 4 NH3 = CHN + 3 NH^.

As all the cyanides can be derived from hydrocyanic acid,
they may be all considered as derivatives of marsh gas. The
carbonates may be similarly considered to be derived from
marsh gas, for wc must assume in the aqueous solution of
carbon dioxide the existence of carbonic acid, C0(0H)2, that is
to say, marsh gas, in which one-half of the hydrogen has been
replaced by oxygen, and the other two by hydroxyl. Indeed
the various varieties of cast-iron may even be regarded as deri-
vatives of hydrocarbons, inasmuch as when cast-iron is dissolved
in hydrochloric or sulphuric acid the carbon which is combined
with the iron gives rise to hydrocarbons in which the hydrogen
may be said to have replaced iron.

35 Only one single carbon compound is known for which the
corresponding hydrocarbon does not exist. This is the simplest
of all carbon compounds, viz. carbon monoxide. All endeavours
to isolate the hydrocarbon CHg have as yet proved abortive,
and there are good reasons for behoving that the existence
of such a body in the jfree state is not possible. No other
hydrocarbon except marsh gas is known which contains only
one atom of carbon. On the other hand, we are acquainted
with three which contain two atoms of carbon :

Ethane, CgH^. Ethylene, CgH^. Ethine, CgHy

In order to explain the constitution of these substances it
is assumed that in ethane the two carbon atoms are connected
together singly ; in ethylene by double linking ; whilst in ethine
or acetylene the three combining units of the two carbon atoms
are supposed to be linked together.

A Large number of carbon atoms may be combined together
in a similar way, and thus the above hydrocarbons form the
first members of groups of which each is distinguished from
the preceding by an increment of CH^. The composition of
these may be expressed by the following general formuloe :

nYDROCARBONS AND THEIR DERIVATIVES.

Series.

CnHsn -f 2.

CnUsn*

Jfethane
Ethane

CH4

Ethylene

C,H,

Propane

^3^8

Propylene

CsHg

Butane

C4H10

Butylene

Gfis

Pentane

C5H12

Pentylene

^6^10

Hexane

CeHu

Hexylene

CcHia

&c.

C„Hsn-

Sn-2>

Ethine
Propine
Butine
Pentine
Hexine
&c.

CgHg
CgHg

Besides these, other groups, such as CnH2n-4 and CnH^-a
&c., are known. The first members of these naturally contain
more than two atoms of carbon.

36 Other carbon compounds can be derived from these various
series. Thus, for instance, just as by the action of chlorine on
marsh gas methyl chloride is obtained, so the other members of
the marsh gas series yield chlorides of monad radicals having
the general formula CnH2n+iCl in which chlorine can be easily
replaced by hydroxyl, and thus a series of hydroxides are ob-
tained to which the names of alcohols have been given, and
to which the general formula CnH2n+20 is applicable.

When methyl chloride is heated with ammonia, a strong base
is obtained, which has received the name of methylamino :

CH3CI + NH3 = CH3NH2 + HCl.

And by a similar reaction with the other chlorides a series of
such bases or amines is obtained having the general formula

Moreover, as methyl alcohol gives rise to formic acid by
oxidation, so these other alcohols yield a scries of acids
Laving the general formula CnH2u02, obtained by the replace,
ment of two atoms of hydrogen in the alcohol by one of oxygen.
Many of these acids are found in fats and oils, and hence they
are termed the fatty acid series, or the adipic series of acids.
Thus we obtain the following series from the marsh gas hydro-
carbons :

Chloride.
c^firide I <^»"»^^

Pentvl } r- TT n
eUonde j ^•""^*

AlcohoL

"ilcXi CH.0

Ethyl i p u n
alcohol ^»"«^

Propyl I p ri n
alcohol i ^»*^8"

iSihol I ^*"*oO
Tkohol 1 ^»Hi,0^

Hcxyl
alcohol

C,H„0

Amine.
Methylamine C HjN

Ethylamine CSH7N

Propylamine C3H9N

Butylamine C^HuN

Pentylamine C^H^sN

Fatty Acid.
Formic acid C H,Cj

Acetic acid C3H4O2

Propionic acid C^Ufi^

Butyric acid C4HgOj

Pentylic acid CjHioO,

Hexylamine QHuN j Hcxylic acid C^Uifi^

38 HISTORICAL INTRODUCTION.

In addition to these, a large number of other derivatives of the
above hydrocarbons is also known, and these again yield other
groups which can all be arranged in corresponding series. All
the hydrocarbons contain an even number of atoms of* hydrogen ;
this being owing to the tetrad nature of carbon. For the
same reason it also follows thcU the sicvi of the atoms of nionad
and triad elements which arc contained in a molecule of a carbon
compound is always an even nu?nber,

37 In 1842 Schiel ^ remarked that the alcohol radicals form
a very simple and regularly graduated series of bodies, of which
the properties as well as the composition exhibit corresponding
regular gradations. He gave the following description, the old
equivalents being used :

Cg-H!, = R

EU . . ." Methyl.

Bjr Ethyl.

R^H Glyceryl

R^H ?

R^H Amyl.

R^qH , . Cetyl.

R^^H Cerotyl.

He also predicted the existence of other series. Shortly
afterwards, Dumas^ showed that the fatty acids form a similar
series, and that in these, as Schiel had pointed out in the case
of the alcohols, the boiling-point regularly rises with the
increment C^H^,

In his Precis de Chimie organique, published in 1844, Ger-
hardt collected together a large number of such groups, and was
the first to give to these the name of homologous scries, whilst he
classed the bodies obtained from one another by definite
chemical metamorphoses, such, for instance, as ethyl chloride,
ethyl alcohol, acetic acid, &c., as Jictcrolojous scHes.

This classification into homologous and heterologous series
Gerhardt compares to the arrangement of a pack of cards.
The cards of each suit being placed in regular order
in a vertical line, those of equal value in the different
suits will be found in a horizontal row. These latter corre-
spond to the homologous series, whilst the first represent

» Ann, Chim. Pharm. xliii. 107. ' Ibid. xlv. 330.

HOMOLOGOUS SERIES. 39

the heterologous series. If one card be wanting, its place is
nevertheless indicated, and, although absent, we know its exact
character. In the same way with organic compounds. When
the series is not complete, the composition of the missing
substance can not only be predicted, but even its more im-
portant properties indicated. Of its possible existence there
can be no doubt, and if it is desired to complete the series, this
can be done by employing suitable reactions.

If we compare the various members of one such series of homo-
logous bodies together, thus, for example, those of the marsh gas
hydrocarbons, CnH2n+2, we find, in the first place, that they difi^er
from one another in physical properties. The lowest members are
gases at the ordinary temperature ; the members next following
are liquids whose boiling-points increase with their molecular
>veights, whilst the highest members are solid bodies, which are
volatilised only at a high temperature. The same holds good
with the other series. Their lowest members are either gases
or volatile liquids; the highest, on the other hand, are solid
bodies either only volatilised with difficulty or undergoing
decomposition when heated.

We next observe that the chemical character of each group
depends essentially upon the mode in which the carbon
atoms are connected with one another, as well as with the
rest of the elements contained in the molecule. For this reason
the corresponding members of each homologous series closely
resemble one another in their chemical relationships. One
result of this is that whilst the comparatively limited number of
compounds which the other elements form renders it possible that
the nature and composition of the compound can be determined
by a few reactions, this, on the other hand, is only exception-
ally possible in the case of the carbon compounds. In most
instances it is necessary for this purpose not only to prepare the
body in the pure state, but also to determine its physical and
chemical characters, and then to pass on to the determination of
its quantitative composition. Not only do newly discovered bodies
require this complete treatment, but frequently this is the only
mode by which substances which have long been known can be
satis&ctorily recognised. Hence we shall now pass on to describe
the methods which have been employed, and are still in use, for
the vMimate analysis of the carbon compounds.

ULTIMATE OBGANIC ANALYSIS.

ULTIMATE OEGANIC ANALYSIS.

DETERMINATION OF CARBON AND HYDROGEN.

38 The first successful analysis of an organic compound
was carried out by Lavoisier, and tlie principle upon which he
founded his method fur the determiuation of carbon and hydro-
gen is the same aa that which is employed for a like piirpose at
the present day. The body to be analysed is completely burnt.

the titiantity of carbon dioxide and watur thus produced being
uccumtoly <)otcni)iiied.

Lavoisier'g Afrthmi. Tho apparatus used by Lavoisier ' for this
purpose is shown iu Fig. 1. Tho glass btli-jar A, carefully

> ilrm. Am^. i;^l (piibliJwd in 1781), ati.I ibid. V.fii (i>ul>tuhed in 1787).

LAVOISIER^S METHOD OF ANALYSIS. 41

calibrated and standing over mercury, contains common air.
Into this is brought a weighed lamp fed with the alcohol or oil
to be analysed ; on the wick a small piece of phosphorus is
placed, and this can be inflamed by contact with a warm bent
wire. The bell- jar s contains a measured volume of oxygen
standing over water. By lowering this, the oxygen can be
passed over into the vessel A for the purpose of completing
the combustioiL As soon as this is eflfected, the carbon dioxide
formed by the combustion is absorbed by caustic potash, and
from the volume of this gas, together with that of the air
which remains behind after the combustion, and from the volume
of unbumt oxygen, Lavoisier calculated the composition of the
alcohol or oil which had undergone combustion in the lamp.
In this way, however, he arrived at altogether erroneous
results, inasmuch as he was not acquainted with the exact com-
position of either carbon dioxide or water, and the numbers
which he used for the specific gravities of the various gases
employed were by no means accurate. Nevertheless, if his
results be recalculated with the adoption of correct constants, it
appears that his analyses were at least as accurate as those of
many chemists who in the following years occupied themselves
with the subject.

LavoLsier even then observed that the indirect determina-
tion of water by the subtraction of the weight of carbon dioxide
from the sum of the weights of the burnt substances and the
oxygen employed for the combustion might with advantage be
replaced by a direct determination of this substance. Later
on, indeed, he described an apparatus for the burning of large
quantities of oil, in which both the water and carbon dioxide
formed are weighed. This method has a special interest, as
the arrangement of the apparatus closely resembles that in use
at the present day.^ The apparatus used is shown in Fig. 2.
The combustion takes place in A, and the oil for the lamp is
introduced at a. The gas-holder (p) is filled with oxygen, and
this gas passes through b, and is dried in the tube p. The
products of combustion pass through c into the absorption-
apparatus. The greater portion of the water collects in the
bottle (/), and that which escapes is deposited in the spiral tube
(A), wlnlst the last traces are taken up in the tube Jc, which
contains a " deliquescent salt." The gases then pass through a
system of bottles (ff), of which only two are represented in the

^ Layoiaicr's Elements (Kerr's translation), 503.

42 ULTIMATE ORGAXIC ANALYSIS

figure, although Lavoisier employed eight or nine. Theae, with
the eiceptioD of the last, contaiD caustic potash, lime-water
being placed in the last one in order that the complete ab-
sorption oC the carbon dioxide may be recognised by the

nuii-turbidity of the lime-water. The first experiments made
with this apparatus did not yield very satisfactory results, and
his endeavours to improve the method were cut short by his
untimely execution in May, 1791.

44 ULTIMATE OBGANIC ANALYSIS.

cumbustioQ was efrecte<l in an apparatus the constructioD of
which is shown in Fig. 3. The closed lower end of the hard glass
tube AA, 2 dciQ. in length and S mm. in diameter, is placed
upon a charcoal fire, or strongly heated by an alcohol lamp
(u). The upper end of this conibustion-tube is closed with a
stopcock, which, however, is uot bored through, but has a cavity
bored into the stopper. A pill is placed in this cavity, and the
stopcock turned, when the pill falls into the ted-hot tube. By
repeatingthis operation, all the air contained in the combustion-
tube is driven out by the side tube. A weighed quantity of
the pills is then gradually added, and the whole of the gas

goneratetl collected in a graduated jar over mercuiy. The
(jxcess of oxygon is detcnnincd by adding a certain volume of
Iiy<lrogon and exploding the mixture, and then the carbon
dioxide is .-ibsorhed by caustic potash, and thus the volumes of
the two gjises are ascertained. These volumes, together with
the weight of the substance burnt, give data for ascertaining
the quantity r>f water formc<l. In this way Gay-Lussac and
Tlit'nanl analyse! no less than fifteen organic substances fr^'e
from nitrogen, ami four substances containing this element.
In the latter case they took the precaution of avoiding a large
excesB of orygon in order to prevent the formation of the oxides

METHOD OF GAY-LUSSAC AND THfiNARD. 46

of nitrogen. Some of the analyses thus conducted are fairly
accurate, when the calculations are corrected, this being neces-
sary because at that time neither the true composition of carbon
dioxide nor that of water was known. Thus corrected. Gay-
Lussac and Th^nard's numbers for the percentage composition
of sugar are as follows. The results calculated from the formula
are added for the sake of comparison.

Found. Calculated.

Carbon 41-36 4210

Hydrogen .... 0-39 6*44

Oxygen 51'14 5r46

98-89 100-00.

This method, however, did not yield satisfactory results in
the case of very volatile bodies, and the composition of these
substances had to be determined, as before, by eudiometric
methods.

We are indebted to Saussure for improving this branch of
analysis, and for determining accurately the composition of
several compounds, such as that of alcohol.* He also analysed
non- volatile bodies, some of them with great exactitude, by com-
bustion in oxygen, determining the volume of this gas needed
for the combustion, as well as that of the carbon dioxide formed.*

41 Berzelivs's Method. Saussure's method would probably
have come into general use had not Berzelius* published in
1814 his much more exact method for the analysis of organic
bodies. It has already been stated in the introduction that
Berzelius began this investigation with the view of ascertain-
ing whether organic bodies obey the same laws of chemical
combination as those which regulate the formation of in-
rirganic substances. Adopting Lavoisier's plan, he absorbed
the water and carbon dioxide formed by the decomposition,
determining their amounts gravimetrically. Like Gay-Lussac
and Thdnard, he employed potassium chlorate as an oxidising
agent, reducing the violence of its action by mixing it with
ten times its weight of common salt. At the closed end of
his glass combustion-tube he placed some of this mixture of

* Ann, Chim. Ixxviii. 57. * Bibl Britan. Ivi. 333.

> Thomson's Ann, Phil. [4], 401.

ULTIMATE ORGANIC ANALYSIS.

commoii salt and
potassium chlorate ;
then came an intimate
mixture of the sub-
stance \vith the same
oxidising material,
whiJst the front por-
tion of the tube was
filled with the oxidis-
ing substance alone.
The open end of the
tube vaa drawn out
to a long point and
the whole placed in a
furnace (Fig. 4), in
which it was heated by
charcoal and placed in
the position indicated
in the figure. For the
sake of precaution the
tube was surrounded
by a coating of copper
foil fastened with iron
wire. The open end
was then connected
with a light glass re-
recciver (a), which in
its turn was joined to
the tube B, contain-
ing calcium chloride,
which served to absorb
the water not con-
densed in A. The
carbon dioxide formed,
together with the ex-
cess of oxygen, was
collected over mercury
in the bell-jar contain-
ing a small glass vessel
filled with caustic
potash. In canying
out the experiment.

BEKZELIUSS METHOD.

the front end of the
tube was first heated,
and the fire gradually
extended to the fur-
ther end, the screen
F being gradually
pushed back. The oxy-
gen evolved at the
end of the operation
served for the pur-
pose of driving the
combustion - products
leftin the tube through
the absorption vessels.
The increase in the
weight of the vessels
A. and B gave the
weight of the water
formed, and that of
the vessel c the
amount of carbon di-
oxide. This method
is not ai^licahle to the
case of nitrogenous
bodies, inasmuch as
oxides of nitrogen
are then formed which
are absorbed by the
caustic potash. Be-
sidea, the method is
liable to various other
errors which render
an exact (leteriiyiiia-
tion of hydrogen and
carbon impossible. If
we desire to obtain an
idea of the accuracy
of this process, the
analydcal numbers
obtained by Berzelius
must be recalculated,
inaBmuch as inexact

4fl ULTIMATE ORGANIC ANALYSIS

atomic weights were employed by Lim. If this be done, we
obtain the following numbers for the percentage composition
of sugnr :

Carbon 427

Hydrogen 6*5

Oxygen 508

100-0

43 Lichiijs MdJud. To Liebig belongs the singular honour
of having so completely perfected and simplified the process of
organic analysis that his method is used at the present day
almost xinaltered. The labour which this investigation involved
was however so great that it was many years (1823-1830) before
it was completed, and the potash appiratus in the form in which
it is now used, was not described until 1831.^ From this time
forward he was able, with the help of his piipiia. to carry out

Fio. 6.

the nomerous important investigations which gave to the Qiessen
laboratory a world-wide reputiitinn.

As an oxidising agent, Liebig employed cupric oxide, CuO, a
substance which lind beon used by Gay-Lussac and Thiinard in
their analyses of nitrogenous substances. This compound is
also oniplnycd for the qualitative detection of carbon and
hydrogen, inasmuch as, when, in the perfectly dry state, it is
ignited with an organic substance, the above elements unite
with its oxygen to form carbon dioxide and water, the presence
of which can be readily deticted.

' Pngg. Ann.

LIEBIG'S ORIGINAL METHOD.

Liebig's original combustion apparatus is shown in Fig. 5,
whilst Fig. 6 exhibits the form in which at a later time it
became generally adopted. It consists of the eombustion-tubo
(Fig. 7) made of difficultly fusible glass, drawn out at the closed
end to a fine point. This is filled in different ways according to
the nature of the body undergoing combustion. If it be a solid,
not too volatile or hygroscopic, the following method described

flG. 7.

by Liebig ^ miiy be used : — A small quantity of finely-divided,
and previously ignited, black oxide of copper which has been
cooled in a closed vessel is first brought into the combus-
tion-tube to the point c ; some more of this oxide is then
placed in a small porcelain mortar, and to this from 0*2 to 0*3
gram of the substance is added. This is then covered with
more oxide, and well mixed by means of the pcstlo. The

Fio. 8.

mixture is next filled into the combustion-tube up to the point
6, and the mortar rinsed out with more oxide, and this also
brought into the tube, which is then filled, though not com-
pletely, from the point a with pure copper oxide. The length
of the la.st layer of pure oxide depends on the combustibility
and volatility of the substance. If an easily volatile substance

' For furtb«»r details of this method we must refer to Frcscnins's Quantitative
Amaiffn's, i>. 455, § 174, sixth cd.

VOr* III. K

ULTIMATE OKGANIC ANALYSIS

has to be burut, or one which, ou heatiug, gives otf large
quantities of combustible vapours, the column of oxide must
be longer than in other cases. The tube is then laid flat on
the table and gently tapped, so that a free passage for the pro-
ducts of combustion is left above the surface of the copper oxide.

Inasmuch as copper oxide is a very hygroscopic substance and
may, thercf(.)re, have absorbed moisture from the air during the
process of mixing, this moisture must be removed when an exact
determination of the hydrogen is required. For this purpose
the tube, prepared in the way described, is placed in connection
with the exhausting syringe (p, Fi'(. 8), the second opening of
which is joined to a U-tube (t) containing chloride of calcium.
The combustion -tube (ah) is warmed in a wa tor-bath or sand-
bath, then exhausted, and dry air allowed to enter, and this
operation repeated several times.

43 In order to avoid this tedious dessicating process, the sub-
stance may, according to BuUvSen's proposal, be mixed with the

Fio. 0

Oh.

Fi(t. 10.

¥u. 11

Fi«: 1-J.

oxide of copi)er in tlie tube itself. This is etfectod by means of
a copper- or hrajs-wire bent at the end like a corkscrew (Fig. 9),
a vertical and, at the same time, a rotatory motion being given
to the wirii. The tube is then placed in the combu.stion-furnaco.

LIEBIG'S IMPllOVKD METHOD. 61

closed by a soft bored cork, through which passes the end of the
chloride of calcium tube (Fig. 10), this being employed for the
abrorption of the water produced. Another form of such a
tube is shown in Fig. 11. The carbon dioxide is collected
in a Liebig's potash-bulb filled
with a concentrated solution of
caustic potasli (Fig. 12). Ano-
ther form of this apparatus is
shown in Fig. 13. All these
forms of bulbs are so arranged
that the gas passes in single
bubbles through the various
bulbs, thus remaining for a Fn;. 13.

considerable time in contact

with the caustic potash. In order to be sure that the carbon
dioxide is completely absorbed (for this gas is, to begin with,
mixed with a large quantity of air), and also to prevent the
exit air from carrying away aqueous vapour from the caustic
potash solution, a few pieces of solid potash are placed in the
U-tube (c) (Figs. 6 and 14) connected to and weigher! with the
potash-bulbs. The bulbs are then connected by means of the
U-tubes to an aspirator (v) (Fig. 6), the stopcock remaining
open.

In carrying out the combustion, the first point to be ascer-
tained is that the apparatus is perfectly air-tight. This is
usually done by first placing the Liebig's bulbs in a slanting
position with the larger bulb uppermost, warming this until a
sufficient quantity of air has escaped through the liquid. When
the air in the apparatus cools, the liquid rises in the bulb, and
there assumes a higher level than in the other part of the ap-
paratus. If this level remains constant for a considerable time,
we may conclude that all the parts of the apparatus are tight,
and the combustion itself cAn now be commenced.

The next operation is to surround the front part of the tube
with red-hot charcoal., care being taken that the end of tlie tube
carrying the cork is placed in such a position that in the first
place no water condenses on it, and in the second that the cork
does not become over-heated and charred. In order to keep the
hot charcoal in its right place, and to prevent the further por-
tions of the tube from becoming heated before the proper time,
the iron screen F (Fig. 6) is used. This is gradually pushed back
as the front portions of the tube have become red-hot. More

E 2

62 ULTIMATE ORGANIC ANALYSIS.

charcoal is now added, and the process is continued until the
whole of the layer of copper oxide is red-hot. The portion con-
taining the substance is now very carefully and gradually heated,
80 that whilst the combustion is going on, not more than one or
two bubbles of gas pass every second through the potash-bulbs.
When the whole of the tube has been surrounded by red-hot
charcoal, and as soon as the evolution of gas ceases, the potash-
bulbs are placed in a vertical position, the charcoal removed
from the drawn-out end of the tube, and the screen placed in
front of the point. Owing to the gradual cooling, and to the
absoq)ti<^n of carbon dioxide, the potash solution will now be seen
to pass back into the large bulb. When this is filled with liquid,
and the pressure within the apparatus being, therefore, somewhat
less than the atmospheric pressure, the pointed end of the tube
is broken by means of pliers. The potash-apparatus is now
brought back into its original slanting position, and, by means
of the aspirator, air is drawn through the apparatus in order to
allow the whole of the carbon dioxide and aqueous vapour to
pass through the absorption vessel. In order to be quite sure
that in this operation none of the carbon dioxide produced by
the combustion of the charcoal liruls its way into the combustion-
tube, a long, closely-fitting glass tube is dropped over the open
point of the combustion-tube. Sometimes, instead of connecting
the tube with an aspirator, air is drawn through the potash-
bulbs by the mouth, by means of a bulb-tube and caoutchouc.
The arrangement, when this ])lan is adopted, is shown in
Fig. 14. As soon as the bubbles passing through the potash-
apparatus no longer diminish in size, tlie current of air is
stopped, and the absorption vessels are ramoved, placed in the
balance case, and, after they are completely cold, their weight
ascertained.

Difficultly volatile and non-volatile liquids are w^eighed out in
short glass tubes open at one end. These are dropped into the
combustion-tube containing some copper oxide, more oxide
added, and then the liquid allowed to run out of the tube into
the oxide of co])per by cirefully sloping the tube. Volatile
liquids must bo w«»ighed out into a small weighed glass bulb
having long (»nds. One end is then broken ofi', an<l the end,
to]r(»tlu.'r with the bulb, alloweil to fall into the combustion-tube,
which is then iiHe<l with oxide of copper. The front of the tube
is first heated to redn(»ss, and afterwards the jwrtion in which the
bulb is placed, so that tlu; li<juid is driven out into the oxide of

I.IKBIG'S METUODS OF COMBrsTION -ANALYSIS u^

coiiper. The combustion is tbcu allowed to proceed in the
urdinary way,

lo his analyses of sugar, Licbtg obtained the following
results, which agree suflicieDtly well with the theoretical
numbers whea they arc re-calculated with the present atomic
weights ;

Carbon +171

Hydrogen 645

Oxygen 51-8*

100 on

44 Oas Coiiibastiun-fimmces. The use of charcoal has the
advantage that the temperature at the various parts of the tube
can be readily controlled, cither by removing or by fanning the
burning charcoal. On the other hand, its employment is accom-
paniod by several disadvantages, which led to the proposal to
replace charcoal by alcohol lamps. A furnace of this kind
constructed by Hess came into use, but was soon superseded
by gas combustion-furnaces when Bunseti introduced his non-
luininiius gas-burner. An ohl form nf gas-furnace introduced by

61 ILTIMATK OltGAXIC ANAIA'SIS.

V. Babo is sliowii in Fijj. lo. Krlciim oyer's furnace exhibited
iu Fig. 16 is luucli used at the present day. Its arrangement
13 reailily understood by refercDce to the figure. In order to
protect the combustion- tube front tlie direct action of the flame,
it is generally placed in a trough made either of fireclay, or of
iron lined with some calcined m:^Jnesia, and, for the purpose of
tlu-owing the hot gases of the flame on to the top of the tube.

tile;* ait.' pliRcl ■in tli:- sides and top of tlie furnaci.'. Erlenmcycr's
furnace iIih^s imt burn nnifh gju<, but ;;reit care must lie taken in
h<-atiij},' tin- tuln-, as it casilv < r,.i-ks unL-ss the temiH.'ratwre be
very;,'Ta,l.i,'.llyrrus<d.

This risk is much Irs-sencil in Ilofinaiin's form of furnace'
(b'igs. 17 and IS), in which a wcll-ditfnscd radiant heat, similar

GAS COMBUSTION-FURNACES.

to that obtaioed fruin red-hot charcoal, is produced by the igni-
tion of heated fireclay cylinders. The hollow cylinders are fixed
upon fish-tail gaa-biirners, and are closed at the top, the sides
being punctured with a large number of small opeuinga, at

which the gas burns mixed with air. In order to concentrate
the beat, plates of fireclay are placed at the sides and top of
the furnace.

Another form of combustion-furnace now much in vogue is
that proposed by Glaser ' mi<1 shown in
Fig. 19. It was first described by Donny,
and the combustion-tube is heatid by
means of perforated pieces of iron shown
ID the figure, forming a trough in which
the combustion-tube lies wound round with
iron gauze. Tlie tube is heated partly by
conduction from the hot iron and pitrtly by
the gas which burns through the perfora-
tions. Perforated clay covers arc employed
for raising and equalisinjj the temperaturt'.

45 Uomhustion in a Viirrejit of O.i-ygcn. When the combustion
is performed accordinjj to Liebig's original nietJiod, it sometimes
happens, especially in the case of bi:dius riuli in carbon, that
some of the carbon is deposited on the upper part of the tube
or even upon the reduced metallic copper, and this is otiiy m-
compietcly burnt v/hen air is passed over it. In order to avoid
' An.i. iiitm. Pkarm. Kuppl. vii. -IIS.

66 ULTIMATE ORGANIC ANALYSIS.

this source of error, some pieces of fused potassium chlorate, or
better, perchlorate, may be placed at the end of the tube, from
which a current of oxygen is evolved at the end of the operation.
When every precaution is taken, the combustion carried out in
this way yields satisfactory results. Thus, for example, the per-
centage of carbon ought never to be more than O'l to 0*05 below
the theoretical amount, whilst the hydrogen should not be more
than about 0*2 per cent, in excess of theory. By this plan, how-
ever, a new tube must be employed for each combustion, and
hence it was long ago proposed to conduct the combustion in a
stream of air or oxygen, and this method is now generally adopted.
Fig. 19 shows the arrangement of an apparatus for carrying out
a combustion of this kind. A tube open at both ends is used ;
one end is connected with the absorption-tubes, and the other
with a drying apparatus (a), through which either dry air or dry
oxygen can be pxssed. The part of the tube near the calcium
chloride tube is filled to two-thirds of its length with granulated
copper oxide, behind which the substance to be analysed is
placed in a platinum or porcelain boat. In front of, and in
connection with the absorption-tubes, is placed an aspirator (ii),
in order to ensure the passage of the products of combustion
through the absorption-tubes, and to prevent them by any
chance from passing into the drying apparatus. After the
copper oxide has been heated to redness, the substance is gra-
dually ignited, a slow current of air being at the same time
pissed through the apparatus from the gas-holder, in order to
carry the products of the combustion into the absorption- tubes.
As soon as the whole tube is red-hot, the current of air is
changed for one of oxygen. By this means any carbon left in
the platinum boat is completely burnt, and all the reiluced
copi)er is re-oxidised. This method is very convenient, as after
each combustion the apjxaratus is in exactly the same state as it
was before the experiment ; and as soon as it has cooled down a
new combustion may bo commenced.

According to this plan the whole of the apparatus is well
dried before the combustion, and henco we might suppose that
the hydrogen determination v.ould be more correct than by
the older process in which the hygroscopic copj)er oxide is
exposed to the air. Experience has, however, shown that this
is not the case, although no satisfactory expltmation for the fact
has been given. ^

COMBUSTION IN A CURRENT OF OXYGEN'. 67

58 ULTIMATE ORGANIC ANALYSI*5.

Another similarly unexplained occurrence in such combustions
is that that the first analyses are ahnost always incorrect, and
hence this method is to be recommended chiefly when a large
number of analyses have to be made quickly one after the
other. It is then ailvisable to make several combustions of

Fig. 20.

some such substance as sugar, for the purpose of getting the
tube into order, and as soon as a correct analysis is obtained the
apparatus is known to be in the right condition. In view of the
fact that the current of gas is constantly passing through the
tube, this method requires much more continued attention than
the combustion in closed tubes ; and this is especially the case
when easily volatile bodies, or bodies which evolve a large
([uantity of gaseous products, aie burnt. On the other hand,
the passage of a current of oxygen at the end of the operation
is a guarantee of the complete combustion of the substance.
For the above reasons combustions are carried out in some
laboratories in a close<l tube, and at the end of the operation
a, current of oxygen is passed over it, the end of the tube being
drawn out in the fonn shown in Fig. 20. The tube is filled, as
in Liebig's or Bunsen's method, with the oxide of copper
substance, and the combustion carried on in the way already
described. As soon as no further bubbles are seen to pass
through the potash apparatus the burners at the end of the
tube are turned down, and this end when cold joined to an
oxygen gasometer by a caoutchouc tube. The closed end of
the combustion-tube is then broken by squeezing with pliers,
and the oxygen allowed to pass slowly throui^h the tube until
the whole of the air has been displaced.

46 CombwUion of nitrofjencus substances. It has alreiuly been
mentionod that in the combustion of nitrogenous bodies, oxides of
nitrogen may be formed ; these will be partly absorbed by the
water and partly carried forward into the potash. It is to Gay-
Lussac that wo owe the suggestion of a method by means of
which carbon and hv<lroi:on contuned in nitro^jenous bcxlies can be
aocwM|y|^6temnn('d. Ah has ]>een stated, he en^.ployod copper

COMBUSTION OF NITROGENOUS SUBSTANCES. 59

oxide as an oxidising agent, and in order to prevent the forma-
tion of oxides of nitrogen finding their way into the measuring
apparatus he filled the front part of the tube with copper turn-
ings. Gay-Lussac carried on his combustion as we do now, and
in 1815 he succeeded in determining the composition of hydro-
cyanic acid, cyanogen gas, uric acid, &c. At a later date this
method was perfected in the classical investigation by Gay-
Lussac and Liebig on the fulminates.

If a nitrogenous substance has to be analysed, the tube is
filled in the usual way, a layer, of from 15 to 20 centimetres in
length, of metallic copper being placed in the front of the tube.
For this purpose either copper turnings may be employed, or the
metal obtained by reduction of the oxide in hydrogen. Some-
times a spiral of copper wire, or, more conveniently, a cylinder
of rolled- up copper gauze is used. The metal must be heated
to -bright redness before the combustion of the substance is com-
menced, in order to insure the complete decomposition of any
oxides of nitrogen which may pass over.

47 Comhustion of Bodies containing Sulplmr. Carbon com-
pounds containing sulphur yield on combustion sulphur di-
oxide, and this would of course be absorbed by the caustic
potash. In order to prevent this, Liebig and Wohler * proposed
to place a small tube containing dried lead dioxide or manganese
dioxide between the chloride of calcium tube and the potash-
bulbs. In passing over these oxides, the sulphur dioxide is
oxidised, the sulphate of lead or of manganese being formed.
Carius ^ proved, however, that when a substance which contains
much sulphur is thus burnt, the oxides of sulphur are not
wholly absorbed, and Buiisen has observed that the above per-
oxides may absorb some carbon dioxide. Hence it is advisable
to burn bodies containing sulphur by means of lead chromate, a
substance which was first used in organic analysis by Berzelius'
in 1838 for the purpose of preventing the formation of carbon
monoxide in the combustion. If care be taken not to heat the
front part of the tube too strongly the whole of the sulphur
dioxide remains, in this case, in the combustion-tube in the
form of lead sulphate.

48 Use of Lead Chromate in Combustions. Lead chromate is
aUo employed in sevenil other cases instead of copper oxide.

* jinn. Pharm. xxvi. 270. ' Ann. Chew. Phami. cxvi. 28.

^ roj/7. Ann. xliv. 301

60 ULTIMATE ORGANIC ANALYSIS.

For the purpose of preparing this compound a solution of lead
acetate is mixed with one of potassium dichromate, the pre-
cipitate well washed, and the dried substance fused at as low a
temperature as possible, and powdered after cooling. Lead
chromate possesses an advantage over copi>er oxide in not
being hygroscopic. It also fuses readily, and hence it is especi-
ally valuable for the analysis of bixlies very rich in carbon
or of those from which carbon readily separates, and in these
cases it is advisable to add to it a small quantity of potassium
' dichromate. It is also used for the combustion of organic salts
of the alkalis and alkaline earths, as these when heated in an
atmosphere of carbon dioxide leave a residue of carbonates.

When the sjime load chromate has been fre([uently employed
for combustion, and a large quantity of chromic oxide and
metallic load has been formed, it may readily be oxidised by
moistening with nitric acid, drying and fusing.

If an organic substance containing an element of the
chlorine group be burnt with copper oxide it may happen that a
iwrtion of the chlorine is set free and this may condense in the
absorption-tubes. In order to avoid this, lead chromate is used,
in which case the haloid salt of lead is formed. Such a com-
bustion may however be carried on with copper oxide if a spiral
of metallic copper bo placed in the front of the tube, and if
tliis bo heated not too strongly. As the above cuprous com-
])0unds are however tolerably easily volatile, they are sometimes
carried forward into the chloride of calcium tube.^ Moreover
those halogen elements may be given off from the cuprous salt
when oxygen is passed over the substance. Hence it is better
in such cases to employ a spiral of fine si Ivor wire or silver foil
instead of copper.-

When a comiMMiml containing mercury is to be burnt, a cop]Xir
spiral is also placed in front of the tube and this must be only
very giintly heati'd, otherwise the deposited mercury may be
volatilised ami pass into the weighed tube.

49 ^h'fjunic AfH//i/sis hi/ mt'an.-i nf Platinum. This metal in its
finely-divi<lod st-ite is well known to i>ossess the power of con-
densing oxygon in lar^^e (luantity, and of giving it up again to
rondmstiblo l)«Mlies. l'^jH)n this tact F. Kopfor'* has foun<led
a method of analysis capable of very gtMiornl application, and

' St iililiT. .III/'. f%in. Pluimi. Ixix. :Vj5.
- IvMut. 'A'iishi'. ,t,\,i}, n„',n, ii. UJi.
' J'nirtt. t'hrni A'"-, xxix. «>•;•».

ORGANIC ANALYSIS BY MEANS OF PLATINUM.

characterised by its exactitude, especially in the determination
of hydrogen, as well as by its simplicity and convenience. The
combustion is carried on in a current of oxygen gas in a tube
open, at both ends about 1*5 cm. in diameter, Fig. 21. At a^,
a,2 and a^ are placed plugs of asbestos wound round with fine
platinum wire, of which the end ones sit loosely in the tube,
whilst fltj is fastened more firmly, and this, in order to prevent
the passage being stopped by volatile bodies, has a prismatic
form. The space between a^ and a^ is filled with an intimate
mixture of about 10 grams of platinum-black^ and the re-
quisite quantity of freshly ignited and woolly asbestos. This
mixture, which is easily obtained by simply shaking up the
two materials in a bottle together, possesses a large amount of

«em.^

so cm

10 cm

I •

It I ■

item

Fig. 21.

30 cm

surface for the mass of the body, and therefore acts very quickly.
Between a^ and a^ is placed the boat or tube containing the
substance. The combustion-tube between a^ and h is sur-
rounded with a double cover of brass wire gauze, whilst that
between h and c is placed in a trough of double wire gauze.
Either air or oxygen may be employed for the purpose of carry-
ing on the combustion. For purifying and drying the gas
Kopfer used a very convenient apparatus. The gases pass
first through a Liebig's potash-bulb containing a fifty per cent,
solution of caustic potash, and from this so small a quantity of
water evaporates that for the purpose of drying only short
chloride of calcium tubes are employed, and these may be used
for a len'jth of time. The combustion furnace is composed of

* In order to prepare this substance, a qnantity of platinum chloride contain -
in;? about 10 grains of metal is heat<'d to boiling with 25 grams of ])ure caustic
f.otash, dissolved in 400 cc. of water. This is then added to a boiling solution
of 10 grams of grape sugar in 400 cc. of water and the whole boiled for a few
minutes.

62 ULTLMATK ORGANIC ANALYSIS.

two moveable boxes of sheet iron of which the first carries four
burners, and the last only one (/), moveable in a slot (Fig. 22).
In order to carry out the combustion the tube is first filled w^ith
oxygen, and then the current so regulated that two bubbles
pass through per second. At this point the four front burners
are lighted, and the substance heated, beginning from c (Fig. 22).
in the direction shown by the arrow, for the purpose of allowing
the greater part of the volatile pro<lucts to condense between
flg and h, a small portion only, passing over the heated
platinum and being completely burnt. The position of the
burner / is then so placed that the combustion goes on regularly.
When a quantity of carbon has separated out, or when diffi-
cultly volatile substances have sublimed between the parts a
and />, a piece of wire gauze is placed over the tube, and this
portion is heated to redness. When the combustion is complete,
the oxygen ij replaced by air, and a new analysis may then be
begun as soon as the tube has cooled. In the case of very easily
oxidisable substances a very vigorous combustion often takes
place about a^, the platinum-b!ack being thereby heated to
redness. In such a case the oxidation must be regulated by
pushing the burner in the opposite direction to that shown
by the arrow.

Should t!ie substance contain the elements of the chlorine
group, fifteen ^;rams of thin silver foil cut into small four-sided
pieces must be mi.xed with the platinum -asbestos. After the
combustion it is then ignited in a current of hydrogen in which
the tube \?> allowed to cool, and lastly it is heated in a rapid
current of air when the apparatus is ready to bc» employed for
a new analvsis.

Compounds which contain nitrogen or sulphur are burnt by
bringing into the front part of the tube a layer of lead dioxide *
about 10 cm. long, and surrounded by an air-bath, the bottom of
which consists of three pieces of brass wire gauze, and the top of
which contains two such layers whereby the temperature is
regulated. This is showTi in Fig 23. It is then heated for an
hour to a temperature of 150*" to 200°, pure carbon dioxide
passed through, and histly this replaced by dry air. During
the combustion the lead dioxide is kept at the same tempera-
ture, when the sulphur is entirely held bjick in the fonn of

' This is l>ost obtaiii(>«l l»y boiling pure rod lead with nitric acid. The residue
i8 first wiwhed with hot dilute nitric arid, and then >iith hot water, and, after
drying on a wator«bath, is broken into small pieces.

KOPFER-S METHOD OP COHBUSTIOX-ANALYSIS. C3

64 ULTIMATK OliGANIC ANALYSIS.

8iil])hatc, au<l nitrogen iu the foim uf uitrute. If, in adJitiou
to these, the substanco contiiius the elements of the chlorine
group, asbestos contaiiiiii',' silver foil must likewise be employed.

DETERMINATION OF NITROGEN.

50 Detection of Nitrojien. ^lany orguiiic bxiios coiitaiiiiiig
nitri>gen, when hcateil with an alkali, evolve either ammonia or
a compound ammonia. Tlie pi-esi-iice i>f these substances may
be (leteeteil by their smull, by tlicii- alkaline reaction, and by
their iiroiH.Tty of yieliling a thick eloml when l>rouj;lit into
contaet with hydriH-hloric acid. The presence of nitrogen can
thus bo readily detected. If however the i^nantity of nitrogen
be but small it may tVius eacajK- ileti!Cti<>n. Moieover a large
iiumhtT "f carbon eomixmnils exi.-it of artificial origin, obtained
by the action of nitric acid or of the oxide* of nitrogen, and
tlie.-ie do not, as a rule, yield ammonia when ignited with an
iilkali.

The smallest trace of nitro;jen can however bo cleteoted in
every case by a niethinl iin)i>osi-d by Las.iaignc' Kor this purpose
tho body is heated in a small tube with metallic sudium. If
the suhhtancc W explosive it nuist bo mixed Inloreliand with

ESTIMATION OF NITROGEN. 05

dry carbonate of soda. In most cases a slight detonation takes
place with separation of carbon. The mixture is then heated
more strongly in order to volatilise the sodium, the mass allowed
to cool, the residue dissolved in water and filtered. The filtrate
which contains cyanide of sodium is then mixed with a solution
of ferrous sulphate which has undergone partial oxidation in the
air, and acidified with dilute sulphuric acid. If a large quantity
of nitrogen be contained in the organic body, an immediate
precipitate of Russian blue is thrown down. If, however,
only smaU traces of nitrogen be present, the acidified liquid
becomes green, and after a time a blue flocculent precipitate
is observed.

51 Estimation of Nitrogen, For the purpose of determining
nitrogen quantitatively, two methods are employed. It may
be obtained either in the form of ammonia or of a compound
ammonia, or it may be liberated and the volume of nitrogen
gas determined.

Will and VarrerUrapp' s Method, The first method, for which
we are indebted to the above-named chemists,^ is by far the
simplest, and it is, therefore, employed in all those cases in which
it is possible to do so. It depends on the fact already mentioned,
first observed by Dumas, that nitrogenous bodies when heated
with an alkali form ammonia, the carbon being oxidised and
the nascent hydrogen uniting with the nitrogen.

C + 4K0H = CO, + 2K,0 + 4H.

K an excess of hydrogen be formed at the same time, it is
either evolved as such or in the form of hydrocarbons. Wohler
and Liebig proposed to employ this for the determination of
nitrogen, and the above-named pupils of Liebig worked out
the process in the exact form in which it is now so much used.
Soda-lime is employed as the alkali, as it does not attack the
glass. This is obtained by slaking two parts of quicklime with
a solution of one part of caustic soda and gently igniting the
mixture. In the process of analysis, soda-lime is brought into
a small combustion tube (a, Fig. 24), and the substance well
mixed with it in the tube, which is then filled up to the end
with pure soda-lime. The tube is then tapped so as to open a

* Ann. Chcm. Phann. xxxix. 257.

ULTIMATE OKGANIC ANALYSIS.

channel at the top, and attached to tlie bulb-apparatus (b),
coDtainiug dilute hydrochloric acid, so airangod that the liquid

Kio. ai.

can neither be blown out by tlie rapid currant of gas nor drawn

back into the tube, if an absorption should take place. Auotlier

bulb-apparatu3 which perhaps secures this

' "^ end more certainly has been proposed by

/^ / Arendt and Knop, and shown in Fig. 25.

^JP' / When the wlinle apparatus is arranged,

Cv Lj *'"^ front layer of soda-lime is ignited, and
T^^l^y^ the mixture of the substance with soda-lime

Fiii. 2S, is then gradually heated. At the end of the

operation tho point is broken, and air drawn
through the ap]>nratus cither by means of the mouth or by an
aspirator, in older to bring tlie whole of the ammonia into
the hydrocldoric acid. The residue left in the tnbe should
be white, and to effect this, tlie tube rcijuires to be jiretty
strongly heated so that any carbon containing nitrogen, or any
cyanogen compounds, may be completely burnt.

Nitrogenous liquids are weighed out in bulb-tubes and treated
in the same way as in the carbon and hydmi^en deter mi nation.
In place of soda-lime a mixture of oipial jiarta of iwiwdorcd
quicklime and soda may, in many cases, be cmpJoyed.' In case
of bodies which contain large quantities of nitrogen, and which
therefore evolve a large quantity of ammonia, it n:ay happen
that, in spite of all care, the acid passes back into tho red-hot
tube. This may Ive jirevented simply by mixing the substance
with some sngar in order that the amnjonia may l>e dilutcil
with hydrogen or some hydrocarbon. The hydrochlmic acid
is then eva|«. rated on a water-bath ivitli an excess of )>latini(;
chl'>ri<l.', and the residti-! thrown on ti. ;i rtlt.r and washed with

DETERMINATION OF KITHOGKN. 67

ether to which only a few drops of alcohol liavo boeu added,
because Hofmann has shown that tlio double plutiuum salts of
the compound ammonias are frequently rather soluble in alcohol.
The residue on the filter is then dried at 100° and weighed.
It ia then ignited and the weight of the residual platinum
ghtaiued. From this it is easy to calculate the quantity of
nitrogen, because all theso platinum double salts coutain two
atoms of nitrogen to one atom of the platiimin. The comparison
of the weight of the double salt with that of platinum is in
many cases of importance, fur by this means we ascertain
whether ammonia or a compound ammonia has been formed.

52 Lubig's Etlative Method. It has already been stated that
Gay-Lussac was the first to employ copper oxide aud metallic
copper in the analysis of nitrojjenoiis cuinpoiiiid;f. Ho collected

t'lu. 213.

the products of combustion over mercury, aud determined the
Tolame of the carbon dioxide aud thut of the free uitii';,'oii by
absorbing the first of these gases with alkali. U:iy-Liia^io
and Liebig, in their investigation on fulminic acid, porfirtod
thifl method, and the latter founded on this bis niethoil for
the relative determination of nitrogen. For tliia purpose an
nnweigbed quantity of the body, mixed with about fifty times
its weight of oxide of copper, is brought into the conibnstion-
tabe, which is closed at the end and half filled with the mixture.
lu the next fourth part of the tube, pure oxide of copper is
added, the last quarter being filled with metallic copper and the
Open end of the tube being furni.shed with a gas-delivery tube.
"Die metallic copper is first heated to re(hiess ; next the furtlier
portion of the combustion-tube is heatcfl, in onler to expel the
nhole of the air contained iu the tube by means of the ga.'*es
evolved during the combustion ; the ignition ia slowly earned
fiirward, and the gases are collected in small graduated tubes
■»ver mercury, as shown iu Fig. 2G. In order to ascertain the

ULTIMATE ORGANIC ANALYSIS.

I'lo. 27.

relation between the carbon dioxide and nitrogen in this gaseous
mixture, the tubes are brought one after the other into a cylinder

filled with mercury (Fig. 27),

and fixed in such a position

that the level of the mercury

inside and outside the tube is

the same. The volume of the

iraseous mixture is then read

oflf, a small quantity of caustic

potash solution blown into the

tube by means of

the pipette (Fig. 28),

and after this has

been moved slowly

up and down in the

tube, the whole of

the carbon dioxide

is absorbed. As soon

Fig. 28. ^^ ^^^^ ^^ eflfected,
the level of the
mercury inside and outside is again equalised, and the volume
of the nitrogen read off, and thus the relation l)etween it and
the carbon dioxide ascertained. The first tube may contain
a small ([uantity of air ; the later ones, on the other hand,
ought, if the experiment has been properly conducted, to yield
identical results.

If the amount of carbon contained in the substance has l)een
previously determined by combustion -analysis, it is easy to
ascertain the absolute amount of nitrogen from the relative
volumes of the carlxm dioxide and nitrogen. This method of
Liebig's for the relative determination of nitrogen is simply
and easily carried out, but only yields, as he himself remarks,
accurate results when the substance does not contain more than
four at<^>ms of carbon to one of nitrogen. Moreover, it possesses
the disiid vantage common to the t>ther relative methods,^ that
the determiijation of the nitrogen is entirely dependent on that
of the carbon.

S3 BiniM'ii'.^ lulntivr Mdhod. Bunsen ^ has proiX)sed another
method of nitrogen determination esjKJcially valuable for the

* Marrhnml, JoHrn. Pr. f'hem. xli. 177; Gottlieb, Ann. Chnn, Pharm.
Ixxviii. 241 : Simppon, ihid. xrv. 03.

BUNSENS HELATIVK METHOD.

analysis of such a substance an gun-cotton, in which the nitrogen
can in fact not be determined by any other method. For this

purpose about five grams of copper oxide and from 03 to 04
gram of the substance mixed with some metallic copper arc

TLTIMATE riHGAXIC ANALYSIS.

placed in a combustion-tube closed at one end, about 50 centi-
metres in length, and having a diameter of about 3 centimetres.
The other end of the tube is then drawn out to a fine but strong
point, as shown in Fig. 32, which is carefully fused after the

whole apparatus has been filled with
«lry hydrogen, and this gas has then
been removed for the most part by
means of an air-pump, the arrange-
ment for this purpose being represented
in Fig. 20. The tubes are then placed
in an iron trough (Figs. 30 and 31),
filled with a paste of pLister of Paris
and water, and when after the lapse
of about an hour this has set, the
whole is heated to dull redness. After
Fig. 82. cooling, the drawn out end is broken

under an eudiometer, and the gas
determined by eudiometric methods.

In order to carry out these operations successfully, a con-
siderable amount of practice and great manual dexterity are
needed ; and hence, in those cases to which the easy method
of Varrentrapp and Will is inapplicable, the process which is
usually adopted is the method of the absolute determination
of nitrogen, known as Dumas's method.

54 Dumas Absolute Method. Into a combustion-tube, closed
at one end, a compound is first brought which easily gives
oflF carbon dioxide on heating. For this purpose either copper
carbonate or white-lead may be employed. Then comes a short
layer of copper oxide, then the mixture of the substance with
copper oxide, and next a long layer of pure copper oxide, and
lastly, in the front part of the tube, a spiral of metallic copper.
By heating the further end of the tube the whole of the air
is completely driven out, being replaced by carbon dioxide, and
this operation may be hastened by adopting Bunsen's sugges-
tion of placing the tube in connection with an air-pump. The
conil)U8tion-tul>e is then fitted with a gas-delivery tube, in order
to enable the products of combustion to pass into the graduated
cylinder over mercury (Fig. 33). When the whole tube has been
i.jnite(l, the gaseous products of combustion contained in the
tube arc driven forward by the evolution of carbon dioxide from
the matericil placed at the end, the whole of this latter gas
being absorbed by the caustic potash solution contained in the

METHODS OF DUMAS AND SIMPSON.

', BO tliat tbo resitlual gas cousists of pure nitrogen. Id
order to determine the volume of this latter, the measuring
tube is withdrawn from the mercury b; mcaus of a small dish
filled witli mercury placed underneath, and brought into a high
cylinder filled with water. The dish ia then removed, and the
cylinder allowed to remain in position until it has attained the
temperature of the surrounding air. As soon as the level of
the water has become constant, the height of the menifcus is
read off, and from this the volume of gas determined.

A disadvantage attaches to this process, inasmuch as in the
analysis of bodies rich in carbon it may easily happen that a
separation of carbon takes place, which may still contain nitro-
gen, and if this be deposited on the upper i>ortions of the eom-
bustion-tube or on the metallic copper, it cannot be completely
burnt. In afldition to this, some quantity of carbon monoxide
may possibly be formed.

55 Simpson's Method.' This method is not open to the above
objections, and yields accurate results. It is, in fact, a
modification of Dumas' method, and is now frequently employed.
For the purpose of evolving carbon dioxide. Maxwell Simpson
recommends the use of carbonate of manganese, but in place of
this it is more convenient to employ magnesite in lumps about
the size of a pea. A layer of about 10 centimetres of this is
placed at the end of the tube, then a mixture of mercuric oxide
and copper oxide, this mixture being separated from the mag-
nesite by a plug of asbestos. In other respects the tube is

' Chtm, Sof. Jaum. vi, 2S0,

72 ULTIMATE ORGANIC ANALYSIS.

filled as described under Dumas' method. The copper spiral
should be about 20 centimetres in length, for the purpose not
only of decomposing the whole of the oxides of nitrogen which
are formed, but also to absorb any excess of oxygen which may
come oflf. The portion of the tube containing the carbonate is
first gently heated, and as soon as the evolution of gas becomes
rapid, the front part of the tube containing the copper spiral is
heated until all the air is driven out of the apparatus, which is
readily ascertained by collecting the gases from time to time in
a test-tube over mercury and adding a small quantity of caustic
potash. As soon as the absorption is complete, the combustion
may be proceeded with. The further end of the tube is allowed
to cool, and the tube slowly heated from the front towards the
back. The gases evolved are collected over mercury in a pear-
shaped vessel (Fig. 34) containing caustic potash. As soon as
the whole tube is red-hot, and no further evolution of gas is
noticed, the gases contained in the tube are swept forward by
re-heating the carbonate contained at the closed end. The
nitrogen is next transferred to an accurately calibrated eudio-
meter, by a process which is rendered sufficiently evident by
Fig. 3o, and as soon as the caustic potash solution is seen to
ascend into the capillary gas-delivery tube, no more mercury is
poured in, and thus the exact volume of nitrogen evolved is
brought into the eudiometer.

Zulkowsky^ has recently described another simpler collecting
apparatus, which avoids the use of mercury, and renders it
possible to work rapidly. It consists of two tubes of about 5S
centimetres in length (a and B, Fig. 36), of which the former
is graduated, and serves for collecting and measuring the gas,
whilst the latter is open at the bottom, and serves for filling in
the caustic potash. Both tubes are held by means of supports
(Kj and k) in a vertical position, and are connected with one
another by the caoutchouc tube. Two fmall tubes {c and r^)
are fused on to tliese tubes. The first of these is connected by
means of a caoutchouc tube with the combustion-tube, and can
be closed by the pinchcock /. The second small tube serves
for letting out the caustic potash, and is also funiishcd with a
pinchcock (r). The small bulbs // contain a few drops of mer-
cury, and .«crve as a safety valve, in order to prevent the caustic
potash solution from passing back into the combustion-tube in

' Lichvjs Annnhn^ clxxxii. 206.

SIMPSON'S NITROGEN DETERMINATION.

case of a slow evoIutioD of gas. When a oitrogen determinatioa
has to be made, the measuring tube is takeu out of the clamp

K, and brought into the position shown in the right-hand figure.
Caustic potaah is then poured in, and if the caoutchouc tube A

ULTIMATE ORGANIC ANALYSIS.

be wide enough, this readily flows down so as to fill the whole
of the tube. The apparatus is now connected with the com-
bustion-tube, and the hinder portion of that tube heated so as
to drive out the air. This is collected in the measuring tube,

Fio. 3G.

and is from time to time allowed to pass out by bringing it into
the position shown at the right hand of the figure. As soon as
the whole of the air has been driven out, the combustion is
carried on in the usual way. The nitrogen is collected in the
measuring tube, and the caustic potash is driven into the second

DETER^UNATION OF CHLORINE. 75

tube, from which, in order to diminish the pressure, it is from
time to time drawn ofiF. When the combustion has been com-
pleted, the apparatus is disconnected from the combustion-tube,
and brought into a situation where the temperature is tolerably
constant, allowed to stand, the temperature of the caustic
potash then determined, and the level of the liquids in the two
tubes equalised by allowing the solution to flow out through
the tube c^. The volume of the gas, thus placed under the
atmospheric pressure, is then read off.

In some rare cases the formation of nitric oxide cannot be
altogether avoided in Dumas' process. It is then necessary to
collect the gas over ferrous sulphate, and to allow for the volume
of this gas thus absorbed.^

Several suggestions have been made for the purpose of
deteruiiniug nitrogen together with carbon and hydrogen u\
a single combustion. The method proposed for this purpose
by Pfliiger* can here be only shortly mentioned. He carries
on the combustion in a vacuous space, and determines gravi-
metrically the quantity of water formed, whilst that of the
carbon dioxide and nitrogen is ascertained by volumetric
measurementfi.

DETERMINATION OP CHLORINE, BROMINE,

AND IODINE.

56 These elements may be determined easily and rapidly by
igniting the substance with pure quicklime. For this purpose,
a narrow combustion-tube about 45 centimetres long is closed
at one end, and into this some quicklime is brought, and then
the substance either mixed beforehand with lime or weighed
out in a small bulb, and this is dropped on to the lime. A
channel is next made at the top by tapping the horizontal tube,
and then the mixture, commencing at the open end, is heated.
When the whole has been ignited and allowed to cool, the
contents of the tube are brought into a flask containing
water. Care must be taken that the material is not thrown
out by the violent slaking of the lime. The whole is then

^ Frankland, Ann. Chem. Phann, xcix. 350.
» Pfliiger's Arch, gcs, Phys. 1878, 117.

7G ULTIMATE ORGANIC ANALYSIS.

made sligJitly acid with dilute nitric acid, and the tube washed
out first with w^ater and then with dilute nitric acid. After
lilteriji^ and washing the residue, the halogens are precipitated
by tsUmr nitrate in the slightly acidified solution.

It s^^metimes happens in the analysis of compounds containing
i^xline that this element separates out on the addition of nitric
acid. In this case it is, therefore, better to dissolve out with
water, to wash, and to add silver nitrate to the filtrate, and
then tr> dissolve out the residue in acid, and add the filtrate
to the first liquid.

Tlie decomposition of very volatile bodies which contain
clilorinc or bromine may be readily eflfected according to Piria's
plan, which has been somewhat improved by Hugo Schiflf.^
Th<? substance is placed in a small platinum crucible with a
uiixiurts of 1 part of anhydrous sodium carbonate and from
4 i/j 5 fiarts of lime. It is then covered with a large crucible,
uwl lh<5 two brought into such a position that the small crucible
iufH iij the large one with its mouth downwards. The space
IMw*;<'Ii the two crucibles h then filled up with the alkaline
f/iixtiinr, the cover placed on the larger crucible, and the whole
\it:iiUu\ it) redness. Substances containing iodine cannot however
Uj ;irialys<;d according to this method, as calcium iodate is
formed, but the determination of iodine may be carried out
if W9^\\^\u\ carbonate alone be employed.

57 CariuHS Mctlwd. In this method,- which is applicable to
all cases in which the haloid element is easily removed, the
siiliMtance is weighed out in thin glass bulbs. The form of bulb
(fif wAiA Iiodi<»s is seen in Fig. 37, whilst Fig. 38 exhibits that in
whieh liquids are contained. These bulbs are then brought
int/i a gl/iss tube half filled with a solution of silver nitrate in
nitric a^iid having a specific gravity of 1*2. The open end of
the tu^ie is then drawn out to a capillary point and the liquid
SytWivA until all air has been expelled. After this the pbint is
tnmaX and allowed to cool (Fig. 39). The bulb is then broken by
Amkiuy^ the tube, and the whole heated gradually in an air-bath
(Fig, 4U), Ui a temperature varying, according to the nature of
iUit mi\mUi\mt, from 150'' to 200^ In the case of bodies rich
ilj carUiri which undergo oxidation with difiSculty, nitric acid
</f %\nMtic (gravity 1*4 nmst be used, and a small quantity of

* MbiffM Ann. cxcv. 293.

* Ann, Chem. Pharm. rxri. I ; cTXXvi. 129.

DETEEMINATION OF CHLORINE.

potassium dichroniate added. As soon as the whole of the
organic substance has disappeared, the tube ia allowed to cool,
the capillary end is carefully softened in the gas-flame so that

a very small opening appears, tli rough wliich the carbon
dioxide formed is allowed to escape, but so that tlic liquid
is not thrown forward. The haloid salts of silver which are

f>rmed in this decomposition are then bronjiiit on to a filtor,
together with the remains of the glass bulb, and these are
weigh «1 togetlier.

78 ULTIMATE ORGANIC ANALYSIS.

DETERMINATION OF SULPHUR.

58 For the purpose of determining sulphur in compounds
which are not volatile, these are fused, according to Liebig's pro-
posal/ with caustic potash and nitre in a silver basin, and the
mass allowed to cool as soon as it has become white. It is then
dissolved in water, acidified with nitric acid, precipitated with
barium chloride, and the precipitate treated in the usual way.

Volatile sulphur compounds are oxidised by a method
analogous to that described for chlorine compounds. They are
placed in a combustion-tube with a mixture of sodium carbonate
and nitre, or, according to Kolbe's^ process, with potassium
chlorate.

Debus's * method may also be employed, in which a mixture
of carbonate of soda and potassium dichromato is used, or that
proposed by Otto, in which pure cupric chromate is employed,
lu all these cases sulphates are obtained, and their amount
determined in the usual way.

Another good method is that proposed by Russell.* In a
combustion-tube closed at one end, from two to three grams
of mercuric oxide are brought ; then a mixture of the sub-
s*mice with mercuric oxide and sodium carbonate, and lastly
only the latter substance. The combustion-tube is then
furnished with a gas-delivery tube, in order to condense the
vai)ours of mercury and of water, and the combustion is carried
on as usual from back to front. After the ignition the contents
of the tube are thrown into water, and the solution acidified
with hydrochloric acid. In order to ascertain that no sodium
sulphide has been formed, a drop or two of mercuric chloride
is added. If no dark precipitate is formed, the solution is
precipitated with sodium carbonate.

Lastly a method has been suggested by Carius depending on
the fact that the substance can be oxidised in a closed tube
with nitric acid, sulphuric acid being formctl. Sometimes it is
necessary to add a small cpiantity of i>ola?sium dichroniate.

' Ifatulwiirtr.i'luch^ i. 8S7.
' IfandtrHrfrrhurh, Siipitl. 20.'».
' Ann, C/icm, Phann, Ixxvi. 1»0.
* i^hiart, Jourf. (%:ni. 6V. vii. '21 J.

DETERMINATION OF PHOSPHORUS.

59 Organic substances containing phosphorus are ignited with
sodium carbonate and nitre or potassium chlorate, in order to
form a phosphate. They may also be oxidised with fuming
uitric acid, when phosphoric acid is obtained. According to
Carius a useful oxidising mixture is sulphuric acid and iodate
of silver, the two being hejited with the substance to 180°.
After the liquid has cooled and is diluted with water, it is
filtered, and some sulphurous acid added to the filtrate, in order
to precipitate any dissolved silver iodate, and thus a solution
of phosphoric acid is obtained, which (as in the other cases) is
determined in the usual way.

DETERMINATION OF OTHER ELEMENTS.

60 In order to determine any of the other elements (with
the exception of oxygen), it is usually necessary to ignite the
organic substance either by itself or mixed with nitre, or else to
destroy the substance completely by heating it with nitric acid.
Tlie element which it is then desired to determine is brought
into solution in the usual way and determined by suitable
methods.

In the case of salts of organic acids, the metal may generally
be determined as in its organic compounds. In some instances,
indeed, the method employed may be simpler. This is the case
in the organic compounds of gold, platinum, and silver, which
only require to be ignited in order to leave the metal in the
pure state in a condition in which it may bo weighed.

The salts of other metals leave on ignition a residue of oxide
or carbonate, or sometimes of the metal mixed with carbon.
These are then brought into solution and determined in the
osiial way.

80 CALCULATION OF ANALYSES.

DETERMINATION OF OXYGEN.

6i This element is very seldom determined directly, its
amount being usually obtained after the percentage of all the
other elements has been determined, for if these numbers do not
add up to 100, the difference is usually taken to be the percent-
age of oxygen. It is however in this case absolutely necessary
that we should know positively what other elements are present,
and that the amount of each of these should be. determined as
accurately as possible, for if one be overlooked, the results of
the analysis will, of course, lead to totally incorrect fomiulaj.

A classical example of this kind of error is that of the
analysis of taurine, a crystalline compound occurring in the
animal kingdom. The formula CgH^NOg was long adopted as
expressing the composition of this substance, until Redtenbacher
found that the body contained sulphur. The reason of the non-
detection of the sulphur was, that both in constitution and in
properties taurine differed from all the sulphur compounds then
known. Moreover, the apparent truth of this formula could be
upheld with some show of reason, inasmuch as the atomic weight
of sulphur is double that of oxygen, and when the amount of
the sulphur was ascertained, the formula of the substance was
shown to be C^H-NO.jS. A method for the direct determina-
tion of oxygen is, therefore, much to be desired, not only for
the purpose of avoiding errors of this kind, but also because
such a determination would serve as a valuable control of the
correctness of the analysis.

Unfortunately, none of the various methods which have been
as yet proposed for this purpose have come into general use,
and the reader is referred to the original papers in which these
proposals arc described.'

CALCULATION OF ANALYSES.

6a Percentage Composition, When a substance has been com-
pletely analysed, its j^ercentage composition is calculated. The
following examples illustrate the nature of this simple operation.

* Wanklyn nnd Frank, Phil, Mag, [4] xxvi. 554 ; Baunihauer, ZciUtch, anal,
M, 1866, 114 ; I>adenl)iirg, Ann, Chein, Phann. cxxxv. 1 ; Mitscherlich,
Ann, C3UEX. 536 : Trcticr, Zcitsch, anal. Chem. 1874, 1.

MOLECULAR WEIGHT DETERMraATION. 81

Example No, 1. 0*146 of a volatile liquid burnt with copper
oxide yielded 0'449 of carbon dioxide and 0*2135 of water.

Now as 43*89 parts by weight of carbon dioxide contain
11*97 parts by weight of carbon, and as these numbers stand
almost exactly in the proportion of 11 to 3, the quantity of
carbon may be obtained by the fraction —

0-449 X 3 X 100 ^^ ^^

= 83-87.

0146 X 11

For the purpose of obtaining the percentage of hydrogen we
have the following expression :

0-2135x100
U*l4t) X 9 ~ ^^'^^•

Hence the compound is a hydrocarbon having the compo-
sition—

Carbon 83*87

Hydrogen .... 16*25

100*12.

Example No, 2. 0*2607 of aurin, a red colouring matter,
yielded 0*7515 carbon dioxide: and 0*1152 water.
Hence 100 parts contain

Carbon 78-61

Hydrogen .... 4*91.

But, as these numbers do not add up to 100, and as the
qualitative analysis has shown that it contains nothing but
carbon, hydrogen, and oxygen, inasmuch as the substance,
when heated, yields water on decomposition, it follows that the
percentage composition is :

Carbon 78*61

Hydrogen .... 491
Oxygen 16*48

100-00.

Example No. 3. (1) 0*3827 of caffeine yielded 06948 of
carbon dioxide and 0*1800 water. (2) By Will and Varrentrapp's
method, 0*1350 of caffeine yielded 0*2750 of platinum.

It has already been stated that one atom of platinum

82 CALCULATION OF ANALYSES.

corresponds to two atoms of nitrogen, and hence the percentage
of nitrogen is :

0-2750 xJS^xlOO

' U1350 X 1967 -2^*^^-

If now the amount of carbon and hydrogen be calculated
from the above analytical results, numbers are obtained which
do not add up to 100, and as no other element can be detected,
the diflference between the amount thus found and 100 must be
the quantity of oxygen caffeine contains. Hence the percentage
composition of the substance is :

Carbon 49-51

Hydrogen .... 5*22

Nitrogen 2899

Oxygen 1628

100-00.

In a deteiTnination of the nitrogen contained in caffeine ac-
cording to Liebig's relative method, it was found that the
gaseous mixture consisted of one volume of nitrogen to four
volumes of carbon dioxide. Hence caffeine must contain one
atom of nitrogen to every two atoms of carbon, and the
percentage of nitrogen is found by the equation :

40-51 X 14

" 24 -28-88.

If the amount of nitrogen be determined ajs gas, the volume
of the dry gas is ascertained at 0"" and 760° from the well-known
formula :

_ viv-n _

760 (1 + 0-003665 x 0'

when / signifies the tension of the vap<;ur of water. As
we know that 1 cbc. uf nitrogen under the above conditions
weighs 000125 gram, it is easy to dotermine the weight of
nitrogen contained in 100 part.-^ of tlie compound.

CALCULATION OF FORMULA.

63 Having ascertained the pcrc(»iitage cc^mposition, the next
point to determine is the formula of tlie compound. In the
case of inorganic compounds the numerical relation in which

CALCULATION OF FORMULA. 83

the various constituent atoms stand to one another can be

readily ascertained. In the case, however, of the much more

complicated compounds of the organic branch of the science,

this cannot be so readily done. Thus, for instance, in the case

of caffeine we have :

49-51 ^ , „
= 413

12
5-22
1
28-99

16-28

= 5-22

= 207
= 102.

These numbers stand in the relation of 4, 5, 2, 1. As, how-
ever, the sum of the monad atoms must be an even number,
we are obliged to take as the simplest formula CgHj^jN^Og.

If, according to the same plan, we calculate the formula of
the volatile hydrocarbon whose analysis has been given in
Example No. 1, we find that this is a paraffin, but which of the
paraffins it is remains doubtful, for, as the following calcu-
lated results show, this compound may be one of at least three ;
inasmuch as the composition of each of these bodies does not
differ from that of the other, more widely than the results of
several analyses of one and the same substance are often found
to do.

Hezane. Heptane. Octane.

Carbon . . 8372 84*0 84*21

Hydrogen .1628 16*0 1579

100-00 100-00 10000.

Again, in other cases, analysis gives no assistance whatever in
the determination of the formula. Thus, for instance, a very
large number of different formultx3 may be found which will agree
sufficiently well with the experimental results in the case of
aurin (Example No. 2). Of these, we will here give only three :

^l.']"-10^2- t^l9"l4^:i- ^*2->"^lS^4-

Carbon . . 7879 78-02 7853

Hydrogen 505 4*88 471

Oxygen . . 1016 16*55 1676

10000 10000 100-00.

G 2

84 DETERMINATION OF VAPOUR DENSITY.

Molecular Formulcc, It is, however, not necessary merely to
determine the simplest formula of a compound, but, if possible,
its molecular formula, and this can readily be accomplished if
we can determine its molecular weight.

The only perfectly reliable method for this purpose, in cases
in which the body can be volatilised without decomposition, is
to ascertain its vapour density. Hence we now proceed to
describe the various methods which have been employed for
this purpose.

DETERMINATION OF VAPOUR DENSITY.

64 By the density or specific gravity of a gas or vapour is
meant the weight of a given volume compared with the same
volume of air taken as the unit.

Two methods for determining vapour density were, until
recently, in common use, and although they are neither of them
now employed in organic chemistry, their description is still of
interest from an historical point of view.

The principle of the first method, which we owe to Gay-
Lussac,^ consists in determining the volume of a given weight of
vapour ; whilst that of the second method, proposed by Dumas,*
consists in the determination of the weight of a given volume of
vapour, and this process is still employed for determining the
vapour density of difficultly volatile liquids. Although the first
is the older of the two methods, the second or Dumas' method
is the simpler, and it, therefore, will be first described.

Duvuis' Method. A thin glass bulb or globe of from 200 to
300 cbc. capacity, having its neck drawn out and bent as shown
in Fig. 41, and filled with dry air, is carefully weighed, the

temperature of the balance-case being ascer-
tained. A quantity of the liquid under ex-
amination, varying according to the capacity
of the globe, is then introduced, such a
quantity b?ing however always taken that the
vapour evolved is sufficient in quantity to
expel the whole of the air. The bulb con-
taining the liquid is then heated in an iron
P ^^ vessel which is filled, according to the vola-

tility of the substance, either with water, oil,
or paraffin (Fig. 42), the temperature being raised to a point

* Biot, Traiti de Phys. i. 291. ' Ann, Chim. PJnja. (1827) xxxir. 326.

DUMAS' METHOD. 85

at least from 30° to 50° above the boiling-point of the liquid,
the reason for thia precaution being that vapours obey the
laws of gaseous expansion and pressure more exactly at tem-
peratures considerably removed from their boiling-points than
at lower temperature?.

When no further vapour issues from the drawn-out point, aa
may be seen by holding a flame in front of the opening, the
capillary tube ia sealed as close as possible to the surface of the
liquid. At the same time the temperature of the bath is read
off by means of a thermometer placed in the heated liquid at a

*'—' t

height corresponding to the centre of the globe. The globe is
next removed, carefully cleaned, and again weighed when cold,
together with the drawn-off point. It is then only necessary to
detenoine the volume of the globe. For this purpose the sea!ed
end ia broken under mercury, and, if the experiment has been
snccesafiilly carried out, the whole of the bulb will be filled by
the mercury with the exception of the small volume occupied by
the condensed hquid, and this volume is usually so small that
it may be disregarded. If, however, it is desired to determine
this amount, the condensed liquid is allowed to pass into the
narrow neck of the bulb, nrtl this then replaced by mercury. In

86 DETERMINATION OF VAPOUR DENSITY.

case the whole of the air has not been completely removed by
the vapour, a bubble of air remains, and its volume may be
ascertained by passing it into a graduated tube over mercury.
To determine the volume of the mercury contained in the globe,
it is poured into a carefully graduated cylinder or else weighed.
This weight in grams divided by 13*59 gives the volume of the
mercuiy in cubic centimeters. The calculation is simple, especi-
ally if no residual air occurs, and this may be readily avoided by
taking enough substance. The following are the experimental
data:

Weight of the globe with air at f — g.

„ „ vapour at .7^ = G,

Capacity of globe . . = C

The weight of the vacuous globe is found from the following
formula, inasmuch as 1 cbc. of air at 0° and 7G0° weighs
0*001293 grm. The height of the barometer may, in this case,
be neglected, as the variation is very slight during the progress
of the experiment. The weight of the air contained in the
globe is :

Cx 0001293

- — j\

1 + 0003665 x^

The vacuous globe will, therefore, weigh y — x, and that of the
vapour G — (jj ^x)=y. We have now to find what an equal
volume of air at the same temperature weighs. We have thus
the equation :

(7x0 001293 _
1 4-0 003665 X T"^'

The vapour density (D) is therefore :

The calculation is considerably simplified if we make use of a
table showing the weight of 1 cbc.- of air at different tempera-
tures. The following table is sufficiently accurate for ordinary
use. This table may be also employed in the calculation of
vapour density according to otlier methods. It gives the value
for every 10**; the intermediate values can easily be obtained
by interpolation.

EXAMPLE OF DUMAS' METHOD.

t'. n.

t .

0 . . OOO1203

170 . .

0000796

10 .

0001243

180 . .

0000779

20 .

0-001205

190 . .

00007G2

30 .

. 0-001165

200 . .

0-000746

. 0-001128

210 .

0000730

. 0001093

220 .

0000715

. 0-001060

230 . .

0-000701

. 0001029

240 .

0000688

. 0001000

250 .

0000674

. 0-000972

260 . ,

. 0000662

100

. 0-000946

270 .

0000650

110

. 0000921

280 .

. 0*000638

120

. 0000898

290 .

. 0000626

130

. 0000876

300 .

0000616

140

. 0 000854

310 .

. 0-000605

150

0-000834

320 .

. 0000595

ICO

. 0000815

TLe following formula may b

e used with this

I table :

T. G-

■n+f'ni

^" CnT '

TLe following example serves to show the limits of error
accompanying the determination of vapour density by this
method.

Example of Dumas Method, A volatile hydrocarbon (hexane,
CgHjJ of the paraffin series, of which the analysis has been
given, yielded the following results:

e =

G =

c =

23-449

15^^-5

23-720

lur

17S cbc.

The density calculated from these numbers is 2'986, whilst
that required by the formula is 2' 979.

65 Gaij'Lu^sac s Method, In this process the graduated and
calibrated glass tube G (Fig. 43) is employed, filled with mercury,
and placed in an iron vessel containing this metal. The sub-
stance is contained in a very thin bulb or small stoppered tube
of known weight (Fig. 44); this is then filled with the liquid,
again weighed, and then passed up to the top of the divided
tube. Surrounding this is a wide glass cylinder open at both

B»

DETEBMINATION OF VAPOUR DENSITY.

ends and filled with water. The iron vessel is now heated by gaa
or charcoal. The expansion due to the heat either causes the
bulb to burst or drives the stopper out of the tube, and the
liquid is soon thus completely converted into vapour. To effect
an equal distribution of temperature the water is continually
stirred. Aa soon as the temperature at which the determina-
tion has to be made is reached, the volume of the vapour, the
temperature of the water, and the height of the barometer are
read off; whilst, at the same time, the temperature of the air
and the difference between the height of the mercuiy inside and
outside the tube are ascertained.

£j.iimplc of Gttij-Zussaes Method. A determination of the
vapour density of pentane, CjUjj, made by this method, gave the
following results :

Weight of pentane ... 0101

Tompernturo of air
Temperature of vapuui
Volume of vapour
Height of baroiiit^tcr
Difference of level .

16'

50 '5 cbc.
752 mm.
tlQ mm.

GAY-LUSSAC'S METHOD. 89

The pressure inside the tube was consequently equal to that
of a column of mercury of 752° mm. at 1G° minus that of
a column of 220"* mm. at 91''. In order to be able to substract
one from the other, these values must first bo reduced to the
same temperature. As the co-efficient of expansion of mercury
for 1** is 0-00018, the heights at 0° will be :

^''- = 749-9

^^^ - =21G'4.

1 + (0-00018 X 16)

220
1 + (O-OOOiS X 9!)

The pressure inside the graduated tube was therefore :

749-9 -21G-4- 5:33-5.

59*5 cbc. of pentane weigh, at 91° and under a pressure of
533*5 mm. of mercury, 0*101 gram. Under the same conditions
an equal volume of air weighs :

0001293x59-5x533-5 ^Q.Q4g3
760xl + (0"003665x91)

Hence the vapour density of pentane is :

^•\^\ = 2-493,
U-0405

and this agrees well with the theoretical value 2494.

Gay-Lussac's method possesses the great advantages of requir-
ing very small quantities of the substance, and of enabling several
determinations to be made at any temperature under 100°. On
the other hand, it is not well adapted to the case of substances
possessing high boiling-points, inasmuch as the cylinder must
then be filled with oil or paraffin, and a constant temperature
of the column cannot in this case be easily attained. Poisonous
mercurial vapours are also given oflf during the process, and
this renders the method dangerous in the case of bodies re-
quiring high temperatures. In order to overcome this objection,
Natanson has constructed an air-bath iu which only the upper
part of the tube is heated, but this modification has not come
into general use.

66 Hofmanns Method. Hofmann ^ conceived the happy idea
of employing a wide barometer-tube in place of the short tube
used by Gay-Lussac, and of heating this by the vapour of a

' Bcr, DeuUch. Chim, Ocs. i. 198.

90 DETERMINATION OF VAPOUR DENSITY.

liquid boiling at a, coDstant tciuperaturG. The apparatus ia
shown in Fig. 45. The graduated barometer-tube (a), more
than 1 meter in length, is filled with dry mercury and placed in
a mercurial trough. Outside this a wide glass tube (b) is placed,
closed at its upper end by a well-fitting cork, through which

Fio. *fi.

the tube d jiivascs fur the entrance of the heated vapour. The
condensed liijuid and the excess of vapour piss away through
the tube e into the condenser (y). A very small stoppered
bottle whose weight is known, having a capacity of from OO-')
to Olcbc. (Fig. 46). is filled with a known weiglit of the sub-
stnuce. The bottle thus filled is passed up to the top of thi>

HOFMANN'S METHOD.

mercury in the barometer, and in the case of the more volatile
liquids this usually displaces the stopper at once, and in other
caaes it is easily driven out when the substance becomes heated.
The copper vessel (/) serves to contain the liquid of constant
boiling-point, and by this means the barometer-tube is easily
brought up to a constant temperature. As soon as the
meniscus of the mercury is seen to remain unchanged,
ike volume of the vapour and the height of the mer-
curial volume are read off by means of a pendulum
cathetometer (i). In many cases water may bo cm-
ployed as the heating liquid, inasmuch as the vaporisa- Fio. 46.
tion of the substance takes place under diminished
pressure, and bodies which boil up to 180° can be completely
volatilised at 100°.i

For the purpose of determining the vapour density at higher
temperatures, Hofmann makes use of the following substances :

noiling-point.

Aniline 181° 5

Toluidine 202

Ethyl benzoate . . . . 212

Amyl benzoate .... 261.

Of course other bodies may be employed provided their boiling-
points do not lie too near that of mercury.

The calculation is carried out in a similar way as in Gay-
Lussac's method, but inasmuch as the lower portion of the
mercurial column is not surrounded by vapour, two calculations
are necessary in order to reduce the height of this column to 0^
In addition to this, the tension of the vapour of mercury must also
be taken into account when high temperatures are necessary.
For this purpose the well-known table of Regnault ^ is employed,
the following extract from which is sufficient for most purposes >

Temperature.

Tension of
Vapour.

5 9 mm.

Temperature.

220°

Tension of
Va|)0ur.

160'

;34-7U mm. !

170

8-09

230

45 -35

180

11-00

240

58-82

190

14-84.

250

75-75

200

19-00

1 260

96-73

210

2G-n5 !

270

12301

* Schroder, Ber, Deutsch. Cliem. Gcs. iv. 472.

Phil. Hag [4] xx. 227.

92 DETERMINATION OF VAPOUR DENSITY.

67 Another great improvement suggested by Hofmann^ is that
of using a plain tube instead of a graduated and calibrated one.
Not only are these plain tubes cheaper than the calibrated ones,
but they are also much less liable to fracture, inasmuch as all
glass tubes in which divisions have been etched are liable to
crack when exposed to rapid changes of temperature. For
this purpose, a tube as cylindrical as possible is chosen, and
when the mercurial column has become stationary, the pendu-
lum cathetometer is placed in position. The apparatus is then
allowed to cool, and, after removing the outer glass tube, a
slip of paper is placed at the point where the meniscus stood.
After the volume of the vapour has been thus determined, the
tube is dismounted and filled with mercury up to the mark, and
then the mercury weighed on a pair of common scales capable of
turning with half a grain. From the weight of the mercury
the volume of gas in cubic centimeters is obtained.

In the apparatus above described, two calculations, as we have
seen, are necessary in order to obtain the height of the mercury
at 0^ This, however, does not give a strictly correct result,
inasmuch as the column of mercury which is not surrounded by
vapour does not possess the same temperature throughout its
length. Tlie temperature of that portion near the cork is
necessarily higher than that of the air. In cases where the
temperature is not high this difference is of little moment, but
at a high temperature it may become of consequence. In order
to avoid this error, Wichelhaus* has proposed to substitute
Hofmann's barometer-tube by a syphon barometer. The ap-
paratus, however, thus becomes much more complicated and
liable to fracture; moreover, the height of the outside tube
requires to be greater, and this necessitates the employment of a
larger quantity of vapour in order to obtain a constant tempera-
ture. Another disadvantage involved in the employment of a
syphon barometer is that only one experiment can be made
with the same material, for when the tube cools, air enters into
the vacuous space. By the use of a straight tube, on the other
hand, the volume of the vapour may not only be redetermined
at the same temperature, but its volume at different temperatures
may be ascertaine<l.

Hofmann has, therefore, improved his apparatus by allowing
the outer tube to dip into the reservoir of mercury at the bottom,
A small tube being sealed on at a distance of from 2 to 3 mm.

> Btr. DeuUth. Chcm, Oes. ix. 1^04. « £cr, DcuUch, Chim, Gca. iii. 106.

HOFMANN'S METHOD. 93

from the surface of the mercury, hy means of which the excess
of vapour and products of condensation can be withdrawn.

Lastly he obtained the same result in a still simpler manner.
The barometer-tube stands upon a thick plate of caoutchouc lying
at the bottom of the mercurial trough, and this plate is fastened
to an iron disc furnished with a handle which is bent so as to
come out of the mercury. In one side of this plate a groove is cut
by means of which the mercury in the tube is brought in contact
with that in the trough. When the vapour passes through the
outer tube, which only needs to be 40 cm. longer than the
barometrical column, the mercury which it contains flows out
into the trough, and as soon as the volume of the vapour has
become constant, the caoutchouc plate is pushed back so that
the mouth of the tube is closed, and thus the mercury in the
tube is separated completely from that in the trough. This is
done by means of the handle, so that the level of the mercury
remains unaltered. As soon as the cathetomcter has been placed
in position, the whole is allowed to cool, and the height of
the mercury is determined at the temperature of the air, the
calculation being then carried out as alrea<ly described.

Further modifications of the apparatus have been made by
J. W. Briihl ^ and C. Engler.^

As the substances employed for the preparation of vapour at
higher temperatures than the boiling-point of aniline are costly,
it became advisable to use as small a quantity of these as
possible. This is arranged for by Hofmann,^ inasmuch as the con-
densed liquid is allowed to run back again into the boiler. By
means of such an arrangement a constant temperature can be
attained in from twenty to twenty-five minutes and maintained
for several hours, with a volume of from 100 to 150 cbc. of liquid.

As an example of the calculation in Hofmann's method we
may take the vapour density determination of ethyl-propinyl
ether, C^HgO :

Weight of substance, 00518 - S,
Volume of the vapour, 525 cbc. =v.
Temperature of the vapour, 100° = 7.
Temperature of the air, 15° = ^.
Height of barometer, 752°'5 mm. = ff.
Height of mercurial column, 484 mm. = A.
Reduced pressure, 275 mm. = h\

1 Bcr. DeutscK Chr.m, Ges. ix. 136S ; xii. 197. » Jhid. ix. 1419.

* Ber, Deutxh, Chcm. Get. 1876, ii. 1304. Chcm. Soc, Jonm, 1877, i. 33.

94 DETERMINATION OF VAPOUR DENSITY.

Hence the vapour density is obtained by the following
formula :

_ /g X 760 X (273 -f T)
0-001293 X 273 X v x cT ^'

Found. Calcuktetl.

2-895 2-909.

Hofmann's method soon almost entirely superseded the two
older methods, Dumas' being employed only for the determination
of the vapour density of substances which have a high boiling-
point, and for this purpose improvements were made in the
method by Troost and Deville,^ as well as by Bunsen.* Dumas'
method is also subject to the serious disadvantage, that the
greater portion of the material employed, frequently more than
3 grams, is lost during the operation, and this, in the case
of expensive preparations, is a matter of serious inconveni-
ence. In order to overcome this diflBculty, various suggestions
have been made, by means of which the escaping vapours could
be caught and condensed, but this leads to complications which
destroy the simplicity of the method.

Habermann * has lately made another suggestion. He con-
nects the fine neck of the globe with a Bunsen filter-pump in
order to* produce a vacuum, whereby the substance, as in
Hofmann's method, boils at a lower temperature. By this
method not less than 1 gram of the substance must be em-
ployed, and this can readily be condensed in a bulb-tube placed
between the globe and the pump. By this means, however,
Habermann has only been able to determine the vapour density
of such substances as boil below 250°.

68 Victor Meyer's Methods, Method No, 1. Victor Meyer * has
recently worked out a plan by means of which, without cm-
ploying a greater quantity of the substance than that used
in Gay-Lussac's or Hofmann's process, the vapour density of
high boiling bodies may be determined at a temperature of
448^ the boiling-point of sulphur. He employs Wood's fusible
metal as the liquid over which to collect the gas, and makes use
of the bulb-tube shown in Fig. 47. In carrying out the ex-
periment, about 50 mgrm. of the substance are allowed to

» Ann. Chim, Phys. [3] Iviii. 257.

• Ann, Chem. Pharm, cxli. 273.
' Lie bigs Anna! en ^ clxxxrii. 341.

* Jkr, Dcut9ch, Chem. Oca, niQ, ii. 1216.

VICTOR MEYER'S METHODS. 'J5

vaporise in a vessel completely filled with the liquid alloy, the
vdume of vapour being ascertained from the weight of the
metal which flows out.^ A substance which is solid at the
ordinary temperature is weighed out iu a short glass tube
sealed up at one end, Fig. 48 (a), whilst liquids are enclosed in
small stoppered bottles, which differ from those used by Hofmanu

Fio. 47. Fio. 48 (S).

by being slightly curved in order that they may more readily
pass up into the bulb-tubo. Fig. 48 (b). The whole apparatus is
then heated to 100°, and afterwards placed on a laiige balance
and weighed to within a decigram.

The apparatus must then be heated iu the vapour of sulphur.
This ia accomplished in a cast-iron crucible of 400 chc. capacity,
which is loosely covered (Fig. 49). The crucible contains from 1 20
to 130 grams of sulphur, and is heated by means of a powerful
burner. After about twenty minutea, when the sulphur is
boiling rapidly and the current of vapour passes out between the
cover and the crucible, the boiling is allowed to go on for about
four minutes, the burner then turned out and tho huib-tube
lifte<l out of the crucible. The vapour contained in the bulb
at the moment the bulb Js withdrawn from tho crucible Ja
under the prosssure of the atmosphere plus that of the short
column of fusible metal in the bent tube. The height of the
column has therefore to be ascertained. For this purpose a
finely drawn-out glass tube, having a drop of seaUng wax at the

' Similar methods for lower temjM'rnturca, by mnking lue of mercuTy, had brcn
fonnftrly snggrated ; Hofmann, Ann. Chern. Pharm. Suppl. i. 10 ; Werthfim,
ibid. cxKiii. 173 ; cxzviL Bl ; ckxx. 269 ; \V. UarshninVatts, Laboratonj, l. 2S5.

96 DETERMINATION OP VAPOUR DENSITY.

end, ia brought oq to the glass at the height of the meniacus in
the iiiDer tube. This leaves a mark by means of which the
height can be ascertained. For the special precautions which
the author recommends, the original paper must be referred to.

The following furmula senses for the calculation : '

.S>^ 760(1 +0-0O3MS y. tU-J^ _ ^__

0001293 [Pt-^p]r('_"— + -'-)(l + 84(|-2x 0-0000803)- -I_l
' ""LV»908 130/ ' »16»J

By collecting the constants, we obtain the equation :

/> r

[/•+3 7']|

-. Dtutseh. Cktm. Ott. x. S07D.

VICTOB MEYER'S METHODa

In these formula; :

5= Weight of the substance.
P = Height of barometer reduced to 0°.
p = Pressure of column of metal, which is two-
thirds that of mercury,
et= Weight of alloy employed.
9-608 = Specific gravity of alloy at 100°.
9 158 = Ditto at 448°.

q = Weight of mercury contained in small bottle.
r = Weight of the remaining alloy.

As the tube containing the substance ia very small, q may
be neglected.

The vapour density of methyl-anthracene, a
body boiling at a higher point than mercury, was m
thus ascertained :

S " 0-0360.

a = 283-33.

r = 168-9

P = 722-3 mm.

p = 34-0 mm.

Foil 11 J.

Calciilitted

Vapour density , . 6-J7

6-63.

69 Method No. 2. In order to determine the
vapour density of bodies boiling below a tempera
ture of 3.)0°, V. Meyer' has proposed a method
by means of which the molecular weight may be
determined with great simplicity and ease. The \
vessel in which the substance is placed is filled
with mercury, as shown in Fig. 50. It is niiide
of thin glass, and hiis a capacity of 35 cbc. This
is filled according to the method already described, but at
the onlinary temperature, at which it is weighed. It n
then hung by a thin wire in the boiling flask {Fig. 51), the
neck of which being lung does not require any condensing
arrangement, and it is then heatcil to the boiling-point of
water, aniline, or any other higher boiling liquid. When no
more mercury is seen to ilow out, the apparatus is removed and

' BtT. DtulKh. Cht!,,. Cm. 1877, IL 2008,

DETERMINATION OF VAPOUR DEN3ITY.

after cooling weigLed again. In order to determine the excess
of pressure in the side-tube, the capillary tube is opened, an<1

the wl.i.l.' is tillrd 1
wid.T tnhr.

iry, and tlio point markoi

VICTOR MEYER'S METHODS. 99

In the calculation the following data are required :

S = Weight of substance.

T = Temperature of vapour.

^ = >, n air.

P= Barometric pressure reduced to 0^

p « Excess of pressure in the side-tube.

8 = Tension of mercury vapour.

a = Weight of mercury employed.

r = Weight of remaining mercury.

q = Weight of mercury contained in the small bottle.

The last number is required only in very exact determinations.
The calculation is effected by the following formula :

_ 5 X 760 (1 -t- 0 0036657) 13-59 _ ^

""(^ +!» - «, 0-U0liy3\o+y; ^l + 0 (HM)0303 [T - <]) - r) (1 -f 0"00UlO [T - tjj (fx 00001b)*

13 '59 is the specific gravity of mercury at 0°.
0*0000303 is the coefficient of expansion of glass.
O'OOOIS ditto of mercury, which above 240° rises to
0-00019.

The constants in the above formula are :

760x13-59
0 001293 -'^»^0^^-

The temperature of the vapour does not need to be deter-
mined, as the boiling-point of the liquid employed is known.
In the case, however, of bodies whose boiling-points approach
tliat of mercury, it is necessary to determine the temperature, as,
according to the recent experiments of Naumann, it appears
that the boiling-points of liquids which are not miscible undergo
considerable depression. Thus he finds that diphenylamine,
which boils at a temperature of 31 0** by itself, boils at 290"*
when mixed with mercury.

The vapour density of benzoic acid was in this way deter-
mined in the vapour of diphenylamine with the following
results :

/S= 00603.

ji> = 21 mm.

a = 471*7 grams.

r-290°.

r = 66*4 grams.

t =15°-2.

q -= 1 gram.

.s = 165*7 mm.

P= 726 mm.

Found. (.'alculated

Vapour density . . .

. . 4-20 4-22.

•

n 2

100

DETERMINATION OF VAPOUR DENSITY.

70 Method No, 3. Victor and Carl Meyer^ have recently
described an easy method for determining the vapour density of
bodies of low, as well as those possessing a very high, boiUng-point.

Fio. 52.

Fig. 53.

This is especially valuable for bodies boiling above 448", and for
such as attack mercury or fusible metal. The temperature to

> lUr. nnifjurh, Chfm. f.Vjr. 187S ii. 22r.r?.

VICTOR AND CARL MEYER'S METHODS. 101

which the vapour is heated does not require to be determined, nor
is it necessary to know the volume of vapour at that tempera-
ture, as both of these values are eliminated in the expression
for the density. The only observation which is required is the
volume of the vapour in the form of its equal volume of air
measured at the atmospheric temperature. The apparatus is
shown in Fig. 52. It consists of the boiling flask c, in which is
placed the glass 6, having a capacity of about 100 cbc.; and on
to this is fused a tube 600 mm. in length, closed with a caoutchouc
stopper (d), and furnished with a short capillary gas-delivery
tube (a). The substance employed for heating purposes may
be any of those already mentioned.

If it be necessary to work at a temperature above 310**, a bath
of molten lead (Fig. 53) is employed, which can be heated to a
temperature sufiSciently high for the complete volatilisation of
the substance. This point is easily ascertained by dipping a
thin tube containing a small quantity of the body into the lead
and seeing whether it boils quickly. The experiment is com-
menced by heating the empty vessel h (at the bottom of which
a small plug is contained) in the long tube or in the lead bath.
The tube is closed by the stopper d, and the gas-delivery tube
dips in the water of the trough. As soon as the temperature
becomes constant, and when, therefore, no further evolution of
air is observed, the stopper is quickly removed, and a weighed
quantity of the substance (such in amount that its vapour does
not occupy more than half the volume of the vessel b) thrown
in and the cork quickly replaced, the graduated cylinder filled
with water having been placed over the end of the gas-delivery
tube. The substance at once evaporates, and in fifteen seconds
displaces its own volume of air which collects in the cylinder.
As soon as no further bubbles are emitted, the tube is removed
into a larger cylinder filled with water, the levels of the liquids
brought to the same point, and after a time the volume of the
air read oflF, the temperature of the water and the height of the
barometer being at the same time observed. These observations
yield sufiScient data for the calculation :

^= Weight of substance.

t = Temperature of the water.

i^ = Barometric pressure reduced to 0'.

iv = Tension of vapour of waters

V~ Volume of air.

102 DETERMINATION OF VAPOUR DENSITY.

The vapour density is calculated by the formula :

Sx760 (1 + 00036650
~{B-'W) rx 0 001293'

or, by collecting the constants:

S (1 + 00036650 X 587780

As examples we may quote the following :

(1) Chloroform, CHCI3, in water vapour.

S- 01008 ^ = 16'-5 J?= 707-5 mm. r=22cbc.

Calculated. Foand.

Vapour density . . 4*13 41 3.

(2) Benzoic acid, C^H^Og, in diphenylamine vapour.

5=0 0855 /=16" J5= 717-8 mm. r=17'8cbc.

Calculated. Found.

Vapour density . . 422 424.

(3) Diphenylamine, CjgHjjN, in lead bath.

S = 00905 ^ - 17' i? = 714-8 mm. r= 136 cbc.

Calculated. Found.

Vapour density , . . o\i3 5*92.

The same experimenters have employed this method for the
determination of the vapour density of inorganic compounds
which volatilise at a red-heat or even at a higher temperature.
For this purpose the glass vessel is replaced by one of porcelain
or platinum heated in a suitable gas-furnace.^

The literature of the subject must be referred to for
further information respecting the subject of vapour density
determination.^

1 Ber. Dtutsck, Chem. Ges. 1879, 1112.

' Gnbowski, Ann. Chem, Pharm, cxxxviii. 174 ; Landolt, Ber. Dcutseh. Chem,
Oet. Y. 497 ; Goldschmidt and Ciamieian, ibul, x. 641 : Uofmann, ilnd. ix. 962 ;
zi. 1884 ; Pfaundler, ibid, xii. 165.

MOLECULAR FORMULAE OF VOLATILE BODIES. 103

DETERMINATION OF MOLECULAR FORMULA.

71 (a) Molecular Formulce of Volatile Bodies, — When the per-
centage composition and the vapour density of a compound are
known, the molecular formula can bo readily ascertained.
Hydrogen is 14'43o times lighter than air, and hence the
molecular weight of a substance is obtained by multiplying
its vapour density by twice 14*435.

Eocample No. 1. Thus, for instance, the molecular weight of
the above-mentioned paraflBn is 2*986 x 2887 = 802, or in round
numbers 86. Now, as the percentage composition of this body
is known, the amount of carbon and hydrogen contained in
86 parts can be readily found.

83*87 X 86 ^o - ^ ,
— — ■ — =- /213 carbon.

^^'--^ ^ ^^ = 13-97 hydrogen.

100 ^ ^

If we divide the numbers thus obtained by the atomic
weights, we 'find that the hydrocarbon is hexaue, C^H^^. The
want of exact afinreement between the numbers thus obtained
and those calculated from the formula is explained by the fact
that the above numbers contain the experimental errors due
both to the analysis and to the vapour density determination.
This error may be partially eliminated if we compare the
theoretical composition and vapour density, directly with the
numbers found by experiment :

Found.

Culculated.

Carbon . . .

. . 83-87

83-72

Hydrogen . .

. . 16-25

16-28

100*12 100-00

Vapour density . . 2986 2*979.

The numbers thus found are seen to agree well with the
calculated values.

Example No. 2. Methyl-anthracene gave on analysis the
following percentage composition :

Carbon 9392

Hydrogen 623

100*15.

104 DETERMINATION OF MOLECULAR FORMULA.

Its vapour density is G'57, and hence its molecular weight
is 100, and the amount of carbon and hvdrogen contained in
190 parts is:

Carbon 178*5

Hydrogen 11*8.

These numbers, divided by the approximate atomic weights,
give:

^'^'^ = 14-9
12 ^*"''

showing that methyl anthracene possesses the formula C^jH^g.
This corresponds to a theoretical vapour density of 6*63, and
a percentage composition of:

Carbon 93-75

Hydrogen 625

10000.

Example No. 3. As a last example of this kind we may take
ethyl propenyl ether, whose vapour density determination has
been already given. Ultimate analysis gave :

Carbon 7126

Hydrogen 9*55

Oxygon 1919

locFoo.

Its molecular weight is 28*87 x 2-895 = 83G.

83 6x71-26 .^^^ ^
, . — — i>9'60 carbon.

83-6 X 9-55 ^ ,,^ , ,

lUO " "" / ••)8 hydrogen.

83-6 X 1919

UK) " =1^^"^^ oxygon.

Hence the molecular formula is C-H^jO, and this corresponds
to :

C. 60 71-43
Hg 8 9-53

O 16 1904

lOOUO.

MOLECULAR FORMULA OF ACIDS. 105

7a (b) Molecular Farmulce of Acids. Many carbon compounds
are acids whose molecular weight, whether they be volatile
or not^ may be readily ascertained by determining in the first
place whether the acid is monobasic or polybasic, and then
analysing one of its salts. As a rule the silver salts are
employed for this purpose because they are easily obtained
anhydrous and in the pure state, and because they leave a
residue of pure silver on ignition.

Example No, 4. The composition of monobasic melissic acid,
according to analysis, is as follows :

Carbon 79-61

Hydrogen 13*48

Oxygen - 6*91

100-00.

Ignition of the silver salt showed that it contained 19*3 per
cent of silver. Hence the molecular weight of this salt is :

100 X 107-7 __
i9-3 -"^^ •

This salt differs from the acid by containing one atom of
silver in place of one atom of hydrogen. Hence the molecular
weight of the acid is :

(558-107-7)+ 1=451-3,

or the even number 452 may be taken as representing the
molecular weight of the acid. The weight of carbon, hydrogen,
and oxygen contained in the molecule will then be respectively :

luo -•^•>'^

13:48 x^52_

100 ~ ^^'^
6 91 X 452

100 ~ ^^ "•

Hence the formula is CsoHg^Oj, and this gives :

C30 360 79-64

H^ 60 13-28

Oj 32 708

452 100-00.

106 DETERMINATION OF MOLECULAR FORMULA.

The calculated percentage of silver, namely, 19*28, in the
above salt, agrees with that which has already been described.

EocamplcNo, 5. Analysis of silver benzoate gave the following
results :

Carbon 36 68

Hydrogen 210

Silver 47*16

Oxygen 13-97

100^00.

Benzoic acid is likewise monobasic^ and the molecular weight
of its silver salt as calculated, as in the last example, is 228*4,
that of the acid being 120*7. If the quantities of the various
elements contained in 228*4 parts of the salt be next calculated,
the formula CyH^AgOj is obtained. Hence the acid is C^H^Og,
as is shown by the following comparison of the theoretical with
the analytical results :

Calculated. Found.

Cy 84 36*73 36*68

H^ 5 2*19 219

Ag 107*7 47*09 47*16

O, 32 1399 13*97

100*00 100*00.

Example Xo. 6. Meconic acid, a compound found in opium,
is a polybasic acid. On adding silver nitrate to its aqueous
solution, a white silver salt is precipitated, but when the same
reagent is added to a solution of the acid previously neutralised
by ammonia, a yellow silver salt is obtained. The composition
of the acid and of the two silver salts is found by experiment
to l>e :

Meconic White Silver Yellow Silver

Acid. Salt. Salt.

Carbon . . . 420 20*2 15*9

Hydrogen . . 20 0*5 0*2

Oxygen . . . 56*0 270 21*9

Silver . . . ~ .52*3 62*0

lOlTo 100^0 100*0.

If in the first analysis the numbers be divided respectively
by the atomic weights of the elements, we obtain the following

MOLECULAR FORMULAE OF ACIDS. lOT

relation between the number of atoms of the constituents of
the acid :

12 ~

3-5,

2
1~

2-0,

56
16 ~

3-5.

The most simple formula of meconic acid deduced from these
numbers is CyH^O^, but whether this, or a multiple of it, ex-
presses the molecular weight cannot be decided by the results
of analysis. In the two salts different quantities of hydrogen
are replaced by silver. The white salt contains for every seven
atoms of carbon :

0*5 X 84

— o7y:«~~ = ^'^ parts, or 2 atoms of hydrogen,

— c^^^^ = 217*0 parts, or 2 atoms of silver.
20*2 ^

In the yellow salt we find :

- , .-.^- = r05 part, or 1 atom of hydrogen,

62*0 X 84

■ "^ , r.(> " = 327*5 parts, or 3 atoms of silver.

From this we conclude that the acid is tribasic, and that the
formula C^H^Oy represents a molecule. A further confirmation
of this conclusion is found in the fact that acid salts containing
only one atom of a monad metal are known.

The molecular formulae of the above compounds are
therefore :

Meconic acid C-.H^07,

White salt , . . C^HgAggO^,
Yellow salt . . . ilUAgfi..

In certain instances, an acid, whose molecular formula has
to be determined, may be known to belong to a given
homologous series. In this case, in order to determine its
molecular formula, we only need to determine the quantity
of silver, or of any other metal, contained in one of its salts.

10« DETERMINATION OF MOLECULAR FORMUL-^l

Example No. 7. An acid, which from its derivation and
chemical relations undoubtedly belongs to the group of fatty
acids, gives a silver-salt which yields, on ignition, 45 'ol per
cent, of metaL Hence the molecular weight of the acid is
130. The general formula, however, of the fatty acid series
is CnH2n02 and the value of n is ascertained by the equation :

14 M + 32 = 130
.'. n = 7.

Hence the molecular formula of the acid is CjH^fi^.

73 (c) Molecular Formvice of Bases. Many carbon compounds
exist which contain nitrogen, and which act as bases, combining
like ammonia with acids. Some of these bases are monacid,
others are polyacid. In order to find the molecular weight
of such a compound, it is only necessary to ascertain the
quantity of acid contained in an anhydrous normal salt, or,
better still, to find the quantity of platinum present in the
double salt formed by the combination of the hydrochloride
with platinic chloride, and which, like ammonium platinic
chloride, contains two molecules of hydrochloric acid to each
molecule of platinic chloride.

Example No, 8. Caflfeine is a monacid base; its platinum
double salt contains two molecules of caffeine and two molecules
of hydrochloric acid combined with one molecule of platinic
chloride, and 100 parts of this compound leave, on ignition,
24*6 per cent, of platinum. Consequently the amount of the
platinum salt which contains one atom, or 196*7 parts of
platinum, is :

196-7 X 100 _

24-6 "" ' ^^'^•

The molecular weight of cafi'eine is found from this by the
equation :

2 71 + (2 X 36-5) -h 338-3 = 7996
.*. n= 194.

As the percentage composition of this base is known, its
molecular formula can easily be found :

194 X 49-51 ^^ , ^ ^
100 ^ carbon,

MOLECULAR FORMULA OF BASES. 109

194.x 5-22 _, ,, ,

100 =10*1 «f hydrogen,

104.x 28-99 .^^ , .

Yq.t — = oo'z of nitrogen,

104 X 16-28

lOU

=* 31-58 of oxygen.

One molecule of caffeine, therefore, consists of:

96-1 ^ , ,

-y^ — 8-0 atoms of carbon,

101

- :j =10-1 atoms of hydrogen.

56-2

- -T- = 40 atoms of nitrogen,

31-58

— - — = 1-97 atom of oxygen.

Its molecular formula is therefore Cj^H^jN^Og, corresponding
to a molecular weight of 194, or more exactly of 193 78.

In the determination of the molecular weiirht of an organic
base we also often know beforehand to which homologous series
it belongs. In such a case, the determination of the platinum
in the double salt is sufficient to determine the formula.

Examflc Ko, 9. A compound ammonia, having the general
formula CnHQu-i-sN forms a double salt, 100 parts of which,
on ignition, leave a residue of 33*02 of platinum.

As the platinum double salt possesses the formula
(C*nH.-»n + 3N,C1H)2 + PtCU, tlie molecular weight of the base is
easily found to be 80, and hence we have the equation :

12/1+271 + 3 + 14 = 80
.-. n = 4-93.

Hence the base possesses the formula C^HjgN, and has a
molecular weight of 80 '86.

74 (d) Molecular Formula' of Non-volatile and Neutral Bodies,
Most carbon compounds, however, neither act as acids nor n.s
bases, and if they are not volatile without decomposition, and
do not enter into combination to form distinct compounds with
other elements by means of which the molecular weight can
be ascertained, the molecular formulae can be ascertained, in-
many cases at least, by a careful examination of their chemical
metamorphoses.

no DETERMINATION OF MOLECULAR FORMULAE.

Example Ko, 10. Numerous analyses of cane-sugar have
shown it to possess the following percentage composition :

Carbon 4210

Hydrogen .... 6*44
Oxygen 51*46

lOO^O.

As in the case of aurin, this result may be expressed by a
number of diflferent formulae. In order to obtain a clue as to
which of these is the correct one, we must consider certain
general properties of the body. In the first place, cane-sugar
when boiled with sulphuric acid is convei'ted into equal quan-
tities of two other kinds of sugar possessing an identical com-
position, but distinguished by certain chemical as well as by
certain physical properties. These two varieties of sugar are
known as grape-sugar and fruit-sugar. That they are formed
from cane-sugar by addition of the elements of water, is proved
by analysis, which gives for the new sugars the following
composition :

Carbon 4000

Hydrogen .... 667
Oxygen 53-3:3

100 00.

On dividing these numbers by the respective atomic weights
of the elements, the following numbers are obtained :

■; .) = 3*33 carbon.

I =0 0/ hydrogen.

:).S-33
p^-= 3-33 oxygen.

Ilcncc those two kinds of sugar contain two atoms of hydrogen
fur every one atom of carbon and one atom of oxygen, and the
simplest fornmhe for them is CH.jO. This, however, cannot
possibly represent the molecular formula of the compound, in-
asmuch as such a simple Ix^dy must either ho a gas or, at any
rate, a very volatile subsUmce. Neither of these kinds of susrar
belong to either of the above categories f'*^ <^»i^ heating they
decomiM»se, leaving a residue of carbon. The molecular formula

MOLECULAR FORMULAE OF NON- VOLATILE BODIES. Ill

must therefore be a multiple of the simplest formula. Both
these sugars yield, on fermentation, equal molecules of alcohol,
CjHjiO, and carbon dioxide, COg ; hence we may conclude that
the molecular formula cannot be less than CgHgOg. Both,
moreover, combine with nascent hydrogen to form manna-sugar,
or mannitol, which possesses the following composition :

Carbon 39-56

Hydrogen .... 7 "69
Oxygen 52*75

100 -00.

As mannitol stands in such a close relationship to grape-sugar,
fruit-sugar, and cane-sugar, it may be well to calculate how
many atoms of hydrogen and oxygen these compounds contain
for every 3 atoms of carbon. Thus we find for cane-sugar,
C3H3.5O2.75, and for mannitol, C3H-O3. Hence, the simplest
formula? of these two bodies, consistent with the foregoing re-
actions, are, cane-sugar, CjoHggOii, mannitol, C^Hj^Og ; and those
of the two other descriptions of sugar, CjjHjgO^j. That this
fornuda for mannitol is its molecular furnmla, mav be seen fnnn
the following considerations. An exact investigation of this
body has shown that it contains six hydroxyls, or that it is an
alcohol of an hexad radical. Hence it possesses the fornmla
CgHg(0H)(5. This may be further proved by a few simple
reactions. The six hydroxy Is may be replaced by six of hydro-
gen, hexane, C^H^^, being thus formed, and this is the original
hydrocarbon of mannitol. It might, notwithstanding, be supposed
that as mannitol is not volatile without decomposition its mole-
cular weight might be a multiple of the above numbers. This
supposition, however, is impossible, as no hydrocarbon can
contain a larger proportion of hydrogen than is contained in a
hvdrocarbon of the series C,iH._>„4-2. Ah the three other
sugars are so clearly connected with mannitol, we may assume
that the above simple formuhe likewise represent the molecular
formula3 of these compounds.

Example No. 11. As a last example of the method by which
the molecular formula of a non-volatile compound may be
determined, we will take that of aurin, the analysis of which has
already been given. This compound is formed when a mixture
of oxnlic acid, C.^HgO^, and jjIiouoI, C^l^p, \.% warmed with
sulphuric arid ; water and formic acid, CH^O.„ bcin^^ at the snme

112 EMPIRICAL AND RATIONAL FORMULAE.

time produced. As oxalic acid easily splits up on heating into
formic acid and carbon dioxide, we must assume that the latter
compound, in the nascent state, acts upon phenol yielding aurin
and water. If we represent this reaction by an equation, we
find that of the three formute which we have already given for
aurin, the second one explains the decomposition most readily :

8 C,H,0 -f CH ), = Ci„H,,03 + 2H,0.

That this, the simplest formula, is at the Siime time the
molecular formula, has been proved, or at any rate rendered
extremely probable, not only by the fact that aurin can be
converted into the hydrocarbon triphenylmethane, C^j^H^^j, whose
derivative it is, but also that aurin can be prepared from this
hydrocarbon by the replacement of two atoms of hydrogen by
one atom of oxygen and two atoms of hydrogen by two of
hydroxyl.

In the numerous cases to which none of these means for
ascertaining the molecular weight of a substance apply, we must
be content to make use of the simplest formula, although it
must be remembered that in certain cases even the simplest
formula cannot be obtained.

EMPIRICAL AND RATIONAL FORMULiE.

75 Law of the Linking of Atoms, By an empirical formula is
understood one which simply expresses the composition of the
body. If at the same time it represents the molecular weight,
it is termed an empirical-molecular fornmla. Besides these,
rationed fonnulcc wxQ employed, especially in organic chemistry,
this name having been first made use of by Berzelius. Such
formuke are intended to indicate the chemical nature of the
compound, and to express the relations in which it stands to
other bodies, or, in otlier words, to i)oint out either the com-
pounds from which it has been derived or those into which it
can be resolvi'd. For the true aim of chemistry, as Kekule justly
remarks, is n«)t so much the study of the existing substance as
that of its past history and its future development. In the
historical intriKlu(*tion reference has Ik'CU mtide, not <»nlv to the
growth of rational fonnuln\ but likewise to the influence which
the theory (►f types has oxert<»d on our knowh'dgt^ of the |)eculiar

CARBON A TETRAD ELEMENT. 115

relations of the atoms in combination and in decomposition. It

-was formerly supposed that the several constituent atoms of the

molecule were held together by the attraction which one of

tliem exerted upon all or upon a large number, and that these,

ia their turn, exerted a corresponding attraction and thus held

each constituent in its place. Chemists have, however, now come

to the conclusion that this attraction is only exerted between the

atoms severally. The atoms may thus be represented as forming

a chain, one atom being linked on to the other, so that when one

of them is removed without altering the position of the others,

the chain is broken.

It next remains to notice how this law of the linking of atoms *
may be explained from the known constitution of the carbon
compounds.

76 Carbon is a tetrad element, and, therefore, one atom of car-
bon unites with four atoms of hydrogen, giving rise to methane or
marsh-gas, CH^, the simplest of the hydrocai*bons. This hydro-
gen may be replaced by other monad elements or residues. Thus
by the action of chlorine we obtain methyl chloride, CHjjCl,
which, on uniting with ammonia, yields mothylamine, CHgNHg,
and on treatment with caustic potash is converted into methyl
alcohol, CH3OH. If two Moms of liydrogen in this latter body
be replaced by oxygen we obtain fonnic acid, COH.OH. These
. formulae may be graphically represented ficcording to A. S.
Couper's suggestion,- as follows, each atom being connected with
another by means of a line indicating the mode in which the
attraction acts :

■if^xi ^ Methvl >r 4.1 1 Methvl Fomiic

Methane. ^j^j^^.^^ Methylannne. ^^^^.^,j^;^j^ ^^.^

H H H H H

I I I I I

H— C— H H— 0— H H— C— H H— C— H C=0

H Ci N 0 O

/\ 1 I

li n H H.

The simplest mode in which two carbon atoms can com- .*
bine together is when one combining unit of the one atom is
linked by one combining unit to the other atom. Six free

' L. Meyer, Modem. Theor. 3te Aitfl. 151.
« Phil. Mag. [4J, xvi. 104..

VOL III. I

m CONSTITUTIONAL FORMULAE.

combining units then remain, or a hexad group is formed
capable of combining with hydrogen to form ethane, possessing
the following graphical formula :

H H
H— C— C-H

H H

More than two carbon atoms can combine together in a similar
way, and the valency of such a group will be increased by two
units for every atom of carbon whicli thus becomes attached.
If n atoms of carbon unite together, the number of free
combining units will be represented by

2 + n(4— 2)=2 + 27i.

If the whole of these units be saturated by hydrogen, members
of the homologous series, CnHsn + s* known as the paraffin
series, are formed. In these, just as in marsh-gas, one atom of
hydrogen may be replaced by monad elements or residues, and
thus the homologous series of chlorides, alcohols, and amines,
which have been already described, may be obtained.

77 Derivatives of EtJiane. Ethane, CjH^, forms the following
derivatives : ethyl chloride, CgH^Cl ; ethyl alcohol, CjH^.OH ;
ethylamine, CgH^. NHg. The graphical formulie of these are
readily obtained, and may shortly be written in three diflferenl
ways, as follows :

(1) CH, CH3 CH,

CHj CHa CHj

I I I

Cl OH NH,

(2) CH, CH, CH,

CH.Cl CHyOH CH..NH2

(3) CH3.CH2CI CH,.CHj.OH CH,.CHj.NHj.

Ethyl alcohol, on oxidation, yields acetic acid, one atom of
oxygen replacing two atoms of hydrogen.

The question now occurs, which two of the six atoms are thus
replaced ? This point is determined on ascertaining that acetic
acid like alcohol contains the radical hydroxy!, a fact with which

CONSTITUTION OF ACETIC ACID. 115

the originators of the theory of types were acquainted, for they
assumed that both these compounds were obtained from water
by the replacement of one atom of hydrogen by a radical :

Ethyl Alcohol. Acetic Acid.

These formulae indicate that ooth compounds contain an atom
of hydrogen capable of acting differently from the other atoms
of the same element, inasmuch as this particular one can be
readily replaced by monad elements or groups. Besides, we know
that the hydroxyl can be replaced by chlorine when these and
similar compounds are acted on by phosphorus pentichloridc,
ethyl chloride, C^HgCl, and acetyl chloride, (J2H3OCI, being
formed, whilst by the process of reverse substitution the chlorine
in these bodies maybe readily replaced by hydroxy). Hence it
follows that the true constitution of acetic acid can only be
represented by one of the following constitutional formula) :

(1)

(2)

CH3

HC - 0

0=0

CH„

\0H

OH OH OH

In order to ascertain whicli of these is to be accepted, two
general methods are employed. The molecule may cither l:e
decomposed by simple reactions into smaller molecules of well-
known constitution, or it may be built up from such molecules.

78 The First or Analytical Method, Ejcamplc 1. When acetic
acid is heated with an alkali, marsh-gas and a carbonate are
obtained :

C^HjOgNa + NaOH = CH, + ^^a,C03.

Example 2. When a galvanic current is passed through a con-
centrated solution of potassium acetate, acid potassium carbonate,
free hydrogen, and ethane are produced :

2 C^HsO^K + 2H2O = 2 KHCO3 + Hg 4- C^H^.

Tlie change which takes place in this reaction is easily
explained. When the salt undergo^ electrolytic decomposition,

I 2

116 CONSTITUTIONAL FORMUL.^..

it first yields the metal potassium and a residue, CgHgOj. But the
metal at once decomposes water, and the residue yields carbon
dioxide and methyl, C^HgOa = COg + CHj. The latter body
cannot, however, exist in the free state, and hence two molecules
combine to form ethane, C^Rq-

The most probable conclusion to be drawn from these decom-
positions is that one atom of carbon of the acetic acid is linked
directly with carbon, and hence its constitution is represented
by the first of the above three constitutional formulae. The
decomposition by electrolysis being represented in the following
way :

CHj, CHg

00.

H,..H

CO.

79 The Seoond <w SifntJictic Method. That acetic acid possesses
the above constitution and contains the group methyl, is more-
over ascertained by the fact that it can be synthetically obtained
from the methyl compounds. Thus, when methyl iodide is heated
with potassium cyanide, methyl cyanide, CHg.CN, is obtained,
and this, when boiled with a solution of caustic potash, yields
potass^ium acetate and ammonia

I H\

C=N + H-O-K + H-O-H = C - O + H-N = C.

H/
OK

By the action of chlorine upon acetic acid, monochloracetic
acid, CgHgClOg. is formed. This is a monobasic acid, like
acetic acid itself, and it is converted by means of phosphorus
pentachloride into monochloracetyl chloride, CgHjCl.OCl, and
from this we conclude thai it also contains the group hydroxy 1,
and that the substitution has taken place in the methyl ^roup.
Its constitution, as well as that of acetic acid, may, therefore, be
represented by the following formula^ :

Ar<'tir Aci«l. Clilor-ftceti«* AcUl.

(1) CH..CO.OH CH.C1.C0.0H.

(2) CIL-CO ) f. CH,C1.C0 ) f.

NON-SATlTiATED COMPOUNDS. 117

Such or similar forniulai were formerly used, but whilst
Berzeliu8*s school intended by the use of these formulae to indi-
cate that methyl is a copulated oxalic acid, the upholders of
the theory of types distinctly stated that such rational formulae
are to be considered not as constitutional formulae, but as for-
mula; of decomposition, simply indicating the chemical meta-
morphoses of the substance in question and its relationships to
other substances, but in no way indicating the constitution or
position of the atoms.

All the formulae for acetic acid which have been mentioned
indicate (1) that it contains two atoms of carbon connected
together by the simplest method of linking; (2) that one of
these atoms is combined with three atoms of hydrogen ; and (3)
that the other is so connected with two atoms of oxygen that
one of the atoms of this latter element is linked to carbon with
both its combining units, the other being connected with only
one combining unit, its second combining unit being saturated
with hydrogen.

8o Noil-Saturated Com2'>ouiids, If we remove two atoms of
hydrogen from ethane, ethylene or olcfiant gas, CgH^, is pro-
duced, and this substance is sharply distinguished from ethane.
The latter, like all paraffins, is attacked by chlorine and bromine
only in daylight, and with the formation of substitution-products,
wliilst ethylene and its homologues unite directly in the dark with
two atoms of the above halogens. Hence we may assume that
the latter hydrocarbon belongs to the class of unsaturated com-
pounds or contains free combining units. In this case the
constitution of ethylene may be represented by the following
formulae :

CH, — CH.,

I I "

=CH — CHj

It is, however, as we shall see later, much more probable
that the two carbon atoms are connected together by two com-
bining units of each, and that the constitution is expressed
more correctly by the formula :

CH,

The easy combination of ethylene with the elements of the
chlorine group can in this case be readily explained by the

118 CONSTITUTIONAL FORMULAE.

tendency which the carbon atoms exhibit to combine in the
simplest possible way. However this may be, it can be easily
shown that the first of the above formulae does not indicate the
constitution of ethylene.

The bromine in ethylene dibromide, CgH^Brg, can readily be
replaced by hydrpxyl, and by the action of hydrochloric acid on
the glycol, C.2H^(OH)2, thus produced, ethylene chlorhydrin,
CgH^ClOH, is formed. This substance on oxidation yields raono-
chloracetic acid, CoHgClO.OH. Hence it follows that the above
compounds possess the following constitutional formulae :

Etliylenc Ethylene Alcohol or Ethylene Mono-chlor-

Dibroinide. Glycol. Chlorhydrin. acetic acid.

CH-Br CH0.OH CH2CI CH2CI

I I " I I

CH^Br CH2.OH CHjOH CO.OH.

By a moderate oxidation ethylene alcohol can be converted
into glycollic aciid, C2H^03, by replacement of two atoms of
hydrogen by one atom of oxygen. This reaction is exactly
parallel to the formation of acetic acid from ethyl alcohol,
and hence the following formula must be given to glycoUic
acid:

CH..OH

CO.OH.

The truth of this is easily proved by the fact that glycollic
acid is also formed when a salt of chloracetic acid is boiled with
water :

CH.Cl CH2.OH

+ HOH = I 4- KCl.

CO.OK CO.OH

Glycollic acid contains two hydroxyls in different positions ;
one of these may be termed the alcoholic hydroxyl, because it
tjccupies the same position as the hydroxyl in alcohol, whilst the
other playing the part of the hydroxyl in acetic acid, and capable
of having its hydrogen replaced by metals, is, on this account,
tailed the basic hvdroxvl.

-fVs wc may assume that analogous constitution gives rise to
analogous properties, we may predict that glycollic acid will act
jMirtly as an alcohol and partly as an acid. This is found to be
the case. Kxnctly as we obtain ethyl chloride by acting on

T20 ISOMEmiSM.

and this was confirmed by the discovery in tlie following year
by Wilham Henry of the existence of a 8imilar hydrocarbon in
coal-^as. Didton states ** that the hydrocarbon contained in
oil-gas is a compound sui generis consisting of the elements of
defiant gas united in the same proportion, but differing in the
number of atoms, most probably the atom of the new giis
consisting of two of o!efiant gas."

This hypothesis was soon proved by Faraday to be correct.
In the year 1825 he published a communication " On certain
new compounds of carbon and hydrogen obtained by the decom-
position of oil by heat."* At that time a Portable Gas Company
was established in London for supplying the public with the
gas obtained from the distillation of oil, and pumped under a
pressure of 30 atmospheres into portable vessels. A considerable
quantity of a liquid was in this way condensed, and this liquid
was examined by Faraday. It readily evaporates under the
atmospheric pressure, and, like olefiaut gas, has the power of
uniting with its own volume of chlorine to form an oily liquid.
Its specific gravity proved to be double that of olefiant gas, and
its chloride contains twice as much carbon and hydrogen as
Dutch-liquid, this being the name which was at that time given
to the oil of olefiant gas from its discoverers.

Shortly before this, Liebig - had shown that the salts of ful-
minic acid |x>ssess exactly the same composition as the corre-
sponding salts of cyanic acid. In a note to his memoir ^ Faraday
refers to this di.scoverv, and adds the foUowinif remark : — " In
reference to the existence of bodies composed of the same
elements, and in the same proportion, but differing in their
qualities, it may be observed that, now we are taught to look
for them, they may probably multiply upon us."

Notwithstanding these early observations, many chemists
believe<l that some error had been made in the analyses of
these substances. Thus, Bi.»rzelius was una])le to conceive that
bodies could exist having the s:une composition but possessing
tijtally different i)roiK»rties. When, however, Wohler proved in the
year 1828, that ammonium cyanate can be converted into urea,
ami when BiTz.-lius liiiuself ten years later showed that raccmic
acid and tartaric acid have the s:ime coini)osition, the fallacy
of the old axiom Ix/caine evident, and it was generally acknow-
li-dged that cht'iiiu-al conij)ounds possessing the same qualitative

» Phil Tnnis. 182.'.. 440. > Ann. Lhim. Phya. xxiv. 298.

^ L*c. (it, ji. 460.

ISOMEKISM IN THE RESTRICTED SENSE. 121

and quantitative composition need not necessarily exhibit the
same physical and chemical properties/

Berzelius himself admitted that the doctrine of isomerism
had now been completely confirmed, inasmuch as the same
number of the same elementary atoms arranged in different
ways not only may give rise to compounds having a dissimilar
crystalline form, but exhibiting distinct chemical properties.
To compounds of the latter kind Berzelius gave the name of
isomers (from la-ofieprj^; ; lao<: equal ; fiepo^, a share or portion),
and soon afterwards he divided these, on the one hand, into
those to which we now give the name oi polymeric compounds,
because they possess a diflferent molecular weight, and, on the
other, into those termed mctamcric bodies, which, with an
equal molecular weight, exhibit different properties.

Since Berzelius's time a large number of such bodies have
been discovered. The radical theory and the theory of types
are capable of explaiuing many cases of isomerism, but it was
not until the doctiiue of the linking of atoms was established
that a clear light was thrown on this subject.

The causes which can produce isomerism are numerous,
and hence we must divide isomeric bodies into different groups.

82 Isomei'ism in the Eestrided Sense. The compounds classed
under this head all contain carbon atoms in direct combination,
and their isomeridcs have the same n\olecular weight.

Let us in the first place investigate the cause of those cases
of isomerism which can be predicted by theory, and notice how
far these predictions have been found to agree with the facts.

The simplest hydrocarbons are those of the series C„H2n + 2.
It is clear that in this series, cases of isomerism can only occur
when the carbon atoms are combined in different ways with one
another. Hence the three first terms of the series cannot give
rise to isomeric forms, and the following substances are the only
ones known :

Methane. Ethane. Propane.

CH,

CH3

CH, I CU,

CH3

CH3.

The fourth term, C^U^q, of the series is derived from propane

» Pojj. xix. 326.

122

ISOMERISM.

by the substitution of one atom of hydrogen by methyl.
This replacement may, however, take place either at the end
of the chain of carbon atoms or in the central carbon group.
Hence two isomerides exist and both of these are known :

Butane.

CH,

I
CH,

Isobutano.

CH,

CHj — C — CH3
CH,

Three isomerides of the next member of the group, CgHj^, are
possible, and these are all of them known :

Pentone.

CH,

I
CH.

Isopentane.

CH3 CH,

Tetramethylmethane,

CH.
CH,
CH,

\ /
CH

I
CH,

CH,

CH,— C— CH,

I
CH,

The number of possible isomerides increases rapidly as wo
ascend the scries. This is seen by the following table : '

(

No. of carbon atoms ....

, So, of |>ossil<le isonivric paraffins

1 '234

5 G

78 9

I I
1112

10: 11

12 i 18

3.5.9 '18 35 75 159 357 799

I I I I I • I '

Of these, however, only a relatively small number has as yet
been prepared.

When an atom of hydrogen in a paraffin is replaced by
a monad element or radical, the comiK)und3 of the alcohol
Ttodioals are obtained. In this case isomerism commences in
the third series, and two propyl alcohols, CaH^O, are known,
viz. :

' Cayler, "On the analytical furmn rallotl trwji, with applications to tho
tlieon* of chrniioal conihi nations," Jirit. j-lstnr. Hep. 1S75, 257. Kor'alrnlattHl by
l>r. Hermann of Wiiitzburg. thf two Inxt an' 3.'i5 an<l *^<"2.

ISOMERISM IN THE RESTRICTED SENSE. 123

Primary Secondary

Propyl alcohol. Propyl alcohol.

CHq CH-

CHj CH.OH

CHo.

2.0H CH3

Four butyl alcohols, C^Hj^O, can in like manner exist accord-
ing to theory. These are all of them known^ viz. :

(I)

rimary
oimal.

(2)
Secomlary
Koriual,

(3)
Iso-alcohol.

Terti«i7.

CH,
CH,

CH3

CH,

CH« CH«

\V '

CH, CH,
\ / ^

■•

C.OH

CH,

CH.OH

CH».OH

CH,

CHs.OH

CH,

Nine pentyl alcohols, C^HjoO, can exist according to theory,
of which only seven are as yet known.

If two atoms of hydrogen in a paraffin be replaced, isomeric
comi)ounds are obtained in the second term of the series.
Thus we have :

Ethyleue Giloride. Ethideno Chloride.

CHgCl t^Ha

CH2CI

CHClj

The chloride CaHgClg can exist according to theory in four
modifications :

. (1) (2)

Trinictliene Projjylene

Chloride. Chloride.

CHoCl CH3

CH2 CHCl

I I

CH.,C1 CH^Cl

In the case of the hydrocarbons, CnHon, a larger number of
isomerides can exist than is possible in the case of the marsh-
gas series. Thus, for example, we know^ only two butanes but
three butylenos :

(3)

Propidene

Chliiride.

Propionene
Chloride.

CH,

CCI,

CH,
CH,

CH,

CHC!,

124 ISOMEUISM.

a-Butvlcue. ^-Butylcne. Isobutylene.

CH3 CH, CH3 CH,

I I \/

CHg CH C

II II

CH CH CHj

CHg CHjj

It has already been stated that the hydrocarbons of the series
CnH2n have been assumed to contain free combining units. If this
wer^ the case, four propylenes and eight butyl enes must exist.
If, however, these hydrocarbons be supposed to contain two
carbon atoms having a double linking, only one propylene and
three butylenes can exist, and this has been proved to be the
fact.

In the case of the hydrocarbons of the series CnH2u-2» a still
larger number of cases of isomerism are possible. Thus, for
instance, we have two substances having the formula CjH^.

Allylene. Iso-allylcne.

CH3 CHj

CH CH.,

A large group of carbon compounds are derivetl from benzene,
Cgll^,. In these the carbon atoms are linked together in a
peculiar way, the nature of which will be hereafter explained.
The homologucs of this series are formed by the replacement
of one or more atoms of hydrogen by alcohol radicals, and
hence a variety of isomerides is formed, such as the foUovsing:

(1) (2)

Kthyl-lwiizoiio. Dimethvl-bcnzeiie.

(1) (2) (3) (4)

IVopyl- Isopropyl- Mctbyl-cthyl- TriiuHthyl-

bi'iizeue. K'uzeiie. benzene. bonzrnt*.

c.Hj.c^H- c,h,.(;h,ch,;, c«h,|J!'J|' c,H3|(!h;;

V^ Oil

• mch.

The foregoing cases do not, however, oxliau t the number of
r.xisting isomeric bodies, inasniuch as two or moio atoms of

METAMERISM. 125

hydrogen in the benzene may be replaced, and this replacement
may take jJace in diflferent positions in the molecule. Thus, as
will be seen hereafter, there may be three isomerides having the
composition of dimethyl-benzene, of methyl-ethyl-benzene, and of
trimethyl-benzene ; thus four hydrocarbons having the formula
Cj,Hj(j exist, and eight having the formula C^H-y

In these compounds, moreover, not only the hydrogen in the
alcohol radical, but that in the benzene residue may be replaced
in different positions, and thus the existence of a still larger
number of isomerides in the benzene derivatives becomes
possible.

83 (2.) MetamcrUm, The compounds classed under this head
possess the same molecular weight, but contain two or more
carbon groups connected together with a divalent or polyvalent
radical. The number of bodies which may thus be grouped
together is very large. A few simple examples will here suffice.
If an atom of hydrogen in an alcohol be replaced by an alcohol-
radical, an oxide or ether is obtained. Thus the following
substances can be obtained, all having the composition CgHj^O.

(1) (2) (2)

3Iethvl-i»entyl Ethyl-butyl Dipropyl

ether. ethor. ether.

CH3 ) ^ C..H, \ ,-. C,H. 1 ^

c^Hu / ^ c:h; / o c;h; } o-

Inasmuch, however, as the radical propyl can exist in two
isomeric forms, butyl in four, and pentyl in nine, it is possible,
according to theory, that sixteen ethers having the above general
formula may exist.

The so-called compound ethers or ethereal salts form a very

important class of isomeric bodies. Thus, for example, the

following compounds of the general formula C^H,oOo are
known :

(1) (2) (3)

Metliyl Ethyl Propvl

pentylate. butynite. propionate.

CH3I0 C.,H,)n C,HaA

and in this case the variety of constitution exhibited by the
radicals leads to the formation of eight distinct isomerides.

As a last example the amines having the general formula
CjHgN may be cited :

126 ISOMERISM.

(1) (2) (3) (4)

Propylamine. Isopropylamine. Methylethylamine. Trimethvlamine.

(C3H. rCH(CHJ. fCH, jCH-

(H (H (h (CH3.

The two first substances are isomeric compounds, the others
metameric.

84 (3.) Polymerism. This division contains compounds pos-
sessing the same composition, but differing in molecular weight.
The hydrocarbons of the series CnH^ may serve as an example :

Ethylene C.,H^

Propylene ^3^5

Butylene C^Hg

Pentylene ^5^10.

The following compounds are also polymeric :

Acetylene ..... CgHg

Benzene C^,Hg

Styrolene CgHg

Uihydronapthalene. . CiqHj^j

Tetrahydroanthracene . Cj^Hj^

Distyroleno .... CigHj^.

As another series we have :

Formyl aldehyde . . CH2O

Acetic acid .... C^H^O,

Lactic acid .... CjH^O,

Grape sugar . . . C^HjjO^

And again :

Acetaldehyde . . . C^H^O
Butyric acid . . . C^HgOg
Paraldehyde . . . C^Hi^Oj.

85 (4.) Physical Isomerism. A number of bodies are known
which according to their general deportment must be considered
to possess the same chemical constitution, but which exhibit
certain distinct differences in physical properties. Thus, they
may crystallize in different systems or possess different melting
points. These substances can readily be converted from the
one into the other modification, and their isomerism is probably

POLYMERISM. 127

due to a different arrangement of their molecules, analogous
to the dimorphous and trimorphous inorganic compounds.

Many carbon compounds possess the property of rotating the
plane of polarization, and such compounds generally exist in
two or three modifications, assuming distinct optical properties,
as for instance that of turning the plane of polarization more or
less either to the right or to the left. In the case of crystalliz-
able compounds this difference is rendered evident in the
existence of hemihedral faces, which in one modification lie
to the right in reference to the other faces, and in another
modification lie to the left, so that the one crystal is the
reflected image of the other. In the case of liquids a similar
difference in molecular structure is exhibited in the phenomenon
known as circular polaHzation, a property which is possessed by
a large number of organic liquids. It has been pointed out by
vant Hoff ^ and LeBel,- that all optically active bodies contain
one or more assymetric carbon atoms. By this is meant a
carbon atom connected with four dissimilar groups of atoms,
as shown by the following examples :

Optically active ,«■ i. .,

^yl alcohol. ^'*^^^ ^»^-

C^Hj CO.OH

H2.OH

Hence we may conclude that optical isomerism is probably
caused by different relative arrangement of the atoms which
form the molecule. Further information on this point will be
given under special heads.

86 (5.) Unexplained Isomerism. Lastly, cases of isomerism
occur for which, up to the present, we have no sufficient expla-
nation. Many cases of this kind have been long observed, but
some of these have disappeared on finding that the differences
were merely due to impurities contained in the substances.

On the other hand, cases are known of distinctly pure sub-
stances differing in their chemical properties and yet possessing
the same constitutional formulae. This, however, is not any

1 Xa Chxmie dans VEspace. ' Bull, Soe, Chim, [2], xxii. 837.

128 CLASSIFICATION OF THE CARBON COINIPOUNDS.

contradiction to the law of the linking of atoms, as might be
supposed, but simply points to the conclusion that graphical
formulae cannot represent the arrangement of the atoms in
space, about which, in fact, nothing is known. These rational
formulae possess a somewhat similar meaning to the parallelogram
of forces in mechanics. They simply serve to give us a notion
of the attraction which the single atoms in the molecule exert
upon one another.

Compounds in which the isomeric relations cannot yet be
explained, can as a rule be readily transformed one into the
other.

CLASSIFICATION OF THE CARBON

COMPOUNDS.

87 The carbon compounds may be classed in different groups
according to the mode of linking of the carbon atoms.

I. The Fatty Group, To this belong all compounds in which
the carbon atoms are connected together by a single linking as
in the paraffins and their derivatives. The group receives its
name from the fact that several of its compounds, such as the
acids of the series CnHouOa and others, occur in the fats of
animals and plants. A characteristic property of these sub-
stances is that their chemical metamorphoses are principally
brought about by substitution, that is, by one atom or group of
atoms being removed and other gniups occupying their places.
For this reason the members of the fatty group have also been
termed saturated compouwh,

II. CompouiuJs containing rdatirelif less Jnjdrogen than the fore-
going. These contain carbon atoms united by double or triple
linkage. Tlie hydrocarbons which belong to this group form the
following series :

<;h.„..

These compounds, as well as their substitution-products, are
termed unsaturated comjwxnuh, as they possess the characteristic
property of combining directly with hydrogen or with the

TIIK A150MATIC GliOUP. 120

elements of the chlorine group or their hydracids, and thus
become saturated compoundH hy addition. Tliis is caused by the
nipture of one of the links of a doubly-linked carbon atom.
The inverse operation can also be carried out, and the various
hydrocarbons of this group can readily be obtained by the
removal of hydrogen or chlorine from the saturated fatty
compounds.

III. The Aromatic Grouf. The compounds belonging to this
group are relatively much richer in carbon than those of the
fatty group. In many chemical metamorphoses, however, they
resemble the members of the latter group, as for example in
their power of readily forming substitution derivatives. Only
in rare instances do they yield additive products, and these, .
it is important to note, are not fatty bodies. Thus, for instance,
the simpler hydrocarbons belonging to this series and having the
general formula CnH^n-o are isomeric with the compounds of
the second group of bodies, containing relatively less hydrogen.
But whilst these latter by the addition, for example, of bromine,
yield octobromides, CjjH^jBr^, only six bromine atoms can bo
added to the simplest aromatic hydrocarbon yielding the hex-
bromide, CgH^jBr^. Hence we conclude that these compounds,
rich in carbon, consist of groups of do^d chuim, each containing
six atoms of carbon. The name arom/itic group has been given
to these because many of the bodies belonging to the group
are contained in ethereal oils, balsams, gum-resins, and other
bodies posseseing an aromatic smell.

IV. Compoiuids of Unknown Constitution, A number of the
compounds occurring in the vegetable and animal organism,
possess constitutions so complicated that their determination has
hitherto not proved possible. Indeed, not many years have
elapsed since this remark applied to by far the larger number
of organic compounds. By degrees, however, this group is be-
coming smaller, and in process of time it will doubtless entirely
disappear.

88 Different Methods of Clas.nfication, Each of these chief
groups contains several subdivisions, and these may be arranged
in different .ways. Perhaps the most systematic method of
arrangement would be to commence each group with a discussion
of the hydrocarbons, and then to follow on with a description of
the series of substances obtained by the replacement of one,
two, three, or more of the constituent atoms of hvdrogen.
Such a method of classification, however, lal>»ur8 under the

VOL. 111. K

130 CLASSIFICATION OF THE CAKDON COMPOUNDS.

disadvantage that compounds which stand as a rule closely
together, as, for example, the alcohols CnH2ii+20 and the acids
OnH2ii02, are thus found widely separated, whilst other groups
possessing but little analogy, except m their empirical formulae,
are brought into proximity.

Hence it is desirable, alike for the sake of perspicuity as for
the purpose of showing the genetic relationships existing be-
tween different bodies, to depart, in many cases, from such a
systematic treatment and to arrange the compounds according
as they are derived one from the other.^

FATTY BODIES AND COMPOUNDS CONTAINING
RELATIVELY LESS HYDROGEN THAN THESE.

89 Hydrocarhons of tlic Series C^-Hin+s or the Paraffin Series.
Before the year 1848 none of the hydrocarbons belonging to
this class were distinctly known, with the single exception of
marsh-gas, the first term of the series. Chemists had, however,
met with other members of the series, and had examined their
properties, but their true nature was not fully understood.
In the above year the investigations of Kolbe ^ on the electro-
lysis of the fatty acids, and those of Frankland ^ on the action
of zinc on the iodidus of the alcohol radicals, opened a new
field of investi«jfation which soon yielded a rich harvest. The
hydrocarbons thus obtained were considered, from their mode of
production, as the free radicals of the alcohols.* Gerhardt,
however, proiX)sed to double their formulas in order to bring
them into co-ordination with Avogadro's law, and he con-
sidered the so-called radicals to be homologues of marsh-gas.
Hofmann* also gave his adhesion to this duplication of the
formulae, pointing out that the adoption of Kolbe and
Frankland's formuhe led to an increment in the boiling
point for each increment of CHj, double that known to exist
in other homoloijous series.

Toi(ethtT with the radicals Frankland discovered what he
believed to be a distinct series of hydrocarbons. These were
obtained by the replacement of the iodine in the iodide of the

» Kekule, Lchrbuch, i. 225.

• Ann, ChcvL Vharm. Ixix. 279 ; Chem, Soc. Jovm, ii. 157.

' " On the Isolation of tho Organic ItailicaU," Chem. Soc. Juurn, ii. 263 ;
iii. 30 ; iii. 322.

* Gerhanlt and Uurent. Cumf>t. Jlnid, 184P, 19; 18.''i0, 11.
» Chan. Soc. Jouni, ii. 121 (1850).

HYDROCARBONS OF THE PARAFFIN SERIES. 131

alcohol radical by hydrogen. Ho assumed these hydrides to be
the true homologues of marsh-gas, and according to the views
first expressed by Brodie,^ these were believed to stand in the
same relation to the radicals as the alcohols to their ethers :

Ethyl hydride. Ethyl.

H ] c,H, r

Ethyl alcohol. Ethyl ether.

Brodie likewise predicted the existence of mixed radicals,
bodies standing in the same relation to the simple radicals
as Williamson's mixed ethers do to common ether :

Ethyl ether. Ethyl.

C,H, ] ^ C,H, ]

Ethyl-amyl other. Ethyl-amyL

C5H11 ) C5H11 3 •

Such mixed radicals were soon afterwards isolated by Wurtz,
who obtained thom by the action of sodium on a mixture of the
two iodides, as well as by the electrolysis of a mixture of two of
the fatty acids. It was at this time generally believed that a
real difference existed between the hydrides and radicals, the mole-
c'lle of the latter being supposed to consist of two atoms. Still
it seemed remarkable that the isomeric members of two such
differently constituted groups not only do not differ in physical
properties, but even exhibit a close analogy in their chemical
characters. Indeed this similarity led Greville Williams,- who
discovered many of the hydrocarbons of this group in the
products of distillation of Boghead cannel, to consider them as
radicals, chiefly because the several members differed from one
another by the increment O.,!!^.

The chemical reactions of the radicals were at that time but
incompletely known. One point, however, was ascertained,
namely, that when a<;ted upon by chlorine the radicals did not
yield, as might have been expected, two molecules of the corre-
sponding chloride, but two or more of the atoms of hydrogen
of the hydrocarbon were found to be replaced by chlorine.

» Clum. Soc Jaum. iii. 405 (1851). « PhiL Trans. 1857, 447.

K 2

1.02 KADICALS AND IIYDUIDES.

The next point requiring examination was tlie action of
chlorine upon the hydrides. Duimis had already found that
the first substitution-product of marsh-gas is the compound
CH3CI, and Berthelot had shown that* this substance is identical
with methyl chloride. On the other hand, Frankland and
Kolbe had obtained from ethyl hydride the chloride C^H-Cl, a
substance which they believed differed from ethyl chloride.^

90 It was not until the year 18G2 that our knowledge of
this point became precise. In that year Pelouze and Cahours '-*
showed that American petroleum consists almost entirely of a
mixture of homologous hydrocarbons of the series CnHon^2» a^J
Schorlemmer^ found the same in the distillation-products of
oannel coal. The examination of these latter products showed
that their monochlorinated substitution-products are really the
chlorides of the alcohol radicals from which the alcohols and
their other derivatives can be prepared, and hence that the
hydrocarbons themselves are hydrides.

The next question was to ascertain precisely the nature of
the action of chlorine upon the radicals themselves, ami
Schorleminer* found that the two following : —

Etlivluinvl ami Di-amyl.

c.h/i C,H„)

O.H,J C,H,J

yielded, respectively, chloride of heptyl, C^Hj-Cl, and chloride
of decatyl, CioHmCl ; and from these the coiTesiX)nding alcohols
were prepared.^

He further proved that the radical methyl, or di-mothyl, as
it was afterwards called, is identical with hydride of ethvl,
inasmuch as not only did the existence of the differences which
had been previ»)usly observed between their physical properties
prove to be a fallacy, but both bodies were converted on treat-
ment with chlorine into ethyl chloride. About the same time
Schiiven ^ showed that Frankland's di-ethyl was converted bv
chlorine into butvl chlorMe.

From this time forward the supposed distinction between
radicals and hydrides may be said to have completely broken

* Chrm. StiC. Journ. i. 00.

' Aiin. Chim, Vhyn, [4J, i. 1 ; Ann, Chnn, Phnrm. cxxiv. 289; cxxvii. ll»0;
cxxix. 87. » Chr,H. .SW. Juitrn. xv. 411» (1802).

* ('hem StK\ Jovrn. xvi. 4'2.V • Prtii^. Una. S>n'. xiv. I'.A.

* Ann, C/"tH. Phaim, rxxx. *203 ; rxxxi. 70 ; oxxxii. 'I'M.

PARAFFIN HYDROCAKBOXS. 133

down, and it was acknowledged that in the formation of
the radicals two carbon atoms are combined exactly in the
same way as they are connected together in the other com-
pounds. That, for instance, in the radical di-methyl, the
two carbon atoms are connected together exactly in the same
way as the two carbon atoms are Unked together in the ethyl
compounds.

The lower members of this series are very volatile liquids.
The boiling point rises with each increment of CH^, and the
highest members are crystalline solids. A mixture of these latter
substances was discovered in the year 1830 by Reichenbach ^
in wood-tar. This was believed by him to be a definite chemical
compound, to which he gave the name of paraffin^ from parnm
affinis, its most important characteristic being its inactive
properties. For a long time it was believed that paraflBn
belonged to the series of hydrocarbons, C„H2n, for in those
days, as has been stated, the only member of the series CnH2n+2
known was marsh-gas. Moreover the percentage compositions
of the higher members of these two groups exhibit diflFcrences so
slight that they fall within the errors of analysis, and it becomes
impossible thus to determine to which of the two groups a
substance belongs. This can, however, be readily ascertained
when the substances are treated either with chlorine or bromine.
These elements combine directly with the group CuH2ni but act
with difficulty on the group CnH.>n+2, giving rise to substitution-
products. In addition to this, the members of the first of these
groups are easily attacked by oxidizing agents, whilst those of
the latter group are only oxidized with difficulty even by the
most energetic reagents. In this respect paraffin distinctly
belongs t^ the latter class.^ On these grounds Henry Watts ^
has suggested that the name of paraffin should be made
generic, and apj^lied to all the members of this series of these
hydrocarbons.

The paraffins are not attacked in the cold either by chromic
acid, concentrated nitric acid, or sulphuric acid, or even by a
inixture of the two latter acids, but if they are heated with
dilute nitric acid, with chromic acid, or with a mixture of
manganese dioxide and dilute sulphuric acid, they are slowly
oxidized, the greater portion being completely converted into

* Jahrh. Chem, PJnjs. (Sclnvcig^-Seidtl) xxix. -lUG.

- iVwm. Soc, Journ. xv. 419.

' Fownes, Manual of Chemistry, Tenth Edition, 5 IS.

134 PROPERTIES OF THE PARAFFINS.

carbon dioxide and water. By the action of nitric acid, small
quantities of the fatty acids as well as succinic acid and nitrates
arc produced, whilst by oxidation with chromic acid a small
quantity of acetic acid is formed.^ Chlorine, in the daylight,
attacks these hydrocarbons but slowly. The liquid become.-}
warm, hydrochloric acid is evolved, and mouochlorides are fir::t
produced. These, however, are readily converted, in the presence
of nascent chlorine, into higher substitution-products. But the
formation of this latter class of bodies may be prevented to a
great extent by passing chlorine into the vapour of the slowly
boiling hydrocarbon instead of into the liquid itself.^ The ex-
planation of this being that the mouochlorides are less volatile
than the hydrocarbons from which they are produced, so that they
condense as soon as they are formed, and thus the chlorine comes
almost exclusively in contact with the vapour of the hydro-
carbon. The apparatus must, however, be protected from the
direct sunlight, as otherwise complete decomposition takes place
with evolution of light and heat and deposition of carbon.

When the mouochlorides are treated with chlorine, further
substitution takes place, but it is only in the c^ise of the two
lowest terms of the series that the whole of the hydrogen can be
replaced by chlorine. Propane, Cgllg, can be converted into
hexchlorpropane, CjHgClQ; and hexane yields hexchlorhexane,
CgHgClg as an end product, and even these are formed with
difficulty. For in order to obtain these bodies, the decomposition
must not only be carried on in the sunlight, but as soon as the
action of the chlorine becomes feeble, iodine must be added.^
The action of this latter element dejiends upon the formation
of iodine chloride, whirh readily decomposes into its elements
the liberated chlorine in the nascent or atomic condition acting
more energetically than the same element in the molecular
state. Then the nascent iodine combines anew with chlorine,
and thus it plays a similar part to that of the oxides of nitrogen
in the sulphuric acid manufacture. The chlorination of the
paraffins can, however, be carried out further by heating the
chlorinateil products in closed tubes, together with chloride of
iodine, under increased pressure. Propane thus treated yields
in the first pla^e octochlorpropane, C^Cl^, and this, by further
action of chloride of iwliue, is converted into hexchloretbane,

* Si'horlfininor, Jim. Ch m. Phnnn, cxlvii. 214.

* Schorlciiiiiirr, /Vi/7. Trmin. 1871.

^ Sihurli-muuT, P-nc. Hoy. S-.m-. xviiL 29.

NORMAL AND ISO-PARAFFINS.

135

CgClg, and tetrachlormethane, CCl^. Under the same con-
ditions hexane yields, together with the two latter compounds,
bexchlormesol, C^Clg, and hexchlorbenzol, C^jClg.^

Bromine likewise yields substitution-products, but not so
readily as chlorine,^ but by the action of excess of bromine
under the influence of heat and pressure, substitution-products
are formed similar to those which are obtained by the action of
chloride of iodine.

CONSTITUTION OF THE PARAFFINS.

91 The paraffins whose constitution is known may be classed
under four groups.

(1) The Normal Paraffins, In these the carbon atoms are
connected together by simple linkage, no one atom being con-
nected with more than two others. Of these the following have
been examined :

Methane

CH,

Boiling
point.

gas

Heptane,

C7H16

Boiling
point.

98°-4

Ethane

C,H,

gas

Octane,

C^s^is

125°

Propane
Butane
Pentane
Hexane

C4H10

gas

38°
70°

Nonane,

Dodecane,

Hecdecane,

^12^26
^16^32

148°
202°
278°.

(2) Isoparaffins. These contain an atom of carbon connected
with three other carbon atoms, the other carbon atoms being
joined by single linkage. The following members of this series
are known :

Trimethylmethane, C H

Boiling point.

CH,

ch; - 17'
ch;

Dimcthylethylmethane, CH^ CJH.^

( aH,

4- 30'

1 Kwirt and Mfiz, Bet. Druts-h, Chrw. Ox. viii. 120rt; KraflTt, ih.
:. 801. « Schoilemnier, PhU. Tmus. for 1877, p. 41).

KraflTt, ih. ix. 10S5 ;

130 CONCTITUTrON OF THE PAKAFFINS.

• 113

f OH,
Methyldiethyhuetliauc, CII-; CHj GO

Dimethylpropylmctliano, CH-( CH., (i2

( oX

(CH,
Dimcthylbutylmethanc, CH- (!H., 91

( < '.H,
Triethvliiwjtlumo, ( IH -J ( CH"

'.Hi'

Diinethylhcptylinethaue, CH-{ OH, loo°.

(aH,.

>« I la

(3) Mesoparajjiiis. lu these two or more carbon atoms occur,
each connected with three other atoms of carbon. The name <>f
this class is derived from the fact that they stand between the
foregoing class and the group next following (fieao^, middle).^
The followin^j terms of this series are known : —

Boilin;; point.

Tetramctliyl(thaiie(CIIj)j:H.(H(rH3)- 5b'

'lViniinethvnmt:iiie(<'n;,)„('H.CH-.CH2.CH(CH.,) lOlP

P. iitamethVlbntfiin* (('M;,)>H.nit<'Il3)CI{3.CH(CH.,) 130"

Ti'tramethylhexaiie (CHaM'n.^'H-.ClIa Cn2.C'H,.CH(('IIa), . . n'2\

(4) Nvopftrt(J/ins. lu those comiwiunds one atom of carbon is
connected with four otlirr carbon atoms. From havm*'' been
lately discovenMl they have received the above name. The
following have Iktu prrjiarfd :

Boiling ]ioiiit.
Tetramethylmtthane, ('((/H.^^ l)'-.>

Trimethvlethylmethanis ( ' i ^f! \V' 45''

Dimcthyldiethylmethane. C'-[ [?}l?\ 86'.

92 JFodrs of Prrparah'cm. Various m(»rh(>ds may bo employed
for the preparation of the iiaralHns. Some of them con.sist in
bringing together two alcoliol radicals, and thus effecting direct

» Odling, rhil, Mtt'j. [:»J, i, 1(5.

PREPAR'ATIOX OF THE PARAFFIKSf. 137

synthesis, as in reactions 1 and 2. Another method, as in re-
actions 4, 5, and 6, is that of liberating the alcohol radical from
a compound and bringing it into combination with hydrogen.
Paraffins are, therefore, obtained by the following reactions:

(1) An alcoholic iodide is heated with zinc to 150° (Frank-
land). In this reaction a compound of the radical with zinc is
first formed, and this is decomposed by an excess of the iodide.

(a) 2 Zn 4- 2 C^H J = Zn(C.,H,)2 + ZnT^
(6) Zn(C,HJ, + 2 CH,I =2 C,H,, 4 Znl^.

(2) Sodium acts in a similar way to zinc, but much more
readily and at a tower temperature (Wurtz). If a mixture of
two iodides, such as those of ethyl and amyl, be employed, the
following reaction takes place :

C,H,I + C.H,^! + 2Na = C.U^^A- 2NaI.

At the same time the hydrocarbons butane (diethyl) and tetra-
methylhexane (diamyl), Cj^IIgQ, are formed by reactions which
are readily understood.

These, however, are not the sole products either of this or of
Frankland's reaction, inasmuch as a small portion of the paraffins
decompose into lower members of the paraffin group and into
the hydrocarbons of the series C„Hon. Thus by the action of
zinc upon ethyl iodide, not only do we obtain butane, but also
ethane and ethylene :

The higher members of the series are especially apt to
undergo such decompositions. Thoq^e and Young ^ found that
when solid "paraffin'' is repeatedly distilled it yields liquid
paraffins which, according to their boiling points, appear to be
normal ones, the w^hole series, beginning with pentane and
reaching up to C^^H^q, being present ; and at the same time the
corresponding hydrocarbons of the series CnHon are produced.

(3) The paraffins may be obtained synthetically by the
electrolysis of the fatty acids (Kolbc). The decomposition
which here occurs will be fully described under the particular
acids. The first paraffin obtained in this way was tetramethyl-
butane or dibutyl, formed from valerianic acid :

2C,Hy.C00H = CgHig-f 2CO,+ H2.

* Chcm, S(K', Jtnirn, xxvi. 2C0.

138 PREPARATION OF THE PARAFFINS.

(4) When an alcoholic iodide is heated with zinc and water
to 150° a paraffin is produced, whose molecule contains the
same number of carbon atoms as the iodide :

2 CgHjI + 2 Zn + 2H,0 = 20 Jl^ + Znlg + Zn(0H)2.

In this case also, the zinc compound of the alcohol radical is
first formed, and this is at once decomposed in contact with
wat<5r. Hence pure paraffins can be readily obtained by bringing
such a zinc compound into contact with water, which acts upon
it with great energy :

Zn(C,H,), + 2H,0 = Zn(OH), + 2 C^H^

Certain of the other metallic compounds of the alcohol
radicals are decomposed by w\ater in the same way, others,
again, such as the mercury compounds, do not act on water, but
are easily attacked by acids :

Hg{C,H,), + HCl = C,H, + Hg(C,H,)CI.

(5) Nascent hydrogen eflFects an inverse substitution in the
iodides. Thus if hexyl iodide be brought in contact with zinc
and hydrochloric acid, hexane is funned :

C^a^i J + Ho = CqH.^^ + HI.

The following reactions, however, take place at the same
time

(a) 2 C,H,3l + Zn = O.oH,, + Znl,

{hj CjoHjg = CoHj^ -I- CgHig,

thus giving rise to small quantities of hexylene and dodecane.

(6) When an alcoholic iodide is heated with an excess of
hydriodic acid a piraffin is formed together with free iodine.
As hydrio<lic acid ooiiverts all the alcohols, even those of the
polyvalent radicals, into io<lides, the alcohols can be readily
converted into ]>araffins. Thus when mannitol is heated with
hydriodic acid the following reactions occur :

(«) C.H,(OH)« + 1 1 HI = C„H„I + 6 H,0 + 5 I,
(i) QHi,I + HI = C.H„+Iy

Bcrtholot ^ has indeed shown that when a large excess of con-
centrated hydrio<lic a<*id is employed, and the mixture exposed

1 A»n, Chwi. Phys, [4] xx. r.92.

FORMATION OF THE PARAFFINS. 139

to a high temperature, ahiiost every carbon compound can be
converted into a paraffin or a mixture of these substances.
Thus, for example, butyric acid and succinic acid treated in
this way yield butane :

(a) C.HgO^ + G HI = C.Hjo + 2 HgO + 3 1,
(6) C,H,0, + 1 2 HI = C,H,, + 4 HgO + 6 1,.

and aniline by this treatment yields hexane :

CcHyN + llHI = CcH,, + NH,I + 5Ij.

Wood, coal, and even charcoal thus treated yield mixtures of
paraffins. Graphite, on the other hand, remains unchanged.

As free iodine may, in these cases, give rise to complications, it
is advisable to add amorphous phosphorus in order to prevent
the liberation of iodine.

(7) Paraffins are likewise formed when the fatty acids or acids
of the series CnHoii-oO^ are heated with alkalis. Acetic acid
thus treated yields methane :

CH3.CO.ONa H- HONa = CH, + CO(ONa),,

whilst by heating suberic acid with baryta hexane is obtained:

CflH^gCCO^H). + ^Ba(0H)2 = C^H,^ + 2BaC03 + 2,11,0.

These reactions are, however, usually not simple ones, a larger
or smaller quantity of bye-products being at the same time
formed.

93 The hydrocarbons obtained by dissolving cast-iron in acids
also contiiin piraffins. By dissolving a manganiferous spiegel-
iron in dilute sulphuric acid, Cloez obtained a lu^uid in which
the series of paraffins from decane, C^oH.22* ^ hecdecane, Cj^Hj^,
were contained.^

Paraffins are also formed by the direct distillation of wood,
coal, bituminous shale, fatty oils, resins, animal matter, and other
organic substances. It has already been stated that Reichen-
bach was the first to obtain the solid members of the series.
In tliis way he also obtained a mixture of the lower members,
which are usually liquids. To this mixture he gave the name
of cupion (ei, good, and ttcov, fat). He observed that these
liquids are not attacked by sulphuric or nitric acid, or even by
potassium or the alkalis.^ Frankland' then noticed that the

^ C(mpi, Rend. Ixxxv. 100.3. • lb. Ixxiv, 57.

' Ana, Chem. Pharnu xiii. 217.

140 OCCUURENX& OF PARAFFIXft

lower boiling portion of this prolxibly consisted of |>eutaQe
(amyl hydride).

Liquid paraffins occur together with solid products in very
large quantities in the products of the distillation of coal or
of bituminous shales containing largo quantities of hydrogen,
such as Boghead cannel (Greville Williams), and cannel coal
(Schorlemmer). From their boiling-points, these all appear
to belong to the normal series of paraffins, and in this
respect resemble those obtained by the distillation of the
lime-soap obtained from Menhaden oil (the oil of the fish Alosa
Menhaden). *

Paraffins also occur in nature. Several are contained in the
different kinds of petroleum. That which is now obtained in
such enormous quantity from Pennsylvania consists almost ex-
clusively of normal paraffins, containing, however, together with
these, small quantities of isomerides, whose constitution has not
yet been ascertained, as well as other series of hy<lrocarbons,
such as the groups CnHsn, CnHon-o, and probably also groups
lying between these.^

Petroleum almost always contains solid paraffin. Canadian
petroleum is especially rich in these solid products, as is also
that obtained by the distillation of Boghead cannel. Indeed,
this latter substance contiins a portion of the solid paraffins
already formed, as may be shown by extracting it from the
mineral vith ether. "^

Similar compounds occur as minerals in the coal measures as
well as in the deposits of brown-coal and bituminous shale.
These are known under the names of oajkerite, hatchettite,
mineral tallow, mineral wax, i^'c. A solid paraffin, which pro-
bably possesses the fornmla t'l^Hg^, is contained in the oil of
roses, and se^xirates out in the crystalline form on cooling
the oil.

A very remarkable occurrence of nonnal heptane has lately
been o])S<'rved by Thorpe* in the resin from a Califomian pine
{Pinus sahinianu). This will be described more specially
hen 'after.

94 Appliratiini of rarajjins, Paraflin as obtiiined on the

* Warrr-ii nml StonT, Mem. Jmcr. Acad. ix. 208.

' SchorlcmiinT, yViiV. Tntns. 1871, vol. clxii. \mTt i. p. Ill ; Chrm, St^\
Journ, [2J, viii. *J16 ; Warrrii, Sillinunis Amrr. Jtwnt. xl. b9, 21C ; Pelouze nml
C'aliourfl, Comjtf, lit lul. liv. I'JJl ; Ann. Chiin, Phys. [4J, i. 5.

' IJoll»'y, A'ut. f'hftn. Phnnu, txv. 61.

* Cheui, .V'/r. Jvurii. 1671*.

AFPLK^ATIONSOF PA1UFFIN3. Ul

manufacturing scale is not chemically pure. The commercial
products always consist of mixtures of paraffins, and frequently
contain hydrocarbons belonging to other series.

The tar obtained by the distillation of bituminous shale.
Boghead caunel, brown-coal or peat, is worked up for a variety
of products, of which the most .important are ; (1) naphtha,
chiefly used as a solvent ; (2) illuminating .ojls, known in com-
merce as kerosene, photogene, paraffin-oil, solar oil, mineral
sperm-oil, &c. ; (3) lubricating oils; and (4) solid paraffins, used
for candle-making, &c.

In order to obtain these several products, the crude oil,
after it has been separated from the watery products of distil-
lation, is distilled a second time, when coke jremains behind.
The distillate is then treated with caustic soda in order to
remove phenol (carbolic acid) and similar bodies which im-
part a disagreeable smell to the oil. Then it is brought
in contact with sulphuric acid, which takes up certain basic
compounds whi«h also have a disagreeable odour, and at the
same time decomposes other bodies which impart a dark
colour to the oil. It is then washed with water and dilute
soda-lye and rectified. The first product which comes over
is the naphtha, the second distillate is the illuminating
oil, and after this comes the portion which is employed
either alone or mixed with other suitable oils for lubricating
purposes. As soon as the distillate begins i)artially to solidify,
the receiver is changed, the solid portions being allowed to
separate out in a cool situation as long as they will crystallise.
The liquid is then drawn off and used as a lubricant, and the
solid mjiss freed from the adherent liquid, dried in a centrifugal
sieve, and then pressed in hair mats placed between iron plates
heated to between 35"* and 40°. The solid mass is then melted
and heated to laC, when it is mixed with 2 per cent, of sul-
phuric acid in order to decompose all adherent impurities. It
is next washed with hot water, and lastly crystallised from
solution in the higher boiling portions of the naphtha. The
mother-liquor is poured off from the crystals, and any adherent
mother-liquor removed from the fused mass by treatment with
superheated steam. The solid paraffin thus obtained is w^hite
and oilourless. As it is a mixture of different compounds, the
melting-point of the different kinds varies between 40'' and G0^
When warmed in the air at a temperature above 120°, it begins
to evajx»rato, and at the same time absorbs oxygen, and becomes

142 OCCURRENCE OF PARAFFINS.

yellow. When the mass is extracted with alcohol, the unaltered
paraffin dissolves, a soft brown elastic mass remaining behind.*

Solid paraffin is also obtained in large quantities from the
impure naturally occurring ozokerite or mineral wax. This is
found at Borislav, in Gallicia, and elsewhere, in the form of a
yellow solid of the hardness of common beeswax, which is
purified by a process similar to that just described.

Solid paraffin is chiefly used for the manufacture of candles.
It is also used in chemical works and laboratories in place of
oil for obtaining constant high temperatures, and for the purpose
of rendering caoutchouc joints tight.

95 PetroUtcm (oleum petrcc), also known as rock-oil or
naphtha. Herodotus states that a substance known as pis-
acuspludtum was obtained from the island of Zante, and was used
for the purpose of embalming. Plutarch mentions the occurrence
of the burning oil at Ecbatana, and Dioscorides, as well as Pliny,
state that the rock-oil from Agrigentum in Sicily was used for
illuminating purposes.

Other localities in which springs of rock-oil occur have been
known for many centuries. These natural oils remained, how-
ever, for a long time almost unused, only small quantities of
the product coming into the market, and being chiefly employed
either for medicinal purposes or as lubricants. These sub-
stances were not introduced on the large scjile until the year
1859, when the remarkable petroleum industry of the United
States arose, and the demand thus aroused soon stimulated the
production in other countries.

Petroleum is an unpleasant-smelling substance which, accord-
ing to its place of occurrence, is either a colourless or yellowish
liquid, usually possessing a bluish lustre, or a bn)wn or bltu'k
semi-solid buttery mass, gradually approaching in appearance
the various minerals known as mineral-pitch, asphalt, or mineral
resin, which have been formed either by the volatilization of
the liquid hydrocarbons or by their gradual oxidation. The
different kinds of petroleum are all mixtures of a number of
hydrocarbons occurring in varying pro|x^rtions.

Petroleum is found in almost all the geological formations from
the oldest up to the most recent of the stratified rocks. The
oil-region of Pennsylvania is a narrow band about GO miles
in length, lying between Pittsburg and Lake Erie. It occurs,

^ Bolley, Schictiz, PoiyL Zcilsch. xiii. 65.

ORIGIN OF PETROLKUM. 143

like the Canadian deposits, in the Devonian formation.^ These
latter extend over a large area, lying between Lake Erie and
the River Hudson. The deposits in Ohio, Virginia, Tennessee,
Kentucky, and California are of less magnitude.

A variety of theories have been broached to explain the
origin of the petroleum springs.^ That which is generally
received is that petroleum is a product of decomposition
of organised mateiial. On the other hand, Byasson* and
Mendelejeflf* are of opinion that it is produced by the infil-
tration of water into the interior of the earth, where, coming in
contact with molten iron or other metals containing combined
carbon, it forms petroleum exactly as a similar mixture of hydro-
carbons is obtained by the solution of cast-iron in dilute acids.
This hypothesis is rendered somewhat more probable by the
observation made by Silvestri ^ of the occurrence of petroleum
in certain lavas of Etna. This amounts to 1 per cent, of the
solid lava, and consists partly of liquid products boiling from
79"" to 400°, and partly of solid paraffins.

In addition to the above-mentioned sources of petroleum, the
following rock-oil springs are of importance. Those already
mentioned, situated in the island of Zante ; those in the Crimea
and the Caucasus, where at Baku, on the west shore of the
Caspian, the sacred fire has burnt for an unknown period, and
where, especially in summer, the springs are so powerful that
a jet of oil issues to a height of 30 feet. Other well-known
sources of petroleum occur in Persia, Burmah, India, China, in
Trinidad, Barbadoes, &c. In Europe petroleum is also found
in Italy, Gallicia, Bavaria, Hanover, Holstein, and Alsace.

96 Hie Petroleum arid Paraffin Oil Manufacture took its rise in
England about the year 1847, when a spring of dense petroleum,
having a specific gravity of 0 9, was discovered in a coalmine at
Alfreton, in Derbyshire, by Dr. Lyon Playfair, who communicated
the fact to Mr. James Young and Mr. Meldrum. In conjunction
with Mr. Meldrum, Mr. Young succeeded in rendering this
available for a period of two or three years. After this period
the spring was exhausted, and it became necessary to seek for a
source from which a material similar to petroleum could be ob-
tained. Common coal, such as that from which Beichenbach

* Die PetroleumiTuiustrU KordamerUcas^ "Wicn, 1877.
- Neucs JIandwdrterbuchf iii 39.

» MonU, Scientif, 1876, 1077. * Piivue Scientif. 1877, 409.

* Qaz, Chinu Ital. 1877, 1 ; Zeitsch, Kryst, L 402.

144 AMKKICAN OIL-WELLS.

first obtaiaed parafiin oil and paraffin, yields, however, so small
an amount of tar products on distillation that it was impossible
to employ this as a source of petroleum. Mr. Binney found
another natural source of petroleum in a peat bog at Down-
holland, and he endeavoured, unsuccessfully, to obtain this
substance artificially by the destructive distillation of the peat.
Another material was, however, discovered, somewhat approxi-
mating to coal, or intermediate between bituminous shale and
what is. commonly known as coal, at Bathgate, in Scotland, and
this was being introduced for gas-making under the name of
Boghead gas-coal just about the time when the exhaustion of the
petroloum spring in Derbyshu*e caused Messrs. Biuney and Young
to search for another source of paraffin for the preparation of
lubricating and burning oils. After many trials with other
materials Mr. Young, in 1850, became ac^iuainted with the
Boghead or Torbane Hill mineral, and found that it yielded on
distillation an unusually large amount of paraffin. He at onco
obtained a patent (No. 13,292) for the manufacture of oils from
it, and thus founded the well-known works at Bathgate, which
exist to the present day, for the preparation of paraffin oils and
solid paraffin.

97 Amcricayi OU-urlls. The occurrence of jxitrolcum in Penn-
sylvania had lonj; been known, and the Indians were in the
habit of employing it as a medicine for outward application.
At the beginning of this century a gallon of this rock-oil cost
upwards of £4, but in the year 1843 its i)rico had sunk to five
shillings. Tiio first j)roposition to employ boro-holes fur obtiiin-
ing a supply of the petroleum was made by G. H. Bissel, and
ontlie 27th August, 185J), Mr. Drake oj)oned the first bore-hole
at Titusvillo. This gave a daily yield of 880 gallons of oil.
Sh(»rtlv afterwards the oil mania broke (»ut. and this reached its

maximum in the year 1801, when Funk bored the first flowin.^^-
well, which yielded daily about 10, QUO gallons, and shortly after-
wards another spring which yielded over 100,000 gallons jkt diem.
Since this time a large number of ecjually fruitful wells have
bei*n l)ored.

Crude petroleum was first worked u]) for illuminating oil,
which, as soon as improved lamps for burning petroleum were
introduced, became widely used throughout Europe, thus giving
rise to the petroleum industry in Crtna<la, Gallicia, and other
places. The oil wells of r«nn.<ylvania yield annually over twenty
million of gallons of oil.

AMERICAN OIL WKLLa 145

The oil is accompanied by a considerable quantity of gaseous
products. These chiefly consist of hydrogen, marsh-gas, and
ethane.* The amount of the gas thus evolved is in some
localities so large that it is used not only at the spot where
it issues for heating and illuminating purposes, but is carried
in pipes for very considerable distances serving to heat boilers,
blast-furnaces and puddling-funiaces, &c.

The following description from the pen of Professor Lawrence
Smith * gives some idea of the size of these gas-springs : — " The
principal oil-wells are found in Butler county, Pennsylvania, lat,
40"* 30', long. 80^ Wells of minor importance are also found
in the neighbouring counties. The two most productive wells
are those of Bums and Delameter, about 30 miles from Pitts-
burg. Their depth is about 1,600 feet, for they are bored down
to the fourth layer of sand. The Burns well has never given
oil, but the one at Delameter was a petroleum well of 1,600
liters; it now gives gas at such a pressure that plummet-lines
weighing 800 kilos can be drawn out of it with the hand. The
Delameter wfcU is situated in a valley surrounded by mountains,
and furnishes heat and light to the whole neighbourhood. A
large number of pipes diverge from this well ; one conducts the
gas direct to the cylinder of an engine which, with this pressure
alone, acquires an enormous speed. Another pipe feeds a flame
capable of reducing as much iron-ore as half the blast-furnaces
of Pittsburg can put out in a day. Twenty yards further on is the
mainpipe of the wells ; from a pipe 3 inches in diameter issues
a flame 40 feet high, the noise of which shakes the hilL\ For
a distance of 50 feet round the earth is burnt up; but further
off the vegetation is tropical, and enjoys a perpetual summer.
On a calm night the noise can be heard at a distance of 15
miles; at 4 miles the noise is like that of a train passing near,
whilst close by it resembles that of a thousaiid locomotives
blowing off steam. At the distance of a furloug the noise is
like the continued roar of artillery, the human voice can scarcely
be heard, and the flame reaches a height of 70 feet. In winter
the surrounding mountains are covered with snow, but on
two acres around the well the grass is green, except in the
immediate neighbourhood, where the soil resembles lava."

The oil, which either flows from the wells or is pumped up,
also contains gaseous parafiins in solution, especially ethane,

' Sadder, Amcrimn Clicmist^ 187C, p. 93 ; Foiiqiu', Ompf. Itcnd. Ixvii. 1015.
a Joum, CJiem, Soc. 1879, i. j). 287.

VOL. in. L

146 THE PAHAFFINS.

propane, and butane.' These gases, which are given off in the
distillation of the crude oil, are again condensed by pressure,
and the liquor obtained, consisting mainly of butane, is termed
cymogene, and is employed for the production of artificial cold.
The products boiling at about 18** are known as rhigolene, and it
has been suggested to employ this as an anaesthetic agent,
• The products boiling up to about 170** are distinguished
as gazoline, naphtha, and benzine, ligroin, or petroleum-spirit.
These are partly used for illuminating purposes, specially con-
structed lamps being employed for burning them ; or they are
used for saturating air or hydrogen, the mixture of vapour
and gas being burnt in an ordinary gas-burner. Another use of
petroleum-spirit is as a substitute for turpentine, as a solvent
for india-rubber, and for oil in the woollen manufacture, &c.

The oil boiling above 170*" is termed "standard kerosene,"
or "mineral sperm" oil, having a "flashing-point" of 150*" F.,
and is used for burning in the ordinary paraffin lamps.

According to the Act passed in 1871 " for the safe keeping of
petroleum," 2 no oil can be sold which evolves combustible
vapour at a temperature of 100° F, (37°'8 C).

At the request of the Government, Professor Abel has lately
investigated the various methods in use for determining the
"flashing-point " of petroleum. He finds these to yield unsatis-
factory results, and he proposed a new system of testing which
has now been adopted by Government, and embodied in an Act of
Parliament. A standard apparatus for this purpose is placed in
charge of the Weights and Measures Office, and every apparatus
has to be stamped and tested so as to be identified as a legal
apparatus. The flashing-point of 73° as furnished by the new
test is equivalent to the minimum flashing-point of 100** as
obtained by the older methods.

Prepdraiion of the Normal Paraffins from Petroleum, It has
already been mentioned that Pennsylvanian petroleum, as well
as the lighter oils obtained from Boghead coal and canncl,
contain the normal paraffins. In order to obtain these in the
pure state, Grevillo Williams decomposes the mixtures which
are contained in the petroleum by carefully treating the oil
with concentrated nitric acid, when the other hydrocarbons, &c.,
are partly oxidised and partly converted into heavy volatile
nitro-compounds. As, however, concentrated nitric acid act«
very violently on the mixture, and sometimes m.iy even cause

» Ronalds, Joum. Chcm. Soc, xviii. 61. • 34 & 35 Vi<t. o. 105.

FRACTIONAL DISTILLATION. 147

the igDition of the oil, it is better first to shake the oil re-
peatedly with concentrated sulphuric acid until the substance
is no longer coloured, and then to act on the residue with con-
centrated nitric acid, or with a mixture of the commercial acid
and sulphuric acid. When no further action takes place, the
oil is separated from the acid, washed with water and caustic
soda solution, and dried over solid caustic potash. It is then
distilled in order to separate it from any adherent nitro-com-
pounds, and repeatedly rectified over sodium, when it may be
separated into its constituents by repeated fractional distillation.
As this process is very often employed for the separation and
purification of volatile bodies, we shall here shortly describe it.

FRACTIONAL DISTILLATION.

98 When a mixture of two liquids whose boiling-points do
not lie close together is subjected to distillation, a large portion
of the more volatile body comes over at the beginning;
but the boiling-point gradually rises, and more and more of
the vapour of the less volatile mixes with that of the more
volatile compound. It is only when the difference between
the boiling-points of the two bodies is very considerable
that it is possible to effect an almost complete separation
by one distillation. In such a case, when the operation is
carried on very slowly, the more volatile body distils at a nearly
constant temperature ; and as soon as all has passed over, the
thermometer rises rapidly to the boiling-point of the less volatile
compound. But in most instances it is impossible to obtain
even an approximate separation by one distillation only. By
collecting separately the portions distilling between certain
intervals of temperature, say between each 5" or 10°, the first
will consist chiefly of the lower boiling body, and the last of
the less volatile substance, whilst the composition of the greater
portion, boiling between those two points, remains very similar
to that of the original mixture.

The following example shows how imperfectly even bodies
whose boiling-points do not lie close together can be separated
by one distillation. A mixture of 100 grams of ethyl alcohol
(boiling-point 78***4) and 100 grams of amyl alcohol (boiling-
point 132'') was distilled from a long-nockcd flask, and the

L 2

148

FRACTIONAL DISTILLATION.

distillate collected in seven fractions, the composition of which
was found by optical analysis to be as follows :

Boiling-point

80*-«l'

90'-100"

lOO'-llO'

iio'-iao*

120*-130'

130'-131'

131M32"

Wei^t of fraction

82
18

521
47-9

Per cent, of ethyl alcohol .
Per cent, of auiyl alcohol .

88 1
11-9

615
38-5

lS-4
SI 6

45
95-5

0-2
99-8

100-0

100

100.0

100 0

100-0

1000

100^

Four grams of pure amyl alcohol remained in the flask.

It is not difficult to explain why, in such a distillation,
the less volatile body distils so much below its boiling-point.
As is well-known, all volatile bodies evaporate below their
boiling-points, and this takes place with the greater facility the
higher the tension of the vapour ard the quicker the surround-
ing atmosphere is changed. Now these conditions are fulfilled
on boiling a mixture of two liquids ; the vapour of the lower
boiling body carries that of the less volatile substance with it
on passing through the mixture, and being quickly condensed,
a new atmosphere is constantly formed.

In ordinary cases such mixtures contain more than two com-
pounds. Thus the so-called fusel-oil is a mixture of several
homologous alcohols. In order to isolate from such mixtures
tolerably pure compounds, the diflferent fractions obtained in
the first distillation must again be submitted to the same
operation, and those portions which distil between the same
intervals of temperature collected separately, and this process
repeated until bodies with a nearly constant boiling-point have
been obtained. A complete separation, however, cannot be
effected in this way; since the substances obtained by this
method, although they may have a constant boiling-point, are
never j)orfectly pure, and require to be afterwards treated by
some different ]>roce88 to ensure their perfect purity.

99 The apparatus used for the purpose of fractional distilla-
tion in the laboratory is that suggested by Wiirtz and shown
in Fig. 54. Tlie flask A contains the boiling mixture ; the
vajKiurs of the hydrocarbons i)ass into the bulb-tube r, in which
a thermometer is ])laced, and the les? volatile portions are here
jxirtly condensed as the vapour comes in contact with a large
surface cooled by the atmosphere. The vapour which is not

WUBTZS TUBES. J49

condensed passes next into the Liebig's condenser, c, surruunded
by cold water, and from this the liquid can be collected in various
fractions in the receiver B.

Linneniann ' has improved on this methoil, inasmuch us he
places cups of platinum gauze in the upright tube through
which the vapour passes (Figs. 55 and 56). The liquid con-
denses on these, and falls back through the meshes. The vapours
arc tlius washed by tlie liquid, and come in contact with a column
of liquid whose temperature is always lower than that of the
mass of the liquid in the flask. When this apparatus is in

use, the tube and bulbs gradually become tilled with liquid and
all the vapour is condensed. It is therefore necessary to remove
the flame from time to time in order that the liquid may flow
back again. In this way the process of distillation is rendered
slower, and an improvement has been introduced by the attach-
ment of aide-tubes to the bulbs (Figs. 57 and 58), down which
the condensed liquid flows regularly back into the flask.

100 Ad apparatus somewhat different from this has been em-
ployed by Warren * in the fractional distillation of tar-oils and

1. CAcm. Fhamt. cll. 195.

' Aim. Chtm. Fharm. Suppl. i

FRACTIONAL DISTILLATION.

petroleum B. This permits a complete control over the temperature
of the vapour, accomplished by &a air-bath (a a, Fig. 59), roood

.-^

which a spiral tube is placed, connected with thob«.iling-flask.
The tempemture of this ftir-l»th is regulat«d by a lamp The

WARREN'S APPAKATUS. 151

liquid used for heating the air-bath may be either water, uil, or
fusible metal, and into this the thermometer (i) is placed. The
boiliDg of the liquid and the temperature of the bath are SO
regulated that the liquid boila somewhat rapidly. In distil-
ling petroleum the difference in temperature between the boil*
ing liquid and the air-bath was, to begin with, about S5°
or even more. This difference became gradually smaller as
the various fractions were redistilled, until at last it almost

Fio.

disappeared. An apparatus of a .timilar kind, but on a lai^er
scale, as used by Warren, is shown in Fig. 00.

loi Even the approximate separation of volatile substances
cannot, however, always be carried out by fractional distillation,
even when the boiling-points are considerably removed from
one another. Thus, for example, if a mixture of aiiiline boiling
at 182° and watc-r be distilled, the aniline distils over firat In
such a case the boiling-point of the mixture is frequently lower
than that of the more volatile bwly. Pierre and Puchot ' found
' Cv,.i2-i- Hcnd. hxiii. .iHn, 788.

FKACriONAL UISTILLATIOS.

DISTILLATION OF MIXTURES. 163

that a mixture of water and of amyl alcohol, which boils at
132*', begins to boil at 96*^, and the distillate contains 2 volumes
of water to 3 of amyl alcohol. Similar observations have been
made with other mixtures.

Wanklyn ^ has shown that, when a mixture of equal parts by
weight of two liquids of different boiling-points is distilled, the
quantity of each constituent in the distillate is proportional to
the product of its vapour density and vapour tension at the
temperature of ebullition of the fraction. Hence, if the vapour
tensions and vapour densities of the two liquids are proportional,
the mixture will distil unchanged. Berthelot has confirmed this
conclusion. He found that a mixture of 90 '9 parts of carbon
disulphide, which boils at 4G°, and 91 parts of ethyl alcohol,
boiling at 78°*4, possesses a constant boiling-point of 78°'4,
and distils without undergoing any alteration in composition.
Thorpe ^ has added another example in corroboration of this
conclusion, as he observed that, when a mixture of equal volumes
of carbon tetrachloride, boiling at 76°*6, and methyl alcohol,
boiling at 65°*2, is distilled, 4G%5 per cent, of the whole boils
between 55**'6 and 59°, that is to say, nearly 10° lower than the
boiling-point of the most volatile constituent. The distillate
contains, to 1 part of methyl alcohol, 3*61 parts of tetrachloride
of carbon, and by multiplying the vapour tensions of the two
liquids at 55°*7 by their vapour densities almost exactly the
same relation is obtained :

372-4 X 7G-69 _^^rj
487-4 X 15 97 "" ^'^^•

When the residue is distilled further, almost pure tetra-
chloride of carbon comes over first, and afterwards pure methyl
alcohol.

A striking lecture experiment, illustrating the effect of
the admixture of the two liquids, is to fill three barometer
tubes with mercury and to pass up into the first a few drops of
methyl alcohol, into the second a few drops of carbon tetra-
chloride, and into the third a small quantity of a mixture of
methyl alcohol and carbon tetmchloride in the proportion of
3 cbc. of the former to 5 cbc. of the latter. In the first tube
the mercury will be depressed about 80 mm., in the second
70 mm., whilst in the third it will sink through 130 mm.
(Thorpe).

J Phil. Marj. [4] xlv. 129. - Jnaru, Chcm. SW. 1879, 514.

164 COMPOUNDS OF MONAD ALCOHOL RADICALS

THE COMPOUNDS OF THE MONAD ALCOHOL

RADICALS.

CnH2n + 1.

102 In the following chapter will be found a short description
of the chief fSeonilies of the above compounds, arranged in the order
in which their chemical history will be considered in the sequel.

These compounds are derived from the paraffins by the
substitution of one atom of hydrogen by other atoms or groups
of atoms. They may, therefore, be regarded as compounds of
monad radicals, to which the name of the alcohol radicals has
been given, because the alcohols were the first compounds of
these bodies which were studied, and even to the present day
these bodies are employed as the point of departure for the
preparation of the other compounds.

The Alcohols are hydroxides, and in many cases exhibit
analogous properties to the hydroxides of the metals. Hence
Liebig, when he established the radical theory, compared ethyl
alcohol to caustic potash. The latter substance was then sup-
posed to be a compound of potassium oxide with water, or
hydrated potash, and alcohol was accordingly considered as the
hydrate of ethyl oxide. According to the theory of types, it was
considered as water, in which 1 atom of hydrogen is replaced by
ethyl, but it may just as truly be considered to be ethane, in
which 1 atom of hydrogen has been replaced by hydroxyl, or,
in other words, it is formed by the union of two monad residues,
ethyl, CjHj, and hydroxyl, OH.

Ethereal Salts or Compound Ethers, The alcohols are con-
verted by the action of acids into compound ethers, the alcohol
radical replacing, either partially or wholly, the hydrogen of the
acid:

Ethyl chloride.

(«) C,Hj.OH + HCl =CjHjCl +HA

Kthyl nitrate.

(6) CjHj.OH + HO.NOs = CjEjCNO, +HjO.

Hydrogen ethyl sulphate.

Other modes of formation of compound ethers^ may be
mentioned :

THE ALCX>HOLS AND ETHERS. 155

(a) A silver salt is heated with an alcoholic iodide :

Ag^COj + 2C2H,I = (G^B.,)fiO^ + 2 Agl.

(6) Absolute alcohol is acted on by an acid chloride :
POCI3 + 3HO.C2H5 = VOiOC^U,)^ + 3HC1.
SiCl, + 4HO.C2H, = Si(OC,H,), + 4HC1.

(c) A salt of the corresponding acid is distilled with a salt of
ethyl — sulphuric acid, or other corresponding alcoholic sulphate :

KCIO, + K(C2HJS0, = C2H,.C10, + K^SO,.

The alcohols can again be obtained from the ethereal salts or
compound ethers by heating them with an alkali, thus :

C2H5O.NO2 + KOH = C2H5OH + KO.NO2.

Haloid Ethers. The compounds of the alcohol radicals with
the elements of the chlorine group are termed haloid ethers.
These are formed in a variety of ways. Thus, for example, the
chlorides and bromides are obtained by the action of the corre-
sponding haloid elements on the paraffins, and also by the action
of the corresponding phosphorus compounds on the alcohols :

{a) C2H5.OH + PCI5 ^CgHjCl+POCla + HCl.
(6) C2H5,OH + PBr5 = C2H5Br + POBr3 + HBr.

When an excess of alcohol is present, the hydracid formed as
well as the phosphoryl compound react upon it, the amount of
the haloid ether being increased :

SCgH.OH + POCI3 = 3C2H5CI + P0(0H)3.

In this case, however, the free phosphoric acid acts upon
another portion of the alcohol, and a phosphate is produced.

In order to prepare the iodides, the alcohols are heated with
concentrated hydriodic acid, or, better, they are treated directly
with iodine and amorphous phosphorus :

5C2H5OH + 51 + P = 5C2H5I + H3PO, + H2O.

The alkalis usually act on the haloid ethers in a different
way, and instead of obtaining the alcohol, the hydracid is
separated and an olefine formed. Hence, in this case, freshl
precipitated moist silver oxide is usually employed, and this
as if it were the hydroxide AgOH.

166 COMPOUNDS OF MONAD ALCOHOL liADICALS.

The alcohols may also be readily obtained from the haloid
ethers by converting the latter into the ethereal salts of organic
acids and then decomposing these by alkalis. The same end
may likewise be attained by heating the haloid ethers with
water under pressure : '

C.HjjCl + HjO = C^HgOH + HCl.

This reaction serves as a striking example of the influence of
mass, for whilst fuming hydrochloric acid easily converts butyl
alcohol into the chloride and water, exactly the opposite reaction
takes place in presence of a large quantity of water, inasmuch
as a weak acid does not attack the alcohol. Hence it follows
that, when an alcohol is heated with an acid, not in excess, a
condition of e<iuilibrium is attained when the acid becomes so
dilute that its action ceases.

X03 Simple and Mixed Ethers are formed when the hydrogen
of an alcoholic hydroxyl is replaced by an alcohol radical. Hence
these bodies are oxides of the radical, standing in the same
relation to the alcohols as potassium oxide does to caustic potash.
These bodies can be obtained by a variety of reactions :
(1.) The alkali-metals dissolve in alcohols with evolution of
hydrogen. Sodium and ethyl alcohol thus form sodium ethylate,
CjHj.ONa, and if this be warmed with ethyl iodide, ethyl oxide
or diethyl ether is obtained :

Ethers which contain the same radical twice are termed

simple ethers, whilst those which contain two different alcohol

radicals are termed mixed ethers. If in the above reaction ethyl

CH )
iodide be replaced by methyl iodide, methyl-ethyl ether, p xf f O,

is obtained.

(2.) Ethers are also formed when the alcohols are heated
with concentrated sulphuric acid. In this case the alcoholic
hydrogen sulphate is first formed, and this is decomposed by
the excess of alcohol, as follows :

The mixed etliers may also be obtiined in this way. Thus

* Nifilcrist, Liebiga Ann, clxxxvi. 388 \ cxcvi. 349.

MIXED ETHERS AND TUIO- ALCOHOLS. 167

methyl-ethyl ether is ohtained hy heating hydrogen ethyl
salphate with methyl alcohol.

(3.) When an alcohol is heated with an iodide, an ether is also
formed, and this occnrs when concentrated hydriodic acid is
heated with an excess of alcohol, the following reactions taking
place:

(1) C,H„.OH + HI « C,Hi,I + HgO.

(2) C,H,,I + C,H,,OH = (C,H J,0 + HI.

A small quantity of hydriodic acid suffices to convert a large
quantity of alcohol into ether. The reaction continues until
a certain quantity of water is formed, when a condition of
equilibrium is attained.

Hydrosulphides and Sulphides. The hydrosulphides are also
termed the thio^lcohoh, as they are obtained (1) from the
alcohols by the substitution of sulphur for oxygen, thus by
acting on the alcohols with phosphorus pentasulphide :

SC^HgOH + P2S5 = oCgH^SH + Tfi,,

Free phosphorus pentoxide is, of course, not formed, out the
thio-phosphates, such as (02H5)2HP02S2 and (C2H5)3 POgSj.

(2.) The hydrosulphides are also formed by the action of an
alcoholic chloride on potassium hydrosulphide :

CgHgCl + KSH = C,H,.SH 4- KCl.

(S,) Also by heating a solution of the latter compound with
potassium ethyl sulphate :

KSH -f K(C2H,)S0, = C2H5.SH + K2SO,.

The thio-alcohols are, like many volatile sulphur compounds,
distinguished by their disagreeable smell. They stand in the
same relation to common alcohol as sulphuretted hydrogen does
to water, and resemble this compound inasmuch as they act as
weak acids, and as one atom of hydrogen can easily be replaced
by metals. Amongst these metallic compounds those with
mercury are the most characteristic. They are formed when a
hydrosulphide is brought in contact with mercuric oxide :

2 C,H,SH + HgO = (C,H5S),Hg + H.O.
In consequence of this relation the thio-alcohols have been

158 COMPOUNDS OF MONAD ALCOHOL RADICALS.

termed mercaptans (mercurium captaiis), and their metallic
compounds vicrcaptides}

The SuljMdcs or Thio-Ethers are always formed in the pre-
paration of the mercaptans from the chlorides, the following
reactions taking place:

(1) C2H5SH + KSH = CgH^SK -f SHj.

(2) C^H^SK + C,H,C1 = (C,H5)2S + KCl.

SiUphine Compmirtds} The sulphides unite with the iodides
and bromides of the alcohol radicals to form crystallisable salts
such as triethylsulphine iodide, S(C2H.)3l. These substances
are not attacked by alkalis, but when freshly precipitated
hilver oxide is added to their aqueous solutions, the corre-
sponding hydroxides are formed, such as triethylsulphine
hydroxide, S(C2H5)30H. These latter are difficultly crystallis-
able, they are deliquescent, and possess alkaline and caustic
properties like caustic soda. They also resemble the alkaline
hydroxides, inasmuch as they precipitate metallic salts, expel
ammonia from its compounds, and form, with acids, neutral salts,
amongst which the chlorides unite with platinum chloride
to form soluble double salts, such as [S(C2H5)3C1]2 + PtCl^.

104 Sidphonic Acids. These acids are easily formed by oxi-
dation of the mercaptans and other sulpho-compounds of the
alcohol-radicals :

^[ercaptan. Ethylsulphonic acid.

C2H5.SH + 30 = C2H,.S02.0H.

They possess the same composition as the corresponding acid
sulphites of the alcohol radicals, which, however, are not known
in the free state, as they decompose with extreme ease, whilst
the sulplionic acids are very stable and powerful acids. They
may be heated pretty strongly without decomposition, are not
altered by boiling caustic alkalis, and only oxidised by nitric
acid with difficulty, forming the acid sulphates.

The sulphonates are also formed when an iodide is brought
in contact with a solution of a normal sulphite : ^

C,H,I + SO3 I J^ = S0o| ^2^5 + KI.

• Zcine asimmed the existence in the«e bodies of the radical CoHsS, to which
he giive the name of mercnptum (mcrcurio a^itum). See I^rzvlius, JeUiresbcr,
xiv. 334.

• V, Ot'frlo, Ann. Chrm. Pharm, cxxvii. 370; cxxxii. 82.

• StDTkcr, ^)m. Chrm, Phnrm. cxlviii. 90; Hemilian, 16. rlxviii. 185.

COMPOUND AMMONIAS. 150

Phosphorus pen ta chloride coDverts them into sulphonic chlorides :

SO2 { g^^^ + PCI, = SO. I g|^5 + KCl + POCI3.

And if this latter compound he treated with sodium ethylate
the ethyl-ether of ethylsulphonic acid is produced :

SO2 { §"^ -h NaOC,H. = SO, I g|?|^ + NaCL

This ether is isomeric with ethyl sulphite, which is formed by
the action of thionyl chloride on ethyl alcohol :

SO I g{ + 2HOC2H, = SO I ^^2^6 4. 2HC1.
Cold caustic potash converts the latter compound into alcohol

r oc H

and potassium ethyl sulphite, SO -I ^^ ^' which is isomeric

with potassium ethyl sulphonate, from which it differs, inasmuch
as its aqueous solution is easily decomposed with formation of
hydrogen-potassium sulphite and alcohol. The rational con-
stitution of this compound is not known. The easy conversion
of mercaptan into sulphonic acid renders it very probable that
in the latter the alcohol radical is in direct linking with sulphur.
The alcohol radicals also form compounds with selenium and
tellurium, the more important of which will be hereafter
described.

X05 The Compound Am fnonids or Amities are formed by heat-
ing the haloid ethers, or the nitrates of the alcohol radicalsy
with ammonia under pressure, when the following consecutive
reactions take place :

Primary Monamines.

(1) CH.Cl + N-^H=N.^H + HCl.

(H (K

.Secondary Mouamiiies,

ran, (C^Hj

2) C,H,C1 + N -.' H' = N -^ C»H. + HCl.

(h jrf

Tertiary Monamines.

(:5) CJI/'l + N -j C;h; = N-«( C4H6+HCI.

no 1 2 U

H (C,H,

ICO COMPOUNDS OF MONAD ALCOHOL RADICALS.

The amines containing the lower members of the series of
alcohol radicals are gaseous at the ordinary temperature ; the
higher ones are mostly liquids. They possess a peculiar
ammoniacal smell, but generally this is accompanied by a fish-
like odour. They precipitate many metallic salts, and combine
directly with acids to form crystallisable compounds. Their
chlorides unite with platinum chloride, like sal-ammoniac,
whilst their sulphates yield alums with aluminium sulphate.

The three groups into which they may bo divided are
distinguished by the following reactions.

(1.) The primary amines are converted into alcohols by means
of nitrous acid. If a solution of hydrochloride of ethylamine
be warmed with silver nitrite, the following reaction takes place :

HJNHO.NO ^^

(2.) The secondary amines under similar circumstances give
rise to nitroso-products :

C^H, ^ N + HO.NO C^H, V N + H,0.

0«Hk ) CgH

^N+ HO.NO C^H, ^
HJ NOj

The nitroso-diethylanune thus obtained is again converted into
diethylamine on heating with aqueous hydrochloric acid.

(8.) The tertiary amiiics are not affected by nitrous acid.
They combine readily with the iodides of the alcohol radicals,
giving rise to an iodide of a compound ammonium, such as
tetramethylammonium iodide, ?s(CH3)^I. These decompose,
on heating, into the compounds from which they have been
formed, just as sal-ammoniac dissociates into hydrochloric acid
and ammonia. In both cases re-combination takes jJace on
cooling ; and hence the compound ammonium iodides apjxjar
to distil without decomposition. They «are not deconj posed by
alkalis. Moist silver oxide converts them into liydroxides,
which are non-volatile, crystalline, very soluble bodies analogous
in properties to the caustic alkalis. Thus they destroy animal
matter such as the skin, sjiponify fats, precipHate many metallic
compounds, &c., and form crystallisable salts with acids. Their
chlorides yield, with ]>hitinum chlori<lo, compounds analogous
to ammonium-})latinum chloride, Jind their suljihates give rise
to alums.

HYDRAZINE COMPOUNDS. 16f

It has alreaxly been stated that frequent cases of isomerism
occur amongst the amines. Thus, for instance, the hydrogen
atoms in ammonia may be replaced by one, two, or three
radicals, and thus a vanety of isomeric compounds result, and,
by the above reactions, it is easy to distinguish whether we
have to do with a primary, secondary, or tertiary compound,
Tlie simplest case in which isomerism can occur is that of
(1) propylamine, (2) methylethylamine, and (3) trimethylamine.
If these bodies be treated with ethyl iodide as long as this
substance produces any action, the following compounds aro
formed :

(1) Propyl triethylammonium iodide, N(C3H-.)(C2H.)3l.

(2) Methyl triethylammonium iodide, N(CH3)(C2H5)3l.

(3) Trimethylethylammonium iodide, N(CH3)3(C2Hg)I.

It is only necessary to detennme the quantity of iodine con-
tained in the body formed to ascertain which of these compounds
is under examination.

xo6 Hydrnzim Compounds, Just as the amines are derived
from ammonia, NHg, so the hydrazines are derived from the as
yet unknown body hydrazine or diamide, HgN — NH^. Com-
pounds analogous to this are to be found in the liquid hydro-
gen phosphide HgP — PHg, and in dimethylarsine (cacodyl),
(CH3)^s - As(CH3)2.

The hydrazme compounds as yet known are obtained by
replacement of one or two atoms of hydrogen in hydrazine,
H^N — NHg, by alcohol radicals. So far, only derivatives with
one or with two alcohol radicals are known. In order to prepare
mono-ethyl hydrazine, H^N — NH(C2H5), it is necessary to
start from diethyl-urea, a secondary amine. This is treated
with nitrous a<jid, giving rise to the nitroso-compound No. (1),
and then this product is acted upon by nascent hydrogen,
yielding the hydrazme-compouud No. (2) :

Dicthylurea. (1). (-2).

PH NH>^^0 >00 >C0

1^,11,. IS n/ aH,.N -NO C,H-.N -NH.,.

If the compound No. (2) be heated with alkalis or acids, it
is decomposed like all ureas, yielding carbon dioxide, ethylamine,
and ethyl hydrazine, as follows :

VOL. in. u

IGi COMPOUNDS OF MONAD ALCOHOL RADICALS.

C4H..NH. H CjHj.NH.,

P H N >C^ + O = CO,

^Hj.JN /jjjj^ jj (C,H5)H.N-NH,.

Nitroso-amiues containing acid radicals, e.g. like

So}^~^^'

C.,H
C

give on reduction no corresponding hydrazines, but the amides
are regenerated :

Hydrazines containing two radicals, or Dihydrazines, are
obtained by the reduction, with zinc dust and acetic acid, of
the nitroso-dcrivatives of secondary amines :

C.H.|N-NO + 2H, = g:S;}xN-NH, + H,0.

The hydrazines are volatile liquids possessing an ammoniacai
odour, and uniting with acids to form salts.

Dihydrazincs unite with the iodides of the alcohol radicals,
giving rise to azonium iodides, such, for instance, as triethyl-
azonium iodide H2N.^(C2H5;3l. These are converted into
powerfully alkaline hydroxides by means of moist silver oxide.
Weak oxitlising agents resolve the dihydrazines into secondary
amines with evolution of nitrogen, whilst stronger reagents
give rise to Tetvazoncs, such as tetraethylazone, N^(C2H5)^ :

H,N-N(0.,H,)o ^ o N-NCaH^),

The tetrazones are non-volatile, oily, alkaline liquids possessing
a garlic-like smell.^

X 07 Cya n id^a of the A hoJwl Eadicah. Those bodies are formed
when an alcoholic iodide is heated with silver cyanide, or
when a mixture of chloroform and an amine is treated with
alcoholic potiish :

CH3NH. + CHCI3 = CH3.NO 4- 3HC1.

The compounds obtained in this way are usually termed

» E. Fisolier, Liihigs Annalen, cxc. 67. Hid. rxcix. 281.

CYANIDES OF THR ALCOHOL RADICALS. 1G3

isocyanidcs or carbami?ies, in order to distinguish them from the
isomeric compounds which had previously been prepared. They
are poisonous liquids possessing a penetrating and highly
unpleasant odour. Aqueous acids decompose them easily into
formic acid and an amine :

CH3NC + 2H2O - CHjNHj + COH.OH.

When heated in closed glass tubes, they are converted into
the isomeric nitrils, which bodies are also formed, together
with small quantities of the carbamines, by heating an iodide
with potassium cyanide, or by heating the latter compound
with a hydrogen sulphate of an alcohol radical :

NCK + ^ § } SO^ = NC.C2H5 + K.SO,.

In this reaction a carbamine is doubtless first formed, and this
is decomposed at the high temperature into a nitril.

The pure nitrils possess a strong but not unpleasant smell.
They are not changed by the action of dilute aqueous acids,
but are converted into the fatty acids and ammonia in the
presence either of strong aciucous mineral acids or of caustic
potash. Thus methyl cyanide or acetonitril, when treated in
this way, yields acetic acid :

CH3.CN -f HCl + 2H2O = CH3.CO.OH + NH,a.

On treatment with nascent hydrogen, the nitrils form amines :

CH3.CN + 2H, = CH,.CHyNH,.

And this reaction proves that in the nitrils the cyanogen is
linked with the alcohol radical by the carbon atom, whilst in
the carbamines it is nitrogen which connects these two, act-
ing in this case, as in sal-ammoniac and similar bodies, as a
pentad. All these compounds decompose on heating, with
formation of bodies in which nitrogen is triad. The pentad
nitrogen in carbamine is also converted on heating into the
triad form, and hence we may assume that the compound first
decomposes into cyanogen and the alcohol radical, and that these
tben unite again :

C=N-CH3 = N^C-»<r-CH3.

Cyanates and Isoqfanates, The cyanates of the alcohol radicals

M 2

164 COMPOUNDS OF MONAD ALCOHOL RADICALS.

are very unstable liquids, formed by the action of cyanogen
chloride on a solution of sodium in an alcohol :

NCCl + NaOC^Hj = NCOC^H, + NaCl.

These bodies are decomposed in contact with the alkalis into
an alcohol and a cyanate. They undergo polymerisation with
extreme ease, and give rise to crystalline cyanuratcs.

Isoq/anates, Carbimidcs, or Carbonylamines, are bodies isomeric
with the cyanates. They were formerly believed to be the
true cyanates. They are, however, distinguished from these
by the fact that alkalis decompose them into carbon dioxide
and an amine :

^{ C(?' + ^^O = N j g^^s + CO,.

This is the reaction by means of which the amines were dis-
covered by Wurtz. Aqueous acids also decompose them in the
same way.

Ethyl carbimide is formed when potassium cyanate is dis-
tilled with potassium ethyl sulphate. Probably ethyl cyanate is
first produced, but this is converted by molecular rearrangement
into ethyl carbimide. The other carbimides are formed in a
similar way. They are obtained from the carbamines by oxida-
tion with mercuric oxide, and are volatile liquids possessing a
penetrating smell which causes a flow of tears, and they are
easily converted into crystalline isocyanurates,

io8 Co)i\i)oviul^Urcns or Carbamides. These bodies are de-
rived from urea by the replacement of the whole or a portion
of its hydrogen by alcohol radicals. They may be formed m

{NH C H
^TT* ^ ^ is ob-
tained by the action of cyanic acid on ethylaniine, as also by
treating ethyl carbimide with ammonia. If ethylamine bo
employed instead of ammonia, a symmetrical diethyl-carbamido
is fonned, which is also obtained by the decomposition of the
carbimide with water:

CO /N\

+ H.O = CO " + CO-
CO \N/"
^N-C.,H, \CM,

COMPOUITO UREAS. 165

A compound isomeric with this may be prepared by acting
with cyanic acid on diethylamine, whilst triethylcarbamide,

^^ i N^OtI ^^' ^^ formed from diethylamine and ethyl car-

bimide. The triamines do not undergo alteration when treated
either with cyanic acid or with the carbimides, but the simple
substituted carbamides are obtained by the action of diamines
on carbonyl chloride. The compound ureas all unite with
acids to form crystallisable salts.

Uretluines or Carbamic Ethers. Carbamic acid, CO <f , is

not known in the free state (VoL I. p. 646), and only a few of
its inorganic salts have been prepared, but many of its com-
pound ethers, or the urethanes, are well-defined substances.
They may be prepared in several ways. Thus, if ethyl car-
bonate be treated with aqueous ammonia, ethyl carbamate is
formed :

COJggl: + NH3 = C0{^H,^^ + HOAH,

By the prolonged action of ammonia, ethyl-urethane is con-
verted into alcohol and urea, whilst, on the other hand, if pure
alcohol be heated with urea to 100°, urethane is formed. These
compounds are also formed by the action of cyanogen chloride
upon an alcohol :

/NH,
CI - C = N + 2HO.C2H5 = CO -h C2H5CI.

\OC2H,

The urethanes are solid crystallisable compounds, which are
decomposed by alkalis, with formation of ammonia, alcohol, and
a carbonate.

AUaphanates. The ethers of allophaiiic acid stand to biuret
(Vol. I. p. 652) in the same relation aa the urethanes (carbamic
ethers) to urea, thus :

(Allophanic Amide). Allophanic

Urea.

Uretlvane.

Biuret.

/NH,
CO

Ethylether.

\NHj.

CO
\O.C4H.

CO
\O.CjH5,.

1C6 COMPOUNDS OF MONAD ALCOHOL RADICALS.

These allophanic ethers are formed by the action of the vapour
of cyauic acid upon the anhydrous alcohols, thus :

2C0.NH + CA-OH - NH { gg;^'^^^

They may also be prepared by heating a chloro-carbonate with
urea:

/OCaH. rCO.NHa

NH-CO-NH2+CO - NH^ + IICl.

H \C1 ( OO.OCjHj

Free allophanic acid is not known, but in addition to the
ethereal salts a few unstable compounds have been prepared,

such as the following : NH < n(\Qn tj

Compound Oiuinidines. These bodies are formed by the
action of cyanamide upon a hydrochloride of a monamine, as
guanidine itself is obtained by the action of cyanamide upon an
ammonium salt (Vol. L p. 680) :

N(CH3)H.HC1
C^N I

I ^ + N(CH8)H3Cl = C = ^^1I.

MI, I

Guanidines containing two alcohol radicals have, as yet, not
been prepared, although some containing three such radicals have
been obtained. These arc formed with separation of carbon
dioxide, when an isocyanuride is heate<l with an alcoholic solu-
tion of sodium ethylate, as also if a disubstituted thio-carbamine
be heated with a monamine and mercuric oxide :

CSCNH.CsH.), + JLX.C'JI, + HgO - CiN.C.H^KNlLC.Hj), + ll^jS -i- Ufi.

Tlie cnmpoimd guanidines resemble guanidine itself in acting
as {)owerfuI bases.

109 77(45 Tlkiocya nates and Isotliiocyanntcs, The first of these
classes of bodies is formed in a similar way to the other ethereal
salts. Thus, for example, ethyl thiocyanato is obtained on heat-
ing potassium thiocyanato with ethyl iodide or |>otassinm ethyl
Bulpliatc. They arc most unpleasant-smelling liquids, which

COMPOUND TIlIO-UREAa 167

are decomposed by alkalis with formation of alcohols and a
•thiocyante.

The isothiocyanates or ihiocarbimidcs are also known as
mustard-ails, because the oil of mustard belongs to this group,
and the various members possess a similar strong pungent
smelL They are formed by a general reaction. Thus ethyl
mustard-oil, SCNCgH^, is obtained by mixing an alcoholic
solution of ethylamino with carbon disulphide, when an ethyl-
thiocarbimic acid is formed, and this, on heating with a salt of
mercury or silver is converted into the thiocarbimide :

NH.C,H, N.aH,

I II

OS + HgCL = OS + HgS + HCl 4

I Etliyl

8(NH3. C^H,) thiocarlimicle. NH3(C2H5)C1.

Iodine acts in a similar way with formation of iodic acid and
free sulphur. Dilute sulphuric acid decomposes these mustard-
oiJs with formation of an amine and carbonyl sulphide :

N I ^^ + H,0 = N -[ ^^^^ + COS.

Compound Thio-Ureas. These are formed by the action of
ammonia or an amine on the mustard-oils. They are crystalline
bodies forming salts with acids.

no The NitrO'ParaffiTis. These compounds are isomeric with
the nitrites of the alcohol radicals, and arc formed together with
the latter, when an alcoholic iodide is acted upon by silver
nitrite. They act as weak acids, and contain one atom of
hydrogen capable of replacement by a metal, whilst the
nitrites are neutral bodies, and easily converted by alkalis
into an alcohol and a nitrite. Nascent hydrogen converts the
nitro-paraffins into compound ammonias, whilst the nitrites
in the same way yield alcohols. This last reaction indicates
the constitution of these two classes of compounds :

Nitro-ethane.

/O /H

(1) C4H..N I + 3H» = QH5.N 2H.,0.

* \0 \H

Ethyl nitrite.

(2) C,H..O— NO + 3H. = CJTj.OH + Nil, + H,0.

tC8 COMPOUNDS OF MONAD ALCOHOL RADICALS.

Phosphorus Bases or Plwsphines. These compounds are
pioduceJ by the replacement of hydrogen in phosphuretted
hydrogen (phosphine) by alcohol radicals. In their chemical
properties these compounds exhibit great analogy with phos-
phine itself, and are classed as primary^ secondary, and tertiary
phosphmes (the name having become generic). The last-named
combine with the iodides of the alcohol radicals to form phos-
plumium iodides, which compounds, as well as the bodies derived
from them, closely resemble the corresponding ammonium
compounds.

The alcohol radicals also form corresponding compounds with
arsenic and antimony, as well as with baron.

Ill Compounds of the Alcohol Badicals unth Silicon. Silicon,
like carbon, is a tetrad. The analogy of the compounds of
these elements has already been pointed out in the first
volume. Hence, it is not surprising that the compounds
of silicon with the alcohol radicals exhibit a close similarity
to the paraffins. For this reason silicon ethyl, Si(C2H5)^, has
been termed siliconanane, SiCgHgQ, that is, it may be con-
sidered to be nonane in which one atom of carbon has been
replaced by silicon.' Silicononane is not attacked by nitric
acid. Chlorine gives rise to substitution-products, especially ta
silico-nonyl chloride, SiCgH^j^Cl, which compound can be con-
verted into the alcohol, ethereal salts, and other derivatives, all
containing silicon.

Compounds of the Alcohol Badicals with Metals. Only a few
of the metals combine directly with the alcohol radicals. Of
these, the more important are the metals of the magnesium
group, aluminium, mercury, lead, and tin. The compounds
thus formed are all licjuids, and most of them volatile. Those
of the magnesium group and aluminium inflame spontane-
ously when brought in contact with air, and are decomposed
by water with the formation of the hydroxides of the metals,
and the paraffins. The other compounds do not undergo
alteration in the air, and are not decomposed by water ; they
are, however, att'icked by acids. When tlie alkali metals act
upon the zinc compounds, a portion of the zinc is replaced,
and a Ixxly having a composition such as NaCgH^ + Zn(C2Hj2
is formed. It has hitherto not proved possible to isolate the

* The Tiew held by Duinan that eren car1)on may nnderflo substitution, a view
to powerfully riiliruleii by Lichig, has thus proved to be true, although not
exactly in the form anticipated by us author.

ORGANO-METALLIC BODIES. 169

compound of the alcohol radical with the alkali metal from this
zinc compound.

In general the metallic compounds of the alcohol radicals
correspond to the chlorides of the metals, though this is not
always the case, as is shown in the following table :

NaCl

NaCjHy

ZnClg
HgCl,
PbCl,

Hg(C,HJ,.

SnjCl,
SnCl,

Sn,(C,U,),.
Sn(C,H^,.

THE ALCOHOLS AND THEIR DERIVATIVES.

112 These compounds may be divided into three distinct
classes or groups, primary, secondary, and tertiary alcohols and
their derivatives.

rriniary Alcohols and Fatty Acids, The primary alcohols,
when slowly oxidised, first lose two atoms of hydrogen, and
are converted into aldehydes (alcohol dehydrogenatum ^), and
these again readily pass into the fatty acids by the addition of
one atom of oxygen, the acids being derived directly from
the alcohols by the replacement of two atoms of hydrogen by
one atom of oxygen :

The reactions by which the constitution of the acetic acid
thus formed has been elucidated, have already been referred to,
namely, by the electrolysis of the acid and by its synthetical
preparation from the methyl compounds. Thus we saw that,
when an electric current is passed through a concentrated
solution of potassium acetate, the salt which is best suited to
the purpose, it first decomposes, like an inorganic salt, into

* Liel»ig, Ann. Chcm. Phann, xiv. 133.*

170 THE ALCOHOLS AND THEIR DERIVATIVES.

CgHgOj + K. The liberated metal, however, at once acts upon
the water, and hydrogen is evolved at the negative pole, whilst
at the same time the group of atoms liberated at the other pole
decomposes into carbon dioxide and methyl, CHj, two of the
latter groups uniting to form ethane, C2Hg. All the other fatty
acids decompose in a similar way according to the equation :

SCnRnOg = H, + 2CO2 + (C„.aH2„.0r

If n-i be written m, "^^ obtain for the hydrocarbon the ex-
pression (CmH2ni + i)s = C!nH2n + 2, which IS the general formula
for the paraffins.

The fatty acids can be obtained synthetically from the alcohols
containing one atom less carbon by replacing the hydroxyl by
cyanogen and thus obtaining the nitril, which, when boiled
with caustic potash, yields the potassium salt of a fatty acid
This reaction is expressed by the following general equation :

CnH2n + 1
CnHjn f 1 I

I H-KOH + HOH = C=0 4- NH,.

The following scheme represents the electrolysis of the fatty
acids:

CnHiii + 1 CnH-m + 1

1 I

CO,

H H

CO,.

It is then clear that the fatty acids are compounds of the

t
organic radicals with carhoxyl, HO — C = O, this latter being

t
formed from methoxyl, HO — CH,, this latter group being

characteristic of the primary alcohols.

Hence a primary alcohol may bo defined as a body derived

from a paraffin by the replacement of an atom of hydrogen in

the methyl group by hydroxyl. Or the alcohols may be con-

nidered as methyl alcohol in which one atom of hydrogen is

replaced by an alcohol radical. Hence the following bodies

arc primary aIcoh<»ls:

PRIMARY ALCOHOLS.

171

Ethyl alcohoL

CH,

Hj.OH.

Butyl alcohol.

CH.

■^8

Isobutyl alcohoL

CH.

HgOH.

CH2.OH.

Inactive amyl alcohol.

H«C CH,
CH

■■8

Active amyl alcohol.

H3C CH2.OH

CH.,.OH.

CH3.

Kolbe ' has proposed a general nomenclature for the alcohols,
under which not only the primary but also the other groups
may be classed, as derivatives of methyl alcohol. To this
latter compound he gives the name of carbinol, and classes the
primary alcohols as follows :

Ethyl alcohol
Butyl alcohol
Isobutyl alcohol.
Amyl alcohol (inactive)
Amyl alcohol (active)

Methyl carbinol.
Propyl carbinol.
Isopropyl carbinol.
Isobutyl carbinol.
Pseudobutyl carbinol.

This nomenclature has not been generally adopted, although the
suggestion is not without merit.

The primary alcohols may not only be distinguished by their
products of oxidation, but they likewise may be detected by
the following very delicate reaction.* The alcohol is first con-
verted into the iodide, and a few drops of this are brought into
a distillation flask, having a capacity of a few cubic centimeters,
in which a mixture of silver nitrite and white sand has pre-
viously been placed. As soon as the violence of the reaction
has subsided, the liquid is distilled off, and the nitro-paraflBn
which has been formed is dissolved by shaking with caustic
potash, and then dilute sulphuric acid added drop by drop,
when a dark-red colouration takes place. This colour dis-
appears as soon as the liquid becomes acid, but again makes its

1 Zei/sch. Chcm. 1866, 118.

• V. Meyer, Lxebiga AnncUcn^ clxxx. 139.

172 THE ALCOHOLS AND THEIR DERIVATIVES.

appearance when the liquid is rendered alkaline by caustic
potash. So far this reaction has only been applied, in the series
of piimary alcohols, as high as octyl-alcohol, and thus far with
success.^ This reaction depends on the formation of a nitrolic
acid in the following way :

CH3 CH3

H2 + ON.OH = C = N.OH + H.O.

I
NOo NO.

A nitrolic acid is also formed when a nitro-paraffin is con-
verted into the dibromo-compound, and this is acted upon by
hydroxylamine :

Ciig CHg

Br^+H^N.OH = C = N.0H + 2HBr.

NO2 NOj

The nitrolic acids are colourless, and crystallise well, forming
with alkalis dark-red salts, which explains the production of
the above reaction. They are extremely unstable compounds,
decomposing easily with formation of a fatty acid. V^hen
heated with sulphuric acid, this simple decomposition takes
place, pure nitrogen monoxide being evolved :

CH3 CH3

J = N.OH = C = 0 + N,0.

NOj OH

113 Aldehydes. It has already been stated that these bodies
occur as intermediate products in the oxidation of the alcohols
to fatty acids. They are oxides of dyad radicals, and in their
formation the first step is, in the cases of acetaldehydes, the
production of ethidenc alcohol :

CH, CH3

CH..OH C]

!H(OH),.
Thisi however, like all other compounds containing two hydroxyl

1 Gutknccht, Ber. Dcuttch. Chcm. Of*, xii. 622.

ALDEHYDES. 173

groups, combined with one carbon atom, splits up with separation
of water, and we have the anhydride or oxide left ; in the above
case ethidene oxide or acetaldehyde being formed :

Ethidene alcohol. Acetaldehyde.

^^3 CH,

^^\0H HC=0

That the above formula expresses the constitution of this
compound is seen from the fact that by the action of phos-
phorus pentachloride it is converted into ethidene chloride or
dichlorethane :

CH3 CJH3

I + PCI5 = I + POCI3.

CHO CHCl,

We may, however, acording to the theory of radicals and of
types, consider aldehyde, CgHgO.H, as the hydride of an acid
radical having the general formula CnHgn-iO. All the alde-
hydes are characterised by possessing a peculiar suffocating
smell, whilst another peculiar characteristic of these bodies is
that they unite with the hydrogen sulphites of the alkali-metals
to form crystalline compounds, which are generally diflScultly
soluble, and are decomposed by acids with separation of the
aldehyde, and hence this property is frequently made use of
for the purification of these bodies.

On oxidation the aldehydes yield the fatty acids, and if
fireshly precipitated oxide of silver be employed as the oxidising
agent, the following reaction takes place :

2 CH3.COH + SAgP = 2 CH3.CO.OAg + HgO + 2 Ag.^

When heated with ammoniacal silver solution a similar reaction
occurs, and if the aldehydes are soluble in water, metallic silver
is deposited on the sides of the containing vessel in the form^of
a bright mirror.

114 Haloid Campoiinds of the Acid Radicals. The chlorides
and bromides of the acid radicals are easily formed by the
action of the cliloride or bromide of phosphorus on the acid :

3 CH3.CO.OH + PCI3 = 3 CH3.COCI -f P(0H)3.

174 THE ALCOHOLS AND THEIR DERIVATIVES.

These bodies are, as a rule, liquids which fume strongly in
contact with the air, and possess a powerful acid smell, depending
on the fact that they are rapidly decomposed by water into the
corresponding fatty acid and the hydracids :

CH3.COCI + Ufi = CH3.CO.OH + HCl.

The iodides, which as yet have been but slightly investigated,
are not formed by the action of iodide of phosphorus on the
acids, inasmuch as a further decomposition takes place witli
separation of iodine. They may, however, be prepared from
the anhydrides, and are decomposed by water in a similar way
to the ddorides and bromides. The haloid compounds of the
acid radicals can thus be distinguished from those of the alcohol
radicals, and this explains the fact that the former cannot be
obtained by the action of the hydracids on the acids as the
alcoholic chlorides are prepared by the action of the hydracids
on the alcohols. They may, however, be obtained in this w^ay
in presence of phosphorus pentoxide : ^

CH3.CO.OH + HCl + P2O5 = CH3.COCI + 2 HPOj.

115 Ethereal Salts or Compound Ethers, The fatty acids are
monobasic, and the one atom of hydrogen can be replaced not
only by metals, but also by acid radicals, and thus the bodies
formerly known as compound ethers are obtained. These are
now generally termed the ethereal salts, and they may be
prepared in a variety of ways:

(1.) An alcohol is brought in contact with an acid chloride :

Ethyl Acetate.
C2H5 \^ , CpHj^O ) C2H5 ) ^ xrpi

(2.) An acid is allowed to act upon an alcohol :

C2H5 } r) , C2H3O ) Q _ C-Hr, ) Q TT Q

In this case the formation of the ethereal salt takes place
slowly in the cold, but more quickly when heated. When a
certain quantity of water is formed, the reaction becomes feeble,
and at lost steps. On the other hand, the ethereal salts are
decomposed by water into the alcohol and the acid.

^ Friedel, Contpi, Rend, Ixviii. 1557.

ETHEREAL SALTS. 175

(3.) When hydrochloric acid is passed into a mixture of the
acid with alcohol, the formation of the ethereal salt takes place
more perfectly and more quickly. Tins depends partly on the
fact that hydrochloric acid acts as a hygroscopic agent, but
partly, no doubt, because hydrochloric acid increases the
yield by the fonnation of the acid chloride, which then acta
according to equation No. 1, as these chlorides will attack the
alcohol more readily than water. It is, moreover, possible
that the alcohol is first converted into the chloride, which then
acts again upon the acid :

C2H5 ) CoH.,0 1 r\ C/oHf

} + '''%}o = ^;g:o}o + Ha

Indeed, perhaps the whole of these reactions come into play.*

(4.) Concentrated sulphuric acid acts in a similar way to
hydrochloric acid. Hence the ethereal salts are frequently
prepared by mixing the acid or an alkaline salt of the same
with the alcohol and concentrated sulphuric acid and heating,
or, again, a mixture of equal molecules of the acid and alcohol
is allowed to run into a warm mixture of the alcohol with an
excess of sulphuric acid, when the ethereal salt is formed to-
gether with water, and both distil over. The following equation
represents the reactions which take place : *

(b) C2H5 1 gQ^ _^ C^H^O I Q ^ ^C^H, J Q ^ g^gQ^

(5.) Ethereal salts are lastly formed by heating the salt of a
fatty acid with (a), a haloid ethereal salt, or (6), with a hydrogen
sulphate of an alcohol radical :

* Demole, Ber. DeuUeh. Chem, Qe$. 1877, 1790 ; Henry, tft. 2041.

* Markownikoff, Ber, DeuUch, Chtm, Ofs. ▼!. 1176.

176 THE ALCOHOLS AND THEIR DERIVATIVES.

Ii6 Anhydrides or Oxides of ilie Add Radicak^ These com-
pounds stand in the same relation to the acids as the ethers
of the alcohol radicals do to the. alcohols.

Tliey are formed by the action of the haloid salts of the acid
radicals on the salts of the acids :

2^3^ ) . C2H3O ) o - ^2^3^ I O 4- NaCl
21/ ^ Na/ ^ " CgHjOj^ + ^^^^•

C.H

The anhydrides are insoluble in water, but when placed in
contact with it, they decompose slowly in the cold, and more
quickly when heated, yielding two molecules of the acid. This
decomposition takes place more rapidly in presence of alkalis or
in presence of alcohol, when an ethereal salt is formed :

Hydrochloric acid decomposes the anhydrides in the following
way:

cSS } O + HCl = W^Oj } 4- ""'^^ ] O,

and the phosphorus compounds of the chlorine group act
similarly :

117 ThtO'Cornjwinids of the Ami Radicals, Thio-Acids are
formed by the action of phosphorus pentasulphide on the fatty
acids :

The phosphorus pentoxide which is thus formed acts on a
portion of the thio-acid with formation of other products of
uncertain composition.

The thio-acids which have hitherto been investiimtcd are
liquids possessing an unpleasant smell, and forming salts of
which some, such as the lead and silver BsAts, are easily dccom-
po.sed with formation of the sulphide of the metal.

T/ic TliiO'Anhydrides or Sulphides of the Acid Radicals are
obtained by the action of sulphi<le of phosphorus on the oxides.

AMIDES. 177

These arc also unpleasant smelling liquids, which are decomposed
by water in the following way :

The thio-acids also give rise to compound thio-ethereal salts
obtained by heating the ordinary acid ether with sulphide of
phosphorus, as also by decomposing the salts of the thio-acids
with haloid ethers, and lastly by the action of the acid chlorides
upon the mercaptides :

CgH

f^}s + ^*'fe?}H = C;h;o}s + NaCl.

Ii8 Amides, The acid radicals are capable of replacing
hydrogen in ammonia, thus giving rise to compound ammonias
which, in order to distinguish them from the amines, are termed
amides. In order to prepare these bodies the following
reactions are employed :

(1.) The acid chloride or the anhydride is treated with dry
ammonia :

(a) C2H3OCI + 2NH, = C2H3O.NH2 4- NH.Cl.

Qj) {G^YLf>\0 + 2NH3 = C2H3O.NH2 + O0H3O2NH,.

(2. ) An ethereal salt is treated with alcoliolic ammonia :

*^7???l0 + NH, = CHaO.NH, + aH^.OH.

(3.) The ammonium salt of the acid is heated :
C.HgO.ONH, = CgHoO.NHg 4- H,0.

When the amides are heated with phosphorus pentoxide
they yield nitrils with liberation of water. Phosphorus penta-
sulphide also produces the same reaction :

5aH,0.>'H. + P.S, = r)C),H„.N + r)HoS4PoO..

If the salt of a monamine be employed in reaction No. 3,

instead of an ammonium compound, an amide is obtained in

which one atom of hydrogen is replaced by an alcohol

vor^ III. M

178 SUBSTITUTION PRODUCTS OF THE FATTY ACIDS.

Such compounds are also formed by acting with a carbimide
on a fatty acid :

jCA ^ C,H30|o = n|^H, 4- CO,.

The amides containing two or three acid radicals have as yet
been but slightly investigated. The first is formed when a
nitril is heated with a fatty acid :

an^o.oH H-

'2*^3

( C2H30

C.HjN = N^aH30

And if instead of the acid, the anhydride be employed, a triamide
is produced :

(C,H80)20 + C^HjN - NCCaHaO),.
The anhydride and a carbimide yield the following reaction :

^^{cb^* ^ c:h;S}o = n|c|:8

+ COo.

Wlien ureas, thio-ureas, and similar compounds are treated
with an acid chloride, one atom of hydrogen is also replaced by
an acid radical.

119 Substitution Products of the Fatty Acids, Chlorine and
bromine attack the fatty acids, especially when heated, or in
presence of iodine, the hydrogen in the alcohol radical being
replaced. Thus acetic acid yields :

Monocliloraoctic ncid. Dicbloracctic acul. Trichloracetic acid.

CH.,C:.CO,H CHCU.CO,H CCI3.CO2H.

In the higher members, this substitution invariably takes place
in connection with the carbon atom which is combined with
the carboxyl. Thus propionic and butyric acids yield as first
substitution products :

a Chlorpropionic acid. a Brombatyric acid.

CHj CH,

CHCl CH,

CO.OH CHBr

oo.uu

SYNTHESIS OF THE PRIMARY ALCOHOLS.

179

Iodine does not. form direct substitution products. In order to
obtain these bodies the ether of the chlorinated or brominaited
acid must be heated with potassium iodide, and the acid set
free from the product. When such an iodo-acid is heated with
hydriodic acid, a fatty acid is again formed, from which it is seen
why free iodine cannot act upon these bodies :

CHgl.CO.OH + HI = CH,,CO.OH + 1^.

SYNTHESIS OF THE PRIMARY ALCOHOLS AND

THE PATTY ACIDS.

120 Whilst almost all the members of the homologous series
of fatty acids have been long known, our knowledge respecting
the corresponding alcohols has only recently been rendered
complete.

As the alcohols may be so easily converted by oxidation into
the fatty acids, a method of realising the inverse reaction, and
of converting the acids into the alcohols, did not appear diflScult
of attainment. This problem attracted the attention of many
chemists, but the first attempts proved abortive, and it was not
until after Mendius * had discovered that the nitrils can unite
with hydrogen to form the amines, that this question was solved.
This method promised, moreover, likely to yield results of more
general interest, inasmuch as it seemed that by this means the
whole series of acids and alcohols could be synthetically built
up. For Frankland and Kolbe,^ as well as Dumas, Malaguti,
and Leblanc,* had shown in 1847 that the nitrils or cyanides of
the alcohol radicals can be converted into the fatty acids by
boiling with potash, and Hofmann * had converted the amines
into the corresponding alcohols by the action of nitrous acid.

Now the lowest member of the nitril series is hydrocyanic
acid or formionitril, and this combines directly with hydrogen
to form methylamine. But methyl alcohol can be obtained
from this latter compound, and this again can be converted into
methyl cyanide or acetonitril, which, in its turn, can be made
to yield acetic acid and ethyl alcohol. Here, however, the
simplicity of the reaction ends, for when the same operation is
conducted in the next group, a mixture of isomeric alcohols is

' Ann. Chen. PJiarm, cxxi, 129.
' Compt. Rend, xxv. 442, 656.

' Chem. Soc, Journ. i. 60.
* Chem. Hoc. Journ. iii. 231.

180 LIE3EN AND ROSSI'S SYNTHETIC METHOD.

obtained, and these cannot readily be separated. The cause of
this will be explained later on.

Other general methods may, however, be employed for the
synthetical formation of the alcohols and acids corresponding to
the normal paraffins.

In I80I Williamson * showed that when a mixture of a for-
mate and a salt of a fatty acid is heated, the aldehyde of the
latter is produced :

Five years later this was confirmed by the experiments of
"Limpricht^ and Piria,^ and when Wurtz* in 1862 had dis-
covered that the aldehydes combine directly with nascent
hydrogen to form the alcohols, no further obstacles were seen
to present themselves to a systematic construction of the homo-
logous series of the acids and alcohols. Many unperceived
difficulties were, however, met with in the practical carrying out
of the process, and it was not until the year 1860 that Lieben
and Rossi ^ sufficiently perfected the methods, by means of
v/hich, beginning with ordinary alcohol, the whole series of
normal primary alcohols and the corresponding acids could be
synthetically obtaine<l.

Lichen and Iiossi*8 Method. The first step of this process is
the preparation of propionic acid from ethyl alcohol by means
of acetonitril, and then heating its calcium salt with calcium
formate. In this way propioaldehyde is obtained, and this com-
bines directly with hydrogen to form propyl alcohol. From
this latter propyl cyanide (butyronitril) can be prepared, and
tliis again, in a similar way, yields butyr-aldehyde and butyl
alcohol, &c.

Fatty acids are also formed by the action of carbon dioxide
on the compounds of the alcohol radicals with the alkali
metals (Wanklyn) : "

(^,H,Na + CO., = (^H,.CO.Na.

Frankitind nrul Dnppa's Method, Another metho<l discoveretl
by Frankland and Duppa and imiT(»vc<l by other chemists, not

» i'hrui, Soc. Journ. iv. 13S. = Ann. Chem. Diarm, li. 201.

' Ami. Ckim, xlviii. 113 : Ann. Chem. Pharm^ c. 104.
* Compt. RrniL liv. IH4.

' Ann. Chnrt. Phann. rlviii. 137 ; rlix. .'JS, 70 : tlxv. 109; olxvii. 203 ; I it-lien
an I .Taii»'«*ok, ih. ilxxwi-. \'1*\. •• Wanklyn, f"hr,ii. Si>c. Joitrn. xi. 1(»3.

FRANKLAND AND DUPPA'S METHOD OP SYNTHESIS. 181

only enables us to prepare the fatty acids synthetically, but also
the other series, and a variety of other compounds.^ This
depends upon the fact that the hydrogen of the methyl in
acetic acid can be replaced by a carbon-containing radical. For
this purpose, sodium is dissolved in acetic ether, when sodium
aceto-acetic ether and sodium ethylate are formed :

(;h, CH

CO.OCH, CO

f iNa^ = I -f NaOCgH, + H...

CH, CHNa

O.OC2H, CO.OCoH,,

In this reaction, however, little or scarcely any hydrogen is
evolved in the free state, as this, in the nascent condition,
reduces a portion of the acetyl in the acetic ether to ethyl,
forming sodium ethylate. If acetic acid be added to the solid
product, aceto-acetic ether is formed. This possesses slightly
acid properties due to the presence of two carbonyl groups, and
when acted upon by sodium, yields the original compound in
the pure state. The sodium in this body may readily be sub-
stituted by an alcohol radical on treatment with an alcoholic
iodide, and in this compound the second atom of hydrogen can
be substituted by sodium, and this in its turn again replaced by
an alcohol radical.^

All these compounds, like acetic ether itself, are decomposed
by concentrated caustic potash, in the following way :

CH3 CH,

CO CO. OK

I + 2H0K = + HO.C»H,.

CXY CHXY

2 o'

CO.OGM, CO.OK.

In these formulsB X and Y represent either hydrogen or an
alcohol radical It is clear that by this reaction not only homo-
logous acids but many isomeric acids may be built up, as, for
example, in the following instances :

* Concerning the history of this subject, see Wislicenus* ** Synthesis of Aceto-
acetic Kthers,** Li^, Ann. clxxxvi. Idl.

* Ob tliis suhject see Conrad and I impach, Lich, Ann cxcii. 153.

182 SECONDARY ALCOHOLS AND KETONE&

Pt'utylic acid.

Valerianic acid.

Methyl-ethyl acetic acid.

CHo Cxia

CH,

CHj
CH,

0 V

CH,

CH CH,.

CH,

CO.OH

Pentylic acid is obtained by replacing one atom of hydrogen
in acetic acid by the primary radical propyl, whereas secondary
propyl yields valerianic acid. In order to obtain the third acid,
sodium aceto-acetic ether is, in the first place, treated with
iodide of ethyl, the ethyl compound is then acted upon by
sodium, and the body thus obtained converted, by means of
methyl iodide, into methyl-ethyl aceto-acetic ether, and this
finally decomposed by caustic potash.

SECONDARY ALCOHOLS AND KETONES.

lai The secondary alcohols, the existence of which was pre-
dicted by Kolbe * in 18GG, may be regarded as methyl alcohol, in
which two atoms of hydrogen are replaced by alcohol radicals.
The first of these secondary alcohols, CjHgO, was prepared by
FriedeP by the action of hydrogen (2) on acetone, CjH^O,
obtained on the dry distillation (1) of calcium acetate :

(I) CH3.C().0 ) ^, _ CHgX.^^ rvPOs

<2) g{5«}C0 + H, = g{j3lcH.0H.

Other fatty acids yield ketones when treated in a similar way,
and these are also formed, as Freund ^ has shown, when an
acid chloride acts upon the zinc compound of an alcohol radical.
Thus acetyl chloride and zinc ethyl give mcthyl-ethyl-kctone :

Zn(C.,HJ, + 2CICO.CH3 = 2CjH,.CO.CH3 + ZnCI,.

» Zeitsch. Cktm. I.<i6«, 118. « rnmpt. Rend, Iv. 50.

^ Ann, f.'hem. Phnrin. rxviii. 1.

SECONDARY ALCOHOLS. 183

The same compound^ together with dimethyl ketone and diethyl
ketone, is obtained when a mixture of calcium acetate and
calcium propionate is heated. The formation of the ketone
from the &tty add is, therefore, exactly analogous to that
of the aldehyde from a mixture of the salt of a fatty acid and
a formate. Whilst just as the aldehydes were formerly con-
sidered to be hydrides of the acid radicals, so the ketones were
looked upon as compounds of the latter with alcohol radicals.

Another general method for the preparation of the ketones
is the decomposition of the acet-acetic ethers by baryta water :

I CH3

CO I

I + Ba(0H)2 = CO + HOCoH, -t BaCO,.

CO.

IHXY

OCjH,

The ketones combine directly with nascent hydrogen with
formation of secondary alcohols.

The secondary alcohols can also be obtained by various other
reactions. Thus all the olefines which contain the groups
— CH = CHg and — CH = CH — dissolve in sulphuric acid
with formation of an acid ethereal salt, which when heated with
water yields the alcohol :

^^\>CH.0.S02.0H + H,0 = ^g3\cH.0H 4- HO.SO2.OH.

These olefines also combine with the hydracids to form the
haloid ethereal salts :

CH3

CHj

CH„

••

CHj

r 1

CHI

GHn.

•1

(JH,

CH,

II
CH

'h} "

CHT
CH.,

CH« CH,

184 SECONDARY ALCOHOLS AND KETONES.

By the action of chlorine upon the paraffins, secondary as
well as primary chlorides are formed, whilst with bromine only
secondary bromides are produced.^

Secondary iodides are formed when the alcohols of polyvalent
radicals are heated with concentrated hydriodic acid and
amorphous phosphorus. Thus, glycerin, 03115(011)3, yields
secondary propyl iodide ;

OH2.OH OH3

OH.OH + 5HI = OHI + 3H.0 + 2L.

OHo-OH OH3

Phosphorus is added for the purpose of preventing the liberation
of iodine:

2 OjHgOg + 2 HoO + P, + Ig = 2 O3H7I + 2H3PO,.

From these iodides, the alcohols may be obtained by the action
of freshly precipitated oxide of silver.

The alcohols may likewise be obtained by heating the iodides
with concentrated acetic acid and anhydrous acetate of lead in
closed tubes, the ethereal acetates thus formed being decomposed
by caustic potash. This latter reaction is also employed in
order to convert the chlorides and bromides into alcohols.

By the action of silver nitrite on the secondary iodides, nitro-
paraffins are obtained. These dissolve in caustic potash, and
when sulphuric acid is added to this solution a deep-blue
colour is produced. When shaken with chloroform this coloured
compound dissolves, and on evaporation of the dark-blue solu-
tion, colourless crystals of a pseudo-nitrol arc obtained :

Propyl-pseudonitrol
]i)0-nitro ])ropanc. or Nitro-nitro80-proi>anc.

CH3 C;H3

I J /NO..

CH— (NO.,) + NO.OH = c; ' + H.,0.

I, ' |\^'^

CH., CH..

Small traces of a secondary compound can be recognised by
this reaction, but it is only applicable to the lower terms of
the series.- The pseudo-nitrols are colourless in the solid state,

» Srhorlemmer, /Vii7. Tnins. rlxii. (1^72) 111 : Ih. dxix. (1878) iO.
' Meyer and Locher, Lieb. Ann, clxxx 139.

CONSTITUTION OF SECONDARY ALCOHOLS. 186

but when fused or in solution they possess a deep-blue colour.
On oxidation they first form ketones :

Propyl-pfiendonitrol. Dimethyl-ketone.

CH3 CH3

O = N— C— NO., + H2O -r 30 = CO

1^ ' I 42HNO3.

The secondary alcohols also easily form ketones on oxidation,
and these on further oxidation decompose in such a way that
the carbonyl remains in combination with one alcohol radical,
whilst the other yields oxidation products like its corresponding
alcohoL* Hence dimethyl ketone yields acetic acid and formic
acid, the latter however, readily undergoes decomposition into

p2 5^ and

( OH
methyl propyl ketone, CO •} n ijf > hot-h yield acetic and propionic

acids, whilst from methyl iso-propyl ketone, CO -J npr/pij \

first acetic acid and then dimethyl ketone is obtained, which
latter is further oxidized as before described.

From this it would appear that the simplest alcohol radical
always remains ip combination with the carbonyl. This is, how-
ever, not always the case. Thus, for example, from tri methyl -

carbylmethyl ketone, CO -! p/rvrj \ ^vc obtain trimethylacetic

^^ 1 rOOH^ *^^ formic acid.

Hence, in many cases, the constitution of the secondary
alcohols can readily be recognised by their products of oxida-
tion. Thus, for example, a secondary alcohol is obtained from
mannite, CoHg(OH)g, which, when completely oxidized, yields
acetic and butyric acids, and, therefore, must bo considered ikh

methyl butyl carbinol, ^^^ \ CO.OII.

The ketones act in many respects, like aldehydes, as oxides
of dyad radicals. Phosphorus pentachloride converts them into
the dichlorides :

3} CO 4 rci, = f^Jl'CCi, + P0CI3.

CH3f^^^' -r -•. = (jHJ

' Popofl", Ann. Chcm. Phann. clxi. 28ri.

186 TERTIARY ALCOHOLS.

Many ketones also combine with the hydrogen sulphites of
the alkali metals to form difficultly soluble crystalline com-
pounds which are decomposed again by an excess of acid or
alkali. Hence this reaction is often employed for the purification
of the ketones.

TERTIARY ALCOHOLS.

122 A general method for the preparation of these alcohols,
the existence of which was also predicted by Kolbe, has been
discovered by Butlerow.^ This consists in placing an excess of
the zinc compound of an alcohol radical in contact with the
acid chloride for severpJ days, when a crystalline mass is
formed :

CH,

4- 2(CH3)JZn = CH3— C— O— Zn— CH3

joci *■ I ^ 7 fCl

CH3 ^ tCH3.

We may assume that as in the case already mentioned,
(p. 182) a ketone is hero first formed, and that this unites with
one molecule of the zinc compound, in a similar way as it does
with hydrogen to form a secondary alcohol. If the above com-
pound be next treated with water, tertiary butyl alcohol, or
trimethyl carbinol, is obtained, and this is the first member of
this scries :

(CH3)3C.O.ZnCH3 + 2H,0 = (CH3)3C.OH + Zn(0H)2 -h CH,.

The tertiary alcohols are also formed by the direct union witli
water of the olefines containing the groups

— [;y: = OH, and Zc/f' = ^^H—

CII3 CH3 CH3 CH,

\/ \/ '

Thus: 0 -h H>C) = OOH

II I

» Zfitjtrh, r^hnn. 1864, 3«r». 702.

OXIDATION OF TERTIARY ALCOHOLS. 187

This combinatiou takes place with especial ease in presence of
sulphuric acid or nitric acid.'

The same defines readily unite with the hydracids to form
tertiary haloid ethereal salts.

The tertiary alcohols are at once broken up on oxidation in
such a manner that the carbon atom which holds the group
together remains in connection with one alcohol radical forming
a fetty acid, whilst the two other alcohol radicals yield the
same oxidation products as their corresponding alcohols do. In
this way ketones frequently occur as intermediate products.
Thus trimethyl carbinol first yields formic acid and dimethyl
ketone, and the latter readily splits up into water, carbon dioxide
and acetic acid. This last product is also obtained from methyl
diethyl carbinol, whilst propionic acid is also formed from the
isomeric dimethyl propyl carbinol. It is a singular tsyct that in
these oxidations a small quantity of a fatty acid is obtained
which contains as much carbon in the molecule as the tertiary
alcohol. This is, however, not difficult to explain. The tertiary
alcohol easily decomposes into water and an olefine, and these
latter, as we have seen, readily combine with water to form a
tertiary alcohol. It is also possible that, under certain circum-
stances, a primary alcohol may be produced, and the formation
of isobutyric acid from trimethyl carbinol may be explained by
the following equations :

(CH3)2C(OH)CH8 = (CH3),C : CH^ + HgO.

(CH3)2C : CH2 4- H.3O = (CH3)2CH.CH20H.

Isobutyl alcohol is thus obtained, which, on oxidation, yields
isobutjnric acid.2

123 Tertiary nitro-paraffins are formed with difficulty. They
do not possess any acid properties, and hence they do not
dissolve in alkalis and do not give any reaction with nitrous
acid.

The reason that these tertiary compounds do not act as acids
is not far to seek. In order that a replacement by a metal can
occur, the carbon compound must contain acid-forming or
negative elements or radicals united to a carbon atom, which
latter must also be united to an atom of hydrogen or hydroxy!.

* Butlerow, Lieb. Ann. clxxx. 245.

* Butlerow, Zcitsch. Chan, 1871, 484; Lich. Ann. clxxxix, 173.

•i

188

TERTIARY ALCOHOLS.

Hence acetic acid is an acid. Its anhydride (acetyl oxide) is,
however, not an acid. The same reasoning applies to the
uitro-paraiBns.

Nitro-e thane.

CH3

CH,

Secondary
Nitropropane.

CH3

NO..

CH.NO,
CHo.

Tertiary
Nitrobutane.

CH3 CH3

C.NO.

CH3.

Bromnitro-ethane. Dibromnitroethane.

CH3

CHBr

NOo.

CBr.

Secondary
Bromnitropropane.

CH3

BrC— NOo

NOo.

CH3.

The two first of these bodies only act as weak acids, whilst
bromnitro-ethane, obtained by the replacement of hydrogen by
negative bromine, is a strong acid. All the other compounds
are, however, perfectly neutral.*

It has already been stated that a mixture of isomeric alcohols
is obtained by the action of nitrous acid upon primary amines
which contain more than two atoms of carbon. The fact that
in this case the alcohols produced are not homogeneous had
been overlooked, and it was thought that propylamine, for
example, was converted by the above reaction into secondary
propyl alcohol, and isobutylamine, in like manner, into tertiary
butyl alcohol.- As soon, however, as the fact of the production
of a mixture of alcohols became apparent, a somewhat far-fetched
hypothesis was made use of, until at last a very simple explana-
tion was found,^ namely, that the reaction goes on quite nonnally
up to a certain point, and that a primary alcohol is pro-
duced from propylamine, but another ]K)rtion of the propyl-
amine is converted into propyleno, which is jMirtly evolved as
a gas and partly combines with water to form a seconilary
alcohol :

* V.MeycT, Lub. Ann, clxxx. iii.
- Liuneinanii, Ann, Chem. Phann, clxi. ATt ; clxii. 3.

=* Mover and Forstcr. Drutsch, f'hrin. Ors. Bcr. ix. .^:j.1 ; Mrvor, Bubicri, and
F<irstir, X. l.'^M.

NITRO-PARAFFINS. 189

CH3 CH3

I I

CHo + HO.NO = CH + N^ + 2H<,0.

CHj.NHo • CH.,

CHj CHj

I I

CH + HjO = CH.OH

II I

In a similar way isobutylamiDO yields isobutyl-alcohol, iso-
butylene, and trimethylcarbinoL

190 THE METHYL GROUP.

THE METHYL GROUP.

METHANE OR METHYL HYDRIDE, CH^.

Z24 The existence of this substance was observed by the an-
cients, as Pliny noticed the occurrence, in several localities, of jets
of combustible gases. In later times we find that Basil Valentine,
in describing the outbreaks of fire which occur in mines, men-
tions a suffocating damp which is noticed before such an outbreak.
He does not, however, appear to consider that the gases issuing
in such emanations are combustible, but rather that the fire
comes out of the rock and drives out the poisonous air. Libavius,
likewise, gives an account of an explosive fire-damp ; and during
the seventeenth and eighteenth centuries a large number of
descriptions arc found of explosions which occur in mines, and
especially in coal-pits. At the same time no distinct statement
is made of the nature of this inflammable fire-damp, which, like
other combustible gases, was not at that time distinguished from
hydrogen.

Fire-damp as well as the gas of marshes was then con-
sidered to be poisonous, nor was it until the year 177G that
Volta^ pointed out the inflammable nature of the latter gas.
He showed that marsh gas differs from hydrogen, in requiring
twice its volume of oxygen for combustion, as well as in giving
rise to carbondioxide, whilst ordinary inflammable air needs only
half its volume of oxygen for combustion and yields no carbon-
dioxide. In 1785 BerthoUct investigated the properties of marsh
gas more accurately, and found that it contains both carbon and
hydrogen, and that it usually occurs mixed with nitrogen. All
the naturally occurring infliimmable gases were, however, con-
sidered to be identical with the gases obtained artificially by the
dry distillation of organic matter, a.s well as with the substance

* JSuir aria injlamniabilc )ui/mi dcUt jmludi. MiUno. 1777.

METHANE OR METHYL HYDRIDE. 191

known as defiant gas, until William Henry,* in 1805, proved
that the gases obtained by the destructive distillation of coal,
oil, and wax, contain two distinct gaseous hydrocarbons, viz.,
defiant gas and carburetted hydrogen (marsh gas) mixed with
carbonic oxide gas. Shortly afterwards Dalton,* Davy, and
Berzelius confirmed the existence of two distinct gaseous com-
pounds of carbon and hydrogen, which, from their difference in
specific gravity, were termed light, and heavy, carburetted hy-
drogen, the former being marsh gas and the latter olefiant gas.
The first of these was afterwards looked upon as methyl hydride,
and the name methane given to it by Hofmann.

125 Properties, Methane is a colourless inodorous gas which,
according to Cailletet, can be liquefied under a pressure of 180
atmospheres at a temperature of — ll^ Its specific gravity
was determined by Thomas Thomson ^ to be 0*555.

Marsh gas is not poisonous, and colliers who frequently
breathe air containing 9 per cent, of this gas do not appear to
suffer. When the percentage increases above this point, pressure
on the forehead and eyes is noticed, which, however, disappears
again on gaining the open air.

Methane is readily inflammable, burning with a slightly lumin-
ous flame, which in the upper part has a yellow, and in the
lower a blue, colour. When mixed with double its volume of
oxygen, and fired by an electric spark or by a flame, it explodes
more violently than the same volume of electrolytic gas, and a
mixture of marsh gas with from seven to eight volumes of air
also explodes with great violence. Mixtures of air and marsh
gas varying from this proportion bum with a weaker explosion,
and if one constituent be present in large excess the electric
spark does not explode the mixture (Davy).

Methane is but slightly soluble in water; its coefficient of
absorption, according to Bunsen, for temperatures between 0**
and 26** is obtained from the following interpolation formula :

c. = 0-05449 - 0 0011807t + 0000010278t*.

It is more soluble in alcohol, the following formula giving its
solubility in that liquid between 2"^ and 24** :

c = 0-52258G - 00028655t + 00000142t2.

* Nicholswi's Jiunuil, xi. p. 65. * Vol. I. p. 612.

'^ NicholsorCs Journal, 1807.

192 TUE METHYL GROUP.

It has already been mentioned that methane occurs in nature.*
Thus it forces its way out together with petroleum at various
points on the earth's surface. Tlie sacred fire at Baku consists
of burning marsh gas containing admixtures of nitrogen, carbon
dioxide, as well as of the vapour of petroleum (Hess). The gas
issuing from the mud volcanoes at Bulganak, in the Crimea, on
the other hand, consists, according to the analyses of Bunsen, of
perfectly pure methane. It has already been stated in the first
volume (p. G08) that the gases which escape in large quantities
from the oil wells of Pennsylvania contain marsh gas and its
homologues, together with hydrogen.

Marsh gas not only occurs in these sources and in very large
quantities in the coal measures, but it is also found in many
sulphur springs in the neighbourhood of active volcanoes, and it
is likewise evolved in the boric acid fumeroles in Tuscany.
Moreover, methane is a never-failing constituent in the pro-
ducts of the dry distillation of organic matter, and hence it is
found in large quantities in coal gas.^

126 Preparation, Methane is obtained when either acetic acid
or acetone is heated with an excess of caustic alkali. In order
to prepare it, an intimate mixture of one part of sodium
acetate and four parts of soda-lime is made and then heated
in a flask or tube of hard glass, or, still better, in one of copper
or iron, until the gas is evolved. In this way, however, the
formation of a certain amount of free hydrogen (according to
Kolbe^ about eight per cent.), as well as of ethylene, cannot be
avoided. This latter may be removed by passing the gas through
U tubes containing pumice stone moistened with strong suN
phuric acid.

According to C. A. Brindley the best mode of preparation is
to mix 750 grams of caustic soda dissolved in 800 cbc. of water
with 750 grams of acetate of soda, and, when this is dissolved,
to add 1,250 grams of coarsely-powdered quick-lime. The
mixture is then evaporated to dryness, and afterwards gradually
heated to redness in an iron bottle. In this way 125 litres of
marsh giis are obtained.

Methane is fonned from acetic acid according: to the following
ecjuation :

CII,.CO.ONa + NaOII = CII, + CO(ONa),.

^ Vol. I. pages 608-10.

- IVwoz, lUrue SciaUif. i. 51 ; Dumns, Amu Chiin. /7ii/j. Ixxiii. 02.

* Aits/. Lrhrb, Org. Chrm. i. 273.

SYNTHESES OF METUANE. 103

In order to prepare it in the perfectly pure state, zinc methyl
is decomposed \vith water. ^

Zn(CH3)2 + 2H0H = Zn(OH), H- 2CH,.

The synthetic formation of methane is of great theoretical
interest. Berthelot* obtained it thus by passing a current of
sulphuretted hydrogen, saturated with the vapour of carbon
disulphide, over ignited metallic copper, when the following
reaction takes place :

CS2 -;- 2H2S 4- 8 Cu = CH, -f 4 CU2S.

By this means about one-fifth to one-tliird of the total
hydrogen in tlie sulphuretted hydrogen is converted into marsh
gas. In order to separate tlie methane, he agitated the
gas with alcohol, in which, as has been stated, marsh gas is
tolerably soluble. By warming the alcoholic solution the pure
gas is driven off.

Methane is also formed by submitting a mixture of hydro-
gen and carbonic oxide gas to the action of electricity in an
induction tube, round which the electricity passes :

CO -I 3H, = CH, + H,0.

After the induction current has acted for five hours, about
6 per cent, of marsh gas is produced.^ Although methane can
be produced in this way, it is decomposed into its constituents
at once, when subjected to the direct action of the electric
spark. This decomposition, however, is not a complete one.
The action of the induction spark ceases after half an hour, the
original volume does not become quite doubled,* whilst a certain
proportion of acetylene is formed. This latter gas, together
with naphthalene, Cj^Hg, is also formed, according to Berthelot,
when methane is exposed to a very high temperature, a portion
of the gas being at the same time converted into its elementary
constituents.

Like all the paraffins, methane is a very stable body, unacted
upon by cold concentrated nitric acid, and even by fuming sul-
phuric acid at a temperature of 150°. On the other hand,
chlorine attacks it so easily that when the mixed gases are

» FranklanJ, Phil Trans. 1853, cxUi. 417.

« C<y7npt. llend. xliii. 236.

^ lirodic, Proc, Ttoy. Soc. xxi. 245.

^ Ruff and Hofmaim, uimi. Chan. Pharm. cxiii. ]*-IJ).

VOL. III. O

194 THE METHYL GROUP.

exposed to the sunlight an explosion may occur with separation
of carbon, whilst in diflfused daylight a series of substitution
products is formed.

METHYL ALCOHOL,

CH3OH.

127 Boyle, in his Sccjytical Chemist (1 GG 1), constantly insists
upon the fact that bodies cannot be resolved into their ulti-
mate constituents by means of fire, a view which was generally
held at .that time, and one which was supported by a mass
of strange experimental evidence, respecting the truth of which
the cautious Boyle gives it as his opinion *' that he that hath
seen it hath more reason to believe it than he that hath not.** *
In particular he states that the volatile product obtained by
the dry distillation of wood is not a simple body, but that
it consists of an acid-, or acetous-, and an indifferent or an
adiaphorous (from aSm<^opo9, iudifferont) spiiit, which latter
he showed to be inflammable.^ These two products he sepa-
rated as follows : " I took eight ounces of the rectified spirit of
box (wooil), wherein the acetous and neutral spirit remained
confounded, as they had been in the first distillation ; and
having poured this upon a quantity of calcined coral, sufficient
to satiate the acid corpuscles (which quickly fell to corrode it
with noise and bubbles), we gently distilled it to dryness in a
glass head and body, by which means we obtained of adiaphorous
spirit but eight grains less than seven ounces and a haltV*

It was not until the year 1819 that this S])irituous liquid again
attracted the attention of chemists. C<din believed it to be
acetone, whilst Dobereiner in 1821 stated that he found it to
contain common alcohol. Upon this Taylor^ remarked that so
early as 1812 he had examined this body, to which he had
given the name of pyrol igneous ether, because it was a sub-
stance which, althou^di it possesses great similarity with ordi-
nary alcohol, still differs from this body, inasmuch as it does
not yield sulphuric ether on treatment with sulphuric acid.
This property was confirmed by Macaire and Marcet (1824), by
Gmelin (1829), and by Liebig (1832). A complete investigation

' Boylo, Ojtrra^ \. 4S6, f«K»tiiotc.

' •*Nrw OhscrvatioiiB about the Adiaphorous Spirits of AV(kx1s and divrrs
other bo<lic8,*' i^jM-ra^ i. 61 G.
* Tillochs, Phil, Mag. Ix. 315.

IVIKTHYL ALCOHOL. 195

of wood -spirit was made, in the year 1834, by Dumas and
Peligot,* who were the first to point out the striking analogy
existing between this body and common alcohol, an analogy
which has exerted a marked influence on the progress of or-
ganic chemistry. 2 They gave to this compound the name of
methyl alcohol (from $ii6v, wine ; i/Xi;, wood). Their analytical
results, however, did not agree with those obtained by Liebig, and
hence Berzelius suggested in 1839 that wood-spirit must contain
diflferent bodies, and this supposition was soon confirmed.

Methyl alcohol is also formed when wood is heated to the
boiling-point of mercury, with an equal weight of caustic
potash and a small quantity of water,^ as well as when wood
is heated with water to a temperature of 200°.* It is also
produced in the dry distillation of other organic materials, and
is likewise contained in the products of the action of heat on
calcium formate (CH02)2Ca.^

Methyl alcohol does not occur in the free state in nature,
although the methyl ethereal salts are contained in a variety of
plants. Thus, for instance, the wintergreen oil obtained from
Oavltheria procumbejis, a plant indigenous to New Jersey and
various other parts of the United States, consists entirely of
methyl salicylate, CHgCyH^Og.^ This compound is also the chief
constituent of the ethereal oils of other species of Gaultheria, as,
for instance, the G, jnuictata and Icucocarpa, which grow on the
top of the extinct volcanoes of Java," and also of the Andromeda
leschcnanUiiy indigenous to the Neelgherry Hills.* The ethereal
oils from the seeds of AnthriscAts cerefolium, Pastinaca sativa
and Heraclcum giganteum, cont^iin the ethereal salts of various
alcoholic radicals, amongst which small quantities of a methyl
compound, probably methyl butyrate, occur.®

128 Commercial Pr€2)aration, Methyl alcohol is prepared on
the large scale from the aqueous liquid obtained in the dry dis-
tillation of wood. This contains a variety of other compounds,
together with methyl alcohol and acetic arid. The most volatile

^ Ann, Chim. Phj/s. Iviii. 5 ; Lxi. 193.
' Kopp, Ocschichie der Chemic. iv. 330.
' Peligot, Ann. Chim. Phys. Ixxiii. 218.

* Greville Williams, Chcin^ News, xxvi. 231, 293.

^ Lieben and Patenio, Ann. Chim. Pharm. clxvii. 293 ; Frieilol ami Silva,
Cirm.pL. Rend. Ixxvi. 1545.

* Cahonrs, Compt. Jimd. xvi. 853 ; xxxix. 255.

'' De Vrij, Pharm-. Joiirn. Trans. [3], ii. .'503 ; Brr. DcuUich. Chem. Ges. xii. 246.
" Bron^hton, Pliarm. Journ. Trans, [3J, ii. 281 ; Kuhlor, Per. Deutsch, Chem,
Gfs. xii. 246.

* Gutzeit, Licbia^i Attn, clxxvii. 344.

o 1

1% THE METHYL GROUP.

portions are first distilled over, and these repeatedly recti-
fied over quicklime in order to remove as much as possible
acetic acid, water, and tarrj' substances. The wood-spirit thus
obtained contains together with methyl alcohol, acetone, allyl
alcohol, methyl acetate, homologiies, and condensation products
of acetone, together with oily bodies and other compounds. The
pure alcohol is obtained by first heating with caustic soda in
order to convert the methyl acetate into alcohol. The disagree-
able smelling impurities are then destroyed by a weak oxidising
agent, and the product subjected to a systematic fractional dis-
tillation, for which purpose an arrangement is used similar to
that employed in the rectification of common alcohol.* The pro-
duct obtaine<l in this way, freed as much as possible from acetous
and allyl alcohol, constitutes the wood-spirit of commerce.

Methyl alcohol is now largely obtained as a by-product in the
beetroot sugar industry. In this industry, as in the manu-
facture of cane-sugar, large quantities of molasses or treacle
remain behind after the whole of the crystallisable sugar has
been withdrawn. These molasses are invariably employed to
yield ordinary alcohol by fermentation. Now the juice of the
beet as well as that of cane-sugar contains, in addition to the
sugar, large quantities of extractive and nitrogenous matter,
together with considerable quantities of potash salts. In some
sugar-pnxlucing localities tlie waste liquor or spent-wash from
the still.s, termed "vinasse** in French, is thrown away; but
in France it has long b(?en the custom of the distiller to eva-
porate these liciuids to <lryness and to calcine the mass in a
reverbcratory funuice, thus destroying the whole of the organic
matter, but recovering the alkaline salts of the beetroot. In
this way 2,000 tons of carbonate of potash are annually pro-
duced in the French distilleries. For more than thirty years
the idea hiis been entertained of collecting the ammonia water,
tar, gas, and oils, given off when this organic matter is calcined;
but the practical realisation of the project has only quite re-
cently been accomplished, and a most unexpected new field of
chemical industry thus opened out through the persevering and
sagacious labours of M. Camille Vincent ^ of Paris. In this
pro<*ess the spent-wash, after evaporation, is submitted to dry
distillation. The distillate consists of a complex mixture of

* litr. Knttr. I'hfin. I ml. ii. 277.

" Comjif. Rend, Ixwiv. 211; />V//. Sm'. Chim. [2], xxvii. IIS; Kxpos. I'liiv.
1S7H, rnnl. Chilli. groiijM* ;'•, rbtsM* 47.

PREPARATION OF METHYL ALCOHOL. 197

chemical products, resembling in this respect the corresponding
product in the manufacture of coal-gas. It is, however, dis-
tinguished from this, and approximates in composition to the
products of the dry distillation of wood, by containing not only
ammoniacal salts, but especially trimethylamine, acetonitril,and
methyl alcohol. The distillate having been neutralised by sul-
phuric acid, is evaporated in retorts, when the two latter com-
pounds distil over. The nitril is decomposed by rectification
over lime into acetic acid and ammonia, and the distillate
contains dilute methyl alcohol, which may be dehydrated by
a second treatment Tvith caustic lime.

The best commercial wcod-spirit contains about 05 per cent.,
the more common varieties 75 to 00 per cent, of the pure alcohol,
whilst some samples may contain only from 85 to 40 per cent, of
pure substance.^ Besides water, it contains acetone and other
bodies.

129 Preparation of pure Methyl Alcohol. In order to prepare
pure methyl alcohol the method suggested by Wohler ^ is best
employed. This consists in preparing from the commercial
article crystalline methyl oxalate, (€113)2020^, a body which
boils at 162'', is easy to purify, and is readily converted into oxalic
acid and pure methyl alcohol by heating with w^ater. According
to Erlenmeyer ^ this ethereal salt is best obtained by dissolving
anhydrous oxalic acid in boiling w^ood-spirit. The crystals which
separate out on cooling are then washed with water by means
of a filter-pump, until the liquid which runs off does not
give the iodoform reaction. It is then boiled with water in
a flask connected with a reversed Liebig's condenser, in order
to decompose the ethereal salt completely, for which purpose the
ebullition must continue for at least three hours; an addition of
caustic soda facilitates the decomposition. According to Carius,*
methjl benzoate, CH^.C-H^Og, may be employed instead of the
oxalate. This is obtained easily by saturating a solution of
benzoic acid in methyl alcohol with hydrochloric acid, and then
removing the more volatile ethereal product by distillation.
The residue is washed with water and thou decomposed by
heating with caustic soda.

It has already been mentioned that the ethereal oil of the
Gaultheriu prorvmhenji chiefly consists of methyl salicylate,

* Bardj ami Rordet, Bull. Soc. Chim. xxxii. 4.

* Ann. Chem. Phanu. Ixxxi. 37G.

* K. Itep. Phnrm. ex. 209. * Ana. Chem. Pharm. ex. 209.

198 TUE METHYL GROUP.

CHyC-H-Oj, boiling at 224°. Tiiis was formerly employed for
the preparation of pure methyl alcohol. As salicylic acid is
now prepared on a large commercial scale, the artificial salt may
be made use of instead of benzoic acid for the purification of
wood-spirit.

Purified wood-spirit, as we have seen., frequently contains
acetone, a body boiling at 56°, or 9° lower than methyl alcohol.
This compound may, however, be almost completely separated
by fractional distillation, and the product thus obtained, termed
in French methyltncs dc queue, easily yields pure methyl alcohol
by converting it into methyl formate, CH3.CHO2, a body which
boils at 32°, and which is readily decomposed by caustic soda.*

Pure methyl alcohol obtained according to one or other of
these methods may be distilled from a water-bath in order to
remove the water with which it is mixed, and then allowed to
stand over ignited carbonate of potash for a long time, and
afterwards rectified over either freshly burnt lime or anhydrous
potassium ferrocyanide. The product thus obtained still con-
tains small (juautities of water which can only be got rid of by
rectification over metallic sodium or phosphorus pentoxide.

130 Properties, Pure methyl alcohol is a colourless mobile
li([uid possessing a pure vinous smell similar to that of common
alcohol and having a specific gravity of 081 42 at 0° (Kopp).
The boiling point as given by various observers varies from 58°*G
to 6C^'5. This is jwirtly to be explained by the fact that the early
exi)erimenters operated upon an impure compound, and partly
also because the substance retains water with the greatest
avidity. The perfectly anhydrous compound boils, according
to Dittmar and Stewart* at 55°1, whilst Kopp^ formerly found
the l)oiling point to he 54^*0 to 55*^-2. The vapour density of
methyl alcohol was lirst determined by Dumas and Pi'ligot, and
found to be 112.

Methyl alcohol is misi'ible with water in aU proportions, a
contraction and consequent evolution of heat occurring, this
Iwing greatest when the relation of caie molecule of methyl
alcohol to three of water is preserved. On ignition it burns
with a jMile blue flame, like common alcohol, which it alt^o
resembles, inasmuch as it acts as a solvent for manv substances
which arc insoluble in water, such ns fats and volatile oi's,

* Kramer and (JioJ/ki, U*r. htuf-^h f'ftcm. Or^. ix. 11»:JS; Ikiidy hikI Ilonlet,
/?*///. Sor, Chim. xxxi. 531.

* f'hem. Xnrx^ xvxiii. :^'». ^ .fi/n. Chrm. Phftmi. xr'iv. 'Jb7.

PKOPEKTIES OF METHYL ALCOHOL. 199

camphor, resins, &c. The alkalis and various salts are also
soluble in this menstruum, whilst bodies which do not dissolve
in common alcohol, such as potassium carbonate, potassium
sulphate, &c., are likewise insoluble in methyl alcohol. Potas-
sium and sodium dissolve in methyl alcohol with evolution of
heat and liberation of hydrogen. Crystals separate out from such
solutions which consist of compounds of the corresponding
methylate with methylic alcohol. The potassium salt possesses
the composition CH3OK + CHgOH.^ These bodies are instantly
decomposed by water, with formation of caustic potash and
methyl alcohol. Anhydrous baryta dissolves in pure methyl
alcohol with evolution of heat, and on evaporating the solution
in a vacuum, crystals of BaO + 2CH4O are deposited (Dumas
and Peligot). When thallium ethylate CgH^OTl, a liquid obtained
by the action of ethyl alcohol on thallium is poured into excess
of methyl alcohol, tliallium methylate, CH3OTI, separates out
in the form of a white granular precipitate, which when ignited
bums with a beautiful green flame. This compound is soluble
in ether and alcohol, and is decomposed by water with formation
of thallium hydroxide (Lamy). Anhydrous calcium chloride
dissolves in methyl alcohol with evolution of heat. Six-sided
tables of the compound CaCl^ 4- 4CH^0 separate out on cooling
the concentrated solution. These are very deliquescent and
quickly decomposed by water, but may be heated in dry air to
] 00° without losing methyl alcohol (Dumas ani P(51igot). Hence
this compound was formerly used for the purification of wood-
spirit. "* The raw product was saturated with calcium chloride,
and this then distilled on a water-bath until the excess of wood-
spirit, acetone, and other easily volatile constituents had passed
over. The residue was then heated with water and distilled,
when the purified wood-spirit first came over, and this was
afterwards dried as above described. Similar compounds with
lithium an<l magnesium chlorides, containing respectively three
and ^ix molecules of methyl alcohol to one molecule of metallic
chloride, have been prepared by Simon.^

Purified wood-spirit was formerly employed instead of spirit
of wine as a source of heat, and as a solvent for various gums
and resins. At the present day it is very largely used in the
manufacture of aniline colours, and it is important for this

^ Wiedmaun and Schweizer, Jouru. Pr. CJum. xxiii. (i.
- Kane, PhiL Mag. [3], x. 45, 116.
'^ Ba-. Vcutsch. ('firm. OV.v. xii. 1281.

200 THE MP:THYL GROUP.

manufacture to be able to determine the quality of the com-
mercial product by a simple method. If the substance should
only contain water the matter is easy enough, for mixtures of
methyl alcohol and of ethyl alcohol with water exhibit, as Deville ^
has proved, almost the same specific gravity for equal percentage
mixtures, and hence tables made for the purpose of obtaining
the strength of dilute spirit of wine may be employed for wood-
spirit. Dup:*6 2 has also determined the specific gravity of dilute
aqueous solutions of wood-spirit of various strengths. More
commonly, however, acetone and other ketones are present, as
well as water, in common wood-spirit, and this lowers the value
of the commercial article, not only by dilution, but also because
their presence acts prejudicially on the colour. For the purpose
of analysing commercial wood-spirit it is usual to prepare methyl
iodide from it, and determine from the quantity of this com-
pound obtained, the value of the methyl alcohol. This metho<l,
first proposed by Krell,* has been worked out by Kramer and
Grodzki,* as well as by Bardy and Bordet.^

METHYL OXIDE OR DI-METHYL ETHER,

131 This compound was first prepared in 1885 by Dumas and
Peligot ® by heating the alcohol with sulphuric acid, and termed
by them hydrate of methylene. Ebelmen ^ afterwards showed
that boron trioxide may be employed instead of sulphuric acid.
It was then supposed that methjl oxide was formed by the
withdrawal of the elements of water from the alcohol. This,
however, is not the case, as will be afterwards explained (see
Etherification, under " Ethyl Ether ").

In onler to prepare this compound, a mixture of thirteen
parts of methyl alcohol an<l twenty of sulphuric acid is gently
heated to a temperature of 140** in a flask provided with a
reversed condenser. The gtus which comes otf is washed
through caustic soda in order to remove sulphur dioxide and
carbonic acid, and then passed into sulphuric acid, which
absorbs GOO times its own volume. It appears that in this
case the comi>ouiul H.^S(\ + (CH,)^ or SO(OH)2(OCH3)2 is

> Ann, Chim. Phfis. [3], v. 131». « Proc. Ro}i. Soc„ xx. 33i5.

' Bcr, DcuUch, Chem, tha, 187^. l.Jlo. * Jhi,l. 1874. 1493.

» /;«//. Soc Chim. xxxii. 4. « Ann, Chim. Phys, [2]. Iviii. ]y.

' Ibid, [3], xvi. 138.

1)I-METIIYL ETHER. 201

formed. This may be preserved without alteration, and when
it is allowed to drop into an equal volume of water methyl
oxide is evolved.^

Methyl ether is now prepared on a large scale for the pro-
duction of artificial cold. For this purpose one part of sulphuric
acid is mixed with rather more than one part of anhydrous
wood-spirit, and the mixture, which must be of specific gravity
1'29, heated to a temperature of 125** to 128**, care being taken
that the temperature does not rise above 130°. As soon as no
more ether is evolved, the liquid is allowed to cool, and a suffi-
cient quantity of wood-spirit added to the residue to bring up
the specific gravity to 1'29. By repeating this operation, a large
quantity of methyl ether can be obtained by the employment of
a small quantity of sulphuric acid. The gas during its evolu-
tion is washed by passing through caustic soda solution and
over chloride of calcium, and being thus freed from carbonic
acid, sulphur dioxide, and water, is then condensed to a liquid
by pressure.^

Methyl ether is an agreeably smelling gas which, when
ignited, burns with a bluish flame, and which maybe condensed
by pressure or cold to a mobile liquid boiling at — 21° (Ber-
thelot). Methyl ether is readily soluble in wood-spirit, spirit
of wine, and common ether ; it is less soluble in water, which,
however, absorbs at 18° about thirty-seven times its volume,
acquiring a burning taste. If methyl oxide be brought in con-
tact with dry hydrochloric acid in a freezing mixture, a colour-
less mobile fuming liquid is formed which begins to boil with
decomposition firom —3° to — 1"*, and which contains thirty-seven
to thirty-nine per cent, of chlorine, nearly corresponding to the
formula {CK^fi^ilCl.^ Water decomposes it instantly into its
constituents. By the action of chlorine on this ether, substitu-
tion-products are obtained, of which the first is monochlor-
methyl ether, CHgOCHgCl, boiling at 59°-7, and the last
perch lormethyl ether, (€013)20, a liquid which on heating
yields tetrachlor-methano, CCl^, and carbonyl chloride, COClg.

' Erlenmeyer and Kriechbaiimcr, DeiUsck, Chem, Oes. Bcr. vii., 699.

' Tellier, Arch, Phann. x. 57.

• Friedel, Cmnpt, Rerid, Ixxxi. 152.

202 THE METHYL GROUP.

ETHEREAL SALTS OF METHYL.

132 Methyl CJUoride, CH3CI, was discovered by Dumas and
Pcligot, who prepared it by heating a mixture of one part of
wood-spirit, two parts of common salt, and three parts of
sulphuric acid. The compound thus obtained is, however, not
pure, but contains methyl oxide and sulphur dioxide.

In order to prepare pure methyl chloride, zinc methyl is
dissolved in double its weight of wood-spirit, and hydrochloric
acid led into the boiling liquid contained in a flask furnished
with a reversed condenser.* Methyl chloride is also obtained
when the so-called basic cacodyl sesquichloride (Bunsen) and
cacodyl dichloride (Baeyer) are heated. It is likewise formed as
the first substitution-product when chlorine is allowed to act
upon methane in diffused daylight (Dumas).

It was formerly believed that the body obtained by this last
process was an isomeride of methyl chloride, as it was said to
exhibit a peculiar reaction with water. Bcrthelot,^ however, has
shown that the substances obtained by these various processes
are identical, and that the last preparation, like the chloride
obtained in other ways, yields methyl alcohol when heated to
100*" with caustic potash, whilst when treated with sulphuric
acid and sulphate of silver or mercury, methyl sulphuric acid is
formed, and this on heating with sodium acetate and acetic
acid to 200"* yields methyl acetate.

Methyl chloride has recently been obtained, as has been
stated, on a large scale in the dry distillation of the beetroot
" vinasses," which contains a large quantity of trimethylamine.
This base is neutralised with hydrochloric acid and the con-
centrated solution heated to 260^ when a regular evolution
of methyl chloride and trimethylamine commences :

:\ N(CH,\ CIH = 2CH3CI -h 2N(CH3)., -h CH3XH, + HCl.

Tlie residue, which also contains hydrochloride of methylamine
jis well as sal-ammoniac, is either worked up for the methyl base,
or by heating it to 300**, mcjre methyl chloride can be obtained
together with methylamine and ammonia. The methyl chloride
thus obtained is si'paratcd from the alkaline compounds bv

* (irovi'S, Jouiti, Chnn. So^-. r**74, 641.

ETHEREAL SALTS OF METHYL. 203

treatment with hydrochloric acid ; and after drying over calcium
chloride it is condensed by pressure and preserved in cylinders
made of strong wrought iron or copper. A mobile ethereal-
smelling liquid is thus obtained which boils at —23°,^ and when
ignited burns like other organic chlorine comjwunds, with a
green bordered flame. Its specific gravity is as follows :

At - 30° = 0-9990
-25" = 0 9915
- 0° = 0-9523
-f 15° = 0-9247

The tension of the vapour being :

At 0^ = 2*48 Atmospheres.
15° = 4 11

20° = 4-81

25° = 5-62

}}

30° = 6-50

)»

35° = 7-50

The vapour density of methyl chloride was first determined by
Dumas and Peligot and found to be 1 -736. Methyl chloride
is only slightly soluble in water, but dissolves readily in alcohol.
The neutral solution is not precipitated by silver nitrate. It
forms with water at 6° a solid hydrate which separates out in
amorphous flakes when the gas is led into cold water, but may
be obtained in large crystals by the cooling of the aqueous
solution.

It has already been mentioned that methyl chloride obtained
from marsh gas was formerly supposed to be an isomeric
modification; this was not only because it was believed to
be less soluble in water that the chloride obtained by other
means, but also that it did not, like the latter, yield a hydrate.
The observations upon which this conclusion was l)ased no
doubt depend on the fact that by the action of chlorine upon
methane a mixture is obtained which contains not only unaltered
marsh gas, but also higher substitution-products.

Methyl chloride is largely used for the preparation of various
aniline colours, as well also as a means of producing artificial
cold. For this latter purpose it will doubtless prove of great
service both in the laboratorv and on the lar^^cr industrial

^ Vin.f lit iiw\ D'^la«lianal, Bull. Sor. t'him. xxxi. 11.

... -.r.' '.i\L i.;iiui:i'.

^„.^; * .^lU'WfJ to escape from the receiver
, vj;ni» to boil, and Ja a few moments
.K- '.utuiU ia lowered by the ebullition to
..i:.ji vmiut of the chloride. The liquid
!iiv;ih of time in a (luiescent state, and
v\Ainj{ agent. By increasing the rapidity
m«>Uf« i>f a current of air blown through
l'_\ pliu'htg the li<nii(l in connection with

Km. fit.

\ ^%- .\ III |<iiitil> 'h" It'iiiJoTiitiirp of the liquid can in n
ii w mmm «n • I'l- n tini'i'il I" ■'''' i f ""' I'lrgo nina.io.'i of mercury
. , .!^ miIl.IiIIoI rill' fiiiiBtriii'timi "f a small freezing m.ichino
. iiiiiKw. .H\i M rmillli' Viui'i-nl is shown in Fig. CI. Itconsists

I 1 ilmKI, i.iwil mi'iui' (I'.HHi'l, iN'twt'cn the two Citsings of
vv'... It vl<«' iHi-ilnl ilil'iiili' I A) i;* int.r<Hlnce<l. The central sj^ce

M* ..Hill. I will t" li.|iii'l H'irh tw alcohol, incai>nblc of w.Ii-

.'...i „i.>n \'\w ilil.iiidi' lit' iiu'lhyl ii sillowi-d to enter from iU-

METHYL CHLORIDE. 205

cylindrical reservoir (P) by the screw tap (B), the screw (S) being
left open to permit of the escape of the gas. As soon as the whole
mass of liquid has been reduced to a temperature of — 23^
ebullition ceases, the screw (S) may be replaced, and if a tem-
perature lower than —23** be required, the tube (B) placed in
connection with a good air-pump. By this simple meaDs a litre
of alcohol can be kept for several hours at temperatures either
of —23** or — 55^ and thus a large number of experiments can be
performed for which hitherto the expensive liquid nitrous oxide
or solid carbonic acid was required.

M. Yincent has recently constructed a much larger and more
perfect and continuous form of freezing machine, in which, by
means of an air-pump and a forcing pump, the chloride of methyl
is evaporated in the freezing machine and again condensed in the
cylinders. This enlarged form of apparatus will probably com-
pete favourably with the ether and the sulphurous acid freez-
ing machines now in use, as it can be simply constructed, and as
the vapour and liquid do not attack metal and are non-poisonous,
and the frigorific effects which it is capable of producing are
most energetic.

133 Methyl Bromide, CHgBr. Tins substance was first pre-
pared by Bunsen,* by gently heating basic cacodyl super-
bromide, as (CHj)^ (0H)2Br. It is a colourless gas which at
—17^ condenses to a colourless liquid. Pierre * obtained it by
acting with ordinary phosphorus on a well-cooled mixture of
wood-spirit and bromine. According to him it is a sweetly
smelling ethereal liquid which boils at + 13° and has a specific
gravityat 0%f 1CG4.

Amorphous phosphorus is now generally employed in this,
as in the preparation of other bromides and iodides.' In
this instance 133 grams of amorphous phosphorus and
800 grams of methyl alcohol are mixed in a large retort sur-
rounded by ice-cold water and furnished with a reversed con-
denser. To this 800 grams of bromine is gradually added by
means of a stoppered funnel After leaving the amorphous
phosphorus in contact for several hours, the liquid is distilled, and
the vapour condensed in a receiver surrounded by a freezing
mixture. The product is washed with alkaline water and dried
over calcium chloride. The bromide thus obtained has a specific
gravity of 1*73 at 0° and boils at 4/5. Morrill explains the

^ Ann. Chem Plunna. xlvi. 4i. - Jhu. ('htm. Phm. [31, xv 325.

» Merrill, Jour.i. Pr. Chen. [2], xviii. 21^3. "

20G THE METHYL GROUP.

difference between his results and those before described, by the
supposition that Pierre's compound contained water.

Pure methyl bromide has a pleasant ethereal smell, resembling
that of chloroform, and a burning taste. Its vapour density
is 3*253 (Bunsen). When a flame is brought near the gaseous
compound it bums with a greenish-brown, slightly luminous
flame, giving off vapours of bromine and hydrobromic acid.
When the source of heat is removed the flame is at once
extinguished. It forms with water a white crystalline hydrate
which does not exist above 4*" and probably consists of
CH3Br + 20H2O (Merrill).

134 Methyl lalide, CH3I, was first prepared by Dumas and
Peligot by the action of iodine on common phosphorus and wood-
spirit. This compound, like many iodides, easily undergoes
double decomposition with other bodies, and therefore is largely
used for the preparation of other methyl compounds. It has
consequently been a matter of some importance to discover the
most economical method of preparation.^

At the present day methyl iodide is prepared on a large scale
by the use of commercial amorphous phosphorus. To a mixture
of 35 parts of purified wood -spirit, 100 parts of iodine and 10
parts of amorphous phosphorus are gradually added :

10 CH3.OH + 5 I2 4- Po = 10 CH3I -f 2 P0(0H)3 -h 2 H2O.

It is here seen that the phosphorus is in excess. A somewhat
smaller quantity may be employed, but the excess appears to in-
crease the rapidity of the reaction, and that which is not used
can easily be regained. The mixture is allowed to stand over
night, and then the methyl iodide distilled off, the distillate
beinff washed with dilute caustic soda and dried over calcium
chloride. Like the chloride and other methyl compounds, the
iodide is largely employed in the manufacture of the various
aniline colours.

Methyl iodide is a colourless, powerfully refracting liquid, liav-
ing a specific gravity of 2'20i) at 25"* and bailing at 42^" 5 (Linne-
mann). Its vai)our density was found by Man-hand to be
5*417.* It pissosses a |>eculiar ethereal smell, and on exposure
to light turns brown from lil>enition c»f iodine. Whcjn heated
with sixteen times its volume uf water for eight hours to 100^ it

* Lindolt, ^Mw. CJinn. Pharm. Ixxxiv. 44 ; Hofmann, Quart. Journ, Chem,
Soe. xiii. 69.

• Journ. Frock. Chrm. zxxiii. 186.

METHYL IODIDE. 207

is decomposed with formation of methyl alcohol and hydriodic
acid.'

Methyl iodide can be inflamed only with difficulty, and bums
when a flame is brought into its neighbourhood with a steel-grey
coloured flame and with evolution of dense violet fumes of
iodine.

Methyl Fluoride, CH3F, was first prepared by Dumas and
Peligot* in 1836, by heating potassium fluoride with potassium
methyl sulphate. It is a colourless gas with an ethereal odour,
which takes fire and bums with a blue flame with formation
of hydrofluoric acid.

135 Normal Methyl Sulphite, (CHg)^ SO3, is formed by the
action of thionyl chloride, SOCU, on wood-spirit. It is a pleasant
smelling liquid boiling at 121°'5 and having a specific gravity
at Iff* of 10456.* Ebelmen and Bouquet found the vapour
density to be 4*78. If a small quantity of caustic potash be
added to its alcoholic solution, needles of potassium methyl
sulphite, K(CH3)S03 are deposited.

Hydrogen Methyl Sulphate, or Methyl Sulphuric Acid,
H(CH3)S04, was obtained by Dumas and Peligot by mixing one
part of methyl alcohol with two parts of sulphuric acid, when
the mixture becomes hot and the following reaction takes place :

CH3.OH + HgSO, = H(CH3)S0, + HgO.

A limit is placed on the reaction by the formation of water,
and for this reason the liquid always contains free sulphuric acid
and methyl alcohol. In order to remove these, the mixture is
diluted with water, neutrab'sed with barium carbonate, filtered,
and sulphuric acid added to the solution until all the barium is
thrown down. The filtrate, on evaporation in a vacuum, is said
to yield methyl sulphuric acid in deliquescent crystals, although
this statement is denied by Claesson.* He obtained the anhy-
drous acid by allowing methyl alcohol to drop into chlorsulphonic
acid cooled by ice :

SO, I ^ + HO.CI-I3 =1 SO, I 2Jf J.J + HCl.

The product, which contains eonie free sulphuric acid
together with hydrochloric acid and methyl chlorosulphonate,

' Xiedeiist, Lichiys Annalen, cxcvi. 349.
2 Ann. Chim. Phys. [2], Ixi. 193.

* Carius, Ann. Chew. Phann. ex. 219 ; 9x1. 97.

* Joiirn. Pr. Chcm. N. F. xix. 231

208 THE METHYL GROUP.

S02Cl(OCH3), is an oily liquid which does not adhere to glass
and does not solidify at —30*. If its aqueous solution be
allowed to evaporate in a vacuum no crystals are obtained.
On heating methyl sulphuric acid with methyl alcohol, methyl
oxide is fonned, this substance being also produced, as has
been stated, by the action of sulphuric acid upon the alcohol :

Methyl sulphuric acid is monobasic, forming salts, most of which
crystallise well.

Potassium Methyl SuIpJiate, 2K(CH3)SO^ + HgO, forms deli-
quescent monoclinic tables.

Calcium Methyl Sulphate, Ca(CH3)2(SOj2» crystallises in
deliquescent octohedrons.

Barium MeHiyl Sulphate, Ba(OH3)o(SOj2 + SH^O, forms
monoclinic tables and possesses a sweet taste.

Lead Methyl Sulphate, Pb(CH3)2(SO^)2 + HgO, crystallises in
long prisms ; it decomposes on heating into lead sulphate and
normal methyl sulphate.

Normal Methyl Sulphate, (0113)280^. This compound, which
has also been called sulphuric methyl ether, was prepared by
Dumas and Peligot ^ by distilling 1 part of methyl alcohol with
8 to 10 parts of sulphuric acid. Acconling to Claessen,* how-
ever, this method yields only a small product, as a large pro-
portion of the alcohol is decomposed by the sulphuric acid
with formation of sulphurous acid even when carefully heated.
A better method is to heat anhydrous methyl sulphuric acid
under diminished pressure to a temperature of 130° to 140**,
when the sulphate distils over :

2 H(CH3)S0, = H,SO, -f (CH3)2SO,.

It is a colourless liquid possessing a smell resembling pepper-
mint antl boiling at 187"* to 188°, undergoing slight decomposi-
tion, but distilling unaltered in a vacuum. Its specific gravity
is 1*327 at 18°. When heated with water it decomposes into
methyl alcohol and methyl sulphuric acid, which on further
boiling yields alcohol and free sulphuric acid.

Methyl y it rite, CH3NO2, was first obtained by Strecker^ by

* Ann. Chim, Vkm. Iviii. TA. ' Jottrn. /V. Cffm. X. F. xix. 243.

' Ann. f'h'.in. Phtinn, xci. 70.

METHYL NITRATE. 2C9

heating wood-spirit and nitric acid together with copper or
arsenic trioxide. The nitro^ren trioxide which is fonned acts
upon the alcohol as follows :

2 CH3.OH + N2O3 = 2 CH,.N02 + H^O.

It is also produced when nitric acid acts upon brucine. It is
an ethereal-smelling gas, which condenses at a low temperature
to a colourless liquid boiling at — 12^

136 Methyl Nitrate^ CH3.NO3. According to Dumas and
Peligot * this ether is formed in small quantity by heating nitric
acid and methyl alcohol. A larger yield was obtaine<l by adding
a freshly-prepared mixture of sulphuric acid and wowl-spirit to
saltpetre, the heat evolved in the reaction being sufficient to
vaporize the compound. The product obtained was, however, not
pure. It began to boil at 60**, whilst the portion coming over
at 66° possessed approximately the composition of the nitrate.
That it chiefly consisted of this substance is s^.*en by the fact
that on the addition of alcoholic potash, cr)stals of nitre were
rapidly formed. Carey Lea,^ however, could not obtain methyl
nitrate in this way. He succeeded in preparing it by employing
the method suggested by Millon for the prejiaration of ethyl
nitrate. Nitric acid alone acts chiefly as an oxidizing agent
with formation of nitrous fumes, and converts the alcohol into
nitrite. This action is, however, avoided by the addition of
urea, which at once destroys the nitrous acid formed. In order
to prepare methyl nitrate, 150 cc. of pure nitric acid, having a
specific gravity of 1*31, are brought into a retort together with
40 grams of nitrate of urea, and to this 200 cc. of methyl
alcohol are added and the mixture carefully distilled to one-third,
130 cc. of nitric acid and 170 cc. of wood-sjnrit are then added,
and the mixture again distilled to one-third, and at last
10 grams of nitrate of urea, 110 cc. of nitric acid, and 150 cc.
of methyl alcohol, and this is again distilled to one-third. The
distillates are then mixed and shaken up with a solution of
common salt, the ether which separates out being washed with
a dilute solution of potassium carbonate. Methyl nitrate is
also easily obtained by adding 2 parts of a cold solution of
methyl alcohol and sulphuric acid to a cold mixture of 1 part
of nitric acid and 2 parts of sulphuric acid.

' Ann. Chim, Phys. Iviii. 37.

* Sillitnan's Am/Journ. [2], xxxiii. 227.

VOL. III. P

tlj MEIIiYL O :-iU*_'l*M<5.

Mibdiji iiiuaie ia a liqiiid of an eih^real odoor, wLkrh at ^O""
ha^ a specific gravinr of 1'1^± Wken ignhe*i it boms with a
bright Te:IloT dame, azid its vapc^nr exploJes when heated aboTe
150' with such f.rce that a cast-iroa bc*iler, in which a glass
hailrxm containing 2>>0 ca of vap>ar was placed, was fractured
bj the explosion ; whikt Dumas and Pcligc*t f^ond that when a
flame waa bronaht u* the month of a glass bolb containii^ the
rapoftir placed in a {Matintim crucible, not onlv was the bulb
broken but the platinum crucible was torn to piecesL The
hqaid abo detonates on percussion. If a piece of filter paper
be impregimted with the liquid and then struck with a hammer
on an anvil, an explosion takes place as violent as that caused
by nitro-glycerin /Girard).

Carey Lea, in 1S62, showed thai this cMupound may be used
instead of the much more expensive iodide of methyl in the
preparation of io^line^violet and iodine-green, and for a long
time it was employed for this purpose. It is, however, no
\iA%%*:x UiM^d, owing to the series of &tal explosions which have
ft^milietl from its employment.

137 liuMphUe of Mflhifl. As yet only the methyl phosphorous
add P(0H;2^0CH^ ia known. This is obtained by acting on
nf^;thyl alcohol with phosphorous trichloride and forms a syrupy
\*:Ty add liquid which cannot be prepared in the anhydrous state
an on h«;ating it decompr^ses into alcohol and phosphorous acid.
It j» monobaiiic ami forms a series of salts which have been
ofily iilj;(htly investigated.*

J'hjHphatfH of Mdhyl. The orthophosphate, P0(0CH3)j, has
not \fiii'.u prejifircd. When phosphorous oxychloride acts on
meth)l ftlcohol, bibasic methyl phosphoric acid, P0(0CH3)(0H)j,
ati/J mowjUiti'ic dimethyl phosphoric acid, PO(OCH3)2(OH), are
{onut'A, VjittU of these yields a series of salts investigated by
Belli ff.' Tlio free acids are only known in solution as thick

ar'irl ItqiliflM.

AfrfJit/l ArscniU, As(OCHj)g, is obtained by the action of
mxUxiui ethylatr* on arsenic tribromide, in the form of a liquid
wliii'li Uiiln at 128" to 129^ and is instantly decomposed by
Wttt^jf iiiUi tirmnic trioxide and methyl alcohol.

Mdlii/l Artie fuUt\ AsO(OCH3)3, is obtained by the action of
methyl iodide on silver arsenate. It is a liquid which under-
gocM |Kutiai d(f('oiii[>o8ition on distillation between 213° and

' Srhirr, ^Inn. Chnn. PItann, nu. 104.
• .tun. Chrm. I'futrm. cii, 3U4.

SALTS OPMETHVL. 211

faCttuia without decompositioB.
arsenic acid and methjrl

E normal ether, or methyl ortlio-

1 by Ebelmen and Bouquet ' by

ide into wood-spirit. The samoconi-

len pure anhydrous methjl alcohol is

toxide.' It is a powerfully-smelling liquid,

nviiig a specific gravity of 0 O-i at 0°. When

with a very britliant green-colon red flanie,

t ibun that of the corresponding ethyl compuund.

B preferable to use wood-spirit instead of cointnon

ting for boric acid.

I Borate, BOjCHj, ia also formed by the aclioii

iotide ou methyl alcohol, together with the normal

"his ia a syrupy Dquid which also bums with a bright

I fiamc and decomposes on beating into the orthu-ctliur

tagUissj residue consisting of the compound B^OnCHj. All

ethers decoTnpnsc water with formation of methyl alcohol

aad boric acid, and for this reason methyl orthoborate becomes
turbid on exposure to moist air.

139 Methyl Ortkomllmie, Si(OCHa)^, is formal by the action
of silicon tetrafiuoridc on anhydroua methyl alcohol. It ia u
liquid of ethereal odour, boiling at 120° to 122° and having a
specific gravity at 0° of 10589. It is tolerably readily solublo
in water, gelatinous .tilicic acid separating out from the solution
after some weeks. If afjueoua methyl alcohol be employed in
the above reactions ethyl disilicato, SijOfOCHj)^, is formed.
This ia also a pleasantly-smelling liquid, boiling between 201"
and 202°- .), and having a specific gravity at 0° of 11441,* The
vapour density is 919.

140 Curlonntci of Methyl. The normal ether {Cll^fiO^ has
not yet been prepared. If a solution c f anhydrous baryta in
methyl alcohol be treated with carbon dioxide a precipitate of
pearly plates separates out This consists of barium methyl
carbonate, Ba(CH3).,(COs)2, easily soluble in cold water. This
solution gradually decomposes in the cold and more quickly on
Iieating, with formation of barium carbonate, methyl alcohol,
and carbon dioxide (Dumas and Peligot),

' Cnifta, BulL Soc. Chem. xiv. 89.

» Ann. Chim. Phgs. [3], xvii. 50.

'■' H. Schiff, Aim. Chtm. PAarm. Suppl. Bd. *. 16*.

' Bull. Soe. Chim. [2], ui. 836.

iV2 METHYL CO^IPOUNDS.

By iictii»c^ on methyl alcoliol with carbonyl chloride, methyl
chlorocarbonate is formed :

CO I ^[ + HO.CH3 = CO I ^^^ + HCl.

This is an irritating-smelling liquid which is insoluble in water,
but gradually decomposes in contact with this into carbon
dioxide, hydrochloric acid, and methyl alcohol.

Methjjl Carbamate, or Methyl Urctlcane, CO ■! Qp A • This was

first obtained by Dumas and Peligot by dissolving the fore-
going compound in aqueous ammonia. It is likewise formed
by passing the vapour of cyanic acid into methyl alcohol.* In
order to explain this reaction we must assume that the unstable
cyanic acid decomposes into an isomeric carbimide and this acts
as follows on the alcohol :

N I ^g + HO.CH, = N I CO.OCH3

Methyl carbamate is also obtained by acting on methyl alcohol
with cyanogen chloride.'- It easily crystallizes in large deli-
(luescont tables which melt at oo", and the liquid boils at 177'.

Mdhyl AUo2fha?mte, NH -j nQQnjj » is also formed together

V. 3

with uretliaue by the action of cyanic acid on wood-spirit. This
c<»nip:)UTid stands in the same relation to biuret asurethane does
to nrra. It is difiicultly soluble in water and crystallizes in

n(.'tMlK\s,

Methyl Thiocarhonatey (0113)2083, is a yellowish disagreeably-
smelling liquid boiling at about 250'' and is obtained by distilling
concentrated solutions of calcium methyl sulphite and potassium
tliiociibomiti' (CJahours).

SULPHUR COMPOUNDS OF METHYL.

141 Mdhyl Hydroaulphide or Methyl Mercaptan, CH3.SH, was
dis*c»vercd by Dumas and Peligot, who obtained it by heating
jH)tassium hydrosuljJiide with methyl sulphate. It was after-
wurds more thoroughly examined by Gregory,^ who prepared it

* Lkbi;; ami Wiihlff, Jnn, ("hem. Pharm, liv. 870; rifihanit and I.aureiit,
i'finftt. JUiul. xxiii. 4r»7 ; l^icbif?, Ann. f%'M. Pharm. Iviii. *iO«>.
- Kilu'varri;!, IhiiK Ixxix. IIU. ' Amu Phiirm. xv. 23i».

SULPHUR COMPOUNDS OF iMETHVL. 213

by distilling concentrated solutions of potassium hydrosulphide
and potassium methyl sulphate. It is a colourless unpleasantly-
smelling liquid, boiling at 2V and quickly uniting with mer-
curic oxide to form mercury methyl mercaptide, (CH3S)2Hg,
a compound which crystallizes from hot alcohol in glistening
white plates.

Methyl Sulphide, (CHj)^^. In order to prepare this substance,
Begnault * recommends a solution of caustic potasli in methyl
alcohol to be divided into two nearly equal parts. The smaller
of these is saturated with sulphuretted hydrogen and then
mixed with the other part, so that potassium monosulj^hide
is formed together with a little free potash but no potassium
hydrosulphide. This solution is then saturated with gaseous
methyl chloride, the solution gently warmed whilst the gas is
being passed in, and the volatile product collected in a reservoir
surrounded with ice. The distillate, which consists of a mixture
of methyl sulphide and methyl alcohol, is next washed with
water which dissolves the alcohol, the sulphide remaining in-
soluble. This latter is again repeatedly washed with water,
and at last dried over calcium chloride.

Methyl sulphide is a colourless mobile liquid possessing an
extremely unpleasant odour. It boils at 41°, and has a specific
gravity of 0*845 at 21°. When allowed to drop into dr}^ chlorine
gas it takes fire and bums with a red flame with separation of
carbon. Substitution-products are however formed by a more
gradual action of chlorine, the last of which, perchlormethyl
sulphide, (€013)28, is a red liquid which decomposes on heating.^
Methyl sulphide combines with mercuric chloride, mercuric
iodide, platinic chloride, and other haloid salts, and these
compounds can be obtained beautifully crystallized from hot
alcohol.^

142 Dimcthyl'Sulphinc Compounds, Methyl sulphide combines
directly with bromine to form the dibromide, (CH3)2SBr2, a
compound which crystallizes from water in amber-yellow octo-
hedrons. If methyl sulphide be dropped into well-cooled fuming
nitric acid, and the solution allowed to evaporate, colourless
deliquescent needles of the nitrate, (CH3)2S(OH)N03, are
obtained. If these are decomposed by barium carbonate, or if
the bromide be decomposed by freshly precipitated oxide of

1 Ann. f'him. Ph^/s, [2], Ixxi. 391.

- Kiche, Ann. C/um. rhi/s. [3]. xliii. i.'l)2.

3 Loir, JhU/. xxxix. 448 ; liv. 42.

MKrilYL a>MPOUNDa

ix... linu I.IIW .lul^khtno oxide, (0113)280, is formed. This is
...ivtUi >>4 \\.«tv t iuul alivhol, and on evaporation and cooling
...ivliii* ' u* i I vkKauU\>4 and inodorous mass. If the nitrate be
U, .l^ I ».» \00 . vlnuothvl-sulphone (0113)2802. is formed. This is
..^•iviM\ Lu waUu uud nitric acid, and crystallizes from the latter

MUtUt>u lu ^m.^inaft which melt at 109'^ although at lOO"" they
l«. >;u» 1^1 wiliitiliao. The liquid boils at 238°.*

I U i\i fHi i/ij/isiitph ine Compoxnids} Methyl sulphide combines
w i*liU vMth UKthyl iodide to form (0113)38!, a compound crys-
i.tlti \\\., \\^^\^\ ui)U(H»us Holution in large colourless prisms, and
III nil aUohiil iu rh(tn)bic tables which soon become brown on
,i^|miikii> til uii'. It is also formed when the sulphide or
iti* lut u-4i'tuh irt htwited to 100'' with hydriodic acid :

^1) li^CUg^S + HI « {0H3)3SI + OH38H.

[±) :um3.sH + HI = (CH3)3Si + 2H2S.

h 1.1 likuwirto obtained by the action of methyl iodide on
tui lit.J ihiocyunate.

liu'. iiiilidi) is decomposed by moist silver oxide with forma-
\yKx\\ ul tiiiiiothylsulphine hydroxide, (OH3)3SOH. The solution
ti( ikiia v'on))M)und is strongly alkaline, and on evaporation yields
\\i^K\ ^bu as an oil having the smell of an isonitril.^ On neu-
V« \luUiou with acids a series of trimethylsulphine salts are
■ll iikual, hiimo of which may be prepared by the action of silver
^11 1 MM iUm iodiile (Letts). The chloride crystallizes in de-
l^iMt' •tv-^tl' I'li'^HiH, and combines with platinic chloride to form
S\\v \l»»ultlM »-*»lti -(,<'H3)3SC1 + PtCl4, crystallizing from boiling
\y\\\\ \\\ ^lillti^Mnh red combinations of the cube and octohedron.
\\\\. \\\v l"««i» li»|»idly absorbs carbon dioxide, giving rise to a
M wii^'i**^'' iiiiimiuilM. Its solution readily absorbs sulphuretted
Iml^m^^u \\\\\\ liirnmtitin of the hydrosulphidc, S'OHjijSH,
\\\\\\\\ \'<hil'H*i till Hm* reactions of the hydrosulphidos of the
\\\\U\^ II *'»»' hyilioxido be added to this solution, trimethyl-
A\\y\\\\\v ».Ml|i|ihhs hOllaljSJjS, is produced. This solution
\lu \u\^H»**4 »• »»H i'nni'0Mliiiti«>n with formation of three molecules
A \\\\\\\\\ »«mI|»I«I«I»v '!''»** nqueous solution of the sulphide
\\\\\U \\\v rhHM»*t»'» !»•<••' H'lirtions of the sulphides of the alkali
\\\\\^\\^ rhu« n- dl"ii"lv«'n antimony trisiilphido, is coloured

» ^\\\\\\ 4*«'» •'*'**• /•*•!» »•■ «'»Jiv. 148.

\ .,l..iui.' **».'.* ■> • •■'•»"• r-l« i^- ^*' 5 -'''''• '''*""■ ^^"^' ^'^' ^' ^^' ^*'^'°»

METHYL SULPIIOXIC ACID. 215

deep violet by sodium nitropnissido, and is decomposed by acids
with evolution of sulphuretted hydrogen.*

Melhyl Disxdphide, (CH3.)oS2, is obtained by acting on methyl
chloride with alcoholic solution of potassium disulphide. It is
a yellowish unpleasantly-amelling liquid boiling at 11 2^ It is
likewise obtained by employing a higher sulphide of potassium,
when the trisulphide of methyl is formed at the same time.
This body closely resembles the disulphide, but boils at 200"*.

144 Methyl Sulphonic Acid, CH3.S()j,H. Tliis aci<l was dis-
covered by Kolbe ^ in 1845, and originally termed methyl liypo-
sulphuric acid. Berzulius and Marcet had found in 1813 that
carbon disulphide on treatment with moist chlorine yielded the
compound CCl^SOg, to which substance they gave tlie name of
sulphite of chloride of carbon. Tnis is also readily obtained
bv treating carbon dioxide with hydrochloric acid and manganese
dioxide, and is, as Kolbe showeil, trichlorniothyl sul})honic
chloride, CClj.SOgCl. If this is heated with baryta water, barium
trichlormethyl sulphonate,(CCl3 S03)2Ba,is produced and the free
acid can easily be obtained from this as a white deliquescent mass.
It is easily reduced by nascent hydrogen, one atom of chlorine
after the other being replaced by hydrogen, and thus methyl
sulphonic acid is formed. The same substance is i)roduced
when methyl mercaptan, methyl disulphide, or methyl thiocya-
nate is heated with nitric acid. On evaporation on the water-
bath the acid remains as a thick syrup w^hich still may contain
some free sulphuric acid. In order to obtain the pure acid, the
barium salt is decomposed with sulphuric acid, or the lead suit
with sulphuretted hydrogen. This substance has not been
obtained in the crystalline state, but only as a strongly acid
thick colourless inodorous liquid, which when heated above 130**
becomes brown and begins to decompose. It may be boiled with
ordinary nitric acid without undergoing change, and chlorine
even in the sunlight does not act upon it. Its salts arc all
soluble in water .and almost all crystalline.

Potassium Methyl Sulphonale, CH3.SO3K, is not only formed
by neutralizing the acid with potash, but also by heating methyl
iodide with an aqueous solution of normal potassium sulphite.
It is easily soluble in water, and crystallizes from hot alcohol in
finely interlaced threads. The double compound, CH3.SO.K -f
CH,^.S03H, separates in deliquescent prisms when a mixed

^ Cniin-Brown an«l lilaickio, Ch^m. Knrny xxxvii. 130; xxxix. fil.
- ^tinu Cht'm. I'll It nn. liv. 174.

21G METHYL COMPOUNDS.

solution of the sulphonate and of the free acid is placed in a
vacuum over sulphuric acid.

Barium Methyl SidplvancUe, (CH3.S08)2Ba + H^O, forms
fine transparent rhombic tables which are unalterable in
the air.

Lead Methyl Sulphonate^ (CH8.S08)2Pb+H20, crystallizes in
large prisms, also unalterable in the air.

Silver Methyl SulpJionate, CHg-SOjAg, forms fine transparent
tablets which have a sweet metallic taste, and remain unaltered
on long exposure to the air.

Methyl StUphonw Chloride, CHj.SOgCl, was obtained by
Carius ^ by acting on the acid with phosphorus pentachloride :

SO2 1 q2» H- PCI5 = SO2 1 gf^3 + POCI3 + HCl.

It is a powerfully-smelling liquid boiling at 150'' to 153^ It is
slowly decomposed by water into hydrochloric acid and methyl
sulphonic acid. On heating with phosphorus pentachloride to
150'-1G0°, the following reaction occurs :

)CH

, I ^p + PCI5 = SO.Cl + CH3CI + POCI3.

SELENIUM COMPOUNDS OF METHYL.

145 Methyl Selenide, (0113)280. By distilling a solution of
potassium methyl sulphate with potassium selenide, Wohler and
Dean obtained a reddish-yellow highly offensive liquid which,
until recently, was held to be the above compound. It is,
however, most probably the diselenide. Methyl monoselenide
is obtained by heating potassium methyl sulphate with caustic
potash and phosphorus pentaselenide :

P^5 + 10 K(CH3)S0, -h 16 :\aOH =
6 (CH^^Se + 5 K^O, -f- 5 Na,SO, + 2 Na3P0, -h 8 H.O.

It is a ooIourlefB strongly refracting liquid, heavier than water,
possessiiig a most unpleasant smell, and boiling at oH'''2. It
decomposes in contact with water in the cold, and more quickly
on bailings with separation of selenium.

* Jhh. Chcm, Pharm. cxiv. 140.

TELLURIUM COMPOUNDS OF METHYL. 217

MethyUeleni-nitratey (CH3)2Se(N03)OH, is formed by dissolv-
ing the selenide in strong cold nitric acid. It crystallizes out
from water in long prisms, melting at 90°'5, and volatilizing
below 100^

Methylsekni'dichhruh, (CH3)2SeCl2, is precipitated by hydro-
chloric acid from a concentrated solution of the nitrate. It
crystallizes from alcoholic solution in mother-of-pearl scales,
which have an unpleasant smell, and melt at oO^'S.

The corresponding bromide and iodide are known, and also
mcthylseleni'platinie chloride, 2(0113)280 + PtCl4, obtained by the
direct combination of its constituents, and crystallizing in yellow
feathery needles from alcohol.^

Methyl Scleiwnic Acid, CHj-SeOgH, is obtained by oxidizing
the diselenide with nitric acid. It crystallizes in prisms which
melt at 122^ having an unpleasant smell and a metallic taste.
It forms a series of crystalline salts.^

TELLURIUM COMPOUNDS OF METHYL.

146 Methyl Telluride, (€113)2X6, was obtained by Wohler and
Dean' on distilling potassium tellurido with a concentrated
solution of potassium methyl sulphate. It is a light-yellow mobile
liquid which boils between 80° and 82^ yielding a yellow vapour,
and has a very unpleasant garlic-like odour, which is so per-
sistent, that when working with the substance the breath
becomes persistently tainted with tlie smell.

Methyl Tellurium Oxide, (CH,)2TeO. Methyl telluride dis-
solves in strong cold nitric acid with the formation of the
nitrate, (CH3)2Te(N03)OH, which crystallizes in large colourless
prisms. Hydrochloric acid throws down the chloride, (CH3)2TeCl2,
from this solution, in the form of a thick white precipitate,
which crystallizes from solution in hot water in long thin
prisms. When heated with water and freshly precipitated
silver oxide, a solution of the oxide, or more probably of
the hydroxide, (0113)2X0(011)2, is obtained. A distinctly crys-
talline mass is produced on evaporation which deliquesces on
exposure to air, and absorbs carbon dioxide. It possesses a

^ C. T-,oriD*? Jackson, Liehitfs Avualrn^ clxxix. 1.
- AVbhlcr and Dean, Ana. Chcm. r/uinn. xcvii. t).
' Ibid, xciii. 233.

218 METHYL COMPOUNDS.

most unpleasant taste, but is odourless. Its solution turns red
litmus-paper blue, and it liberates ammonia from sal-ammoniac
at the ordinary temperature, and gives a blue precipitate with a
solution of copper sulphate.

Sulphur dioxide precipitates methyl telluride from its
solutions :

(CH3)2TeO + SO2 + H.O = (CH3),Te + H^SO,.

The oxide forms, with acids, salts which have been examined by
Wohler and Dean, and also by Hceren.* They are, as a rule
soluble in water, and crystallize well.

NITROGEN BASES OF METHYL.

METHYLA^nNE, N(CH3)H2.

147 Methylamine was discovered by Wurtz,^ in 1849, who
obtained it by the action of caustic potash on methyl isocyanato,
or isocyanurate (see p. 225). Hofmann ^ then prepared it by
heating methyl iodide with ammonia, and Carey Lea,* as well
as Juncadella,^ showed that it is also easily obtained when
methyl nitrate is used instead of the iodide. This base is also
formed by various other reactions, of which the following are
the most important.

Mendius^ found that methylamine is pro<luced when hydro-
cyanic acid is acted upon with dilute sulphuric acid and zinc ; and
Debus" showed that it is likewise produced when a mixture of
hydrogen with the vapour of hydrocyanic acid is jjassed over
platinum bhick heated to 110°; again Bert helot® obtained it
by heating methyl alcohol with ammonium iodide to 100^ cr
with sal-amnxmiac to 3()0^ According to Dusart and Bardy,*^
only a small quantity of the base is formed when sal-ammoniac
alone is utod, but if hydrochloric acid be added, and the mix-
ture heat<?d for thirty hours to a tem]H>rature of 20o*'-20S'*, :i
better yield is obtained. On the other hand, "VVeith ^^ found
that when an excess of methyl alcohol is employed, the sal-
ammoniac can be completely methylateti. On heating two
grams of this salt with 12 cbc. of pui*e methyl alcohol

' CTirm. Centra^b, ISOl, OIG. • Ann. Chim. Phys. [3], xxx. WW.

» PhU, Tmn». 1851. p. 381. * Chfm. JNVir«. vi.'48.

* OmpL Rend. zItiu. 342. * Ann, Chfm, Pkarm, rxxi. 130.

' GUm, Soe. Joum. xvi. 240. • Ann. Chim. Phyn, [3\ xxxviii. CO.

^ roM|if. Bemd, Iiiiv. 180. >* Ber. JkuUeM. Cktm, O*. viii. 45S.

METHYLAMINE. 219

to 280°-285'' for ten liours, methyl ether, hydrochloride of
trimethylamine. and tetramethylammonium chloride were
formed. On heating three grams of sal-ammoniac with 12
cbc. of methyl alcohol for six hours to the same tem-
perature, hydrochloride of methylamine was obtained in
addition to the above compounds.

Methylamine occurs in nature in Mereurialis annua and
Af. perennis,^ being formerly known in the impure state as
mercurialine. It is also found in herring brine, and occurs
frequently as a product of the decomposition of the alkaloids,
and similar compounds. It has likewise been observed by
Anderson in the products of distillation of animal matter, and
also of that of wood (Camille Vincent), and it is now obtained
on the large scale in Vincent's process. It has already been
stated (p. 202) that hydrochloride of trimethylamine decom-
poses, at a temperature of about 285°, into methyl chloride
and trimethylamine which volatilize, and hydrochloride of
methylamine, which remains behind. This is always mixed
with some sal-ammoniac, from which it may, however, be
separated by solution in absolute alcohol ; the spirit is then
distilled off, and the residual salt decomposed with caustic
soda.

Methylamine is a colourless gas condensing at a few degrees
above 0°, to a mobile liquid which does not solidify on exposure
to the temperature obtained by a mixture of ether and solid
carbon dioxide. It has a strong ammoniacal, but also a slight
fish-Uke smell, and is more soluble in water than is ammonia,
which it resembles very closely. At 12°*5 one volume of water
dissolves 1,150, and at 25^ 059 volumes of the gas. It is easily
combustible, and may in this way readily be distinguished from
ammonia. It burns with a bright yellow flame, forming water,
carbon dioxide, and nitrogen. If an insufficient supply of air be
present, small quantities of cyanogen and hydrocyanic acid are
also formed. Tins latter compound is produced, together with
ammonium cyanide, when the gas is led through a red-hot tube
filled with pieces of porcelain. When it is heated with potas-
sium, potassium cyanide is formed, with evolution of free
hydrogen.

Like ammonia, the aqueous solution precipitates many
metallic salts, and these precipitates partially dissolve in an
excess of the reagent. Silver chloride also dissolves in excess

' Schmidt, Licbig's Ann. cxciiL 73.

220 METHYL COMPOUNDS.

of inetbylamine. On the other hand, the hydroxides of cadmium,
nickel, and cobalt do not do so, and these reactions serve as
another means of distinguishing it from ammonia, and in addi-
tion we have the fact that aluminium hydroxide dissolves in
methylamine but is insoluble in ammonia.

Hydrochloride of Meihylamin4^ or Jdctftyl-ammonium Chloride,
N(CH3)H3C1, crystallizes from alcohol in large iridescent tablets
which deliquesce on exposure to moist air. It forms with gold
chloride the double salt N(CH3)H3Cl + AuCl3+H20, which
crystallizes in splendid large golden yellow needles, whilst the
platinum salt, [N(CH3) H3Cl].,PtCl4, forms golden yellow scales or
large hexagonal tables, soluble in water but insoluble in alcohol.

Sulphate of Meihylamiiie or Methyl-am monium Sidplvatc,
[N(CH3)H3l2SO^, is easily soluble in water but insoluble in
alcohol. It crystallizes in deliquescent stellar needles. It
forms an alum with aluminium sulphate, [N(CH3)H3]2SO^ +
Al2(SO^)8+24H20, which crystallizes in large regular octo-
hedrons.

Nitrate of Methylamine or Methyl 'ammonium Xttrate, N(CHg)
H3NO3, forms orthorhombic prisms which are deliquescent and
easily soluble in alcohol.

Carbonate of Methylamine or McthyUammonium Carhoimte,
[X(CH3)H3]2C03, is produced on distiilation cf a mixture of
calcium carbonate and hydrochloride of methylamine. It has,
however, not yet been obtained in the pure state. It forms
hard prisms which are very deliquescent, has a strongly alkaline
reaction, and undergoes volatilization at the ordinary tem-
perature of the air. At the s^inie time, methylanimonium-
methylcarbamate is formed. This also is ]>roduced by the
direct union of methylamine and carbon dioxide.

With platinous chloride, methylamine forms several com-
pounds corresponding to certain of the platinanmionias
(Wttrtz).

DlMETHYLAMINE, N(CH3)2H.

148 This was discovered by Hofmann, who obtained it by
heating methyl iodide with an alcoholic solution of am-
rnonia^ when the hydriodides of ammonia, methylamine,
dimethylamine, and trimethylamine, as well as tetra-
methylamnionium iodide are formed. The last salt is,
however, soluble in alcohol, and it, therefore, can be readilv
Mparated from the other four. These are then distilled

DI- AND TRI-METHYL AMINE. 221

with caustic potash, and the vapours led into a well-cooled tube,
when tiimethylamine, dimethylamine, and a portion of the
methylamine are condensed, the remainder of the last-named
substance passing forward with the ammonia, and being afterwards
absorbed in hydrochloric acid. The mixture of the three bases
is then treated with ethyl oxalate, 020^(02115)2, which does
not act upon the trimethylamine, whilst the methylamine is
converted into dimcthyloxamide, 0203(^11.0113)2, and the
dimethylamine into the ethyl ether of methyl oxamic acid.
This latter can be separated by cold water from the difficultly
soluble diethyl oxamide ; on distillation with caustic potash
it is converted into potassium oxalate, alcohol, and dimethyl-
amine :

CA { N^l\+^ KOH=CA { g| + HO.C,H. + N { g^*)^

The alcoholic solution is neutralized with hydrochloric acid,
evaporated down, and the residue, on distillation with potash,
yields dimethylamine.

This base is also formed on distillation of the so-called
sulphite of aldehyde-ammonia with lime. This product, how-
ever, was at one time supposed by Hofniann to be its isomeride,
ethylamine.^

Dimethylamine also occurs in Peruvian guano 2 as well as in
the products of distillation of wood (Oamille Vincent). It
is an ammoniacal -smelling, readily inflammable liquid boiling
at between 8° and O"*.

Hydrochloinde of Dimethylamine or iJimrfhyl-ammonivm CMo-
ride, N(OH3)2H201, is a white deliquescent mass crystallizing
in scales, and forming with gold chloride, and platinum chloride,
crystallizable compounds.

Trimethylamine, N(0H3)3.

149 This occurs somewhat widely distributed in nature. Thus,
for instance, it is found in various plants, as the Chenopodium
mdvaria. Arnica montana, Mercurialis annua, the bloom of the
hawthorn, that of the wild cherry, and of the pear, as well as
in ergot, and other fungi parasitic ou cereals. It also occurs
in various animal liquids, and especially in herring- brine. It
is likewise found as a product of decomposition of various

* rjossmaiiii and Petersen, Ann, Chem. Pharm, cii. 317.
- Lucius, IbUL ciii. 105.

222 METUYL COMPOUNDa

alkaloids, and amongst the products of the dry distillation of
nitrogenous organic matter and of wood.

Before Hofmann's investigation on the amines it was believed
that the base occurring in nature was the isomeride, propylamine.
He prepared it first according to the method described, and
afterwards he and Winkles ^ obtained it in larger quantity by
distilling herring-brine, in which Wertheim * had first found it,
together with lime..

It has lately been prepared in large quanties by Vincent in
the distillation of the **vinasses" of the French beet-root
sugar refineries. A solution of the sulphates of ammonia and
trimethylaminc is thus obtained from which the first salt can
be partially separated by crystallization. The darkly-coloured
mother-liquor is then distilled with lime, and the product passed
into hydrochloric acid. This solution is then boiled down until the
temperature reaches 140°. The sal-ammoniac present crystallizes
out on cooling, and the mother-liquor is drawn off from this, and
further evaporated until the boiling-point rises to 200° ; the
residue thus obtained consists of commercial hydrochloride
of trimethylaminc, from which the free base can be readily
prepared by treatment with an alkali.

Trimethylaminc is a mobile liquid boiling at from 9° to 10**
and having a specific gravity of 0*673 at 0° (Rlennard). It
has a powerful and penetrating characteristic fish-like smell.
It is very soluble in water and the concentrated aqueous solu-
tion, as well as the pure base, is easily combustible. Devillier
and Buisine^ found from 5 to 10 per cent, of this base in the
commercial trimethylaminc, together with 50 per cent, of
dimethylamine, whilst the remaining, and about equal part,
consisted of ethylamine, propylamine and iso-butylamine.
According to Vincent* this depends upon the fact that the
*' vinasses " of different preparations do not always yield the
same products, and that their relative amount depends upon the
circumstances under which the distillation is conducted.

Trimethylaminc is now used for the purpose of preparing
pure potassium carbonate from potassium chloride, the process
adopted being exactly similar to that described in Vcl. II.
Fkrt I. p. 152 as the ammonia-soda process. The reason that
anunonia cannot be employed in the preparation of potassium
carbonate is that sal-ammoniac and hydrogen potassium

» Chem. ftoc, Joum, v. 28<». ' Wicn, Akad, Brr. vL 113.

> Ompt, Bend, lixxix 4m. * Ibid, Ixxxix. 238.

TETRAMETHYLAMMONIUM COMFOUNDS. 22:^

carbonate are about equally soluble in water, whilst the hydro-
chloride of trimethvlaniine is a much more soluble salt. In
addition to this, it has been employed in medicine, and is said
to have been of value in cases of acute rheumatism and gout.

Hydrochloride of Triraethylavihie or Trimethylammonium
Hydrochloride, N(CH3)j,HCl, forms deliquescent crystals, and
serves, as has been mentioned, for the preparation of methyl
chloride. It unites with platinum chloride to form the com-
pound 2N(CH3)3HC1 + PtCl^, crystallizing in orange-coloured
octohedrons. The sulphate forms, with aluminium sulphate,
the alum [N(CH3)3H]2SO, + Al2(SO,)3 + 24H2O, crystallizing
in transparent octohedix>ns, possessing an astringent taste, and
smelling of herring-brine. Trimethylamine combines with
carbon disulphide, yielding, with considerable evolution of
heat, the compound CS2,N(CH3)3, which crystallizes in rhom-
bic needles from alcoholic solution, and is decomposed by both
alkalis and strong acids into its constituents. Dilute acids, on
the other hand, unite with it to form salts. When it is brought
in contact \^ith an equal number of molecules of hydrochloric
acid, the neutral compound, CS2,N(CHg)3,HCl, is formed,
which, when in contact with more acid, yields the compound
2CS2,N(CH3)3, 3HC1.

Nitric acid and sulphuric acid form corresponding compounds.*

TETRAMETnYLAMMONIirM COMPOUNDS.

150 The iodide, N(CH3)4l, as har, been mentioned, is the
chief product of the action of ammonia on methyl iodide, and
is readily formed by the union of the latter compound with tri-
methylamine. It crystallizes from hot water in shining white
needles, which possess an intensely bitter taste. On heating, it
decomposes into trimethylamine and methyl chloride, which,
however, reunite on cooling. The iodide possesses the property
of yielding, with chlorine and iodine, several crystalline poly-
chlorides and polyiodidcs, which easily undergo decomposition.
When freshly precipitated silver oxide is added to a solution of
the iodide, the hydroxide, !N(CH3)40H, is formed. This yields
on evaporation in a vacuum, a crystalline mass, which rapidly
absorbs water and carbon dioxide from the air. It acts as a
powerful caustic, is strongly alkaline, and generally resembles
the fixed caustic alkalis in its behaviour. On neutralization

^ Blennard, Compt. IteruL Ixxxvii. 1040.

226 METHYL COMPOLXLa

ether of cyanic acid. It is obtained by distilling a mixture of
freshly - prepared potassium cyanide with potassium methyl
sulphate, and it is a mobile liquid which has an excessively
suffocating odour, its vapour vigorously attacking the mucous
membranes. Aqueous acids and alkalis decomposes it with
formation of carbon dioxide and methylamine :

When dry, ammonia acts upon methyl carbimide, methyl urea
18 formed, and this is likewise produced when the vapour of
cyanic acid is passed over methylamine, or when a solution of
potassium cyanate is evaporated with sulphate of methylamine.
The formation from the carbimide occurs as follows :

M(»tliyl urea forms long transparent prisms easily soluble in
wiitor, and combining with acids to form cry stall izable salts
(Wilrt/J.

WIhmi nirthyl carbimide is brought in contact with water,
Jimffliyl'Hirn in formed :

•j(-().N(Cir3) + H,o : 0.1) 1 5i[!'|y[[ + m^

Tlin HtiUM^ compound is proilucfd by acting on cyanic acid
Willi innthj'Iiunine. Dimethyl-uroa forniH crystals which melt
III. jOO", find it boils without decomiMisition at 270". It is
MMttily Mnlubh? in water, and combines with iwids (Wlirtz).

Ti'tmeihi/l Ttncarhimide, CjOjCXCH,),, is a polymeric modi-
rti'iilinii of carbimide formed in the preparation of the latter
i<otii|»oMtid, and also produced when this sulstanco is allowed
|o mImihI. It iM likewise obtained, as above described, from
I III* ryiuiunito, iiM well as when potassium cyanurat^j is distilled
with iHitim>«iinn mothyl sulphate. It crystallizes in sliort prisms,
wliicli do not diMm>Ive in cold water, are slightly soluble in hot
WMtiT, anil cnwily wihiblo in alcohol. They melt at 175" and
boil III 271".

Alft/n/f Thinn/tnwtf, NO.SCH^.was first obtained byCahours'
on difitilling a <*onc(*ntratiHl solution of equal parts of potas-
ntuni thi(N'yanat(« and cah'ium methyl sulphate. It is a colour-

> Ann. iltim. /7ij/j». p). xviii. 281.

XITRO-COMPOUNDS OF METHYL. £27

less alliaceous-smelling liquid. At O'' its specific gravity is
1-088, and it boils at 133".

Methyl Thiocarbimide or Methyl Mustard Oil, CS.NCH,. When
methylamine is brought in contact with carbon disulphide,
metbyl-thiocarbamic acid, CS(NH.CH3)SH, is produced, the
silver salt of which, when heated with water, decomposes as
follows :

CS ( si^^^'^ - 2N { ^^3 + Ag,S + H,S.

Methyl thiocarbimide is a white crystalline solid, which melts
at 34'' and boils at ll9^and smelh strongly of horse-radish.
It combines with ammonia to form crystalline methyl thio-
carbamide, CS(NCH3.H)NH2. The crystalline hydriodide is
isomeric with methyl thiocarbamide iodide, CS(NH2)2CH3T,
obtained by the union of carbamide with methyl iodide. It
possesses the characters of a sulphino compound, yielding
with silver oxide and water a strongly alkaline hydroxide,
CS(NH2)2CH3.0H, which yields well crystallizable salts with
adds.*

NITRO-COMPOUNDS OF METHYL.

152 KitrO' Methane, CH^NOg, is formed when concentrated
solutions of potassium nitrate and potassium chloracetate arc
boiled together :

CH.Cl.CO.K + KNO2 + H2O zr CH3NO2 + KCl + HKCO;,.

The compound thus formed was termed by Kolbo - nitro-car-
binol. About the same time V. Meyer and Stiibcr ^ obtained
the same compound by acting on methyl iodide with silver
nitrite, when a violent action occurs.

Nitro-methane is a heavy liquid, possessing a peculiar smell,
and boiling at 101°. It acts as a weak acid, solidifying with an
alcoholic soda solution to a mass of fine needles, having the
composition CHgNaNOg + CoHgO. These, when dried over
sulphuric acid, fall to a light powder, which detonates on
heating, and undergoes spontaneous decomposition when kept.
Its concentrated aqueous solution is still more unstable, for

' Bernthsen and Klingcr, Bcr. Dculsch. Chem. Ges. xi. 492.

- Journ, frac. Chem. [2], v. 42 7.

3 Drr, Deutsrh. Chcvi, Ocs, v. .'514 : Liehv/s Ann. clxxi

228 METHYL COMPOUXD&

after a few moments it suddenly suffers decomposition with
evolution of heat.

The freshly prepared solution gives characteristic precipitates
with many metallic salts. Of these, the yellow mercury com-
pound is the most singular, as it is extremely explosive, deto-
nating strongly if merely touched, when in the dry state, with a
glass rod. Two milligrams of the compound when heated on a
platinum cover explode with a noise equal to that of the
discharge of a pistol.

On heating nitro-methane with fuming sulphuric acid, carbon
dioxide and hydroxy lam ine are formed.^

CH3 NO2 = CO + NOH3.

When nitro-methane is dissolved in caustic potash, and some
potassium nitrate added and then dilute sulphuric acid, a deep
red solution is obtained, the colour of which disappears on addi-
tion of more sulphuric acid, and is reproduced on the addition
of alkalis. This reaction depends on the formation of methyl
nitrolic add, CH(N02)N0H, of which the alkaline salts have a
deep red colour (see p. 171). The free acid forms large glisten-
ing crystals, soluble in water, alcohol and ether. It is an ex-
tremely unstable body decomposing on standing. When heated
to 64** it melts with evolution of red fumes, whilst formic acid
remains behind. This latter compound is also formed on boiling
with dilute sulphuric acid, when nitrogen monoxide is evolved.*

CHjNjOg = CH2O2 + NjO.

If nitro-methane be heated with alcoholic solution of caustic
soda, a crystalline mass of sodium methazonate is formed, which
is permanent in the air and highly explosive.

Mdhazonic acid, CjH^NjOj, obtained from this, can be ob-
tained from solution in ether or benzol in large crystals, which,
on heating, decompose with explosive violence^ and at the ordi-
nary temperature undergo rapid change with formation of a red
colour.*

' Pn'ibisch, Joum, Prac Chem, [2], viii 816.

• Meyer, Licbigs Ann, clxxv. 97 ; Tachernink, ibid, clxxx. 166.

» Frkae, Btr, DciUsch. Chem. Get. ix. 894 ; Lecco, Hid. 705.

METHYL PHOSPHINE. 220

PHOSPHORUS COMPOUNDS OF METHYL.

153 Paul Thenard ^ in 1846 examined the properties of several
volatile compounds containing phosphorus which he hail ob-
tained by acting on calcium phosphide with methyl chlorido.
Amongst these occurred trimethylphosphine, P(CH3)^and tetra-
methyldiphosphine, "2^(01^^. In 1855 Cahours and Hofmunn '
investigated the substances obtained by the action of methyl
iodide on sodium phosphide, and discovered, in addition to the
two bodies just mentioned, tetramethylpbosphonium iodide,
P{CIl3)4T. They likewise found that by this process explosive
bodies are produced, and, for this reason, the investigation is
not without danger. On this account they sought for and suc-
ceeded in finding a better method of prcjnration, which will
afterwards be described.

Monomethylphosphine and dimethylphosphine were discovered
by Hofmann in 1871.*

Methyl Phosphine, V{GK^Y{^, is formed by the action of
phosphonium iodide on methyl iodide in the presence: of zinc
oxide :

2 CH3I + 2 PHJ + ZnO = 2 PCCigH^I + Znl,-f- H/).

The secondary base is formed at the same time, according to
the equation :

2 CH3T -f- PI I J -f- ZnO = PCCiygH^I + Znl^ + H^O.

In order to prepare these compounds, the materials are mixed
in the proportions indicated by the fir:st equation, placed in
carefully closed tubes, and then heated from six to eight hours
to 100°. After this operation, the contents of the tubes fonn a
crystalline mass* consisting of the two double zinc salts. The
primary base is obtained from these by decomposition with
water, whilst the diniethyljibospbine salt remains unaltered, but
may be decomposed by alkalis.*

In order to prepare the free bases, the product of the reaction
is brought into the vessel A, Fig. 62, filled with hydrogen, and
water is allowed to drop upon the mass. Methyl phosphine gas

' Compt, Rend. xxv. 289.

« Fhil. Trans, 1857, 575 ; see also Chein. Soc. Joiim. xiii. 289 ; xiv. 73, 316.

• Proe. Eoy. Soc, xx. 221.

* llofmano, Ber. Dcutsch. Chem. G(8. iv. 605.

SltTBVL COMPOLSI^,

u then evolved willi liUsio^ and effenescence ; tLU is allowed
to pass tliFOugb a spiral tube surrouudcid by a freezing mixtore
into tbe vessel H, aUo well cooled, in wLicb it is ooodensed.
Wlieu lit t:v-;>!iitioD of ^as lakvs place oq farther addition of
wau^r, tiie cri.'stalline mass is heated until the whole is dissolved,
when a t-udfJen torrent of gas is frequently given off, and hence
the receiver is connected with a condenstug flask, K, containing
crjnceiitnited byilii'jdic acid, in wliich any uncoadeosed gas
v.'liiclt riii^ht otherwise escape i:i absorbed.

Methyl phosphinc itt a colourless gim, possessing an cxi'essivcly
poweiful odour It condenses on cooling or under pressure to n
liiliitd I»oiliii^' ut -14°, and its vapour density is 1GS7. On
lixposurc to air, it evolves white fumes, and takes firo even when
hut slightly warmeil. In contact with chlorisc, bromine, or
nitric oirid, it burns with a bright flame. It f'lrins with acids
a well-dufmed Hcrics of salts which, like those of pliosphurotted
hy(Iro;ieu, are dcconipoitcd by water, and possess moreover the

PHOSPHORUS COMPOUNDS OF METHYL. 131

singular property of bleaching vegetable colours like chlorine,
a reaction which is not exhibited by the free base. This may
be well shown by bringing a piece of litmus-paper, half moist-
ened with water and half with acid, into the gas, when the latter
lialf only will be bleached.

Methyl Phosphonium Chhride, P(CH3)H3C1, is formed by the
union of its two anhydrous constituents. It crystallizes in four-
sided tables, which are so volatile that their ethereal solution
evaporates as a whole.

Methyl Phosphonium Iodide, P(CH3)H3T, separates from con-
centrated hydriodic acid in large compact crystals, and can
easily be obtained pure by sublimation.

Methyl PJiosphinic Acid, P(CH3)0(0H)jj, is obtained when the
base is passed into concentrated nitric acid. It forms a hygro-
scopic, spermaceti-like, crystalliue mass, which melts at 105°, is
easily soluble in water, and posse&ses a purely acid taste. Being
a dibasic acid, it yields two series of salts.*

Phosphorus pentachlorido decomposes it into the chloride,
P(CH3)OCl2, a white crystalline body which melts at 32° and
boils at 163°, and is decomposed with explosive violence by
water.*

This compound is isomeric with metliylphosphorous acid,
from which, however, it is sharply distinguished by its
properties.

154 Diniethylphosphine, P(CH3)2H. If caustic soda solution bo
added to the liquid from which methyl phosphino has been ob-
tained, the secondary base is liberated, and separates out in a
layer on the top of the liquid. It is a colourless liquid, boiling
at 25°, and taking fire instantly on exposure to the air, burning
with a very luminous, phosphorus-like flame. If the atmo-
sphere of hydrogen in which it is prepared contains even a trace
of air, this is instantly observed by the formation of a white
cloud, and dangerous explosions may ensue in the preparation of
this body, unless great care le taken. It forms with acids ea:?ily
soluble salts. The hydrochloride yields with platinic chloride a
well crvstallizable double salt.^

Nitric acid oxidizes the base to dimethylphosphinic acid,
P(CH3)20.0H, a white paraffin-like mass, melting at 7G°, and
volatilizing without decomposition. It is a monobasic acid, and
yields a well-defined series of salts.* Phosphorus pentachloride

» Hofiimjiii, />Vr. Deutsch. Chcm. Grs. v. 104. ^ Ibid. vi. 303.

» m-f. iv. (qo. -» Hid, V. 108.

232 MKTHYL COMPOUNDS.

couverts it iato tho chloride. P(CHj)jOCl, a cryatalline body
melting at 66", aud boiling at 204>°, and being slowly decomposed
by water.'

155 Trimethyl PkospUne, P(CH,)j, is obtained by acting on
pboaphorus trichloride with zinc methj'l :

3 Zn{CH,)^ + 2PCI, = SZuCI, + 2 PCCHg),.

The apparatus employed for preparing this substance 13
shown in Fig. C3. A pipette furnished with a stopcock contains
phosphorus trichloride, and the retort a mixture of ether and
zinc methide. This is connected with a bent tube, in which a
few drops of phosphorus trichloride are placed, whilst to this is

attached a cylinder (c) containingdry carbon dioxide, the whole of
the apparatus being filled with the s»nie gas before thu beginning
of the experiment from the evolution flask (a). The tricldorido
is then allowed to pa^s drop by drop into the retort, when
a reaction takes place as violent as that observed when sul-
phur trioxide acts on caustic baryta, so tluit the zinc methyl
is partly volatilized, and cnrriod forward not only into the re-
ceiver but into the bent tube, where it meets with the phosphorus
trichloride, and is absorbed. The drop of trichloride scr\-es also
as an indicator of the prt^nress of the reaction. After a time the
action Ifccomes less violent, and when no further evolution of
' H.-fiiiunn, B/^r. Ik-iilxh. rhnn. fir,, vi. 307.

TKIMETHYL PHOSPHINE. 233

beat takes place, it is complete. In the receiver and bent tube,
and sometimes even in the cylinder (c), two layers of liquid are
found, of which the upper one consists of a mixture of ether and
phosphorus trichloride, which may again be employed in a
second preparation of the base ; the second and heavy layer is a
compound of trimethylphosphine with zinc chloride. For the
purpose of obtaining the free base, solid caustic potash is added
to this liquid, and water gradually allowed to drop in, when so
much heat is evolved that the base distils over ; this then is dried
over caustic potash and rectified. These operations must be
carried on in an atmosphere of carbon dioxide.

Trimethylphosphine is also easily formed by heating methyl
alcohol with phosphonium iodide in sealed tubes. ^

3CH3.OH -f PH,I :=z P(CH3)3HI 4- 3H2O.

If it is desireil to prepare it according to this process, two
molecules of the iodide are added to only five molecules of
alcohol in order to avoid the formation of tetramethyl phospho-
nium iodide. In this case, however, large quantities of phos-
phine are formed by a secondary reaction, and hence it is
necessary to employ strong and well fused tubes, which must
be beated for many hours to 180^ The product thus obtained
yields the firee base on treatment with caustic soda solution.

The formation of this compound by heating phosphonium-
iodide with carbon disulphido to 150° is of great theoretical
interest : *

SCS^ + 4PH,I = P(CH3)3HI + ;3H,S -f 3PSI.

Trimethylphosphine is a light, mobile, powerfully refracting
liquid, which boils at from 40° to 42°, and has a most indescrib-
able and penetrating odour. It fumes in the air, and on ex-
posure becomes surrounded by a crystalline crust of trimethyl-
phosphine oxide, P(CH3)30, and frequently takes fire. It also
combines directly with sulphur, selenium, and the elements of
the chlorine group, as well as with carbon bisulphide. The
compounds thus obtained closely resemble the corresponding
triethylphosphines.

156 Tctramcth/lphosplionium Iodide , Pi'CHj)^!, is formed by the
union of methyl iodide with trimethylpliosp'.iine, and, together

* llofmann, Bcr. Dcittsch, Chem. Gcs, iv. 205, 372.

* Drcchsel, Joxmu Proc. Chcm, ['!], x. 180.

234 METHYL COMPOUNDS.

with the tertiary base, by heating methyl alcohol with
phosphonium iodide : '

4 CH3.0H + PH,I=P(CH3),I + 2H20.

It crystallizes from hot alcohol in beautiful glistening white
crystals, which assume a reddish colour on exposure to air. A
strongly alkaline hydroxide is obtained by acting with moist
silver oxide on its aqueous solution, and this decomposes on
distillation into methane and trimethylphosphine oxide :

P(CH3),01I =CH, + P(CH3)30.

Tetraniethyl Dipliosphidc, P2(CH3)^. This compound, cor-
responding to liquid phosphuretted hydrogen, was, as has been
stated, discovered by Paul Thenard, and then observed by Cahours
and Hofmann. It is a thick, colourless liquid, possessing a most
unpleasant smell, boiling at 250°, and flaking fire on exposure
to air.

ARSENIC COMPOUNDS OF METHYL.

157 In the year 17G0, the French chemist Cadet observed that
a mixture of equal parts of acetate of potash and white arsenic,
when heated, yields, together with white arsenic and acetic acid
containing arsenic, a heavy brownish-red liquid which has a
most frightful smell, and fumes strongly in the air.^ This fact
was confirmed by Duraude,^ whilst Thdnard * investigated this
compound, which was termed Cadet* s fumhuj arsenical liquid,
and gave to it the name of *'acetiie oho-arsenical" It is, however,
to the classical research of Bunsen,^ carried on for many years
under circumstances of no slight danger, that we owe an exact
knowledge of the arsenical methyl compounds.

Bunsen showed that Cadet's liquid, as well as its numerous
derivatives, contains a radical having the formula C^H^As,
and that this substance, in its chemical relations, exhibits
striking analogies with a metal. He succeeded in isolating this
body, and as we have already seen, this discovery contributed
largely to the development of the theory of compound radicals.

* Hofmann, Brr, Deutsch, Chcm. Gts. iv. 20.'».

• Mi in, lie Math, et Phys. Pres. ikn Savants £iranff. iii. 6U3.

• Xvurfaii Chilli. Prnc. Thcor. iii. 89.

* Jun, dc Chim. Hi. f)!.

' Ann. f'hriii. Ph(tn>i. xxiv. 'J?! ; xxvii. 14S ; xxxi. 175 ; xxxvii. 1 ; xlii. 14 ;
xlvi. 1 ; and Clum. Sjc. Man, 1M41, i. 4l» ; Phif, May. [:tj, xx. 180, 395 ; xxii. 180.

ARSENIC COMPOUNDS OF METHYL. 235

This body, like most of its compounds, possesses a frightfully
offensive odour, so much so that the air of a room contain-
ing even a trace of the vapour is rendered so unbearable as
frequently to cause vomiting. For this reason the name
cacodyl {KaKwSrj*:, stinking) was given to this compound by
Berzelius.

Various hypotheses have been put forward respecting the
constitution of this radical. Kolbe * first suggested the view
that it was arseU'dimethyl, As(CH.^)2. This was rendered very
probable by the experiments of Frankland,^ and this view was
afterwards corroborated by Cahours and Riche.^ The latter also
<liscovered trimethylarsine and the tetravidhijlarsonium com-
pounds. But it is to Baeyer,* who at a later period, in a
masterly investigation, first prepared the arsai-jnoTwrnethyl com-
pcninds, that we are indebted for the full explanation of the
relations which these various bodies bear to one another.

The arsenic compounds of methyl and of the other alcoholic
radicals played an important part in the development of theo-
retical views, not only because they furnished us with the first
example of an isolable organic radical, but also because they
served Frankland ^ and Kekule ^ as a means of more exactly
illustrating the meaning of the term ''chemical valency."

The arsenic compounds of methyl may be considered as being
derived from arsenic trichloride by the partial or complete
replacement of the chlorine by the alcohol radical :

Arsenic trichloride. Arsen-methvi dichloriile.

( Cl ( CH3

As-|Cl As-^Cl

( 01. ( Cl.

Arseii- dimethyl cliloride. Triniethylai-siiie.

As^CH, -JCH3

Cl. V CH.w

The chlorine of these compounds may be replaced by other
elements or radicals, and for this reason arsen-monomethyl is

1 IlaiidworUrh. iii. 442 ; iv. 222. • Joum, Chem, Soc. ii. 297.

* Compt. Jitmi, xxxvi. 1001 ; xxxix. 541 ; Ann. Chem. Pharm. Ixxxvili. 316,
xc-ii. 3G1.

* Ann, Chem, Phann. cvii. 257.

' Phil. Trans. 1852, p. 440; or L'jcjKrimaiht I Pc'scarchc^^lSS,
'' Ann. Chan. Pharm. cvi 120.

236 MKTHYL COMPOUNDS.

considered as a dyad, and arsen-di methyl as a monad radical.
These arsenic compounds are, as Baeyer has shown, mutually
convertible. They combine like phosphorus trichloride, with
one molecule of chlorine, and the bodies thus obtained easily
decompose with evolution of methyl chloride. The compound
of arsen-mouomethyl is, however, so unstable that it can only
be preserved in a freezing mixture :

As(CH3)3Cl2 --= CH3CI + As(CH3)2Cl.
As(CH3)2Cl3 = CH3CI + AsCChJcIj.
As(CH3) CI, -^ CH3CI + ASCI3.

THmethylarsine, As(CH3)3, is obtained, together with cacodyl
and tetramethylarsonium iodide, by the action of sodium
arsenide on methyl iodide (Cahours and Riche). It is produced
on treating arsenic trichloride with zinc methyl : ^

2ASCI3 + SZnCCHy), = 2As:CH3)3 + SZnClj.

In place of arsenic trichloride, cacod}l iodide may be
employed. It is, however, best prepared by distilling potash
with tetramethylarsonium iodide or one of its double salts,^
which will be described hereafter. It is a strongly refracting
liquid, boiling at about 70"*, and possessing a highly penetrating
and disagreeable odour. It does not form salts with acids, but
on exposure to air becomes heated, without taking fire, owing
to its absorption of oxygen to form a crystalline oxide. It also
unites directly with sulphur and the elements of the chlorine
group, yielding crystalline compounds.

Tetramethylarsonium Compounds, The iodide, As(CHj),I, is
the chief product, of the action of methyl iodide on sodium
arsenide, and remains behind as a white crystalline mass when
the trimethylarsine and cacodyl, which are formed at the same
time, are removed by distillation in an atmosphere of carbon
dioxide. It is also forrped by the action of methyl iodide on
cadodyl :

(CHj^As., + 2CH3I = (CH3),AsI -f (CH3)2AsI.

When treated with silver oxide, the aqueous solution yields
the corresponding hydroxide, As(CH3),0H. This substance
has a strongly alkaline reaction, and, on evaporation, is de-
posited in the form of deliquescent tabular crystals. When

* Cahoan and Kiche, Compfrji Jlenfius, xxxix. 5*1.
'"' Cahouris ComfittM llendtu^ I. 1022.

THE CACODYL COMPOUNDS. 237

arsenic is heated with methyl iodide to 200°, the compound
As(CH3)^I + Aslg is obtained, crystallizing from hot alcohol in
red glittering needles. On heating arsenide of zinc with methyl
iodide to 180**, the double salt AsCCHj)^! + Znig is obtained,
and this separates from hot alcohol in white needles. A
corresponding cadmium compound is also known.

When zinc methyl acts upon tetramethylarsonium iodide, and
the product thus obtained is distilled, a considerable quantity of
trimethylarsine passes over first, and then a liquid which,
according to Cahours,^ is pentamethylarsine, As(CH3)5. It is de-
composed by iodine into methyl iodide and tetramethylarsonium
iodide whilst hydrochloric acid yields the corresponding chloride,
together with marsh gas. This singular body deserves further
examination.

The Cacodyl or Dimethylarsine Compounds.

158 The point of departure of these bodies is Cadet's liquid,
or alcarsin, as Bunsen termed it, giving it this name because he
at first believed it might be considered as a polymeric alcohol,
oxygen being replaced by arsenic.

According to Baeyer, the best mode of preparing this sub-
stance is to heat equal parts of white arsenic and anhydrous
sodium acetate in a retort in quantities of about 3 kg. at a
time, allowing the vapours to pass through a Liebig's condenser
into a receiver containing water. Highly poisonous gases are
thus given off, which must be allowed to pass up a flue into
the open air. The heavy oily liquid consists chiefly of cacodyl
oxide, which is formed according to the following equation :

4CH5.CO2K + AS2O3 r_- [(CH3)2As]20 + 2K/JO3 + 2C0,.

In addition to this, some free cacodyl is formed by reduction,
and this it is which gives to the crude product the property of
spontaneous ignition. Acetic acid, acetone, marsh gas, ethylene,
water, and arsenic occur as by-products. For the purpose of
purification, the crude oil is distilled with several times its
weight of hydrochloric acid and corrosive sublimate. In this
way pure cacodyl chloride can be obtained, w^hich may be
converted into the pure oxide by distillation with caustic
potash.

^ Ann. Chtm. Pharm. cxxii. 338,

238 METHYL COMPOUNDa

Cacodyl Oxide or Dimethylarsine Oxide, /pTj^\*A f ^- '^^*^

is a colourless, heavy liquid, which is not soluble in water, but
dissolves in alcohol and ether. It boils at about 150^, and solidifies
a few degrees below —23°, forming a crystalline mass ; it does
not fume in the air, but its vapour, when mixed with air, explodes
if heated above 50°, It possesses a frightfully irritating smell,
destroying the mucous membrane and producing insensibility,
and acts as a very powerful poison. Although it does not
possess an alkaline reaction, it is a very strong base readily
uniting with acids to form salts.

Cacodyl Chloride,- (CH3)2AsCl. When the oxide is heated
with hydrochloric acid alone, not only is the chloride formed
but also the oxychloride in considerable quantity; the pro-
duction of this latter being avoided by the employment of
corrosive sublimate. Cacodyl chloride is a heavy, colourless,
transparent liquid which boils at a temperature not far from
100^ yielding a vapour whose density is 4 56. The vapour
ignites spontaneously on exposure to air, burning with a
pale arsenic-like flame. Heated in oxygen it explodes most
violently. It does not fume on exposure to air but absorbs
oxygen, forming crystals the composition of which has not been
ascertained. Its smell is very penetrating and stupefying, far
surpassing in this respect the smell of the oxide. Inhaled in
even moderate quantity it produces such inflammation of the
mucous membrane of the nose that the vessels swell up, and
the eyes are congested with blood. Cacodyl chloride forms double
salts with various metallic chlorides such as sal-ammoniac. The
platinum compound, 2 (CH3)2AsCl + PtCl^, is obtained as a
red precipitate by mixing alcoholic solutions of the chloride and
platinum chloride. When this is dissolved in hot water yellow
needles of cacoplatylchloride, (CH3)4A520.PtCl2 -f HgO, and
from this other cacoplatyl compounds can be obtained.

Cacodyl Trichloride, (6113)2 ASCI3. Cacodyl monochloride takes
fire in chlorine gas. If, however, it be dissolved in carbon
disulphide and chlorine led on to the surface of the liquid the
trichloride crystallizes out in transparent prisms which decompose
at 40° into methyl chloride and methyl-arsen-dichloride.

The compounds of cacodyl with, the other members of the
chlorine group chxdjr rciiiobte the chl<mdea. ^

Cacodyl CJy04l4b^G|U|^ffll)|)» ii fonned by distilling the
oxide milytfiHiJ^^^^HliHrflL^^ m well as by acting

THE CACODYL COMFOUKDS. 239

on llie same substance with mercuric chloride. It crystallizes in
large glistening four-sided prisms which can be sublimed. They
melt at 33^ and boil at about 140^ This compound is scarcely
soluble in water though easily so in alcohol and ether. When
heated in the air it takes fire and bums with a reddish-blue
flame. This substance is extraordinarily poisonous, and for this
reason its preparation and purification can only be carried on in
the open air ; indeed even under these circumstances it is neces-
sary for the operator to breathe through a long glass tube
open at both ends, and thus to ensure the inspiration of air
free from impregnation with every trace of the vapour of this very
volatile compound. If only a few grains of this substance be
allowed to evaporate in a room at the ordinary temperature, the
effect upon any one inspiring the air is that of sudden giddiness
and insensibility amounting to complete unconsciousness. These
symptoms, however, last only for a short time, and are without
subsequent evil effects, provided the operator withdraws himself
in good time from the action of the poison (Bunsen).

Cacoilyl Sulphide, /pxr*!^ a c S, was obtained by Bunsen by

distilling the chloride with a solution of barium liydrosulphide.
It is a colourless liquid which does not fume in the air, and
possesses a highly disagreeable and unpleasant smell, reminding
one at the same time of mercaptan and alcarsin, and one which
remains attached to articles with which it has been in contact
for a great length of time. It boils far above 100®, but volati'
lizes together with aqueous vapour, and is very easily inflam-
mable. It is decomposed by acids with evolution of sulphuretted
hydrogen, and it yields, with solutions of various metallic salts,
precipitates like those produced by sulphide of ammrnium. It
combines with sulphur to form the disulphide (CH3)^As2S2,
crystallizing from alcohol in large clear rhombic tables
possessing an unpleasant smell, and fusing at 50°.

Cacodyl Selenide, Ivilt x^ I Se, is obtained by distilling the

(l^Jrlg^gAS )

chloride with sodium selcnide. It is a yellow liquid which in
smell resembles the sulphide, but, at the same time, has an
aromatic odour. It behaves towards solutions of the metallic
salts like the selenides of the alkali metals.

159 Dicacodijl, (CH3)^As2. This is the free radical of the
dimethylarsine compounds. It is easily formed by heating the
chloride with zinc from 90** to 100°:

- z

'I ■' '"i* ■■ II"*- T ■• -r

.■\ w i : ".. : . i's 1 . V ■■• [

• f iiriii'is|)l:.:-ri :'.- -.-
•' : «.'* . Tliv \>:.i>

■■ ■« :; tii..xi(.le. Tlit-
v-jMunp into tlio

1 ■ «

1 • ■ ■ ^

- • • ■ I - ;

■ * ■

« I 1 f 1-

CACOmXlC AOD. 341

Dicacodyl is a heaTT, clear, moMe, Miun^f niaamiz iitpbi
which smells like the oxide, and undexgoes tnch a xkieBt oxiiia-
tiou on exposure to air that when it is attenqned to drop ihe
liquid firom a bottle the liquid takes firebefoteitleaTesthegiiw
When air is allowed to con:e into contact with it alow It, it iocms
a thick white cloud, and is conrerted into caoodjl oxide ai>l
cacodylic acid. It boils at 170' and aolidines at —0^. f-rnusz
large quadratic prisms. The Tapour density of caoodTi chkriie
is 7'101. It bums in oxygen with a pale bhie flame, an>i
when thrown into chlorine bums with a bright light with
deposition of carbon. Shaken up with chlorine water it f.>nns
cacodyl chloride. It also combines directly with sulphur and
other elements yielding the compounds which hare been alneady
described, and for this reason Bunseo correctlv obser\'es that this
radical in every respect plays the part of a simple electro-
positive element, and that it is indeed a true oryfinie fUment.

With the haloid salts of the organic radicab it forms the
arsenium compounds :

(CH3J,Asj -f 2CJl5a = (CH^u(aH5)5AsC-l -h (CH3;:jAsCL

CncoHylic Acid or Dinuthylarsenic Acil, AsOiCH^uOH, is
formed by the further oxidation of the oxide in the air. It may
be obtained more rapidly by pouring water on the last-named
compound mixed with mercuric oxide :

(CH3),A.%0 + 2 H-0 -f H^O = 2 (CH3),AsO.OH + 2 Hg.

It is easily soluble in water, has an acid reaction, is odourless,
and crystallizes from alcoholic solution in deliquescent oblique
rhombic prisms. It is not attacked by fuming nitric acid or
even by aqua regia, and according to Bunsen it is not poisonous,
although the experiments of Lebahn and Schultz ^ have not alto-
gether corroborated this statement, as they found that doses of
four decigrams act fatally upon a rabbit. Phosphorus penta-
chloride decomposes cacodylic acid into arsendimethyl trichloride :

(CH.). AsO.OH + 2 PCI5 := (CH3)2AsCl3 -f 2 POCI3 + HCl.

Concentmted hydrochloric acid converts cacodylic acid into the
compound (0H3)As(OH)2Cl, to which Bunsen has given the
name of cacodyl perchloride, as it is also obtained by the action

^ Dcr, DjiitKk. Chtm, Ges, xii. 22.
VOL. III. U

2«

THE llETHVL liROi

of moist air oa the trichlorido. Water
niiitioa of cacodvlic aci J. The salts of c:
in vater ami crvstallize wiili difBcu
(CHjijOAs-OAg, separates out from lio
groups of needles.

MOSOMETHVL ArSISE Co

i6o Cacothl trichloriJe decoiikposes, as

when heated to 4l>'-50° ioto inetiiyl el

liieUaridf, As,CH,iOL wUicli compound

heating cacoilylic acid in a current of h;

A5,CH,.U>.0H + 3 HCl = AsfOH^jC

It is a heavy, mobile, strongly rt'fractii
Itd.>cs not fume in the nir and is not d
which ii dissolves with tolerahle readine;
Kxly attack the mucous membrane ii
manner. If even smelt, the eyes, tlie i
strell n'insidenibly. and a peculiar pierc
the tbioat iBaeyen. The crvstalline te<
is formeii when this boily is treated wit
ivniivund is stable outy at a low ten
dtivmji,>ses into methyl chloride and ara
div-h!\*ride be saturatinl mulor water wi
;;.:,W fAd,.. ../^ As CHjiO, is formed v
eviilvi>vl, Slethylarsenoxide is soluble i
and varbiui disulphide, and may be ol
s.>lvent in lar^^ crvstals, apparently cuhi
the repilar system. These melt at 95'
itsafu'-tida. In a short time they uud<
jK'iwUin-Iike mass, and in this respect
jkrsv'nio trk>xidi- ; indeed in its general pi
ai^penrs to hold a middle place betwe<
ca^wtyl oxide. It fcnnswith hydriodic ac
As,OHj'I,. crystallizing in long gHtteri
s«-ssin): im smell, which melt at 25°,
without d<.xt>niji<^siti.>n altove 200°.

.Vit.\i\,-^us»lfJiu{.; M{CH^)S. is fo
siOplmn-tt»>l hydi\>-;:eu on the chloride, f
■.\vUol iToarlvn disulpliide in glittering
»•' -h U.we a faint smell of us-tfcetida

246 THE METHYL GROUP.

ZinC'Methyl or Zinc Methide, Zn(CH3)2. This important body
was discovered, together with its homologue, zinc-ethyl, in 1849,
by Frankland.^ By this discovery our science was enriched
with a new class of bodies, not only of the highest impoi-tance
for the development of our theoretical knowledge, but also
serving as the means of preparing a number of highly interesting
carbon compounds, such as those of the alcohol radicals, with
boron, phosphorus, and silicon, the tertiary alcohols, and many
other bodies, some of which have already been described, and
many others which will be mentioned in the sequel.

Frankland obtained these zinc compounds by heating the
corresponding iodides with zinc to a temperature of 150^ and
subjecting the crystalline product of the reaction to dry dis-
tillation. In the case of methyl iodide the compound obtained
is Zn(CH3)I, and this when heated decomposes as follows :

He also found that this reaction easily takes place at 100* in
the presence of anhydrous ether, but then the ether cannot
readily be separated from the zinc-methyl. If, however, the
compound thus obtained be repeatedly heated with zinc and
methyl iodide, nearly pure zinc-methyl can be obtained.^

Butlerow, who has employed large quantities of zinc-methyl
in his researches, found it advisable to employ granulated zinc
which had previously been treated with acid. This was then
quickly dried and placed with the iodide in sealed tubes, which
were afterwards heated to 100** until the whole of the liquid
had disappeared.'

Another method for the preparation of zinc-methyl in
quantity consists in heating mercury-methyl, (CH3)2Hg, which
can be readily prepared, with a large excess of zinc for twenty-
four hours to 120V

It is, however, most readily obtained according to the process
described by Gladstone and Tribe.* These obser\*ers found that
when copper is present under certain conditions, the reaction
takes place very readily. For this purpose they make use of a

' Journ. Chem. So^. ii. 297.

* Wanklrn, Joum. Chem Soc. xiii. 124.
» ZcitKh,/. Chem. 1863, 497.

* Fmnkland and Duppa, Joum, fhnn. SW. xvii. 29.

* Joum. Cfifm. /^or. 1879. i. 107.

ZINC-METHYL. 247

"copper-zinc couple/* prepared in the following way: Thin
zinc foil, of which about 9 square dm. weigh about 2 grams, is cut
into small pieces. These are then brought into the flask which
serves for the preparation of the zinc-methyl. Eighty-four cbc.
of a solution of sulphate of copper containing 2 per cent, of the
anhydrous salt is then poured in, and in this way a spongy coating
of copper is deposited upon the zinc. The zinc sulphate formed
is then poured off, the metal washed with water, alcohol, and after-
wards with ether, and dried in a current of coal gas or hydrogen.
To this, methyl chloride is then added, and the crystalline zinc
methyl iodide is formed slowly at the ordinary temperature, but
quickly when warmed. This is then distilled in an atmosphere
of carbon dioxide, and thus pure .zinc-methyl obtained. The
same chemists have lately given a simpler method for preparing
the " copper-zinc couple." Copper oxide is reduced in a current
of hydrogen at as low a temperature as possible. One part of
the metal thus obtained is brought into a flask with 9 parts of
coarsely divided zinc filings, and the mixture, constantly shaken
and turned round, is warmed over a gas-flame until the zinc
filings begin to alter their form and become yellow. Then the
powder is once more strongly shaken, and if the experiment
succeeds the product must be a dark powder having a metallic
lustre.^

In order to prepare zinc-methyl the apparatus shown in
Fig. 66 is best employed. The flask (a) in which the mixture
is contained is always connected to a reversed condenser, the
upper end of which is placed in connection with a small bulb
apparatus containing mercury, in order to prevent the access of
air. Before the vessel is heated, the whole apparatus is filled
^vith carbon dioxide. The end of the reaction is easily ascer-
tained by no more methyl iodide running tack. The flask is
then connected with the upper end of the condenser and the
zinc-methyl distilled off and collected in a receiver filled with
carbon dioxide and shut off from the air by means of mercury.

165 Properties. — Zinc-methyl is a colovirless, mobile, strongly
refracting li([uid, boiling at 46° and having a specific gravity
at 10°-5 of 1-386. Its vapour density is 3*29 (Wanklyn). It has
^ strong disagreeable odour, and instantly takes fire when
bi:ought in contact with the air, burning with a bright greenish-
blue flame with formation of thick clouds of zinc oxide. It bums

^ Journ. Chan. Soc, 1879, i. r»»57.

248 THE METHYL GKOUP.

explosively in oxygen, and is decomposed with great violeiMs
by water with evolution of marsh gas :

Zn(CHj), + 2 H,0 := 2 CH, + ZnfOH),.

Henco it 18 necessary in the preparation to avoid the presence
of all moisture.

According to Frankland, the accidental inhalation of its vapour
produces symptoms of poisoning indicated by its powerful action

Fiu. «<.

on the nervous system. Friedel and Crafts ' also considered it
highly poisonous. On the other hand, Wanklyn and Butlerow *
state that it is not poisonous. The latter chemist ^vho, as has
been said, lias worked for a long time with tliis material, men-
tions thnt although it possesses an unpleasant smell, and for
some time exerts a disagreeable sensation in the throat, and
gives rise to dlHicuIty of breathing and violent coughing when
inhaletl, these symptoms disappear after a few hours without any
■ B^l. .Sot. Ciiiu. 1S45. ii 3.'.'. > ..^nti. CA^m. P/iann. •iliv. 8».

ZINC-METHYL. 249

visible effects remaining. By the action of methyl iodide or of
zinc-methyl iodide at a high temperature, ethane is formed :

(1) Zn J ^^8 + 2 CH3T = 2 C^H, + Ziil^.

(2) Zn I ^^"3 ^ CH3 =. C,H, -f ZnT,.

It is therefore necessary in the preparation of zinc-methyl
that an excess of metal should be present, but in spite of this
almost always some quantity of ethane, as well as of marsh gas,
is formed, inasmuch as it is impossible to obtain either the
apparatus or the material absolutely dry.

When dry air is slowly brought in contact with zinc-methyl a
crystalline mass smelling like camphor is obtained, having tho
composition Zn(CCH3)CH3. This is decomposed by water into
methyl alcohol, marsh gas, and zinc hydroxide. The same com-
pound is also formed when zinc-methyl is acted upon by a small
quantity of methyl alcohol, whilst when an excess is employed
a second solid compound, Zn{OCH3)2, is formed (Butlerow).

Iodine converts zinc-methyl first into zinc-methyl iodide,
CHjZnl, a body already mentioned, and this on further treat-
ment with iodine yields methyl iodide and zinc iodide. It has
already been stated that the formation of zinc-methyl is assisted
by the presence of ether, but that it is not possible to separate
these two bodies by fractional distillation. This is not in con-
sequence of the two substances boiling at nearly the same
temperature, but because a distinct compound of the two is
formed, having the composition 2 Zn(CH3)2 + (C.fl^)fi. Frank-
land has proved this by emj loying, instead of common ether,
methyl ether, which boils at 21°, and he thus obtained the homo-
logous compound 2 Zn(CH3)2 + (CH3>20, which boils at the
same temperature as zinc-methyl itself. Zinc-methyl readily
absorbs sulphur dioxide with formation of methyl-zinc-sulpho-
nate, (CH3.S02)2Zn, a compound examined by Hobson,^ who
described it first as zinc-methyl- dithionate. He aloo prepared
a series of other salts by double decomposition. Zinc-methyl
combines slowly with nitric oxide, giving rise to a colourless
crystalline body having the composition Zn(CH3)2(N02)2. which
oxidizes so quickly on exposure to air that it readily takes fire.
It is at once decomposed by water with formation of marsh gas,

^ Joiirn. Chrvi. Soc. x 243.

250 THE METHYL GROUP.

zinc hydroxide, and ziiic dinitromethylate, Zn{CB[3)2(Nj02)2 +
HgO, which yields, with sodium carbonate, the corresponding
sodium salt Na(CH3)N202 + HgO. This separates from its alco-
holic solution in crystals which on heating deflagrate powerfully.
The constitution of these singular bodies is not known. The
following formulae and equation may, however, probably express
their composition :

Zn(CH3)2 + 2 NO HZ CH3.Zn.O.N:N.O.CH5.
2 CH3.Zn.0.N : N.O.CH3 + 2 H^O z= Zn^Q JJ ; ^ q c&

+ 2 CH, + Zn(0H)2.

When sodium is allowed to act on an ethereal solution of
zinc-methyl, sodium methyl, NaCH3, is formed. This body
has probably not yet been obtained in the pure state. Its
existence is, however, proved by the products obtained by the
action of carbon dioxide on this substance, when heat is
evolved and sodium acetate is produced : ^

NaCHg + CO, ^ NaCO^CHj.

x66 Mercury-Mcthyl, Hg(CH3)2, was discovered by Frankland,
who obtained it by the action of light on methyl iodide in
presence of mercury, when the crystalline compound, mercury
methyl iodide, Hg(CH3)I, is formed, and this, when heated
with zinc-methyl, is converted into mercury-methyl. The same
compound is obtained by the action of zinc-methyl on mercuric
chloride, and Frankland and Duppa ^ discovered another very
simple method by which this body can be obtained in any
desired quantity. Sodium amalgam does not act upon methyl-
iodide in the cold, but if methyl acetate be added, heat is
evolved and mercury-methyl is formed :

2CH3I + HgNa, =r HgCCH^), + 2Nal.

In order to prepare it according to this method s(j<liuni amal-
gam containing one per cent, of the alkali met-xl is gradually
added to a mixture of ten volumes of methyl iodide and one
volume of methyl acetate, and the mixture shaken. In the
first instance it is necessary that this should be well-cooled, and
as soon as a sufficient quantity of sodium methyl is formed to
render the mass syrupy the volatile portion is distilled olf on a

» Wauklyn, /Vor. Hoy, Soc. (lftr»J»), x. 4. « Jomn, (.'htm, ^Vw. xvi. 41.';.

METALLIC COxMPOUNDS OF METHYL. 251

water-bath, and the amalgam again heated until no further
action takes place. The products of the reaction are then
distilled with water, and the mercury-methyl which passes over
is shaken with caustic potash in order to decompose any ethyl
acetate wliich may be present ; then washed with water, and
lastly dried over calcium chloride. The part which the ethyl
acetate plays in the reaction is not understood, it appearing to
undergo no alteration.

Mercury-methyl is a transparent liquid having a specific
gravity of 3 0C9, boiling at do"", and possessing a pecuh'ar,
rather sweetish odour, which becomes exceedingly unpleasant
on long acquaintance. It is unalterable in the air, but can
however be readily inflamed, and burns with a luminous flame,
with evolution of mercury vapours. On heating with other
metals the mercury can readily be replaced, and compounds
are thus obtained which can only with difficulty be otherwise
prepared. Unfortunately mercury-methyl is a very poison-
ous substance, and a prolonged inspiration of its vapour
produces phenomena of chronic poisoning which are afterwards
fatal

According to unpublished experiments* performed in the
Physiological Laboratory of Owens College, Dr. Gamgee has
found that, when an atmosphere saturated with mercuric
niethide is inhaled, the respiratory movelnents of both frogs
and mammals cease. The action is apparently one exerted on
the respiratory centre in the medulla oblongata. There is no
paralysis of muscles or nerves. The heart is unaffected.

Mercury-Methyl Chloride, Hg(CH3)Cl, is formed when methyl
iodide is heated with an excess of corrosive sublimate. It is
also obtained by the action of concentrated hydrochloric acid
on mercury-methyl :

Hg I gJJ* + HCl -^ Hg I gj^3 + CH,.

It forms colourless crystals, and yields, by double decomposition
with silver nitrate, the corresponding nitrate, which crystallizes
in tablets and is very soluble in water.

Mercxcry-Methyl Iodide, Hg(CH3)I, is easily obtained by the
action of methyl-iodide on mercury in the sunlight, as well as
by treating mercury -methyl in alcoholic solution with iodine :

HgiCH.,), + 1, ■'- Hg(CH,)r -f C^HJ.

252 THE METHYL GROUP.

It is soluble in water, and crystallizes in colourless tablets,
having an unpleasant smell and taste. It melts at 143°, and
volatilizes at a higher temperature. It sublimes, however, at
the ordinary temperature of the air, and when it or the chloride
is treated with moist silver oxide a solution of the hydroxide,
having a strongly alkaline reaction, is obtained.

Mcracry-Mcthyl Sulphate, {¥LgCK^^O^, is obtained in the
form of crystals, together with marsh gas, by the action of
concentrated sulphuric acid on mercury-methyl.

The solutions of all these salts yield a yellow precipitate, with
sulphide of ammonium, oi Tnercury-methyl sulphide (Frank laud.)

167 Aluminiuvi'Methyl, A1(CH3)3. By heating methyl iodide
with aluminium foil Cahours obtained a colourless liquid,
which contains iodine, and is spontaneously inflammable, and
this, when treated with zinc-methyl yielded aluminium-methyl.
The same body is obtained more simply by heating aluminium
with mercury-methyl. It is a colourless mobile liquid, crystal-
lizing a few degrees above 0° to a mass of white tablets. It
takes Are instantly on exposure to air, and is decomposed with
great violence by water. Its vapour density at 160° corresponds
nearly to the formula Al2(CH3)g ; it diminishes, however, when
the temperature is raised, and at 220'' closely corresponds to the
formula Al(CH3)8.i

Lead-Methyl, Pb(CH3)^, was obtained by Cahours ^ by acting
with methyl iodide on an alloy of lead and sodium, as well as
by the action of zinc-methyl on chloride of lead :

2PbCl2 + 2Zn(CH3)2 -^ PKCHg), + 2ZnCl^ + Pb.

According to Butlerow,* who has carefully examined this sub-
stance, it is a mobile liquid, unalterable in the air, and having
a slight smell resembling raspberries. It toils at 110°, and has
a specific gravity at O'' of 2*034, its vapour density being 9G.
Methyl is withdrawn from this substance by the action of the
haloid elements or their hydroxides, and crystalline salts of
lead-trimethyl are formed. The iodide, Pb(CH3)jI, forms h»ng
colourless needles difficultly soluble in water. When this body
is distilled with solid caustic potash the hydroxide, Pb(CH3)30H,
isobttiined as a mustard-like smelling liquid, solidifying to acute
prisms, and acting as a strong alkali (Cahours).

' Buck ton and Odling, Proc, lioy^ Soc. xiv. 19.
' Ann. Chim. Phfs. [31, Ixii. 285.
* Zriti*ch. Chrm. Pharm, 18tf3, 497.

METALLIC COMPOUNDS OP METHYL. 253

i68 Tin Tetramethyl, Sn(CH3)^, is produced when methyl iodide
is heated together with an amalgam of tin and sodium. It is
an ethereal-smelling liquid, boiling at 78°, and having a specific
gravity at 13° of 1'187.^ Its vapour density is GOO. By the ac-
tion of iodine tin trimdhyl iodide, Sn(CH3)3l, is obtained, a liquid
smelling like mustard-oil, boiling at 170°, and having at 0° a
specific gravity of 21 432. Caustic soda converts it into the
corresponding hydroxide, Sn(CH3)30H, which crystallizes in
colourless prisms, slightly soluble in water, yielding a strongly
alkaline solution, and gives rise to crystalline salts when brought
into contact with acids. It is volatile without decomposition ;
but if it is heated for some time near its boiling-point it loses

water and is converted into the oxide, O ^ o /nir^x

( Sn(CH3)2.

Tin Dimethyl or StannO'teiramethyl, Sn2(CH3)^. According to
Cahours this substance is formed in the reaction already de-
scribed together with tin tetramethyl. Ladenburg, however,
could only obtain a few drops of a liquid which was probably
this compound.

Tin Dimethyl Iodide, Sn(CH3)2l2, is formed together with
zinc trimethyl iodide when tin foil is heated with methyl iodide
to 160^ It crystallizes in yellow oblique rhombic prisms which
melt at 22°, and dissolve in water and still more readily in
alcohol. It boils at 228° and is decomposed by ammonia with
formation of the amorphous oxide Sn(CH3)20, which does not
dissolve in water but is soluble in caustic potash and yields with
acids a series of crystalline salts.

OTHER DERIVATIVES OF METHYL.

169 The methyl compounds are mono-substitution-products of
methane. If, however, two or more atoms of hydrogen in this
body be replaced, substances are obtained which may be regarded
as compounds of dyad or polyvalent radicals. Though these
belong to other groups of carbon compounds, yet they exhibit
but slight analogy with other groups and are best considered in
this place.

Dichlormethane or Methylene Dichloride, Cfl2^K* ^^ ^^^
obtained by Regnault " by acting on methyl chloride with

* Ladenburg, Ann. Chcm. Pharm. Siijipl. Btl. viiL 60.

* Ann. Chim. Phyx. Ixxi. 879.

254 THE METHYL GROUP.

chlorine in the sunlight. It was after-rards more thoroughly
examined by Perkin ^ and Butlerow.* It is not only formed ac-
cording to Regnault's procc^ss, but also by treating an alcoholic
solution of chloroform with zinc and sulphuric acid (Geuther) or
with zinc and ammonia (Richardson, Williams, Perkin) as also
by the action of chlorine on di-iodomethane.

Dichlormethane is a colourless liquid boiling at 40° possess-
ing a smell similar to that of chloroform and having a specific
gravity at 0° of 1*360 and a vapour density of 3*012. The
inhalation of its vapour produces the same effects as that of
chloroform.

Trichlobmbthane or Chloroform, CHCI3.

170 Chloroform was discovered in 1831 by Liebig,^ who ob-
tained it by the action of alkalis on chloral (trichlor^etaldehyde)
and by treating acetone and alcohol with bleaching powder.
Almost at the same time Soubeiran * obtained it by the latter of
these reactions and termed it &her bicIUoriqtie. This chemist was
considered to be the discoverer of the substance until Liebig* put
forward his claim as having first prepared the compound, although
he originally believed it to be a new chloride of carbon. It is to
Dumas^ (1834) that we owe the recognition of the fact that the
compound contains hydrogen, and the determination of its true
formula.^ Regnault then proved that it is the second substitution-
product of nielhyl chloride.

Chloroform is likewise produced by the action of bleaching-
powder on a large number of organic substances, but not on
pure methyl alcohol, sodium acetate, or methyl oxalate, as was
formerly believe<l to be the case.® (Sec Iodoform).

rreparation. — Chloroform is manufactured on the large scale
by warming an aqueous solution of bleaching powder with
alcohol. Many processes are given for its manu&cture, all of
which recommend that bleaching powder should be well stirred
up to a thin paste with water, and this then heated with strong
alcohol. A gowl yield is obtained when 10 parts of bleaching

Joum. Chem. Soc. xxii. 2fi0. ' ZeiUch, Ckem. 18(J9, 27(J.

• Pogg. Ann, xxiii. Hi ; Ann. Pharm, i. 81, 198.

* Ann Chitn. Phys. [2], xlriii. 131 ; Ann. Pharm. i. 272.

* Ann. Chem. Pharm. clxii. 161.

• Ann. Chim. Phyg. Ivi. 115 ; Ann. Pharm. xvi. 164.
' IhUL [21. Ixxi. 353.

■ BclohonWk, Wien, Akad. Htr. Ixvi. 188.

CHLOROFORM. 265

powder are rubbed up with 40 parts of hot water and 1 part of
alcohol of specific gravity 0*834 added, the temperature of the
mixture being 65°. A violent reaction then takes place, and
the larger portion of the chloroform distils over without further
heating, the rest being driven over by passing steam into the
vessel. The chloroform is then washed with water and dried
over calcium chloride, or rectified over concentrated sulphuric
acid.

Of late years a large quantity of chloroform has been ob-
tained by the action of caustic soda on chloral hydrate, which
is now prepared on a commercial scale, formic acid being
produced at the same time :

CCl3.CH(OH)2 + NaOH r= CCI3H + CHNaO^ -f H^O.

The formation of chloroform from spirit of wine cannot be
represented by means of a simple equation. Bleaching powder
acts upon this substance both as a chlorinating and as an
oxidizing agent. The mass froths strongly from evolution of
carbon dioxide, and for this reason large vessels have to be used
in its preparation. The following ec^uation serves fairly to
represent the principal reaction that takes place in the conver-
sion of the alcohol into chloroform :

3 CgH^O + 8 Ca(0Cl)2 = 2 CHCI3 + 30aC03 + COg

+ 8 H2O -f 5 CaCl^.

171 Properties. — Ciiloroform is a colourless mobile liquid,
possessing a peculiar ethereal smell and a burning taste. It
boils at 61** (Liebig, Regnault), and has a specific gravity at 0° of
1'5252. Its vapour density was determined by Dumas to be
4*20. Chloroform is almost insoluble in water, but is miscible
in all proportions with ether, alcohol, and other organic liquids.
It rejvdily dissolves phosphonis, bromine, iodine, and many
organic substances. For this reason it is employed in analytical
processes, as well as in the preparation and purification of a large
number of compounds. It is not inflammable, but colours the
non-luminous flame green, and an alcoholic solution bums with
a smoky flame, evolving fumes of hydrochloric acid.

This discovery of the amesthetic properties of chloroform was
made by Sir James Simpson of Edinburgh in 1848,^ and since

* " All. 'esthetic and other Therapeutical Effects of the Inhalatiou of Chloro-
form," £diiir. Monthhj Jouni, of Med. Science, viii. 41.'>.

266 THE METHYL GROUP.

that time the inhalation of the vapour of chloroform has been
largely practised for the purpose of procuring insensibility to
pain in the case of surgical operations. Chloroform is likewise
used as a medicine.

Chloroform used for medicinal purposes must, of course, be
pure, and this is often not the case with the commercial article.
It sometimes contains hydrochloric acid, and even free chlorine ;
the presence of both of these can be detected by the action of
such impure chloroform upon litmus, as well as by the fact that it
renders silver nitrate solution turbid, whilst the pure substance
does not do so. If a cold solution of potassium dichromate
in dilute sulphuric acid be coloured green by chloroform, the
presence of alcohol or other easily oxidizable bodies is indicated.
Pure chloroform is not coloured brown either by caustic potash
or by sulphuric acid. It does not attack bright metallic sodium
even at the boiling point, and if this metal should, under these
circumstances, become covered with a white coating of chloride,
the presence of other chlorine compounds, such as dichlorethane
or ethylene dichloride, may be presumed. These same im-
purities may also be recognised, inasmuch as when heated with
alcoholic potash the impure chloroform evolves a combustible
gas, viz. ethylene. When chloroform is evaporated on a watch-
glass without warming it or blowing air upon it, it ought not
to leave a residue either of water or of bodies possessing a strong
smell. Should the latter be found to be the case, the chlorofonn
has been prepared from alcohol containing fusel oil.

It has already been stated that monamines can easily be
detected by the help of chloroform (p. 162). So inversely the
latter compounds may be employed for the detection of small
quantities of chloroform. As the most easily obtainable amine,
aniline is used for this purpose ; a few drops of this liquid being
heated with the substance under investigation together with
alcoholic caustic soda solution. The characteristic smell of
carbamine is observed, according to Hofmann, in solution con-
taining one part of chloroform to 6,000 parts of water.

Chloroform undergoes a series of decompositions which will
be described under the corresponding bodies, only a few of the
more important being mentioned :

(1) When heated with concentrated sulphuric acid and
potassium bichromate, carbonyl chloride, COClg (see Vol. I.,
p. 621) is formed.

(2) When heated with alkalis chloroform is converted into

TETRACHLORMFniANE. -257

formic acid, and for this reason it was tbrmerly termed formyl
chloride :

CHCi, + 4 KOH = CHO.OK + 3 KCl + 2H2O.

(3) Wlien heated with alcoholic ammonia, ammonium cyanide
is formed :

CHCl, + 6NH3 = ON(NH,) + 3 NH.Cl ;

(4) On treatment with bromine, brom-chloroform, CBrClg,
is produced as a colourless li([uid boiling at 104*', which has a
specific gravity at 0° of 2060 (Paterno, Frie<lel, Silva).

17a TetraMcrmdhane or Carbon Tetrachloride, CCl^. This
compound, the final product of the chlorination of niarsli gas, wiis
discovered by Regnault^ in 1839, .and obtaincnl by the action of
chlorine on chloroform in the sunlight. It is also fonned when
a mixture of carbon disiilphide and chloroform is passed through
a porcelain tube filled with pieces of porcelain heated to redness.^
It is best prepared by acting with chlorine gas on a boiling
mixture of sulphide of carbon containing some antimony penta-
chloride, the latter compound serving fis a carrier of I'hlorine.
The liquid is then distilled, and the portion boiling under lOO**
separated and treated witli boiling caustic potash in ortler to
remove chloride of silver, trichloride of antimony, and undecom-
posed carbon bisulphide.' Tetrachlormethanc^ is also formed
when chloroform is heated with chloride of io<line to 160** — 170°
(Hpfmann).

It is a colourless liquid boiling at 78", having a specific gravity
at 0** of 1*6298, and possessing a smell similar to that of chloro-
form. Its vapour has a density of 5*24 (Kolbe).

Dibrommethane or Methcne Dihromidr. CH.,Br.„ is formed
by the action of bromine on the corresponding io<lidc, and
together with tribrommethnne by acting with bromine on
methyl bromide for some hours at a temperature of 150°. It
is a liquid which boils at 80''-82'* and at ll°r) has a specific
gravity of 2*0844,* its vapour density Ix'in/ .") 0.") (Steiner).

173 Tribrommethanc or Bromoform, CHBra. This compound
was discovered by Lowig,^ in 1832, who prepared it by de-
composing bromal (tribrom-acetaldehyde) witli aqueous alkalis.

* v^wn. Chim, Phys. Ixxi. 377. ' K«»Hx', ,//*//. Chcm. Phann.\\y. 41 ,
' Hofmann, Chan. Soc. Juuni. xiii. &2.

* Steiner, Ber, Deufsch. Vhrm. Or^. vii. 507.
^ Ann. Phami. iii. 29.1.

VOL. III. 8

258 THE METHYL GROUP.

Lowig considered it to be a bromide of carbon, but Dumas *
ascertained its true composition, and obtained it by the action
of bromide lime upon spirit of wine, or on acetone. It is also
produced when bromine is added to alcohol, or better, when
bromine is poured into an alcoholic solution of caustic potash.
It is likewise found in crude bromine.^ Bromoform smells
and tastes like chloroform; it boils at 149°-150'', and has a
specific gravity at l^'^'b of 2775,* and a vapour density of
8-63 (Cahours).

Tetrab7'07nmethane 07* Carbon Tetrahromide, CBr^, was discovered
by Bojus and Gi oves * and is formed by heating carbon disulphide,
bromoform, iodoform or bromopicrin with bromine in presence
of bromide of iodine or certain metallic bromides.

In order to prepare it, 2 parts of carbon bisulphide, 14 parts
of bromine and 3 parts of iodine, are placed in a sealed tube and
heated for 48 hours to a temperature of 250'', and then the
contents of the tube distilled with caustic soda. When water
is added to a mixture of bromoform and bromine, tetrabrom-
methane is also fonned on exposing the mixture to daylight;
but the reaction only takes place slowly, whereas if some
caustic soda be added, it proceeds much more rapidly, inasmuch
as the hydrobromic acid formed is at once neutralized.^

It crystallizes from hot alcohol in white glistening tablets,
which have a sweetish taste, and an ethereal smell. It has a
specific gravity at 14° of 3*42, fuses at 91°, and boils with
partial decomposition at 189*''5. It may, however, be sublimed
without change by careful heating.

174 Di-iodomctlmne or Methylene Di-iodUley CHgIg, was first
prepared by Butlerow ® by acting on sodium ethylate with
iodoform. This chemist showed that the body formerly ob-
tained by Brlining by the action of iodoform on caustic potash
is identical with this compound. It is also formed when
chloroform is brought in contact with concentrated hydriodic
acid : "

CHCls + 4 HI = CHjIj + 3 HCl + I^.

This bcxly, wliich is used for the preparation of several other

» Ann. Chim. Phy$. [2], Ivi. I'JO.

^ Hermann, ^mji. Ch-m, Phann, xcv. 211.

3 Sclimidt, Ber. DeuOtch, CKem, Oea. x. 193.

* Chcm, Soc. Jonrn. xxiii. 164, 161 ; xxiv. 773.

* Habermann, Ber. Drutsch. Chftn, Otn. vi. 549.

* Ann. Chem. Pharm, cvii. 110; cxi. 242.

" Lwb«n, ZfUiith. Chem. 1868, 712 ; BIjuducho. Ibid. 1S71. 258.

lODOFOR^r. 259

compounds, is, however, best obtained by the following method
proposed by Baeyer.* An upright condenser is fixed to a liter
flask by means of a wide tube, the upper end of which is
connected with a T-tube, so that the materials can be brought
in by the one limb whilst the hydriodic acid formed can escape
by the other. 200 grams of hydriodic acid, having a boiling
point of 12T*, are brought into the flask, and to this 50 grams
of iodoform are added, and the mixture is then heated to the
boiling point, and phosphorus added little by little until no
further evolution of iodine takes place. Then 100 grams of
iodoform and the necessary quantity of phosphorus are
added alternately. The formation of the di-iodomethane is ex-'
plained by the following reaction :

CHI3 + HI = CH^Ig + Ig.

Di-iodomethane is a yellowish strongly refracting liquid, boiling
with partial decomposition, at 181°, solidifying to glistening
tablets at 2°, and possessing a specific gravity at 5** of 3*342.

175 Tri'iodmnethane or Iodoform , CHI3. This compound
was discovered by Serullas^ in 1822 and termed by him
** carbide d*iode." It is to Dumas^ that we are indebted for first
pointing out that this compound contains hydrogen. There is
no substance in which the hydrogen can be so readily overlooked
as in this, for iodoform of all known compounds contains the
relatively smallest quantity of this element, namely 0*26 per
cent

Iodoform is formed by the action of iodine upon alcohol in
presence of the caustic alkalis or their carbonates. Instead of
alcohol a number of other substances may be used ; these will
be mentioned hereafter. A number of processes are given for its
preparation ; the following, recommended by Filhol,* is usually
employed. Two parts of crystallized carbonate of soda are
dissolved in ten parts of water, one part of alcohol poured into
the solution, and then one part of iodine gradually added to
the liquid heated to 60°-80*', when iodoform gradually begins to
separate out. The liquid is filtered, and the above mentioned
(juantity of carbonate of soda again added to the filtrate heated
to 80**. Chlorine is then passed into the liquid, which is shaken
from time to time, the object being to decompose the iodide of

* Ber, Deutsch. Chein. Oes. v. 1094.

* Ann. Chim, Phys. [2], xx. 165 ; xxii. J 72 ; xxv. 311 ; xxxix. 230.
» lUd, IvL 122. ♦ Journ, Pharm. vii. 267.

S 2

i*'*i» TIIK MKTITYL GROUP.

SiVili\nn wliirli i> t^viuiNi. :uui to obtain the iodine in a £>e!r
t)i\i.liul ^t•)(r Wlu^n no more iodoform separates am
current o\' ihlovnto im Mopixni, tlio liquid allowed to
it Invonu's roIo\itIrss. i\\\\\ thou, on cooling, theiodofonn
ou a tilUT iuul \\it^)uHi with oold water.

A gi^Hl vioKl is aiNo oht-ainod by warming toge^sba Hat
follow iui^ oonsiittionijt until tito liquid becomes
i^^line. S:2 ]vu'ts; iH^tJiMsiutn oarUmato, 32 parts; 95
al'/obol. li»)vii*t.s; Avatvi S() f^vrt.s. The liquid is then pooTBd
off from thi* iiviot'onn whioh is (io)H)sited, and the foUowixig is
cviJcJ to tholiqniii: )>otjuss\nm diohromate 2 to 3 parts^ hjdio-
c:.joric aoivl li» to l*i |vut,s. This 8t>rves to decompose the
irjhkZf: and iinliilo nnd to liln^nUo iinline. The whole is then
r.ei:r:Jizeil hv tho !ul«liiiou of :i2 {kuI.s of carbonate of soda» 6
j/^r.i: '.f i«:Klino, and \k\ \M\\'ts of* ahnthol. the liquid again panned
/ff from the iixlofonn. and thcst' o|>oralions repeated until the
.>^'iid contaius tint hu^o a ipiantitv of salt in solution.^ The
f'/nfiAiiun of iiHlofonn is i\'j«\»si»nt4Hl hv the following equation:

rif,CH^0H + 4L^ i\K.n\ iMn, + OHKO, + 5KI + 5H,0.

In luJditiuu to this. oXhvY jmnhtits ai\» fonneil, such as potas-
^ilirfJ i<i<Iate. acetic ethrr. Ac.

I'>iof<»nn is insoluble in water. b\it dissolves readily in alcohol,
'TVbtallizing from this menstni urn in largi* lemon-yellow bright
hix-isided tables whieh melt at XW^' and sublime when strongly
Le:jite<l. undergoini; {Kirtial iiei*onq>osition with formation of iodine
\ajxjurK. It may, howtxrr, Ih» volatiliziHl without decomposition
iji u current of steam. It (Htssessi's a si)tVron-like smell, and a
hv.<-i.-t t*»st4.\ In the ywYv state* it diH»s not \uulergo alteration on
<-x|><iMire to ii^lit. but its s«>hition in bisulphide of carbon is ex-
cessively sensitive to hj^ht, quirk ly lHH*t>ming iH>loured violet
owiij;^: to sejianitiou n( free imline.-

It has alreadv been mentioned that manv other bodies, in
addition to aleohol, yield iodofi»rm. Amongst the simpler of
thes<*, ethyl ether an<l jicetic acid have fn^quently been classed.
Liebeu,^ in a very complete series of exiHTiments, has, how-
ever, shown that these substam-es, if perfectly pure, do not
vield the slightest trace of iinlofonu. On the other hand, the
nonnal primary and si'Condary alcohi»l9as well as their aldehydes

> I'hnnn. Jouni. Trans. [rJ], iv. riS»3.

- HuTnln-rt, ./. urn, I'nann. Chim, |.M], x\ix. S.'2.

' yimi. f%t". P/i(i -i'l, Su|»|il vii. '.M^ ami o77.

NITROCHLOROFORM OR CHLOROPICRIN. 261

and ketones all yield iodoform, but their isomerides do not
Hence the formation of iodoform serves as an excellent means
in many cases for ascertaining the purity of these bodies, and
also as a test for their presence even in very small traces.
Thus, for example, if water containing only T^nnr^^ P*"^ ^^ alcohol
be gently warmed with crystals of iodine, and then caustic soda
added, and the liquid allowed to stand for some time, a distinct
precipitate is observed, and this when examined under a micro-
scope exhibits the six-sided tablets or stellar crystals characteristic
of iodoform.

Iodoform possesses anaesthetic properties, acting especially on
the muscles. It is used as a medicine and has been employed for
outw^ard application, especially in cases of cancer.

Chloriodoform, CHIClg, is a yellow oily liquid, boiling at 131*,
obtained by heating iodoform with the chlorides of lead, mercury
or tin.

Tetra-iodomethane ar Carhmi Tetra-iodide, CI^, was obtained
by Gustavson ^ by acting on aluminium iodide with tetrachlor-
methane in presence of carbon disulphide. It crystallizes in
large regular octohedroDs, which decompose slowly in the air
at the ordinary temperature, but quickly at 100°, into iodine
and carbon.

176 CMoniUrom^thave, CH2C1(N02). To prepare this com-
pound, sodium nitromethane is brought in small quantities into
saturated chlorine water, and when no further action takes place
the mixture is distilled. It is a colourless oily liquid, having
a penetrating smell, boiling at 122°-123°, and possessing a
specific gravity at 16° of 1*466. It easily dissolves in alkalis,
and gives the nitrolic acid reaction like other primary nitro-
compounds (see p. 171).*

177 Tricldoi'nitroTrutlmiie, Nitrochlorofoi-^n, or Chloropicrin,
CCl^{l!^0^, was discovered by Stenhouse,* who obtained it by
distilling an aqueous solution of picric acid (trinitrophenol),
CgH2(N02)s.OH, with bleaching powder. Its correct composition
was first recognised by Gerhardt.* Chloropicrin is also formed
by a similar reaction from many other aromatic nitro-compounds,
and may also be prepared as Geisse ^ has shown, by the following
reactions :

' Coinpt. Reiid. Ixxviii. 882.

- Tschemiak, Ber. Dcutsch. CJum. (Jes. viii. 608,

3 PhU, Maq. [3], xxxiii. 53.

< Compt. Rend Trav. Chivi. 1859, 34.

' Ann. CJirm, Pliann, cix. 282.

'ic,t THE METHYL GROUP.

{\) Cyhloral (trichlordcctaldehyde) is distilled with fuming
iiiiri<; a<'i(l :

i)i\yA)\\ + 3HO.N02= CCIjCNO,) + 2H,0 + CO,+N,0,.

it) Methyl alcohol is heated with nitre, common salt, and
Mil|iliiiri<; acid :

i\\\j^)\\ + NO^OII + 201^ = CClaCNO^ + 2H,0+HCL

(\\) Alroliol and <'ommon salt are distilled with nitric acid. .
It JK likowiw; obUiiucd, though with greater difficulty, by
iH'utiiig ('hloi'oforiii with concentrated nitric acid :^

(;ilC:i, 4- NO^-OH - C(N02)Cl3 + H,0.

Ai'^/idiii^ \m ilofiiiann''' the following is a useful method of
|^i<r|Miiiii.ioii : ."»() kilos of freshly-prepared bleaching-powder are
uk\i^i'A to It thirk |>iiHto with cold water and placed in a still
teiiiii/iiii<|i'<l l»y cold water. To this, a saturated solution of
\it kilo.i of |)icri(: lU'id heated to 30"" is added. After a few
wwwwVi-^ ii violnit rcfu'tion tiikos place, and the greater part of
\\\i: « liloio|iiriiii iliMtilH «»vi!r. The remainder is driven oflF by
li'Mitiiipf thn nlill

riiloiopii'iiii JN a mobile liquid, boiling at 113^ having a
blHriiir ^mvily ol' I (l(ir»7, and possessing a very penetrating
MiiH'll ii'ioiiibliii^^ that of chloride of cyanogen. Its vapour
iM'i.i |H»woi fully oil ihn fyoH and mucous membranes, but the
iiritiition ilocM not Inst lon^. IIeate<l in tlie form of vapour it
(Icconi|Hm('H with explosion. It is insoluble in alkalis, and is
not atUicki'il by Hulplmric or nitric acid even when boiled.
When treaU^d with iron filings and acetic acid it is converted
into methylamine :

CCIjCNOJ \- 6Hj = (JHjCNH.^ + 3 HCl 4- 2H2O.

Heated with ammonia under pressure it yields guanidine*
(Vol. I. p. G80) :

C(N02)Cl3 + 7 NH3 - CXNH)(NH2)2 4- 3 NH.Cl + 2 Hp + >%.

Dichlordinitrometluinc, ^^^(NOj)^, was di.'^covered by Mari-
gnac,* who obtained it by distilling naphthalene tetrachloride,

' Mills, Joum, Chem. Sor, xxiv. 641 ; Coma, Gas. Chim. Ital. 1872, 181.

' Chem, Sor. Joum, xix. 249.

' Hofriiano, B^r. Dfu'srh. f'hew. ^V« i. I4f>.

* Jjin. '"hr.ii. rhnrm. xxxviii. 14.

TRINITROMETHANE OR NITROFORM. 263

Cj^HgCl^, with concentrated nitric acid, and hence it was
formerly known as " Marignac's oil." It is a colourless liquid,
smelling like chloropicrin, and having a specific gravity at 16°
of 1'685. It is easily volatilized in a current of steam.

Manobramnitromethane, CH2Br(N02), is formed by the action
of bromine on sodium-nitromethane. It is a colourless, very
strongly-smelling liquid, boiling at 146°-14T', and is soluble in
alkalis.

Dibromnitromethaiiey CHBr2(N02), is obtained by the action of
bromine upon a freshly-prepared solution of the foregoing com-
pound. It is an oily, strongly-smelling liquid, which decomposes
on distillation, and possesses acid properties.'

Tribromnitromethane or Broinopia^in, CBr3(N02), was obtained
by Stenhouse ^ by distilling a solution of picric acid with bromide
of lime. It is also formed when nitro-methane is treated alter-
nately with bromine and caustic potash.* It is a liquid closely
resembling chloropicrin, and when strongly cooled forms prismatic
crystals, melting at 10*''25. Its specific gravity at 12°*5 is 2*811.
It may be distilled in a vacuum without decomposition, but
decomposes even when carefully warmed under the ordinary
circumstances with formation of tetrabrommethane, carbon
dioxide, the oxides of nitrogen, and other bodies.*

Chlordibromnitromethane, CClBr2(N02), is obtained when
chlomitromethane is dissolved in caustic potash and bromine
added. It is a liquid possessing a similar smell to chloropicrin,
having at 15° a specific gravity of 2421, and being volatile in
a current of steam .^

178 Trinitrom^tliaiu or Nitroform, CH(N03)2, was discovered
by Schischkoff^ in 1857, who prepared it by heating trinitro-
acetonitril with water. This substance dissolves with violent
evolution of carbon dioxide, and the yellow solution contains
the ammonium salt of trinitromethane :

{ CN ^"^^ + 2 H2O = C(N02)3NH, 4- CO2.

Under certain conditions, which are not well understood, this
action of water on trinitroacetonitril may be accompanied by

^ Tschei'uiak, Bet. DeuUtch. Ckem, Gis. vii. 916.

- Phil. Mag, [4], viii. 36.

' V. Meyer, Bcr, DetUsch, Cliem. Ges. \aii. 816.

* Bolas and Groves, Jaum. Ckcm. Soc. xxiii. 153 ; xxiv. 773,

^ Tscherniak, Bcr. Dctctuch. Chon. Gca. viii. 608.

^' Ann. Chm. Phorm. ri. 213 ; riii. 364 : rxix. 247.

fM THE HETHYL GKOUP.

leriofu expktfknuL^ On eTipondon ihe sah sepumtes oat in
jellow moDoduiic prisms. If dihite caosde potaaii be used
instead of vater, the jellow ciTBtaDine polaainm ttlt is ob-
tained ; and if solphmic add be added to anj of these salfts*
nitrofbrm separates oat in a liquid lajer, which on coding
stdidifies to a mass of laige obliqae crjrstalsu It has a bitter
taste and disagreeable 8ii»ell, is t^t inflammable, and when
wanned begins to decompose under IWf with rapid eTolation
of gas, exploding violendy when qoicklj heated. Its yellow
salts are also eTflotive, and frequently decompose spcxitaneously
with evolution of ga&

When a mixture of nitroform and bromine is exposed to sun-
light, bromnitro/orm, C(NO,)^r, is formed as a colourless liquid,
which crystallixes at 12^ and is decomposed at 140^ but may be
▼olatiliied in a current of steam.

Tetmniiromethane, C(SO^^, is formed when a continuous
current of air is passed through a mixture of nitroform, con-
centrated sulphuric add, and nitric add heated to 100^ On
addition of water to the distiUate, this compound separates uiit
as a colourless mobile liquid, which crystallizes at 13^, boils at
12(r, and is neither explosive nor inflammable. If, however, it
be dropped on to glowing charcoal it bums with a bright flash.

179 Metheru Digulphonic Acid, CH^(SOJS)^ This compound,
which was formerly called methionic acid, was first prepared by
Licbig,^ together with other products, by the action of sulphur
trioxide on ether. Buckton and Hofmann' obtained it by
treating acetonitrii (methyl cyanide) with concentrated sulphuric
add, acetic add, carbon dioxide and ammonia being formed
at the same time. It may also be obtained from sulphoaceUc
acid, acetamide, and lactic add, and also by heating chloroform
with a solution of potassium sulphite.^ In this case, methene
dichloride is first formed, which is then converted into potassium
methene dinulphonate :

(a) 2 CHCl, + 3 K^SO, + H,0 = 2 CH.a, + 2 K,SO^ + 2KC1 + SO^

{h) CH,a, + 2 K^, := CH,(SO,K), + 2 KCl. /

The free acid is best prepared by the action of sulphuretted hy-
drogen on an aqueous solution of the lead salt. On evaporation

' V. Meyer, Ber, DeulsrA. Chfm. Ges. vii. 1744.

* Ann, rharm. xiii. 85.

* nkem Sor. Joitrn. iz. 241.

* Stn'ckfT, Ann, Chem. Pharm. cxlviii. 00.

METHINE TRISULPHONIC ACID. 265

in a vacuum it may be obtained in the form of a deliquescent
striated crystalline mass. It is a very strong acid, and forms a
series of well crystallizable salts.

Methine Triaulphonic Add, CH(S03H)3, is formed when dry
calcium methyl sulphate is heated to 100'' with a large excess of
fuming sulphuric acid. The free acid is obtained by decompos-
ing the lead salt with sulphuretted hydrogen; it forms long
deliquescent colourless needles, and is a tribasic acid. It decom-
poses chlorides and nitrates, and forms well crystallizable salts.

Fbtasaium Methine Trisulphoriate, CH(S03K)3, crystallizes in
small hard glistening prisms, and is formed when chloropicrin is
heated with a concentrated solution of potassium sulphite. As
an intermediate product potassium nitro-methene distdphancUe,
CH(N02)(S03K)2 is formed as a crystalline slightly soluble
powder which deflagrates on heating.^

Barium Methine Trisulphonate, [CH(S03)3]2Ba3, crystallizes
from boiling water in glistening tablets. Its solution throws
down the insoluble lead salt from a solution of acetate of lead.^

Methyl-mercaptan Trisulphonic Add, C(S03H)3SH. If bi-
sulphide of carbon be treated with manganese dioxide and
hydrochloric acid, a reaction takes place which becomes more
rapid on the addition of a small quantity of iodine ; and besides
thiocarbonyl chloride, CSClg, and trichlor-methyl sulphonic
chloride, CClg-SOgCl, the compound, percMar-methyl mercap-
tan, CCI3.SCI, is fonned. This latter compound is a golden
yellow, very powerfully-smelling liquid, boiling at from 146'' to
147°.* It acts on an aqueous solution of potassium sulphite
giving rise to the salt C(S03K)3SH, which forms large, hard,
colourless triclinic crystals. The same salt is formed by the
action of potassium sulphite on thiocarbonyl chloride :

CSClj -f 3 K2SO3 -f H2O = C(S03K)3SH 4- 2 KCl + KOH.

It gives a white precipitate with basic lead acetate, from
which the free acid can be obtained by treatment with sul-
phuretted hydrogen. In a concentrated state this forms a
thick very deliquescent ayrup. Its dilute solution gives a deep
blue coloration with ferric chloride. The free acid and its
salts are readily decomposed in presence of water, with forma-
tion of sulphuric acid and viethyl-mcrcaptan-disulphonic acid,

' Kuthke, Ann, Cfum. Pfiaj^n. clxi. 149 ; clxvii. 219.
- Thcilkuhl, Ann. Chem. Pharm. cxlvii. 134.
^ Ratlike, Bcr. Dcutsch. Chnn. Gcs. iii. 858.

206 THE FORMYL GROUP.

CH(S03H),SH. This forms crystallizable salts, and is a dibasic
acid. The hydrogea which is combined with the sulphur can,
however, be replaced by metals possessing a strong aflSnity for
sulphur, such as lead. This is not the case with the trisul-
phonic acid. By the action of nitric acid on the potassium
salt of the latter compound potassium methyl oxytrisulphonate,
C(S08K)30H, is formed, crystallizing in strongly refracting
monoclinic prisms. The free acid is a deliquescent mass, and
the salts crystallize well.'

THE FORMYL GROUP.

Formic Aldehyde, COHg.

i8o This interesting body may be regarded as the aldehyde
and ketone of formic acid, or as the oxide of the dyad radical
methene. Many attempts to prepare this substance have been
unsuccessfully made, inasmuch as the oxidizing agents usually
employed for the preparation of aldehydes yield at once formic
acid. Hofmann was the first, in 1867, to succeed in pre-
paring the substance by passing the vapour of methyl alcohol
together with air over ignited platinum. For this purpose he
employed the following apparatus. A three-necked flask of
about two liters capacity is filled about five cm. high with
warm methyl alcohol. One of the necks of tlie flask is
furnished with a cork, and a tube which passes to the surface
of the liquid. The other necks are furnished with open glass
tubes ; the middle one carries a spiral of platinum wire fastened
to a loosely-fitting cork, the spiral being brought nearly to the
surface of the methyl alcohol. The third opening is connecte<l
with the upper end of the condenser, the lower end of which is
fastened into a two-necked receiver; this receiver is in its turn
connecteil with a series of wash-bottles, and the last of these
communicates with a water-jet aspirator, by which a rapid current
of air can be dniwn through the whole system. The platinum
spinil is next heated and lowered into the bottle, when the
flameless combustion of the methyl alcohol begins to manifest
itself by the evolution of vapour powerfully affecting the nose
and eyes. Gradually the tempeniture of the apparatus rises
and drops of a colourless lic^uid are soon rondeiised in the

' Albrorht, .luii. Chem. Vhnmi. dxi. 12i». - /V^-. /»W. Sf*>'. wi. l.'.t;.

FORMrC ALDEHYDE. 267

-, anil if the apj^ratus be properly constructed a solution
of aldehyde in dilute methyl aIc;)hol is obtained
whilst the portion which is not collected here
passes into the wash-bottles. At the begoinnig
of tiie experiment a sharp explosion sometimes
takes place, which drives the cork with the
spiial out of the bottle. In order to prevent
this, an improved apparatus has been su^ested
by Volhard.' This consists of a Davy's glow-
lamp shown in Fig. 67, tilled with methyl
alcohol, over which a funnel is placed connected
with a condenser as before. A stream of air
can now be regulated so that the ignition of the platinum
spiral is not visible in the daylight.

The solution of aldehyde, prepared by one or other of these
means, only contains about 1 per cent, of formic aldeliyde. In
order to prepare a more concentrated solution, a regulated
mixture of air and methyl alcohol vapour is passed through a
tolerably wide platinum tube contiiiuing a bundle of iiue
platinum wires. By gently heating this, a current of formic
aldehyde is obtained. This can be condensed to a liquid, which
however does not contain more than 5 per cent, of aldehyde ;
biit this apparatus when in proper action may be kept going
for several months without intermission. If the methyl alcohol
be driven out of the solution by distillation a certain amount of
aldehyde passes over with it. A better plan is to expose the
residual liqiiid repeatedly to a freezing mixture, the ice formed
being each time removed ; the residual liquid contains 10 per
cent of formic aldeliydc.^

A solution of formic aldehyde possesses a very penetrating
smell, and when warmed with ammoniitcal silver solution, a
mirror-like deposit of metallic silver is formed. Ammonium
formate is in this case produced. Up to the present time the
separation of the aldehyde from its solution has not proved
possible. If it be evaporated in a vacuum over sulphuric acid,
part of the aldehyde passes into the state of vapour with the
water, whilst another portion assumes a polymeric modification.'
i8i Para/ormaldekyde, C^H^Og, has been known for some
time, and was first obtaineii by Butlerow,* by acting on silver

' Ann. Clicm. ri'a.ui. clixvi. 128.

' Hofmann, Ber. PriiMi. Vhcm. 6rv. li. 1GS.1. ^ Ihi't. ii. 153

268 THE FORMYL GROUP.

oxalate with methene di-iodide, and was described as dioxy-
methylene:

3 CHjI, + 3 AggCgO, = CjH^Og + 6 Agl + 3 CO^ + 3 CO.

This substance is, however, best prepared by heating glycollic
acid with sulphuric acid to 160**, when it sublimes:

3 CH,(OH)CO.OH - 3 CjHeOg + 3 CO + 3 H^O.

Paraformaldehyde is a white indistinctly crystalline body,
which is insoluble in water, alcohol, and ether. It possesses no
smell and sublimes at 100^ melting, however, at 152^. Heated
more strongly it dissociates into three molecules of formic alde-
hyde, the irritating smell of the gas being at once perceived.
If this gas be collected over mercury and allowed to cool, it
gradually disappears with formation of the trimolecular form.

Wheu paraformaldehyde is heated with much water in a
closed tube to 130''-150'' it enters into solution again, splitting
up into the simpler molecule. This solution does not under-
go change in absence of air, probably because the aldehyde
is combined with water, methylene alcohol, CHjCOH),, being
formed.

Farathioformaldehyde, CgH^Sg, was first described by Girard,^
who obtained it by the action of nascent hydrogen on carbon
disulphide. It has likewise been prepared by heating methene
di-iodide with sodium sulphide,' as well as by treating the
solution of formaldehyde or the para-compound with sul-
phuretted hydrogen, and then heating with hydrochloric acid.
It is also formed by treating thiocjranic acid with nascent
hydrogen : *

CH,

3SCNH + 6Hj = I I 4- 3NH,.

ILC CH,

This compound crystallizes in a shining white crystalline mass
which melts at 216°. It combines with silver nitrate to form
the crystalline compounds C,HjSj + AgNO, and CgH^S, +
SAgNO,, whilst with platinic chloride it forms yellow needles
of 2 CjHeS, + PtCl^.

* Comjifn/ Jlf-ndusy xliii. 306. ' Iliujciiiaiin, Ann. Chem. Pharm, cxxri. 201.

3 Ilijfniunu, ZciUch. Chcm, [2], iv. 689.

FORMIC ACID. 269

FORMIC ACID,

x8a In the sixteenth century Brunfels, and at the beginning
of the seventeenth Baukin, noticed that red ants have the
power of emitting an acid liquid which turns vegetable blue
colours red. Formic acid was first obtained by John Ray
in 1670, by distilling red ants, and he observed that this
substance has the power of forming with white lead a kind
of sugar of lead, which, like ordinary sugar of lead, pos-
sesses an astringent taste. Hence he concluded that the acid
in question is similar to acetic acid.^ About the same time
a German chemist, Samuel Fischer, is said to have pre-
pared formic acid. These observations were confirmed by
Hiame, Homberg, and Marggraf, the latter of whom found that
this acid does not precipitate the salts of silver, lead and
mercury, or nitrate of lime, and he adds that this shows that it
is neither hydrochloric acid nor vitriolic acid. Calx of silver
however dissolves in it, and calx of mercury on being warmed
with it yields metallic mercury.^ From this time forward, the
acid compound obtained from ants was looked upon as a
peculiar acid. Arvedson and Oehm described the acid and its
salts more exactly in a Dissertatio de addoformicarum in 1777,
but even in 1802 it was stated by Fourcroy and Vauquelin ithat
it was simply a mixture of acetic acid and malic acid. This
statement was however contradicted by Suersen in 1805 and by
Gehlenin 1810.

In addition to its occurrence in ants, this acid is also found in
bodies of a caterpillar {Boinhyx processionea), in common stinging
nettles, in the fruit of the soapnut-tree (Sapindtis saponaria), in
tamarinds, and in shoots of various pines. It also occurs in small
quantity in various animal liquids, as sweat, urine, the juice of
muscle, &c. It is remarkable that this substance occurs together
with other fatty acids in the putrefaction of diabetic urine, and
that it occurs together witli acetic Jicid and other homologues in
small quantities in various natural mineral waters. It is likewise
produced in the dry distillation of various organic substances,
as well as by the oxidation of a large number of such bodies.

In his investigation on manganese in 1774 Scheele remarks

» Phil. Trans. 1670, Jan. 13. * Bfriiu Akad. 1749.

♦270 THE FORMYL GROUP.

that when a mixture of this substance and sulphuric acid is
Iieated with sugar or gum an acid vapour is evolved which when
<'ollected in a receiver turns out to be vinegar. Westrumb then
mentions in 1785 that acetic acid is produced by the dephlo-
gistication of tartaric acid by means of oxide of manganese,
upon which Dobereiner in 1822 showed that the acid produced
in this reaction is really formic acid. This observation gave rise
to the process for its artificial production.

Starch was found to be the best material for the preparation
of this acid, and, according to Liebig's receipt, 100 parts of
starch, 370 parts of finely-divided oxide of manganese, and 300
parts of water are mixed together, and 300 parts of concen-
trated sulphuric acid added to the mixture whilst it is being
stirred. By careful distillation the strongly frothing mixture
yields about 33o parts of dilute formic acid, of which 100 parts
saturate 15 parts of dry carbonate of sodium. This method, how-
ever, as well as other similar processes are now no longer used,
formic acid being always prepared from oxalic acid, which, when
heated, splits up directly into carbon dioxide and formic acid :

Gfifi, = CO, + CHjO^

Gerhardt found that, when oxalic acid is mixed with fine
quartz sand, a better yield of formic acid is obtained, but even
in this case, and especially when the oxalic acid is heated
alone, a large quantity of oxalic acid passes over undecom-
posed, whilst a part of the formic acid decomposes with
formation of carbon monoxide and water. On the other hand,
the above reaction takes place much more completely if the
oxalic acid be carefully heated with glycerin. On this observa-
tion Berthelot has founded a method which now has come into
general use for the preparation of formic acid, the details of the
process having been carefully worked out by Lorin. According
to this method, anhydrous glycerin is gradually heated with
crystftllized oxalic acid to a temperature of 75*'-90'' until the
whole of the carbon dioxide has been evolved. Oxalic acid is
Again added and the mixture heated as before, this process
being capable of repetition for any number of times. At the
beginning of the reaction very dilute formic acid passes over,
and this becomes stronger on each addition of oxalic acid until
at last a liquid containing 56 per cent, of the acid distils over.
Crystallized oxalic acid, CgH^O^ + 2YI/), first decomposes into
water,fiHhD|^dioxide, and formic acid, which in the nascent

SYNTHESIS OF FORMIC ACID. 271

+ COH.OH = CA-

s-"«

state acts upon the glycerin, CjH5(0H)j, with formation of
monofonnyl ether or monoformin :

roH

OH + HjO.
lO.COH

If oxalic acid be again added, the water of crystallization
decomposes a part of this ether with formation of formic acid
and glycerin, but, at the same time, a fresh quantity of the
ctber is produced, and this continues until the liquid is
saturated with monoformin, at which point both reactions
take place simultaneously, and the acid of the above strength
distils over. If anhydrous oxalic acid be employed, the
reaction begins at 50'', and is accompanied by violent frothing ; a
dilute acid first distils over, triformin, CsHj(CH02)3, is formed
which soon saturates the liquid, and an aqueous formic acid,
containiDg from 87 to 88 per cent, of the pure acid, distils
over. When, however, a certain quantity of oxalic acid has
been employed, the normal reaction does not hold good.

In place of glycerin many other polyatomic alcohols may be
employed for the preparation of formic acid from oxalic acid. ^

183 Synthesis of Formic Acid. The various methods for the
synthetical formation of formic acid are of great theoretical
interest.

(1) Berthelot has shown that it is formed when carbon mon-
oxide is treated with caustic potash or other alkalis :

CO + g}o = ^^5}o.

This reaction requires about seventy hours to complete it at a
temperature of 100°, whilst it is completed in ten hours at a
temperature of 220°.^ According to Merz and Tibirica,^ the
action proceeds more quickly when moist carbon dioxide is
passed over porous soda-lime loosely arranged in large U-tubes,
and heated to about 200° in an oil-bath. Above 220° decom-
position commences, with evolution of hydrogen and formation
of carbonate.

(2) When moist carbon dioxide (which may be regarded as
carbonic acid) acts upon potassium at the ordinary temperature,

^ Loriu, Bull. Sor. Chim. [2], v. 7, 12; xx. 2il ; xxiv. 22 and 436.
^ Ann. C/ir.m. Pharm. xcvii. 12r» ; Compt. Jfrml, xli. 9f)5.
5 Bcr, Jkutsch. Chem. Gcs. x. 2117, IhUl. xiii. 23.

:«::

THE rORMYL GROUP.

a mixtore of potaaBimi caibooate and puUeinm fonnate is
produced:*

(3) In a nmilar way, sodium fomiate is produced when a
' uriution of carbonate of ammonia is treated with sodium
amalcam.*

(4; If carbon disulphide be heated with water and iron borings
at 100^ kmfUB fcvmate is produced, together with sulphide of
iron, carbon dioxide, and other bodiea'

(5; A small quantity of the acid is likewise formed by the
direct union of carbon dioxide and hydrogen under the influence
of the silent electric dischaige. Thus, if the electric dischaige
be paved through the mixed gases by a Siemens induction-
tube, small drops of an add liquid are formed, together with
carbon monoxide and a small quantity of marsh gas, this liquid
exhibiting the chaiacteristic reactions of formic add.^

(6) Hydrocyanic acid, HCN (Vol. I. p. 659), is the nitril of
formic acid, and therefore, in the presence of alkalis or adds, it
easily passes into the latter compound by absorption of water :

HCN + 2 HjO + HCl = HCO.OH + NH.Cl.

(7) Formic acid is likewise produced when chloroform is
heated with caustic potash :

CHCI3 + 4 KOH = 3 KCl + CHKO, + 2 H,0.

184 Preparation of Anhydrous Formic Acid, In order to
obtain pure anhydrous formic acid, the lead salt is prepared from
the dilute add, and this, when completely dried, is brought into
a wide glass tube or retort and dry sulphuretted hydrogen
passed over it. The lead salt is then gently heated just
to the point at which the acid distils over, inasmuch as at
higher temperatures disagreeably smelling sulphur products aro
formed.^ Amongst these a body crystallizing in colourless needles
is obtained, the exact naturo of which has not yet been properly
ascertained.^ The distillate thus prepared usually contains some

•

^ Kolbe and Schmidt, Ann, Oum, Phcvrm. cxix. 251.
« Maly, PhU. Mag. [4], xxx. 860.

* Lotw., Bet, DeuUch Chan. Oes. xiii. 824.

* Brodie, Proe, JUfy. Soc, xzi. 245.
' lieb^. Ann. Pkarm, xvii. C9.

* Wdhler, Ann. Chnju Pkarm. xci. 125 ; Limprecht, Ibid, xcvil 861 ; Hurst,
Joum. Chem. Soc. zv. 278.

PROPERTIES OF FORMIC ACID. 273

sulphuretted hydrogen, and this can be best got rid of by recti-
fication over powdered lead formate (Landolt). Concentrated
formic acid may also be obtained by distilling the anhydrous
sodium salt with anhvdrous oxalic acid/

A strong acid, containing 77*5 per cent., may be obtained by
simply distilling the dilute acid obtained from crystallized oxalic
acid, a weaker acid passing over first. If anhydrous oxalic acid
bo dissolved in this warmed acid, it takes up the water, and then,
when the cold liquid poured oflf from the crystals which are
separated out is distilled, an almost anhydrous acid is obtained,
from which, as well as from the distillate obtained by the other
methods, pure formic acid can be obtained by cooling, the
aqueous liquid being poured off from the crystals of formic acid
which are deposited (Lorin).

185 Properties. — Formic acid is a colourless, slightly fuming
liquid, possessing a penetrating acid smell, and acting so power-
fully on the skin that one or two drops produce extreme pain and
swelling, leaving a white blister, which afterwards forms a painful
wound. The dilute acid has a peculiar acrid smell, and a purely
acid taste (Liebig). The anhydrous acid boils at 99°'9, and at
20* has a specific gravity of 1*2211.^ The vajDour density at
lir-5 is 2-38; at 1G0^ 1-81; and at 214°, 1-62.8 At a low
temperature formic acid solidifies to a mass of crystals which
melt at S'^C*

Mere traces of water lower the melting-point considerably,
whilst, on the other hand, the boiling-point is raised by tlie
presence of water. According to Liebig, the hydrate CHgOg + HgO
boils constantly at 106^ This compound has been termed
orthoformic acid, CH(0H)3, inasmuch as corresponding ethers
such as ethyl orthoformate, CH(OC2H5)3, are known, this latter
body being obtained by the action of sodium ethylate, CgH^ONa,
on chloroform. Roscoe ^ has, however, shown that this hydrate
does not exist, and that a mixture of formic acid and water behaves
like the various other aciueous acids. On repeated distillation
under the ordinary pressure, a final product is always obtained,
containing 77 per cent, of formic acid, and boiling constantly at
107*'l, whether a dilute or concentrated acid be employed. That

* Lorin, Bull, Soc. Chim. [2], xxv. 519.

* LoDdolt, Pogg. Ann. cxvii. 3C2 ; ami Aim. Chem. Pharm. Sujfjil. vi. 170.
' Petersen and Ekstrand, Ber, Dcutsch, Cfipm, (k*. xiii. 11^4.

* Berthelot, Bull. Soc. Chivu [2], xxii. 440.

* Joum, Chcm. Soc, xv. 270.

VOL. UL T

27-J

a mixture of pota*.
pnxJucc'd : *

"^^ (OH ^

(}i) In a siniil I
solution of carl'
amalgam.*

(4) If carbon •!
at 100'', ferrous
iron, carbon <li«».\

(5) A small <
direct union of
of the silent <•.
be passctl tin
tube, small •:*
carbon monox
exhibiting tli

00 Hj-chv
formic acid,
easily jiassi'-

(7) For:
heated vvi»

184 /
obtain )•
the dilir
a wid«'
passed
to th»-
highei
foniH
is olit

ascci'f

' K
M

• r

* I:

T
(

- - v' ATI

-..-:• ml

-* -.:.:. is

. -•• 'y]itn

• ".rriijir,

J :«LVnt3

f txj'laiijs

* ^1

• •• 'l ,•

•

i.rioulty in

> . :. •-♦■.•lihi:,

'.' -> ' • Ik' n.'-

. :..'. M- .sahs

•..:^r. It is
.■•.vstallizabK-

.:*• rradilv in

>^ ^> .1 o»ol and

. '.tv r aiid for-

., .\^::;jMsition

. \.%v* raii«»n ot
r^- r!i.>iid»i«'

•- \ 1

THE FORMATEa 276

cxystals, which dissolve in from eight to ten parts of cold and in
not much less hot water, and are insoluble in alcohol.

Barium Formate, (CH.O^^Sk, forms transparent rhombic
prisms, which are soluble in four parts of water, but do not
dissolve in alcohol.

Lead FomuUe, (CH02)j)Pb, a very characteristic salt of formic
acid, crystallizes in glistening white prisms, which are isomor-
phous with the barium salt. It possesses a sweet styptic taste,
dissolves in sixty-three parts of cold and 5*5 parts of boil-
ing water, but, like the foregoing salt, is insoluble in alcohoL
When the solution is warmed with oxide of lead, the following
basic salts are obtained :

O I ?Jf^l^* O I Pl»C!HO, (J f PbCHO,

t PbCHO, j pjj \^^

^ { PbCHO. ^ {

°{

PbCHOy

These are soluble in water, exhibit an alkaline reaction, and
crystallize in needles.*

Copper Formate, (CKO^JOn + 4H2O, crystallizes in light-bine
monoclinic prisms, and yields with formic acid the compound
(CiaO^fiM + 2CH2O2 + 3H2O, which also crystallizes in the
monoclinic system.^

Silver Formate, CHOjAg. Silver oxide or silver carbonate
dissolves in cold formic acid, although silver is reduced when the
acid is hot. On evaporating in a vacuum, small six-sided
rhombohedral tables are obtained, which are also deposited
when a concentrated solution of silver nitrate is mixed with one
of sodium formate. From concentrated solutions it separates
out as a curdy precipitate. It blackens easily even in the dark,
and especially when moist, and decomposes on heating according
to the equation :

2 CHOjjAg = 2 Ag + CH,0, + CO,.

Mercuric Formate, (CH02)2Hg, is obtained by dissolving mer-
curic oxide in cold dilute formic acid, and remains, when the
solution is evaporated in a vacuum at 0^ in the form of a white
granular crystalline mass easily soluble in water.

^ Barfoed, Joum. Pr. Chem, CYiii. 1.
3 V. llauer, Wien, Akad, Ber, zliii. 548

276 THE FOR^nrL GROUP.

Mercurom Formate, (CHOJjHgj, is formed when the solution
of the foregoing salt is gently warmed :

2 (CH02)2Hg = (CH02)2Hg2 + CH^O, + CO^

It crystallizes in microscopic four-sided or six-sided tables, and
dissolves at IT'' in 520 parts of water. Like the silver salt, it
blackoDS even in the dark, and, when heated with water, decom-
poses into mercury, carbon dioxide, and formic acid. The dry
salt deflagrates slightly when it is quickly heated, and decomposes
on percussion.

187 Methyl Formate, CH02(CH3). This ethereal salt was first
prepared by Dumas and Peligot by distilling methyl sulphate
with sodium formate. Vol hard ^ recommends the following
method : 130 parts of hydrochloric acid recently saturated with
wood spirit are added gradually to 100 parts of calcium formate.
As soon as the somewhat violent reaction is over, the distillate
found in the cooled receiver is poured back into the retort, the
whole warmed for a short time and then distilled on a water-
bath. The liquid which passes over is washed with a saturated
solution of common salt containing a little carbonate of soda,
and then dried over a large quantity of finely powdered anhy-
drous calcium chloride, with which substance the ethereal salt
combines on slightly warming, forming an apparently dry mass.
This is then again distilled from a water-bath, and the first
portions, which contain chlorine, are collected apart. According
to Bardy and Bordet, ^ it is better to use a mixture of methyl
alcohol and aqueous hydrochloric acid, and to act with this upon
dry sodium formate. Methyl formate is also readily obtained by
digesting methyl alcohol with concentrated formic acid,^ as well
as by acting upon hydrocyanic acid with wood spirit saturated
with hydrochloric acid (Volhard) :

HCN + HO.CH3 + HCl 4- HgO = NH.Cl + HCO.OCH3.

Methyl formate is a mobile liquid possessing a peculiar smell,
boiling at 30°'4 under a pressure of 712 mm. and having a
specific gravity at 0° of 0-9928 (Volhanl), and a vapour density
of 2084 (Dumas and Peligot). If its Tapour be passed through
a red-hot tube, it decomposes almost completely into carbon
monoxide and methyl alcohol :

HCO.OCH3 - CO + HO.CHj.

' Licbi(i*n Ann. clxxvi. 12S. ' RuH. Sor. f*h'm, xxxi. 631.

' Kracmer and Grodzki, JJrr. /kuf^tch, Chtm. Ucs, ix. 1928.

FOBMAMIDE. 277

Acted upon by chlorine, it yields as the last product jMreUor-
methyl formate, CICO.OCI3, a powerfiiUy smelling liquid, boiling
at 180'', which when heated to 320"* splits up by intermolecular
interchange into two molecules of carbonyl chloride, COCl^

Methylorthqformatc, GTiI(pGJI^^, is prepared by the action of
chloroform on a solution of sodium methylate, and is a colour-
less, mobile liquid, with a pleasant odour, and boiling at 101^
to 102^^ Substitution-'products of fonnic acid are unknown, as
the acid is decomposed by chlorine :

CH2O2 + CI2 = 2HC1 + COy

The chlorocarbonic ethers, however, obtained by the action of
carbonyl chloiide on the alcohols, may be regarded as ethers
of monochlorformic acid. Of these the methyl compound,
CClOgCCHj), has been already described. It is also formed by
the action of perchlormethylformate on wood spirit. The formyl
chloride, corresponding to formic acid, is likewise unknovm, for
by the action of phosphorus pentachloride on formic acid only
carbon monoxide and hydrochloric acid are obtained. The
anhydride is consequently unknown, nor has thioformic add
been prepared.

Formamide, N(C0H)H2, was discovered by Hofmann * in 1863.
He obtained it by heating ethyl formate, saturated with
ammonia, for two days at 100^ in sealed tubes :

Behrend ' prepared it by heating two parts of ammonium formate
with one of urea to 140^ as long as ammonium carbonate
escaped. The ammonium salt thus decomposes into formamide
and water ; the latter, which would retard the reaction, at onoe
combines with the urea to form ammonium carbonate, and thus
becomes inactive. Lorin^ has found that it can be readily
obtained through dry distillation of ammonium formate, and
also occurs as one of the products of the distillation of am-
monium oxalate. It is a colourless liquid, soluble in water and
alcohol, but insoluble in pure ether, and boiling at 192* to 196**,
with partial decomposition. This takes place in two directions,

^ Ber, Detitxh Ckem, Oes. xii. 117. ^ Joum. Okem,

* Ann, Chem, Pharm, cxxviii. 383. ^ Compi* Bend,

278 THE FORMYL GROUP.

one part decomposing into water and formionitiil (hydrocyanic

acid):

COH

H = H.0 + NCH,

and another part splitting up into ammonia and carbonic oxide.
Under diminished pressure it volatilizes without decomposition
at 140' to 150*. Phosphorus pentoxide withdraws water from
this compound, forming hydrocyanic acid, and concentrated
caustic potash decomposes it in the cold with formation of
potassium formate and ammonia.

(COH
Methyl Formamide, N < CH3 This body, metameric with

(H.

acetamide, is obtained by evaporating an aqueous solution of
methyl ammonium formate to a syrupy consistency and dis-
tilling the residue. On the addition of potash to the distillate
the amide separates out, and it is purified by rectification. It
is a thick inodorous liquid, having a specific gravity of 1011,
and boils under a pressure of 740 mm. at 190^ It is soluble
in water and alcohol, but insoluble in ether. It is inflammable,
burning with a purple-bordered flame. Phosphorus pentoxide
acts violently upon it, decomposing it into carbon monoxide
and methylamine, and at the same time some hydrocyanic acid
is formed.'

lieactions of Fomiic Acid and the Formates. Some of the
more important reactions by which formic acid and its salts
can be recognised have already been given.

On heating with concentrated sulphuric acid, pure carbon
monoxide is evolved without any blackening, this gas burning,
when ignited, with its characteristic pale blue flame. Ferric
chloride colours neutral solutions of a formate a red brown with
production of ferric formate. This reaction is, however, ex-
hibits! by acetic acid and the sulphites, but formic acid can
readily be distinguished from these, inasmuch as its solution,
when warmed with silver solution, evolves carbon dioxide, finely
divided silver being at the same time precipitated and deposited
in a mirror on the tube.

^ Liiincrnaiin, Bcr, U'i^n Akad, Ix. 44.

7f . ■ •

;our.

KS48 by FranklancI and

nil on moist acctonitril

upon as the free radic«al

>•' showed that this same

■ sis of acetic acid (methyl

i.se obtained it by heating

sure. When the truth of

V recoimised bv chemists,

d, and for some time tliis

It was believed to diflfor

;ias had been obtained by

with zinc and water. The

was, however, afterwards

ily to agree exactly in their

;il properties, inasmucli as

iiose various processes all

with chlorine as the first
I

i\'nsylvanian petroleum^ as
"Ived from the oil wells.^
■'1 in many ways. Of these
as yield it easily and in a
a stated that Kolbe obtained
111 acetate. The ap[)aratus
ihes as follows : ^ A small

« JbuL n. ir,7.

ti'lM of Ethyl," Chi-.ia. fiitc, Jtmrn,

Siidtler, AmtTi

1707

TOE ETHYL GEOCP.

glass cvltnd«^r t^^.Fig. 6S. open at both eoild, is finulv bstened by
& piece of shc«t c&ontt-houc to tb€ top of a. small porous cell (a)
of the same diameter. The cylinder is '
, closed a: the top with a well-fittii^ cork,

to which two thin glass tubes are fixed ;
down one of these a stout fdatinum wire
passies. to the lower end of which is attached
a piece of platinum foil, bent as shown by
the doited lines, and serving as the electrode.
The second tube (0 is connected with a gas-
ilelivery tube. The whole apjMratus stands
ill a wide glass cylinder open at the top (rr.
Fig. (>!•', and is sumHuujed by a cylindrical
pittv of sheet copper placed outside the porous
Ki>t. es. i.vll, anil sei^'ing as the other electrode. Both

vessels aiv filled to the same height with
a solution of a«.x>tate of {totash ; the liquid is poured into the
inner one by means of the tube until the columns of liquid
inside and outside stand about two inches above the top of the

huiid of riiiiiitcliiiiK'. 'I'lio MiliiMi'ii of |K'tiuuiiini acetate must
1m) tolerably i-i.iirriitnitj-il nml U'" fi""i chlorine. If the nega-
tive jiolc of n luiHmy 'if f'ltn Ifniioeii's 'lemunts be connected
with lluf copiK-r I'ImtriMir . ni»l (liu |Krtitive with the platinum

ETHANE OR ETHYL HYDRIDE. 281

cylinder, pure hydrogen is first evolved, and afterwards a mix-
ture of carbon dioxide and ethane, and this gaseous mixture
passes through the bulb-tubes (/) filled with potash solution.
The ethane is still mixed with another gas possessing a peculiar
smell, whose nature has not yet been properly ascertained. To
separate this gas, the ethane is next passed through the bulb-
tube (g) containing fuming sulphuric acid. The gas is after-
wards washed by passing through the bulbs {h) containing
caustic potash, and again dried by passing through the bulb (i)
containing strong sulphuric acid. The gas thus purified and
consisting of a mixture of 66 volumes of hydrogen with 28 8
volumes of ethane is next passed into the smaU mercury gas-
holder (k), which is so arranged that by gradually raising the
inner bell-jar any excess of pressure in the apparatus may be
avoided.

Pure ethane can also be obtained by allowing zinc ethyl to
pass drop by drop into water. The reaction is very violent, and
the liquid must be well cooled to begin with (Frankland).

It is likewise easily formed by the action of sulphuric acid
on mercuric ethyl, according to the following reaction :

2 Hg(C,Hs), + HjSO, = 2 C^ + (CjH5Hg)^0,.

In order to purify the gas thus obtained from traces of mercuric
ethyl which evaporates with it, it is led through fuming
sulphuric acid and then through water (Schorlemmer).

According to ScTiutzenberger ^ it is also obtained by the
action of barium dioxide on acetic anhydride, according to the
following equation:

2 cS::CO } O + BaO, = g|» } + g5gg;0 } Ba + 2 CO,

Darling,^ who endeavoured to prepare it in this way, only suc-
ceded in obtaining a gaseous mixture containing less than
one-fifth its volume of ethane, the remainder consisting of
marsh gas and a small quantity of carbon monoxide.

189 Properties. — Ethane is a colourless odourless gas condensing
to a liquid under a pressure of 46 atmospheres. It is a singular
fact that the vapour-tensions of ethane, CgH^ ethylene, CjH^,
acetylene, CjHg, stand in the same relation to one another as
the quantities of hydrogen contained in their molecules do,
that is as 3:2:1.'

* Conipt. Reiid. Ixi. 487. » Loc. eit,

» Cailletet, Compt, Rtnd, Ixxxv. 861.

282 THE ETHYL GROrP.

Ethane is easily iuflammable, burning with a faintly luminous
flame. It is slightly soluble in water, according to Schicken-
dantz, its absorption-coeflScient is represented by the following
expression :

C = 0094556 - 0-0035824 1 + 000006278t'.

At the ordinary temperature alcohol dissolves about its own
volume of this gas.

ETHYL ALCOHOL.

190 Fermented drinks were known in very early times. Wine
is mentioned in Homer and in the Old Testament, and the
Egyptians, Gauls, and Germans, and other ancient nations,
understood the art of brewing beer from malted grain, whilst
the northern peoples prepared mead from honey. The exist-
ence of alcohol in all such substances was first recognised after
the Alexandrians had perfected the extremely rough methods
of distillation which had up to their times been employed.

Distillation. — This appears to be a fitting place to give some
account of the history of distillation,^ a process constantly
employed by chemists. Aristotle refers to the fact that sea-
water can be rendered fit for drinking by evaporation, but he
does not explain by what means the vapour is condensed. Still
there can be little doubt that this was effected by means of the
cover of the vessel, for Alexander of Aphrodisias writing in the
third century describes an apparatus of this kind.

Both Dioscoridcs and Pliny mention that an oil can be obtained
from rosin by heating it in a vessel in the upper part of which
some wool is placed for the condensation of the oil. The first-
named author also mentions that quicksilver is obtained by
heating cinnabar in an earthenware pot together with iron, a
cover termed a/i/8tf being placed over the pot. An important
improvement in distillation was made by the Alexandrians, as
they employed two vessels, one for evaporating the liquid and
the other for condensing the vapour. The forms of apparatus
which they employed are shown in Figs. 70 and 71. In prin-
ciple they are similar to those used at the present-day.

The two parts of the distilling apparatus were, first the

» Kopp, OfAch. Her Chemir, ii. 26, iv. 273; BtUrajt, i. 217.

HISTORY OF DISTILLATION.

283

body, or still, and secondly the head, from which either
one or several tubes passed to the receiver. The Arabians
termed the head or cover alavibic or alembic, and this word
was subsequently employed to designate the whole apparatus.^
The invention of the retort, a long-necked flask in which the
neck was bent back (Betorta, ampvlla), we also owe to the
Arabians.

Basil Valentine was the first to mention a tubulated retort,
and he illustrates its form by a figure. The cooling-vessel
and condensing-worm wete also first described by Valentine.
Fig. 72 represents a form of distilling apparatus from a German
edition of Geber's works dated 1710.

Fio. 70.

Fio. 71.

Other improvements in the arrangements for distillation will
be described under the manufacture of alcohol.

igi The discovery of a combustible spirit of wine soon led
to attempts to obtain it of a greater strength than was found
possible by repeated distillation. Raymond Lully described
this method, and also noticed that a still stronger spirit can be
obtained by rectification over dry carbonate of potash, whilst
Basil Valentine states, more precisely than Lully, the method
to be adopted for obtaining strong spirit by means of calcined
tartar and subsequent distillation. Thus in the Offenharung
der Handgriffe, &c., p. 487, he says: "Having now prepared

* See E. "Wiedemann, Zur Cliemie der Araber, Deuhch, Morgenldnd. Oes. 1878.

284 THE ETHYL GROUP.

this aqua vitm by distillation and rectification (take care that
thou comest not near with a light during the process, and doest
thyself damage), place in a still to every quart of this prepared
aqua vUm a quarter of a pound of well calcined sal tartari.
Adapt to this a good sized alembic (headj, and distil in a
RM. (water-bath)."

Robert Boyle likewise specially describes the means necessary
ba obtaining " depbl^^ed spirit of wine " from ordinary spirit.
He recommends ' for this purpose not only the use of " white
calx of tartar," but also of quick-lime. He atatos that on careful
distillation " the phlegmatic part of the spirit of wine is soaked
up by the alcalizate salt, and the inflammable part is freed from

it ; " adding, " therefore, this alcohol of wine we peculiarly call
the alcalizato spirit of wine." Basil Valentine also mentioos the
use of freshly-burnt lime, but this process was used by him
rather with the view of making the lime stronger than of
preparing a more active spirit

Bectification at a low temperature was, however, a much
more common mode of dehydration than the use of potashes
or lime, tn order to condense the vapours completely they
were passed through long cooling tubes, often curved and bent
in on extraordinary fashion. Not unfrequently the head was
■ Doj'lc, Oftm. i. 333.

ALCOHOL : HISTORY OF ITS PREPARATIOX. 285

raised high above the body of the still in order to retard the
passing over of aqueous vapours. Indeed Michael Savonarola,
in his treatise, De Arte Confidendi aquam Vitos Simplicem et
compositam (1532), relates that a friend of his had built a still
having its body in the cellar and its head under the roof of
the house.

zga Alcohol was formerly designated by very different and often
by most fanciful names. Thus, for instance, Marcus Grsecus,
who is said to have lived in the eighth century, calls it aqua
aniens, and the Latin translators of Geber's writings term it
aqua vitas; and in addition to these names, of which the
latter has come into general use, we also find aqua vitis (beet-
root water), spiritus vivus, mercurius vegetahUis, and a number of
other pharmaceutical names. Moreover, as it is used as one of
the most important medicines, Raymond Lully terms it con-
solatio ultiriia corporis humani. The name of spirit of wine
(spiritus vini) first occurs in Basil Valentine, and the name
alcohol was first used in the sixteenth century. It has
already been stated in the second volume (Part II., p. 301) that
the word was first employed for designating the native sulphide
of antimony (speissglass), and was afterwards made use of to
denote any finely divided, but especially metallic, powder.

It is difficult to say how it came to be applied to spirits of
wine. Libavius, in his Alchf/mia, published in 1594, says:
** Quando vini spiritus rectificatur per suum salem (that is,
carbonate of potash prepared with cream of tartar), sou potius
exasperatur, nominant vini alcool, vel vinum alcalisatum."
In Johnson's Lexicon Chymicum, published in 1657, pages 12
and 13, we find the following explanation : *' Alcohol, est
antimonium sive stibium." And again, " Alcohol, vini, quando
ominis superfluistas vini k vino separatur, ita ut accensum
ardeat, donee totum consumatur, nihilque faecum aut phlegmatis
in fundo remaneat."

The extract from Libavius, and that already cited from
Boyle, appear to point to the fact that strong alcohol was
formerly termed vinum alcalisatum (that is, wine strength-
ened by means of alkali), and that, perhaps by some misun-
derstanding, this came to be written innum alcoholisatum, from
which afterwards it became alcolcol vini.

Another derivation which appears to bo about as probable as
the one just stated, is that the word alcohol, after its general
employment to signify a very finely divided body, was made use

28G THE ETHYL GROUP.

of to designate spirits of wine^ because this was wine freed from
all grosser particles.

193 Manvfadure of Alcohol, — The manufacture of alcohol on
a large scale is carried on by distillers, and forms an important
branch of industry, the gradual development of which haa
exerted no inconsiderable influence upon the history of civili-
zation. Of all chemical compounds, alcohol is the one which
has most materially affected human progress. Alcohol was
originally obtained, as has been remarked, by the distillation
of wine, and the fact that it was contained in beer naturally
led to its preparation by the action of yeast upon malted grain.
Up to the end of the fifteenth century, alcohol was used as
a medicine, its taste being rendered agreeable by admixture
of sugar, herbs, aromatic berries and essential oils, and so
it gradually came into general demand, inasmuch as it was
believed that, if daily taken in small doses, it had the effect
of preserving youth and health, and thus it was that brandy
soon became a recognised drink throughout Europe.

As soon as alcohol began to be used in the arts and manu-
factures, means were taken to find a cheaper method of preparing
it than from malted grain, and for this purpose not only were
potatoes and beet-root employed, but also cane-sugar, beet-root
sugar, and molasses. The marcs, or residues of the wine presses,
and sweet fruits, such as cherries, plums, all of which contain
both sugar anil starch, are also used for the preparation of spirit
of wine, whilst, in the East, rice and sorghum are the chief
sources, and in America, spirit is obtained from potatoes and
Indian corn. The materials which are thus used in the pre-
paration of spirit of wine may, therefore, be arranged in three
groups. In the first of these are classed the grape and other
sweet fruits which contain fermentable sugar, or glucose,
C^jHjjO^j. The juice of such fruit enters into fermentation
spontaneously on exposure to air, under the action of a ferment
contained in the nitrogenous constituents of the juice, the sugar
thus being converted into alcohol. Further remarks on this
subject will be found in the chapter on Fermentation.

The second group includes substances which contain common
or cane-sugar, C^^^ifiiv ^^^ order to bring this into a state of
fermentation, the ferment, yeast, must be added to a dilute
solution, the first step in the process being the formation of
fermentable sugar by assumption of the elements of water.

To the third class bcl<»ng the variuusi kinds of grain, ]><>tatoes,

THE MANUFACTURE OF ALCOHOL. 287

and other substances containing starch, (CgHi^,05)n. This sub-
stance is insoluble in cold water, but forms a gelatinous mass
when boiled with water, and can then be converted into fer-
mentable sugar by the addition of malt or malt extract. This
contains a peculiar ferment termed diastase, which is also
formed in the process of malting the grain. Dilute sulphuric
acid also possesses the power of effecting this* same change,
converting the starch meal into sugar on boiling with water.

Grain Spirit is usually prepared from barley, rye, wheat, or
oats, but maize and rice and other grain are likewise employed
for the purpose. In general, a mixture of several sorts of grain
is made use of, inasmuch as it has been shown that when two
kinds, such as barley and oats or wheat, are used, the yield of
spirit is larger than when one kind is treated by itself. To
1 part of malted barley 2 to 3 parts of unmalted grain
[termed the grist) are usually added, but in some cases the
proportion of the latter is still larger. The grain is broken up
tolerably finely, either between ordinary grindstones, or, in the
case of the softer malted grain, between rollers of a suitable form.

Mashing, — The crushed grain and malt is next run into the
mash-tun, where it is mixed, in the proportion of 1 litre to
1 kilo of malt, with water having a temperature of about
GO* and carefully stirred so as to avoid the formation of lumps.
After the first mash has stood for about half an hour, the liquid
is drawn off, a second supply of water added, and the mash
warmed by passing in steam until the whole is raised to a
temperature of about 65°. The tun is then covered for some
hours and allowed to stand, in order to permit the complete
conversion of the starch of the grain into sugar by means of
the soluble diastase of the malt. The cold wort is then brought
into a fermenting vat and yeast added, in the proportion of 2y
to 3 kilos of dry brewer's yeast for every 100 kilos of grain.
The fermentation begins after a few hours, and should last four
or five days. The attenuated wort, the specific gravity of which
ought to be nearly equal to that of pure water, is then sub-
mitted to distillation with as little delay as possible ; and at
the conclusion of the operations 100 kilos of grain should yield
about 28 litres of pure alcohol.

Spirit of wine is largely obtained from potatoes, especially
in Germany. The roots are first softened with steam, then
rasped on a machine with warm water. Malt is then added to
convert the potato-starch into sugar, and the processes of

2d8 THE ETHYL GBOUP.

mimhing, infusion, and fennentation carried on as in the
mannfactore of grain spirit.

Beet-root is worked up in different ways. The root is ruhhed
down and the juice pressed out ; or the root is cut into slices
and the sugar washed out hy hot water, or hy the residue of a
distillation of a former operation. To the liquid, yeast is added,
and the liquor allowed to ferment Alcohol is also manu£Eu>
tured from the molasses ohtained in the cane and beet-root
sugar industries. The syrup, after sufficient dilution with
water, is allowed to ferment, and on distillation a spirit, known
as rum, is obtained.

Z94 Lavoisier, and at a later date Gay-Lussac, showed that
the alcoholic fermentation of sugar proceeds according to the
following equation :

CeH^Oe = 2 0,11^0 + 2 CO^

Pasteur afterwards found that the whole of the sugar does
not undergo the above change, but that from 5 to 6 per cent,
is converted partly into glycerin, CjHgO,, and succinic acid,
C^H^O^ and partly used up for developing the growth of the
ferment In addition to this, and under conditions which are
not yet properly understood, the alcoholic fermentation gives
rise to higher homologues of common alcohol, fatty acids, and
ethereal salts, which impart to the various spirituous liquors, as
well as to plain spirit, its peculiar smell. These bodies, all
of which boil higher than common alcohol, are classed together
under the name of fusel-oil, though sometimes the name is
applied uiiiiply to those which impa4 to the spirit a disagreeable
odour.

195 The first crude forms of distillating apparatus have already
been described. As soon as spirit was required in larger quan-
tity these stills were increased in size, and made of copper and
other metals instead of pottery. A simple apparatus which was
formerly in general use and is still employed on the small scale
for the manufacture of the more valuable kinds of brandy
(from the old German Brandewein), is shown in Fig. 73. The
wort is heated on the body of the still, and the vapour is con-
densed in the worm.

The distillate consists of a dilute alcohol termed "low
wines " or " singlings,'* and from this, by a second distillation
or "doubling," a stronger alcoholic distillate is obtained.
This process is carried on until the spirit begins to acquire

RECriFICATlON OF SPIRIT ^89

a (lisagreeable taste and smell, and to tliis the name of
"faints" is given. By repetition of this operation, strong or
rectified spirit is made, and at last a highly rectified spirit, con-
taining 80 per cent, or more of alcohol, is obtained. The older
operations for separating the spirit from tJie water are tedious
and costly, and hence a simpler and cheaper method for efiTecting
this object became a desideratum. The first apparatus of this
kind was iovented by Adam, in France, and introduced into
industry by Bernard.' This original apparatus waa soon im-
proved, and has now been brought to a high degree of perfection.
The stills employed at the present day consist essentially of

Fro. 73.

two parts, (1) the analyzer, and (2) the rectifier. The action of
the first depends upon the fact that when mixtures of the
vapours of alcohol and water arc cooled down by suitable
arrangements, the condensed liquid is separated into two parts,
one containing a large quantity, and the other a small quantity,
of alcohol. This principle is made use of on the small scale in
laboratories in the process of fractional distillation, when Wurtz's
distillation -bulbs are employed (see p. 150). In the second
part of the apparatus, the vapours are condensed in a rectifier, but
none of the liquid is allowed to run back, as in the first part,
the whole being heated by a current of steam to the boiling-
point of the hquid, when vapour richer in alcohol is given off.
Thi.s is condensed in a second vessel, again brought to the
' am. Ann. xxiu. 129,
VOL. III. U

2ao

THE ETHYL GROUP.

boiling-pomt by action of steam, and condensed in a third vessel
ID the fonn of stron*,' alcohol, and thb process repeated. This
principle is likewise applied on the small scale for fractional
distillatioD in the laboratory'.

ig6 The nppanitus uacd for rectifying is constructed in very
different ways. Of these various forms we shall first describe
the Iarfj;e apparatux of Pislorius with direct heating, formerly
iiHirh iisoil in flonnany, as it serves as the point of de-
(Mirture fur almost all tin- oilier forms of stills and rectifiers
now in use. At tin- ivtinnienconiciit of the i>perntiou the first

THE RECTIFICATION OF SPIRIT. 291

charge of wort is allowed to enter by the pipe {h/) (Fig. 74),
passing first into the heater (c), thence by the pipe (y) into
the first boiler (b), and from this into the second boiler
(a). The second charge is then brought into (b), the third
remaining in the heater (c). The wort in boiler (a) is
now heated to the boiling-point, the liquid being constantly
stirred with the chain (/) to prevent it boiling over. The
vapours from this pass through the tube (ff) into boiler (b),
which is warmed by the waste heat from the fire (g), and the
contents are soon raised to the boiling-point The vapours
here given off pass by the tube (f) in the head of the still into
the rectifying vessel (c). In this vessel a considerable portion
of the water or weak spirit is condensed, flowing down to the
lower portion, where it coUeets, and is from time to time allowed
to enter the boiler (b). The vapour of the strong spirit passes
through the tubes (vv') into the condenser (d), where again
weaker spirit runs back, and the uncondensed vapour passes into
a second and third condenser (not shown in the drawing), until
at last it comes to the tube (d"), whence it passes into a large
condensing worm, placed in a tub of cold water, from the end
of which it runs into the receiver.

Fig. 75 represents a Pistorius still, worked, as is now usual, by
steam instead of an open fire. The boilers (a) and (b) are placed
vertically above one another, (c) is the rectifier and (d) the con-
denser. The direction taken by the vapour is indicated by arrows.

197 When very large quantities of spirit have to be distilled,
and especially in this country, where, owing to Excise regula-
tions, large distilleries are the rule and grain-spirit is alone
manufactured, an arrangement known as " CoflFey's still " is em-
ployed. It consists of two columns (a) and (b) (Fig. 76) placed
side by side. These are made of wood 5 or 6 inches thick, and
are lined with copper. The "analyzer" (a) is divided into 12
small compartments by 11 horizontal plates of copper (a) per-
forated with numerous holes and furnished with valves opening
upwards. Dropping pipes (6 b) are also attached to each plate,
the upper end of the pipe being an inch or two above the
plate, and the lower end dipping into a shallow pan (c) placed
on the lower plate.

The second column or " rectifier '* (b) receives the spirituous
vapours passing from the column (a) through the pipe (ff).
This column is also divided into compartments like (a), but
there are 15 instead of 12. The 10 lower diaphragms (/) are

U 2

THE KTHVL GROUP.

"COFFEVS" STILL.

294 THE ETHYL GROUP.

pierced with small holes and furnished with drop-pii)es, whilst
the upper 5 have only one large opening surrounded by a ring
to prevent the finished spirit from returning.

Between each of these compartments passes a bend of a long
zigzag pipe (n n n"), one end of which is attached to the pump (w),
whilst the other end discharges the contents of the pipe into
the top of the column (a), as indicated by the arrow. The
following is the working of the appsuratus. In the first place,
the fermented liquor or wash is pumped up by the pump (m)
until the zigzag pipe is filled and the wort flows over the com-
partments (a a a). Steam is then admitted into the analyzer
by the pipe {d) and heats the wash, which is deprived of all its
alcohol by the time it reaches the bottom of the cylinder and
flows off by (e/) as spent wash. The sti"ong spirituous vapour
passes through (^) to the rectifier, and at last through the worm
(c) of the refrigerator into the receiver.

198 In order to separate completely the spirit of wine from
the strongly scented fusel-oil, the crude spirit may be filtered
tlirough freshly ignited and finely divided wood-charcoal, or, its
vapoiir may be passed through a cylindncal vessel provided with
a he<a(l, containing a large number of perforated plates upon
whi(^h coarsely divided charcoal is placed.

Experience has however shown that the spirit may be freed
from fusel-oil by bringing it up to a concentration of 90 per
cent, of alcohol by rectification, as the fusel-oil boils higher than
alcohol. Hence the simplest means of removing the fusel-oil is
to concentrate the spirit. Coffey's still answers these require-
ments, producing a pure neutral spirit up to 68° over proof, and
free from fusel-oils. In France and Germany, where Coffey's
still is pot used, a second distillation is carried on in a rectifying
still. Fig. 77 shows the construction of such a still, much used
on the continent and known as the French column apparatus.
It consists of a boiler (a) heated by a steam-pipe ; the vapours
pass through the rectifier (b), then pass to the condenser (c), and
tluj highly concentrated spirit condenses in the refrigerator (d),
whilst the ** phlegma " (or aqueous portion) flows by the tube (e)
back into the rectifier.

Various products are obtained in the foregoing process. The
first portion of the distillate serves to wash out the apparatus ;
It contains bodies which are much more volatile than alcohol,
such as aldehyde.^ Next comes the fine spirit, containing from

' KninitT and Pinnvr, Btr. DeuttcK Chem. Ots, iii. 75.

THE FRENCH COLUMN APPARATUS. 296

90 to 95 per cent, of alcohol according to the more or less
complete manner in which the apparatus works ; and after this
common spirit, containing 85 to 86 per cent., comes over, and
lastly the " faints" containing the strong-scented fusel-oil. The
first and last niDnings are generally mixed together, and either
sold as common spirit or worked up a^ain by the distiller.

199 "^^^ preparation of rice-spirit, or shochu, is conducted in
Japan accordii^ to the following primitive plan. Rice is allowed
to undei^o a peculiar kind of fermentation : this yields the
beverage called sak^ (from ki, spirit), containing from 11 to
15 pet cent, of alcohoi The residue, after pressing out the
sak4 moistened with some poor qualities of sak^, is then

Tw TuMh * j itvi!:^ Ji. *. -ah ;B"TTU*=i ■wnn i yniiTMgrf.

- - r

""Jc ^OICE. T3ji:3. 'ai3L Mlt-
• i "iu: awl ~ ■ <i!pC 'SkiL

jiiii tie itx^ 3 . Tie

'p^ '^^A.ftiii^ *wr,r 6".nv Vjt r^jiKCe ■■:ii::az3i!i: in. !';ittaii:o

j»7^ -i-^i *,. ;:ij-,n fj» ia,; ir^tar^L a 11:111 ^aa; h .-'.aaianl
•■.;fr>'.v,.-.j', v.i.'i '*tt,7i wilir. irii- I.:-.: \ b»:«rr fc-cn:*i s» Jbtt
•"w"^. -,^ •iv.pf.:-..'i<*. «rwi -,r. i^,c.,L. icii wiiai wora oeased
m.ff. 9\rfr f^ji* klrr,i.r,i uA iiilpc^irv: SiZLi.' Tbis iaipocuai
'.t^H^iTituxt »f»ri^>fli r/T;! l.-.f.;* ^-jui-re •^z.-zl «cirni*«i by Ber-
'i',*;/.' ,'. I <-'.' ■ Tr.U lr.rt*3ijO ■■■»« :ii* Mt step in th* frnthestt

f'ttstt. iui;f.tj^. '^1, \^ '.>jtair,*»i by direct <~j[LLbioAdon of iu
t:$tf,'i.'*. xiA 'iiit rliia r-ottiyinad ombines with iusc«iit
'•/''"*'*■ *'' ^''"> 'rtfiy!«ifc. The aunt cLemift also pr^pand
>l",K'>i l,y ',(.(« f/jt^.h'/l fr',t»i '.-ool-^aa, an-J riDrt: that time many
f>t'fj^)*i\' }•*■■•■: \^ntti ;o»rl«; u> fAtry '*ut tliL* reaction on s large
w*l'-. Tti'/ tiAV: liow';vi;r liith«ru> pTovot unEnutful. an.i will

*H|ii-f 'yril.fi"v;<i nf tt\'j<iii,\ bavt already been Ji«tribed

.,, m,

%bt Ak'iliul '((-(iir« ill iiatrir':, although in small quantities, in
tin- v('Ki'inlilc V\u'fi\'tM. TliiiB it iH fotiDii Ixjth in the free slate
ttuA ' <.M,ln(i«-(l t^, furff) r-iltyl Imtyratc aiwl other ethereal salts, in

' -On «<■■» ('iiini'niii'U iif ( •rUrt, mi-l lljdrofftn,'' Wi/. TVom, 182J. 4tS.
■ '■ "I, ih. MtiiMil A'lii,!. '.r Miilt-I'ilnr Arid aii'l Alcohol, "mi7. Tmiu. 18S4^
• A»*. Ckim. P/igt. (3], xliii 985.

PREPARATION OF ABSOLUTE ALCOHOL. 297

the unripe fruit of Heracleum ffiganteum;^ also in those of
Anthriscus cerefolium and Pastinaca mtiva, which also contains a
volatile ethyl compound, probably the butyrate.^ Ethyl
alcohol is also formed in small quantity in the dry distillation of
organic substances. Thus, for instafice, it occurs in coal-tar*
and in bone-oil,* as well as in wood-spirit.*^ It also occurs in
bread, being formed by the fermentation of dough, and not being
completely removed in the process of baking. According to the
experiments of Bolas,* new bread, made with yeast, contains on
an average 0*314 per. cent., whilst in slices of bread a week old
012 to 0 13 per cent, of alcohol was found. Ethyl alcohol is
also said to occur together with acetone, in the urine of diabetic
patients,^ and, according to B^champ, it is found in small quan-
tities in several of the animal fluids, and in larger quantities in
their products of decomposition.

202 Preparation of Absolute Alcohol. — Although ethyl alcohol
is a more volatile liquid than water, it cannot be obtained in the
anhydrous state from an aqueous spirit by fractional distillation.
In order to prepare anhydrous or absolute alcohol, substances
must be added which possess a more powerful attraction for
water than alcohol itself. It has already been stated that
Raymond LuUy employed potashes in order to strengthen
alcohol, and the later chemists used the same means. As, for
this purpose, they employed the air-dried salt which still contains
water, they were unable thus to obtain anhydrous alcohol,
which was first prepared by Lowitz in 1796, by the use of
freshly ignited potashes. In the same year Richter showed that
fused hydrochlorate of lime (calcium chloride) may be used for
the same purpose. Caustic lime is however much more effective
than either of these salts, and this substance too, it seems, was
used in early times for strengthening spirit.

In order to prepare absolute alcohol a retort or flask is two-
thirds filled with freshly burnt lime broken into small lumps,
and so much spirit is poured on as not quite to cover the solid
lime. The whole is allowed to stand overnight, and is then
distilled from a water-bath. The distillate is usually not

» Gutzeit, Ber, Deutach. Chtrn. Gcs. xii 2016.

* Gutzeit, Litbigs Ann. clxxvii. 344.

* O. Witt, Ber. Deutsch. Cfiem. Oes. x. 2227 ; Vincent and Delachanal,
Comptes RenduSf Ixxxvi. 349.

* Richard, Bull Soc, Chim. xxxii. 486.

* Hemilian, Ber, Deutsch. Chan, Oes. viii. 661.

* CTiem. News, xxviL 271.

^ Markownikoff, Liehigs Annaieiiy clxxxii. 362.

298 THE ETHYL GROUP.

anhydrous, and for this reason the treatment must be repeated,
or, the whole may be boiled for an hour with a reversed con-
denser and then the alcohol distilled off. In this last process,
however, a spirit should be used which does not contain more
than 5 per cent of water. If a weaker alcohol be employed, the
distillation over lime must be repeated several times, and indeed,
if too much water be present, less than half the retort must be
filled with lime, as otherwise the vessel may burst from the
expansion and heat caused by the slaking of this substance.

Anhydrous caustic baryta acts like lime. It is however much
more costly, but a small quantity added to lime is useful, inas-
much as it possesses the property of dissolving completely in
anhydrous alcohol, giving a yellow-coloured solution, and in this
way the point when the last traces of water disappear may be
easily recognised.^

The absolute alcohol of commerce, obtained from over-proof
spirit by use of lime, usually contains half a per cent, of water,
which can be got rid of by treating the alcohol with sodium.^
This metal is also employed for separating the last traces of
water from alcohol prepared by other methods, but in tliis case
care must be taken not to add as much sodium as is needed to
convert the whole of the water into caustic soda, otherwise a
distillate is obtained which is weaker than the original alcohol
This singular result has been explained by Lieben.* It depends
upon the fact that caustic soda partially decomposes in contact
with anhydrous alcohol with formation of sodium ethylate and
water. If only a small quantity of sodium be dissolved in
anhydrous alcohol a decomposition takes place between the
caustic soda and sodium ethylate, and at first a strong, but still
not absolutely anhydrous, alcohol passes over ; and if this treat-
ment be repeated, the production of absolute anhydrous alcohol
may be approached as near as is desired.

In order to ascertain whether alcohol contains water, it was
formerly customary to add to the liquid white anhydrous copper
sulphate, a substance which has also been employed for the
preparation of absolute alcohol This however is not suitable
for the latter purpose, although it may be used as a test, as it
quickly absorbs water from aqueous alcohol, thereby acquiring a
blue colour.*

' Mendelejeff, Pogg. Ann, cxxxviii. 246.
3 Ber. Chem, Industrie, ii. 278.
' Ann, Chan. Pharm, clviii. 151.
* Caasoria, Jaum, Ch^tm, Med. 1840.

PROPERTIES OF ALCOHOL. 290

Pure anhydrous alcohol does not give any turbidity when
shaken up with benzene ; ^ it mixes in every proportion with
carbon disulphide, and the more water it contains, the less
carbon disulphide does it take tip, the point of saturation
in this case being rendered evident by a distinct turbidity
occurring.^ Another very delicate reaction for the presence of
water in alcohol is a solution of caustic baryta in absolute
alcohol, which instantly throws down a precipitate of barium
hydroxide when brought in contact with alcohol containing
water.*

203 Properties. — Pure ethyl alcohol has a peculiar pleasant
smell, and when dehydrated by means of lime, it possesses ac-
cording to Mendelejeff a somewhat ethereal smell, which however
after several distillations is said to disappear. When anhydrous
alcohol is cooled with a mixture of solid carbon dioxide and ether,
it assumes a thick viscous condition, but even when exposed to
the still lower temperature obtained by use of liquid nitrous
oxide, alcohol does not freeze. Alcohol is easily inflammable,
bummg with a blue non-luminous flame, and depositing soot
only when burnt with an insufficient supply of oxygen. That
its vapour mixed with air forms an explosive mixture is a fact
which was known to Basil Valentine.

The physical constants of pure and aqueous alcohol have
been determined with the greatest care by many investigators.
According to Mendelejeff, absolute alcohol boils under the
normal pressure at 78°'3, and has the following specific gravity
compared with water at S'^'O :

0* 5' 10* 16« 20' 25" 30*

0-80625 0-80207 079788 0-793G7 0*78945 078522 078096.

For the purpose of calculating the specific gravity at other
temperatures, Kopp*s* formula may be employed, in which
t? at 0^ = 1 :

V = 1 -h 000104139 1 + 0 0000007836 t^ + 0000000001768 i\

The specific heat, latent heat, and vapour-tension have been
determined by Regnault.^ The vapour density of alcohol has
been found by Gay Lussac * to bo 1*6133.

* Gorgen, Compt. Rend xxx 691.

* Tuchschmidt and Follenius, Ber, DtuUch. Chem. Oea. iy. 583.
' Berthelot, Ann. Ckim. Phys. [8], xlvi 180.

* Pogg. Ann. Ixxii. 1 and 223.

* Mim, Acad, xxvi .701. « Ann, Chim. [1], xcy. 311.

330 THE ETHYL GKOCP.

AbscJute alcohol is a very hjrgroocopic sabstance, quickly
absorbing water from the air, and hence care most be taken in
its preparation that only dry air can find its way into the dis-
tilling apparatus. A pecaliar obeenration was made by Som-
mering/ namely, that aqneons alcohol contained in a bladder
and hung up in a warm room loses water by evaporation,
nearly absolute alcohol remaining behind. This observation
has been confirmed by other persons.-

Boyle mentions in his Erperimental History of Cold that
when strong spirit of urine "drawn off from quick-lime, the
better to dephlegm it," is mixed with snow^ a freezing-mixture
is formed ; ' whilst Boerhave in 1732 observed that when spirit
is mixed with water a rise of temperature occurs ; and Reaumur
showed, in the following year, that a diminution of volume
likewise takes place. This contraction is greatest when one
molecule of alcohol is mixed with three molecules of water
(Mendelejefl). In order to exhibit this contraction a long glass
tube is half filled with coloured water, and then strong spirit
poured carefully on to the surfBu^e until the tube is nearly
filled and the volume of the two layers indicated. The liquids
are then mixed by shaking and reversing the tube, and the
diminution of volume noticed.

It has already been stated that alcohol and water, in spite
of the difference in their boiling-points, cannot be completely
separated by distillation. By means of a suitable fractionating
apfiamtus, spirit containing 96*5 per cent, of alcohol may, how-
ever, 1x5 obtained. On the other hand, a residue of almost abso-
lute alcohol can be procured, as Sommering observed long ago, by
diHtilling weaker alcohol off first. Thus by using fractionating
tuW'S containing 33 cups of wire-gauze a spirit containing 98
per cent, of alcohol yields a distillate containing 97*4 per cent,
and a ronidue c^nitaining 99 5 per cent, of alcohol. Hence it is
ch.*ar that a mixture of ninety-seven parts of alcohol and three
parts of water Ixnls without any alteration in composition.*

» Iknkachr. Akad. AfUnchni, 1811, 1814, 1820, 1821

« GwrMn'i HamWook, viii. 260.

» Boyl<?$ Works, ii. 611.

« Lc IW, Compt, Rend, bucxviil 912.

THE PROCESSES OF ALCOHOLOMETRY. 301

ALCOHOLOMETRY.

204 The commercial value of alcoholic liquids, except those
Dvhicb are used as beverages, depends as a rule on the percentage
of alcohol which they contain. Hence a means by which the
strength of spirit could be readily ascertained became a matter
of importance at an early date. Raymond LuUy considered
alcohol to be pure when a cloth moistened with it took fire
after the alcohol had burnt oflF, "id est aqua vitae rectificata
ut ardeat pannus madefactus in ea."

This method was employed until the introduction of gun-
powder into Europe, which then was used instead of the cloth.
This powder-test was in common use during the last century,
and from this is derived the name of proof -spirit, to which we
shall have to refer hereafter. Basil Valentine supposed that
alcohol was pure when it left no water behind after it was
burnt. This test was long used, and C. J. Geoffrey in 1718
suggested that the alcohol should be burnt in a graduated
cylinder in order to compare the volume of the spirit with that
of the residual phlegm. Bergmann, in 1775, also recommended
this process.

The so-called oil-test was likewise in common use. Michael
Savonarola (p. 285) explains this test by stating that the alcohol
is poured on to the surface of oil, and notice is taken as to
whether it remains on the surface or not. In a work published
by Michael Schrick in 1483 we find, " Oil poured on to the
surface of brandy falls to the bottom." Even at the beginning
of the eighteenth century this method was in vogue, being
believed to be a fairly accurate one.

Tables representing the contraction which ensues when
alcohol is mixed with water, as well as the specific gravities of
these mixtures, were given by R^umur in 1733-5, and also by
Brisson in the Memoirs of the Paris Academy for 1768. The first
complete investigation which had for its object the determina-
tion of the composition of aqueous spirit from the specific gravity
was, however, made at the suggestion of the English government
in the year 1790 for Revenue purposes, and Sir Charles Blagden
was employed to draw up these tables from the results of ex-
periments made by Gilpin and published in the Philosophical

302

THE ETHYL GROUP.

Transactions for 1794. Gilpin's experiments were so numerous
and so remarkably accurate that they form, even at the present
day, the foundation of the processes of alcoholometry, notwith-
standing the &ct that absolute alcohol was at that time
unknown. On the discovery of anhydrous alcohol by Lowitz
and Richter (p. 297), it was shown by Tralles,^ in 1811, that
Gilpin's normal alcohol contained 10*8 per cent, of water.
He re-calculated Gilpin's numbers, and the tables thus obtained
are those which are now in use. Tralles likewise made a series
of experiments himself for the purpose of controlling Gilpin's
results.

In France the standard alcoholometric tables are founded on
experiments made by Gay-Lussac, the results of which have
only been recently published.* These agree closely with
Gilpin's, as Gay-Lussac's normal alcohol contained 10*86 per
cent, of water. Several other investigations on this subject have
since been made. Of these we may mention those of Drink-
water,* Fownes,* and Baumhauer,^ and these very careful re-
searches entirely confirm the experiments of Gilpin. More
recently Mendelejeff ® has investigated the matter again, dis-
cussing the errors of the various experimenters, and he finds that
in the case of the most accurate of these older measurements the
specific gravity is determined to within a mean error of 0 002,
and the percentiige of alcohol to within an error of 0 '025. In
his experiments Gilpin employed the Fahrenheit thermometer,
which then was, as it now is, chiefly used in this country, whilst
iu Germany the measurements of temperature for alcoholometric
purposes were made on Reaumur's scale.

205 The proportion between spirit and water contained in the
aqueous spirit may be stated either by weight or by volume.
For scientific purposes the former expression is always used, as
this is independent of change of temperature. In commerce,
however, it is usual to employ the proportion by volume,
inasmuch as spirituous liquors are generally sold by measure.

Hence it is important to be able to calculate the composi-
tion by volume from that by weight. For this purpose some
normal temperature must be chosen, and 60"* Fahr. orlS'^o C. is
the one adopted in Gilpin and Tralles* determinations, whilst
( lay-Lussac's experiments were made at l^C

* Gilbcrtt Annalcn, xxxviii. 349.
3 Phil. Mag. [3J. xxxii. 123.

Poffg. Ann. ex 659.

• Pi>iiillet. M^m. Accul. xxx. 1859.
** Pharm. Journ. Trans, viu 375.

* Piiffg Ann. cxxxviii. 103 and 280

A LCOHOLOMETR Y. . 303

Let ^=8pec. grav. of the aqueous spirit; a the weight in
grains of alcohol in 100 parts of the same; F=the volume of
the alcohol expressed in cbc., then 100 — a = the weight of the
water, and

100 = V,S.

If further s = spec. grav. of alcohol (compared with water at
the same temperature) then the volumes of alcohol and water

contained in the spirit are - and 100 — a respectively, and hence

the percentage vohimes of alcohol and water in the spirit are

a 100 ^ ^ r 1 u 1

- • -jjr~ or a. - volumes ot alcohol,

SYS

(100 — a) . -- or (100 — a) S volumes of water.

and

For the purpose of accurately determining the percentage of
alcohol in aqueous spirit, its specific gravity must be determined
by means of a specific gravity bottle. For excise, and general
purposes, on the other hand, hydrometers are employed, special
instruments being manufactured in which the percentages of
alcohol by volume are marked on a scale. Thus for example
80 per cent. Tralles means that 100 volumes of such a spirit
measured at 60° F. contain 80 volumes of absolute alcohol
at the same temperature, but not that, when the latter quantity
is mixed with 20 volumes of water, an alcohol of the above
strength is obtained, as a contraction ensues when these liquids
are mixed.

In England the normal temperature adopted at the present
time is 5V F., and the spirit is not valued according to its
percentage of absolute alcohol, but according to the amount
of proof spirit it contains. This term is defined by the Act 58
George III. as " being sucli as shall at a temperature of 5V F.
weigh exactly j|ths part of an equal measure of distilled
water." Proof spirit, therefore, contains 49*3 per cent, by weight
or 57 09 per cent, by volume according to Tralles. Weaker
spirits are termed underproof, and stronger spirits overproof.
Thus 25** over proof means that 100 volumes of this spirit
diluted with water yield 125 volumes of proof spirit, whilst 25°
under proof means that it contains in 100 volumes seventy-five
volumes of proof spirit.

The hydrometer chiefly used in England and sanctioned by the

THE ETHYL GROUP.

^cifie Weight (8.) and CapaHly (C.) of Alcohol, at 60° P., relalire to WaU
0/6O' P. at unify (more exaeUy 12^" R. or ISg" C), at 12-6° R.-lfrS' C.

', L'ontenta of Alrohol by PeKdUtage I. b, Contenla of Alcohol by Peicsutagc
ofVolanie. 7. ;] ofWeighr. ■/.

7, [ »■

roooo

1-0000

50' 0-9343

1-0703

0-998S

1-0016

51, 0-9323

1-0726

0-9070

1-0030

62 0-9303

1-07*9

O'Bese

1-0044

53, 0-9283

1-0772

09942

1-0058

64, 0-0263

1-0795

0-9928

10073

65 0-0242

1-0820

0-9915

]-008fl

66, 0-0221

1-0845

0-9902

1-0099

57, 0-9200

1 -08-0

0-9890

1-0111

68 0-9178

1-0896

0-9878

1-0124

69 0-9150

1-0922

0-9866

1-0138

60 0-9131

1-0948

0-9854

1-0148

61 11-9112

1-0975

0-9813

1-0180

82 0-9090

l-lOi.l

0-9832

1-0171

63 0-9067

11029

0-9821

1-0182

01 0-9044

1-1057

0-9811

1-01B3

65 0-9021

1-1085

0-980U

1-0204

66; 0-8907

1-1115

0-9790

1-0216

67, 0-89T3

1-1145

0-9780

1-0225

68 0-8949

11175

0-9770

1-0235

69 0-8925

1-1201

0-»7«0

1*0246

7'i O-8900

1-1330

0-9750

1-0256

71 0-8876

1-1368

0-9740

1-0267

72 0-8850

1-1299

0-9729

1 -0279

73, 0-8825

1-1332

0-9719

r02S9

74 0-8799

1-1305

0-9709

1-0300

75 0-8773

1-1399

0-9698

1-0311

79 0-8747

1-1433

0-9688

1 -0323

77 0-8720

1-1468

0-9677

1-0334

78 0-8603

1-1504

0-9fifi6

1-0345

79 0-8660

1-1511

O-91I55

1-0357

80 0-8639

1-1577

■31

0-9043

1-0370

81 0-8611

1-1013

;32

0-91131

1-0383

82 0-8583

1-1051

0-91118

1-0397

83 0-8655

1-1689

\;u

0-9605

r0411

84 0-8526

1-1729

■ 35

0-9592

1-0435

85 0-8406

11770

3'!

0-9579

1-0440

86 0-8466

1-1812

0-9565

1 0155

87 0-8136

1-1854

31-

0-9550

88 0-8105

1 1898

39
10

0-9535
0 9519

1-0488
1-0505

89 0-8373

90 0-8339

1-1943
1-1992

0-9503

1-05-23

91 0-8300

1-2040

0-9487

1-0541

92 0-8272

1-2089

0-9470

1-C560

93 0-82.17

1-2140

■41

0-9452

10580

94 0-82O1

1-3194

i45

0-9435

1-0599

9B 0-8164

1-3340

141

0-9417

1-0019

96 0-8135

1-3308

0-9399

1-0639

97 0-8084

1-2370

0-9381

1-0660

98 0-8tiir

1-2136

|4fl

0-936-2
09343

1-0683
1-0703

99 0 7995
100 0-7916

1-2308
1 ■2.185

1-0000
00981
0-0963 j
0 0044

U-9751

0-9739

0-9727

0-9714

0-9702

0-96911

0-9677

0-9664

0-8651

0-9837

0-9622

0-9607

(1-9592

0-9577

0-8560

0-9644

0-9520

0-9508

0-9490

0-9472

0-9453

;iH

0-9433

0-9113

0-9394

46 I 0-9309

47 I 0-9210
18 0-9337

53 0-9116

54 0-9091

65 0-9072

66 0-9019

57 0-9027

58 0-9001
69 0-8981

60 0-8958

61 0-8935

62 0-8811
03 0-8888
S* 0-8805

07 0-8795
68 0-8772

1-1370,
1-1400 1

09 0-8748

11131

70 0-8724

11493

71; 0-8700

1-1494

72 0-8676

1-15-20

73 0-8652

1-1558

71, 0-8629

1-1589

76 0-8605

1-1621

70, 0-8681

1-165*

77 0-8667

11686

78 0-8533

1-1719

79 0-8509

11753

80 0-8484

11787

81 ; 0-8468

1-1822

82 0-8435

1-1856

83, 0-8409

r!802

84 0-8386

1-1929

85' 0-8350

1-1963

80 0-8333

1-2000

87 0-8307

1-2038

88 0-8282

1-207* ;

80 0-82,W

1-2112 1

90 0-8229

1-2152!

91' 0-8203

1-2191

B2 0-8170

12231

93 0-8149

1-2272

94 0-8122

1-281 a

95 0-809*

1-23.55

90 0-8O65

1-2309

97 0-8030

1-244*

98 0-8006
09 O-TllTA

1 -2*91
1 -2537

SYKES'S HYDROMETER.

Excise is known as Sykes's hydrometer, Fig. 79. It is mado of
metal, and has a four-sided st«m divided into ten equal parts,
fitting into a brass ball, carrying a small
conical stem, terminating in a pear-shaped
loaded bulb. The instrument is also pro-
vided with nine circular weights numbered
10, 20, 30, 40, 50, 60, 70, 80, 90, each
having a slit by which it cau be fixed on
to the stem. The instrument is so
adjusted as to float with the zero of the
scale coincident with the surface of the
liquid when it is immersed in spirit having
a specific gravity of 0-82.J at 60°, this being
the standard alcohol of the Excise. If the
alcoholometer be placed ia weaker spiiit
than this, it will need to be weighted, in
order to bring the zero point to the level
of the liquid; and the sum of weights,
together with the number on the scab at
the level of the spirit, give by reference to
a table the quantity of proof spirit con-
tained in the sample.

As the alteration of volume effected in
spirit by the variation of a few degrees of
temperature is considcmble, the reading
on the hydrometer will only be correct at
the normal temperature. As. howevcf,
this point is dlHicuIt to attain, Gilpia
determined the specific gravity of aqueous
spirit of diflferent strengths at differeut
temperatures. All these tables were re- Fio. 79.

calculated by Tralles, and have since his

time been corrected by the investigations of Brix, ' von Kupffer,*
and others.^

By the help of these results, a table of corrections is obtained,
by means of which the true percentage of alcohol contained
in any spirit at any given temperature may be ascertained
from its apparent percentage iis read off on the hydrometer
{sfe Tables pp. 306-7).

' Das AlhMlnin^tet, he., IV'rliii, 1864.

• na«Ah. AU-olmhmclrir, B.-llill, 1865.

• Stc alio Watts'M nictionan-, vol. i. nrticlf " Akoholoinplry."

THE ETHYL GBOUP.

IS
iS

j t

hi-

III I

S eTw"-;=-c»of«^-»=-«'Vrf'w-^'-o- o.--Mef rfV-o

" «■«-•=■ cT a «t--oB.-,oVn-n-r--o- <=n,-ef««»>o

3 , 1 2"«-SS2-rf"-"°-S-«-v«-«-S--2- o---3S«-"-S

a , ; B-M--^-o-ffl.c't--<-»0'r'nei-».'--o' <=-^-e»'rf-.fV«i-

' g »-,**.--.-o*o«f<-J.--<D-o*-«««-o' o'-'M-n-VrfB

, 3 -'««* 2 ;:£"•■ »-"»>«"«''■««'-■= <9"-«« Vvf«-

'= ' «-.-n'rrn-S'S-s-»-^-5s^'«-S"-3- sr-S'B-52-s-

' B 1 ' 2 iss's'sn's'* '■'■■'= "-■''""■"''=' 'f-c*'>^"«»

n ■ .i2''^"2'H'::s"=--""'-'-"-'""^"'* ?"'"«"5

1 1 <"- 1- 5E IS 'o i.-n,-ni ,.-1 n ei m Ti rj CT " "'■- ■- — — = o»

£. i b«c:i = cce-me:>-'e»o?> «.<=F.a>-»«

ALCOnOLOMETRY.

Mil, r,TrriTi ,-| - , ,

o'of-'-*—* wef

|NiMMiS5;.5-.:.:.53

oo^-- ««-«-,

M ' ' 1 1 oV*»«»Mo.-.--^-o-o-

o-o«---er«-rf

e,„^o„„„

-i

-1

[11''! «.■«'«-• V «■«■*■ 5- --5 5-

^•53355;-

! l55~-S5S5S5;:-5335;

=■ S' B »' L- .- 5 iTo .- * « IN ,! -■ = =•

^■s-:-3S5v

s-5a:-5:!-;;-5s-:-:-«-s-3:-5s-

p.....

=- o'oTb «■ tC«- o «■ «- ,-« no.-- = o-

o =---««' W

; -■ a »■»- «- r.'.~' o « « *' *-«- el nJ *- 3-

~ M a r- v-w n ri
oo'r--ei-«---.o

■

ll.

[ So-o-SSS'-So'c-^J^SSSS

M j

^- = ='a «r« r.- o o-« ^- ^' » «• -* o'o-

oo-^-eJ«^-« ■

i-i

t""""

— ;-.- ^T--*-w «-i,TT^-BS-«*-«-BO-o.-

I M -- =- o" a aTr-'t-' o « «■ »'»' « ^- ^' e

o--'n-«Vo-

'=..^.„

o -r--ef «--*-«-

u :

i S-^"^'o-a'S'S-'-S-S3-Vn-S---3S-

-0,2

i|b

2.9
8,7

6|6

t> r'"-""""""""""--

22L~2SSS 1

308 THE ETHYL GROUP.

206 Determination of Alcohol in Beers and Wines. — The
percentage of alcohol contained in liquids such as beer, wine, &c.,
in which other materials besides water and alcohol are present in
solution, cannot be directly ascertained by the use of the hydro-
meter. In such cases the simplest plan is to take a measured
volume of the liquid and to prepare pure aqueous alcohol from
this by distillation, and then to determine its volume and specific
gravity. For the purpose of making such estimations, which often
require to be quickly and accurately carried out, an apparatus has
been devised by Descroizelles, which was afterwards improved by
Gay-Lussac, and others. Savalle uses an apparatus, the construc-
tion of which depends upon the same principle as the rectifica-
tion of spirit and is shown in Fig. 80. The liquid to be exa-
mined, several liters of which should be used, is brought into the
still, a, and heated with gas to the boiling point. The vapour
passes through the tube 5, to the worm c, cooled by the water
d. When the water in c becomes warm, the vapours condense in
the cooler, and the distillate is collected in the cylinder e. For
liquids which do not contain more than 16 per cent, of alcohol it
is only necessary to distil off one-third ; if they contain more, a
larger amount must be driven off. In this way 5 liters of wine
give 751 cbc. of a distillate containing 56*99 per cent, and hence
the wine contains ""^^^^ = 856 per cent. By means of this ap-
paratus the amount of spirit in weak alcohols can be ascertained
even when they contain as little as 0*01 per cent.

If only a small quantity of liquid be at disposal, Gay-Lussac's
wine-tester as modified by Mohr may be employed, and by
means of this instrument the quantity of alcohol in so small a
volume of liquid as ten cbc. may be determined with tolerable
accuracy. For this purpose 10 cbc. or a larger volume, is
measured out in a pipette, and brought into the flask. Fig. 81,
an equal volume of water added, and the whole distilled over
into a small wide flask upon the neck of which a mark is made,
indicating exactly the same volume of distillate as that of the
original wine or beer. In order to prevent the liquid from
bumping it is advisable to add a small quantity of tannic acid,
and to distil the liquid until the distillate comes nearly up to
the mark. The distillate is then cooled to the normal tem-
perature, and water added to fill up to the mark, and the
whole again weighed. The weight in grams divided by the
number of cubic centimeters gives the specific gravity. Another
arrangement for distilling wines is shown in Fig. 82.

KffriMATION OF ALCOHOL IN WINEa

307 The ebullioscope is an iD&trument by means of which the
amount of alcohol in a liquid can be determined by ascertaining
its boiling point, na this is higher the less alcohol is contained
in it. YariouA kinds of instruments of this sort have been
made. Fig. 83 shows the construction of Fohl's ebullioscope.

Usually the thermometer has an empirical division from which

the percentage amount can he directly read off. According to

Griessmaycr ' the ebullioscope of UalHgand * is the best for the

' DiDgler, Polyl. Journ, ccxHii. 282. ' Campt. lUnd. Ixm.-llll.

TEsrriNa of wines akd beeks.

determinatioD of the amouut of alcohol contained id beer and
wine, icasmuch as the process is much simpler and quicker
than by the method of distillation. For over-proof spirit this
method is, however, perfectly useless, because the difference in
boiling-point becomes very slight for a considerable difference
in the percentage of alcohol.

Fig. H^ shows Crockford's patent spirit indicator, as described
in Tliudicumand D up re's treatise on wines. A small condenser
13 fixed on the top of the boiler to prevent loss of alcohol during
boiling.

208 Another instrument designed with the same object
depends upon the determination of the tension of aqueous alcohol
at 100° as determined by Plucker.' The instrument, shown in

THE ETHVL GROIT.

Fig. Hq, has been made by the well-koown glass-blower Gelssler,*
and termed by him the raporitneUr. The tube (o) Fig. 85
lirst contains merairy up to the mark, and then is filled
completely with the beer or wine to be examined. It is then

fMtene<l tnt^i lh<: ground neck of a Ryphon barometer tube
(B), ibtH lifiiin placed in a vertirnl position, and then
exposed t> the action of steam coming from boiling water,
when the ]i<]ui<l evolves a large quantity of vapour and
the nierniry in the tube if) driven up tn a certain height

' P-liri. C'almlh. 1S34, 14^8.

CBOCKPORD'S PATENT SPIRIT ISDICATOR.

according to the amouot of alcohol contained in the liquid.
An empirical scale is placed on the barometer tube by

Tta. 85.

means of which the percentage of alcohol can be rend off.
Should the liquid under examination contain carbon dioxide.

THE Ermx GRorp-

tbis gas must, of cuurse, be removed before tbe opention,
aiid this is best effected by ahaking it with
freshly barnt lime. If the solution contain
a large quautitr of dissolved matter, the re-
sults are usually inexact, and, in this case, a
given vulume of the liquid is distilled off and
this treated as abovK described.

Alcohol expands on warming much more
rapidly than water; and founded upon this pro-
perty Silbermann* has described an inatniuent
termed a dUaiomeUr (Fig. 86). This conaista
of a thermometer tnbe baring a scale etched
upon it, into which a certain volume of the
liquid is brought at £5°, and the expansion
•jbser\'ed which this undergoes in heating to

.-,o\

Many other methods are employed for de-
tenniuing the strength of alcoholic liquidB.
For a (lescription of these wo must refer to
the uiidermentioued works.*
''"'■ *^- 309 The following table gives the percentage

4if alrohul cuntaiuc-d in vatiou.o wines and other fermented

liqiK

P. It (old bottled) .
,, (newly bottled)
Montilla sherry (1S.'>4
Fine Marsala
Madeira , . . .
Jit-auue ....
< iberingelliciuit r
Asiiman nshiiuacr
( 'hatcAU-Latitte
Urdiuary Bordeaux
.loliannisborger (\mi]
Kiidosilieimer
Aucrbachcr ...
Burton Ale . .
Kiliiibur^h Alo . .
London Porter . .
Munich Lagcrbicr .
Sflienkbier . . .
BiTlin Weissbier

io-i

161

13:>

9 +

;V7 to 61
5 -t to 6-9

i. 2A7 ; Slammer, BnttkHltrrinbrftitif

ALCOHOL IN WINES AND BEERS. 315

The value of a wine does not, as is well known, depend upon
its percentage of alcohol. Thus, the price of Chateau Lafitte
containing only 8*7 per cent, is much higher than any ordinary
port containing about 20 per cent. So, too, the percentage of
sugar and of acids contained in the wine may be almost
identical in the case of different wines of the same class, as for
instance, in clarets, but the value of these various clarets may
be very different. On the other hand, it appears that the total
amount of solid constituents contained in a pure wine bears a
very distinct relation to its value, which is also of course greatly
determined by its bouquet

In order to show the presence of alcohol in beer or wine the
liquid may be boiled in a flask having a tube 1^ m. long and
1 cm. wide fastened to it, and which serves as a rectifying
column so that the alcohol vapour becomes so concentrated that
it may be lighted at the end of the tube.^

When pure alcohol is taken in small quantities in the form
of good beer or pure wine it appears to improve the diges-
tion by an increase of the secretion of the gastric juice.
Especially for old persons and those having weak digestions
it is useful, and indeed wine and spirits are frequently termed
the milk of old age. In large doses however it acts as a
powerful poison.

After the imbibition of alcohol small quantities of this sub-
stance are found in the urine. ^

The feeling of warmth experienced after indulgence in alcohol
is a subjective phenomenon, as the temperature of the body sinks
under such circumstances from O^'o to 2°'0, according to the
quantity of alcohol taken. ^ If alcohol be taken during a
meal no such diminution of temperature is observed.*

The higher homologues of ethyl alcohol exert a still more
distinct physiological action than common alcohol does, and to
these is especially to be ascribed the evil effects which ensue
from an indulgence in common brandy.^ Manufactured wine
also produces, even when taken in small quantity, headache
and unpleasant symptoms, whilst pure wine does not produce
these effects unless it is taken in excess. Wine is manufactured

' Tollens, Bcr. Deutsch, Chem. Ges. ix. 1540.

' Lieben, Ann. Chem, Pharm. SuppL vii. 236 ; Dupre, Pi'oc, Roy, Soc. xx.
2..8.

» Binz. Ber. Daitsch. Chem. Ges. v. 1082.

* Parkes, Proc, Hoy. Soc, xxii. 172.

^ DnjardinlWaumetz and Audige, Compt. Rend. IxxxL 1/>2.

316 THE ETHVL GROUP.

bj Gall s proces bj the adibcion of starch sugar before fer-
mentation to a grape-must poor in sugar. The starch sugar i^
obtained from potato-starch, and is. hoirever, not pore, but leaves
behind a qoantitv of unfermentaUe residue, which, as experi-
ments with dogs have shown, acts in a similarly poisonous
manner to potato fusel oiL^

2IO Uses of Alcohul in tlur Ari^ — Pure as well as impure
spirit of wine is used for a great variety of purposes. In the
first place, strong alcohol is largely employed as a fuel, as
it rearlily bums with a non-luminous and smokeless flame.
Before Bunsen invented his well-known gas-lamp, spirit-lamps
were in general use in almost all laboratories.

In the second place, it is largely emjdoyed both in the arts
and in scientific investigations as a solvent, and as a means of
separating one substance from another. This depends on the
fact that many bodies which are insoluble or difficultly soluble
m water, dissolve in alcohol, and, on the other hand, that mxay
substances readily soluble in water do not dissolve in this
menstruum. Thus, for example, the carbonates and sulphates
of the metals are insoluble in alcohol; whilst some chlorides,
bromides, and iodides readily dissolve, others again not possess-
ing this property. Raymond Lully observed long ago that this
substance creates a turbidity in a solution of ammonium
carlK>nate : ''Hie etiam spiritus (animal is) habet proprietatem
congelandi spiritus vegetabilis vel aquam vitae perfecte rectiti-
catum. Nam earn in salem convertit, qui plurimas proprietates
et virtutes excel lentissimas habet." Boyle showed in 1675 that
stron;( alcohol precipitates a saturated solution of common salt,
and Boulduc in 1726 employed alcohol for the separation of
salts in mineral-water analysis. In 1762 Macquer determined
more exactly the solubility of many salts in alcohol, and
Lavoisier, as well as Bergmann, used this solvent in their
analytical researches. At the present day its employment in
analysis is somewhat restricted. It is, however, used in
qualitative analysis for the separation of strontium chloride
from barium clilori<le, an<l in quantitative analysis for washing
preci])itates which are slightly soluble in water, such as lead
HuI])hato, lea^l chloride, potassium platinichloride, ammonium
platinum chloride, &c.

Sjiirit of wine is likewise employed in the laboratory for the
purification of commercial caustic potash which dissolves in it,

» Schmidt, Bitderm. Ctntralbl, 1879, 712.

METHYLATED SPIRIT. 317

leaving a residue of carbonate, sulphate, alumina, &c. Amongst
the solid and liquid elements, phosphorus and sulphur dissolve
slightly in alcohol, and iodine and bromine to a much larger
extent

Some gases are absorbed by alcohol even in larger quantity
than by water. In this respect the hydrocarbons are especially
distinguished. The coefl&cients of absorption of the different
gases in alcohol have been determined by Carius.^

Alcohol is used as a solvent especially for ethereal oils, resins,
alkaloids, and many other carbon compounds which are insoluble
or difficultly soluble in water. For this reason it is em-
ployed in the preparation and purification of such compounds,
and it is also used for the manufacture of tinctures, essences,
liqueurs, perfumes, colours of various kinds, varnishes, lacs,
polishes, &c.

Methylated Spirit, — For most of the above purposes methylated
spirit is employed instead of pure alcohol. In this country a
heavy excise duty on spirit of wine has always existed, and
the manufiacture and sale of this aiticle is placed under strict
supervision. Hence many branches of manufacturing industry,
as well as the investigations of the scientific chemist, were, in
this country, much impeded, until in 1856 the late Mr. John
Wood, Chairman of the Board of Inland Revenue, obtained
Government permission for the manufacture of methylated spirit
which is sold by licensed dealers free of duty. This substance
is a mixture of 90 per cent of spirit of wine of density not less
than 0830 sp. gr., and 10 per cent, of purified wood-spirit. Such
a mixture is unfit for human consumption, and the wood- spirit
cannot again be separated from the spirit of wine by any
commercial process.

Methylated spirit is largely used instead of pure spirit in the
manufacture of the aniline colours as well as of ether, chloro-
form, fulminating mercury, iodide of ethyl, olefiant gas, and a
number of other substances. The same mixture is used for the
preservation of anatomical preparations, and of small animals
and other zoological specimens.

The possibility of thus obtaining cheap alcohol has moreover
beneficially influenced the recent progress of organic chemistry
in this country.^

* Ann. Chem. Phann, xciv. 129.

' " Report to the Chairman of Inland Uevenue on the Supply of Sprit free
from Duty," hv Professors Graham, Hofroann, and Redwood, Quart. Jmim. Chatu
iS'oc. viii. 120 (1856).

318 THE ETHYL GKOUP.

211 Detection ofAkolwh — In order to detect small quantities of
alcohol in an aqueous liquid, it is gently warmed, a few crystals
of iodine added, and then so much caustic potash that the
solution just becomes colourless, when, either at once or after a
short time, a bright yellow precipitate of iodoform is thrown
down. In this way one part of alcohol may be detected in
2,000 parts of water, but in the case of such dilutions the liquid
must be allowed to stand for a night in order to allow the pre-
cipitate to subside. The deposit consists of microscopic six-
sided tablets or six-sided stellar groups.^

Alcohol may be detected in presence of ether, chloroform, &c.,
by withdrawing it from such liquids by shaking with water, and
then acting on the aqueous extract as above described. It must,
however, not be forgotten that several other substances yield
iodoform by the same reaction.

Another good reagent for alcohol is benzoyl chloride. K a
few drops of this be added to dihite alcohol and the mixture
gently warmed, ethyl benzoate is formed. As, however, the
chloride is only slightly decomposed by water, it is better to add
caustic potash when the characteristic smell of the ether is
rendered evident. By means of this reaction 01 per cent, of
alcohol may be detected.^ It must, however, be remembered
that other alcohols treated in the same way yield ethers
possessing a similar smell.

If large quantities of an aqueous liquid have to be examined
for alcohol, it is, of course, best to fractiouate the liquid, the first
portions coming over being collected and concentrated, until,
on addition of potassium carbonate,' a layer of light liquid
separates out, which then can be further examined (Lieben).

In order to (hitect the presence of fusel oil in spirits of wine,
the simplest plan is to pour a fow drojw on to the hand and rub
the palms together, when evaporation takes place, and the more
dithcultly volatile fusel oil remains on the skin and can readily
be detected by its unpleasant smell. A more reliable process,
however, is to allow the liquid gradually to evaporate in an
open glass dish, and then to notice the smell of the residue.
As fusil oil consists chiefly of higher homologues, the spirit
under examination may be oxidized by the action of a solu-
tion of potassium dichromate in dilute sulphuric aci«l, when
acetic acid is mainly produced, together, however, with it«?

- Hcrtlu'lttt, *'*nttftt. limti, ly.xiii. 4i»»J.

DETECTION OF ALCOHOL. 319

homologues, if fusel oil be present. These latter, in contradistinc-
tion to acetic acid, distil over first with the aqueous vapour, and
from the smell of the first portions of the distillate it ia often
possible to detect the presence of the higher homologues of
acetic acid. A more certain plan is to saturate the acid dis-
tillate with baryta-water, and to determine the quantity of
baryta contained in the salts produced.^

It sometimes happens in this country that the unpleasant
smell of the methylated spirit is partially removed by means of
acids or oxidizing agents, and that the spirit thus obtained,
though still containing methyl-alcohol, is sufl&ciently tasteless
to be used for adulterating the commoner kinds of whisky and
other alcoholic liquors. According to Dupr^ such an adultera-
tion may be detected by Geissler's vaporimeter, as the tension
of methyl alcohol is much higher than that of spirits of wine.
Its presence may also be ascertained by oxidizing the spirit as
above described ; in presence of methyl alcohol an evolution of
carbon dioxide is, under these circumstances, observed.

Methyl alcohol, as well as its various derivatives, are largely
used (as has been already stated) for the preparation of aniline
colours. The wood-spirit used for this purpose must, however,
not contain any ethyl alcohol, as the presence of this substance
greatly influences the shades of the colours produced. In order
to detect its presence the alcohol is treated with permanganic
acid, which oxidizes the methyl alcohol to carbonic acid and the
ethyl alcohol to aldehyde. The mixture is then distilled, and a
solution of rosaniline, rendered acid by sulphuric acid, added
to the distillate. If the methyl alcohol be pure this will
remain yellow, but in the presence of aldehyde it becomes
violet or blue coloured.^ The alcohol to be tested may also be
heated with double its volume of concentrated sulphuric acid,
whereby the methyl alcohol is converted into methyl ether, and
this is readily soluble in water and concentrated sulphuric acid,
whilst ethyl alcohol is almost entirely resolved into olefiant gas,
which is only slightly soluble in water and dissolves but slowly
in sulphuric acid, and is easily recognised, and its quantity ascer-
tained by its reaction with bromine. The other bodies usually
present in common wood-spirit do not yield any ethylene, and in
this way 1 per cent, of alcohol may be readily detected.^

^ Dupre, Pharm. Journ. Tram. (3) vi. 867.
^ liiche and Bardv, Compt. Rend, Ixxxii. 768.
^ Berthelot, rompt. nnid. Ixxx. 103i'.

320 THE ETHYL GROUP.

212 Decompositions of Alcohol, — ^Alcohol serves as a point of
departure for all other ethyl compounds. These can be obtained
from it by various reactions, and hence the action of chemical
agents on alcohol has been most carefully examined. In some
of these, the radical ethyl remains unchanged, whilst in other
reactions, however, the radical undergoes alteration. Thus,
for example, by a moderate oxidation, aldehyde, CjH^O, and
acetic acid, CjH^O,, are formed. This change can also be
brought about by the oxygen of the air, but not immediately,
for concentrated as well as dilute spirit of wine are not at-
tacked at the ordinary temperature by oxygen. If, however,
platinum-black be mixed with alcohol, or if this powder be
placed on paper and moistened with alcohol, oxidation takes
place, accompanied by an evolution of heat and followed by
ignition of the alcohol. Addition of water diminishes the
intensity of this action. Upon this observation of Edmund
Davy's, Dobereiner founded his vinegar-lamp. This consists
of a flask filled with alcohol, in the neck of which is placed a
glass funnel, upon which slightly moistened platinum-black
is spread, whilst a piece of cotton wick brings the alcohol into
contact with this powder. The flask or bottle stands on a
dish, over which a glass bell-jar is so placed that a small
amount of air is allowed to enter. In this way the alcohol
undergoes oxidation, the vapour of acetic acid being formed,
and this gradually collects on the inside of the bell-jar. Accord-
ing to Dobereiner, platinum-black used in this way is an
excellent means of detecting small traces of alcohol. If a drop
of alcohol be allowed to evaporate in 50 or 60 cbc. of air and
a small quantity of platinum-black put into this, the formation
of acetic acid can be readily noticed.^

When strongly heated platinum wire or platinum foil is
brought into a mixture of air and alcohol vapour, the metal
gradually becomes heated to redness (Vol. II. Part II. p. 307).

Whilst pure alcohol does not undergo spontaneous oxidation
on exposure to air, beer or wine soon becomes sour with
formation of acetic acid. This depends on the presence of nitro-
genous Ixxlies, which act as carriers of oxygen from the air to
the alcohol.

Oxidizing bodies, according to their nature and the mode in
which they act, convert alcohol into other products in addition
to alcohol and acetic arid. Thu.s, for exam])le, if strong nitric

* Ginclin's Unndbookf viii. *J07.

ALCOHOLATES AND ETHYLATES. 321

acid be added to alcohol, an explosive action takes place, and,
in addition to the oxides of nitrogen and the above-named com-
pounds, we find amongst the products ethyl nitrate, fonnic acid',
oxalic acid, hydrocyanic acid, &c. A more moderate action
yields chiefly glycollic acid, and aldehydes of oxalic acid.

A mixture of dilute sulphuric acid and manganese dioxide,
as well as a solution of chromium trioxide, yield acetal,
CjH^COCoHJg, together with aldehyde and acetic acid. If,
however, strong alcohol be dropped on to dry chromium tri-
oxide, ignition and complete combustion take place.

Alcohol is also readily acted upon by chlorine and bromine,
oxidation-products being first formed and then substitution-
products being produced, the description of which will be found
later on.

Alcohol vapour may be heated to 300° without decomposition
occurring. At a red-heat, however, dry distillation commences,
hydrogen, marsh gas, ethylene, acetylene, benzene, naphtha-
lene, carbon monoxide, aldehyde, acetic acid, phenol, &c., being
produced (Berthelot).

The Alcoholates.

a 13 This name was given by Graham to compounds discovered
by him in 1828,^ and formed by the combination of anhydrous salts
with alcohol, the latter substance playing the part of water
of crystallization. Other chemists have increased our know-
ledge of these compounds,- and from these investigations it
appears that only those salts form alcoholates which are easily
soluble in water, and which usually contain water of crystal-
lization. The following are some of the more important of
these :

LiCI + 4C2H^O, is formed with evolution of heat when lithium
chloride is brought into contact with absolute alcohol. It
crystallizes on cooling in nacreous glistening prisms.

CaClg+^CgHgO, is produced in the same way as the foregoing ^
compound, and forms a white crystalline mass.

MgClg + GCgHj^O corresponds closely to the lithium compound
and is very deliquescent.

» Phil. Mag iv. 26,'>, 331.

^ Cboilncw, Ann. C/o:m. Pharm. Ixxi. 241 ; I-.€vy, Ann. Chim, Phys, [3], xvi.
309 ; Robiquet, Journ. dc Pharm, [3], xxvi. 161 ; (le JiUyncs, Joiim. Pr. Clitin,
Ixxx. 503; Bauer, ih. Ixxx. 3r»l ; Simon, ih, [2J. xx. 371.

VOL. III. Y

y&*t TliE ETHYL GEOr?.

Mg'NO^j-rCCjH^O forms a peariy orysiaLiae
In ^^YvCihu to these, manT other chlorides and nitrates, as well
as certain bromides, form alooholates.

Ethtlates,

214 Tbe^se componnds are formed from alcohol by the re|daoe-
ment of the hydrogen of the hydroxyl by metals, and this may
be accomplished in a variety of ways. The ethylates are readily
decompose'l by water with formation of alcohol and the cor-
responding hydroxide.

Potavnt/m Ethjflate, C^H^OK. Potassium dissolves in abso-
lute alcohol with evolution of heat and liberation of hydrogen.
Tran.sparent colourless crystals separate out on cooling the con-
centrat^.'fl solution, and these contain alcohol of crystallization.

fi/xlium Ethylnte, C^H.ONa, is obtained in a similar way,*
and forms a mass consisting of transparent needles, which
liave the composition C^H^ONa 4 2C2H^O. The alcohol of
crystallization is easily lost in a vacuum over sulphuric acid.
Wanklyn obtained crystals of the formula C\H.ONa + 3CjH^O,
melting at 100' without losing their alcohol of crystallization,
which, however, escapes at a higher temperature, and is com-
pletely rlriven off on heating to 200'. The comjx>und, free from
alcohol, is a light amorphous powder, which, when prepared in
:i\mtu('M of air, is perfectly white, and may Ik? heated to 290*^
without any <lecoinposition taking plar e.-

ThnU'uivi KthylcUr, C2Hr,0Tl, is formed by the action of
alcohol vapour on finely divi»led thallium. It is a colourless liquid
having a sjKJcific gravity of 3*5."), and possessing a refracting
pr)w<»r as strong as that of carbon disulphide. It solidifies at
-.T, ;ind is easily inflammable, burning with a bright green
flame. ^

linrivm Ethyl ntc, (C2H.0)^Ba, is formed by dissolving anhy-
drous baryta in al)solute alcohol and boiling, when a precipitate
is thrown down. This must be dried at 100"* in a current of
hydrogen, and is difficult to obtain in the pure state.*

Zinr Etkyhte, {fj^r())Jun, is a white amorphous mass formed
by the slow oxi<lation c»f zinc etliide,

^ (viH'riti Varn*. Journ. S'-irnfr Phijs. iil 273.
- Wanklyn, Phil. Mmj. [41, xxxvii. 117.
' Lnniv.*'W»;>/. nnvi. Ixv.' 8-J»5 ; lix. 780.
* llerllii'lot, //«//. Si^. rfiim, [21, viii. 389.

ETHYL ETHER OR ETHYL OXIDE. 323

Aluminium Uthylate, (C2iifi)QA\^ This is formed by the
action of iodine and fine aluminium foil on alcohol, hydrogen
being given oflf, whilst the compound (021150)3 Algl, is also formed
in small quantities ; when the whole is heated to 270°, the latter
compound decomposes into ethyl iodide and alumina. If the
residue be distilled in a vacuum, or under diminished pressure,
aluminium ethylate passes over, solidifying to a yellowish white
mass, melting at 115°, and boiling at the same temperature as
mercury.^ It is somewhat soluble in absolute alcohol, and is
quickly decomposed by water.

ETHYL ETHER OR ETHYL OXIDE.

a 15 Raymond Lully, as well as Basil Valentine, examined
the action of sulphuric acid upon spirit of wine, and hence it is
generally assumed that they were acquainted with ethyl oxide, or
ether, as it is still generally termed. This is possible, for Basil
Valentine speaks gf a spirit obtained in this way which has
a " subtle, penetrating, pleasant taste, and an agreeable smell."

We owe our special knowledge of the existence of ether to
Valerius Cordus, a German physician, who died in Italy in
1544. His process for the preparation of this body was pub-
lished by Conrad Gessner in 1552, and occurs in the later
editions of the first German Pharmacopoeia, this work, which
was first published in 1535, having been re-edited by Cordus
at the request of the Council of Nuremberg. Accordmg to
this receipt, equal parts of thrice rectified spirit of wine
and oil of vitriol are allowed to remain in contact for two
months, and then the mixture is distilled from a water- or sand-
bath. The distillate consists of two layers of liquid, of which
the upper one is the oleum vitrioli dulce vcrum.

Various chemists mention this body, but at the beginning
of the eighteenth century the details of its preparation appear
to have been almost entirely lost, although, at this period, a
mixture of spirit of wine and ether was used in medicine ;
indeed it seems not improbable that Paracelsus employed such
a mixture. It was, however, first brought into commerce by an

' GlaUstone, Joum, Chem, Soc, 1876, i. ir»8.

Y 2

324 tup: ethyl group.

apothecary in Halle, under the name of Panacea Vitrioli, and
afterwards having been recommended by Hoffmann, it received
the name of Liquor anodymi8 Hoffmanni, or Hoffmann s drops.
Under this name it soon became generally known, and even to
the present time is thus designated in Germany. The pre-
paration of this medicine was long kept secret, and the positive
existence of ether was not proved uutil it was first prepared
free from spirit of wine, and then it was found that it swiius
on the surface of water, and is not miscible with this liquid.

In 1730 Sigismund Augustus Frobenius published a memoir
in the Pliilosophical Transactions,^ entitled, " Of a spiritits vini
athereuSy* in which he describes, in general terms, the pre-
paration of this compound, though without giving any details.
Ho manufactured the ether in Godfrey Hanckewitz*s laboratory,
and as he sold it at a high price, he endeavoured to keep the
process a secret one, and in forwarding some of the new substance
to St. F. Geoffrey, he writes, after extolling its virtues, as
follows : " Paratur ex sale volatili urinoso, plantarum phlogisto,
aceto valde subtili, per summain fermcntationem cunctis sub-
tillissime resolutis et unitis." On the 18th November, 1731,
he made experiments with ether and phosphorus before a
meeting of the Royal Society, which are thus described
by Dr. Mortimer, the secretary : ^ " He took a solution of
phosphorus in the ethereal spirit of wine, which he called
Liquor lurninosds, and poured it into a tub of warm water,
whereuj>on it gave a blue flame and smoke, attended with so
small a degree of heat as not to burn the hand if put into it
He i>oured some of his ethereal spirit of wine upon a tub of
cold water and set it on fire with the point of his dagger (which
being first heated a little, he touched with it a ])iece of phos-
phorus lodged beforehand on th6 side of the tub). After the
deflagration the water was cold."

In his second oommunication to the Societv he described
more fully his method for the preparation of ether ; this descrip-
tion was, however, at his request not made public until after his
death in 1741, when the following receipt was published by the
secretarv : ^

*' Take 4 lbs. in weight of the best oil of vitriol, and as much
in weight (not measure) of the best alcohol, or the highest
rectified spirit f'f wine.

» xxxvi. 2ji3, Fcl). 19. 17-J0-3O. = Phil. Trans, Al.sJr. ix. .M72.

=* Phil, Tram. Abiitlg. ix. :5M>.

HISTORICAL COXCEllXIXG ETHKI^. S26

** 1. First, pour tho alcohol into a chosen glass retort, then
pour in, by little and little, ^ of oil of vitriol ; then shake the
rotort till the two liquors are thoroughly mixed, when tho retort
will begin to grow warm; then pour in more of the spirit of
vitriol, and shake it again; then the retort will become very
hot. Do not pour in the spirit of vitriol too fast, or too much
at a time, lest the glass rotort, by being heated too suddenly,
should burst; you must allow about an hours time for pouring
in the spirit of vitriol, not pouring in above an ounce at a time,
and always shaking the retort, till the whole quantity of the
jwnderous mineral spirit is intimately united with the light
inflammable vinous spirit.

" 2. In the next place, examine witb^our hand the heat of
the glass retort, and have a furnace ready, with the sand in
the iron pot heated exactly to the same degree as acquired
by the mixture of the two liquors ; take out some of the
sand, and, having placed your rotort in the middle of the iron
pot, put in the hot sand agaia round the retort, and apply a
capacious receiver to it ; set it into cold water, and wTap it over
with double flannel dippe<l in cold water.

" Raise your tire gradually, that the drops may fall so
fast that you may count Ave or six between each, and that,
iK'Side this quick discharge of the drops, the upper hemisphere
of your receiver ap{x?nr always filled with a white mist or
fumes; continue this heat as long as they emit the scent of
true marjoram. As soon as the sn)ell changes to an acid,
suffocating one, like that of brimstone, take out the fire
and lift the retort out of the sand, and change the receiver,
for all that aiises afterwards is only a mere gas of brimstone,
and of no use.

" If you do not use the greatest precaution, the liquor in the
retort will run over ; the fire must cease as f oon as the ethereal
spirits are gone over, for there remains behind an oleirm vini,
v.hich is extracte<l by the foice of the acid out of the spirit,
which will arise, run over, and often cau.se explosions.

" The second day, when your gla.ss is cold, infuse the
remainder with half as much alcohol, and distil again as
before, and you will have the same ; the third day again
with as much, and proceed as at first, it gives it again. Go
on as long as you can obtain any (of the ethereal spirit)
till all turns to a carlo ; then separate it, and alcalize it with
spirits of sf/if. ffnna/iitfr made without spirits of wine, till all

:;2C THE ETHYL GROUP.

c-nen'esceDce ceases, and distil it once more € Balneo Maria;
M> is it ready for experiments.'*

This mode of making ether was soon pretty generally adopted ;
various German and French chemists having occupied them-
strives with the preparation of this body. Amongst the more
complete d^.-scriptions of the substance may be mentioned
Baume's Dis^iertation sur lether (1757).

By reason of its easy inflammability it was also called at this
time ** naphtha/' a name originally given to rock-oil, whilst at
the same time it was termed vitriolic ether, sulphuric ether, or
ellur suiphnricus, and vitriol-naphtha, or naphtha vitrioli, inas-
much as it was obtained by the action of sulphuric acid on
;dcohol in much the same way as other similar volatile etliereal
liquids are prepared by the action of other acids on alcohol.

In 1800 Valentin Rose^ showed that the name sulpburic-
ethc-r is a mihlearliug one, inasmuch as this substance does not
contain any sulphur or sulphuric acid. Fourcroy* was the first
to pro[K>und the idea that ether is formed from alcohol by the
withdrawal of the elements of water; and he and Vauquelin'
endeavoured to enforce this view by experiments, the results of
which wcrrj confirmed in 1807 by Saussure's analysis of ether,
and subsequently by Gay Lussac's analysis in 1815. It was then
lif;Iieved tli.it the action of sulphuric acid upon alcohol could be
simjily I'Xplainod by the fact that this acid removed from the
alcohol either the elements of water, or water already present
in the conqiouiKl. Many facts, however, contradicted this view.
Thus, as we have seen, Frobenius had observed that the
residue in the manufacture of ether may again be employed
for a further ronversion of alcohol into ether, a fact which was
confirmed by many other chemists, and especially by Cadet
in 1774.

By tlio introduction of a simple process of manufacture the
price of ether was considerably diminished, as is seen from a
discussion between Beaume and Cadet, in which the former
criticised the new method of Cadet, and the latter stated that
whilst Beaunir sold tin* compound at twelve livres per ounce,
he char^^t^d <m\y forty sous for the sani»? quantity.

It is to Boullfiy* that we owe the discovery of the continuous
process now univrrsully employc«l for the manufacture of ether,
clcpending on the t:u-t that a small quantity of sulphuric acid

' Si'hrnr. Jt^itm. iv. •2.'».'{. - Khiurnf.s fT/ftJifniiu' Xnfur-'f** rf dr ('/ii)tn>,

■* Srhn-r. Jntnn. vi. <'". * .'•*'/;», }'hnf},i. \. 07.

THEORIES OF ETHERIFICATION. 327

is suflScieut to convert a large quantity of spirit of wine into
ether. From this observation it appears very improbable that
sulphuric acid acts in this case simply as a hygroscopic sub-
stance ; indeed, it soon became evident that this explanation was
insufficient, because it was found that the whole of the water
produced in the reaction distils over together with the ether,
and it can scarcely be imagined that the sulphuric acid first
exerts its power of removing water from the alcohol and then
immediately parts with the water again which distils over with
the ether.

216 Theories of EtJierification, — As in many other reactions
where a sufficient explanation is wanting, chemists (as well as
other men) have long been in the habit of taking refuge in a
name, and this peculiar action of the sulphuric acid was termed
a catalytic or contact action,

** Denn eben wo Begriffe fclilen.
Da stellt ein Wort zur rechten Zeit sich ein."

This catalytic hypothesis was first proposed by Mitscher-
lich,^ and Berzelius gave his adhesion to the view. These
observers omitted, however, to notice that the first action
of sulphuric acid on alcohol, in the manufacture of ether, is
the production of sulphovinic acid (hydrogen ethyl sulphate).
This fact did not, however, escape the observation of Hennell,
who found that a concentrated solution of this acid yielded
ether on distillation ; whilst a dilute solution, on similar treat-
ment, yielded only alcohol. This subject was more care-
fully investigated by Liebig,^ who came to the conclusion
that ethyl sulphuric acid which is first formed, decomposes at
a temperature of 126° to 140° into ether, sulphuric acid, and
anhydrous sulphuric acid (sulphur trioxide), this latter com-
bining instantly with the water formed in the reaction with
production of sulphuric acid ; this again forming ethyl sulphuric
acid with the alcohol, which is being constantly added. This^
according to Liebig, accounted for the continuous nature of the
reaction. The simultaneous evolution of water and of strong
sulphuric acid was explained by assuming that this latter only
combined with the water in its immediate neighbourhood, whilst,
in the other parts of the liquid, the passage of the ether vapour
carried away some aqueous vapour with it. The singular fact

' Fogg. Ann. xxxi. 273 ; liii. 95 ; Iv. 209 ; Taylor, Sc M>'m. iv. 1.
" Ann. Phanti. Ix. 31 : xxiii. 39 , xxx. 129

328 THE ETHYL GROUP.

that ethyl sulphuric acid should be both formed and decomposed
at the same time and in the same liquid was explained hj
Heinrich Bose, by the suggestion that a diminution of tempera-
ture sufl&cient to permit of the formation of ethyl sulphuric add
took place at the point where the alcohol flowed in, but that
the other portions of the liquid were sufficiently hot to cause
the decomposition of this acid. Mitscherlich soon rendered this
hypothesis untenable by showing that the continuous formation
of ether may be carried on under circumstances in which no
such local diminution of temperature can occur, as it 13 pro-
duced equally well when a current of the vapour of alcohol is
passed in, in place of the liquid.^ Upon thisj Leopold Gmelin
remarked that at the point where the vapour enters tlie liquid
we have an excess of alcohol present, and there the formation
of ethyl sulphuric acid may take place more easily in conse-
quence of the presence of this excess of alcohol. Qraliam next
proved that ethyl sulphuric acid when heated by itself to 140*
does not yield any ether, and that on addition of water only
alcohol ia formed, whereas ether is produced when the ethyl
sulphuric acid is heated with alcohol to 140^ It has already
been stated that Hennell also found that when the acid is
heated with water it yields alcohol, whilst a concentrated
solution gives rise to ether; and the same fact was also ob-
served by Sertiirner. In the latter case we must assume that
alcohol is also formed, but that it contains a small quantity of
water only, and forms ether with the excess of ethyl sulphuric
acid present, which when dilute it cannot do. Still no com-
pletely satisfactory theory of the formation of ether could be
established upon the facts which were then known. In order
to understand this it must be remembered that the equivalent
weights were then in general use, and that the following
formulae were adopted :

Alcohol. Etliyl Snlphuric Acid. Ktker.

217 Williamson's Theory of Ethcrijication, — Graham, like Mit-
scherlich and Berzclius, assumed the existence of contact action,
but shortly afterwards the classical researches of Williamson «
placed the true theory of the continuous etherificatiou process
on the firm basis of experiment. This theory of the fonnation

"^ Jtmrn Chew. Soc. iii. 24,

" Brit, AssiK, JirjHtrfs, 1850, p. 65 ; 2'hil. Mug, [-3] xxxvii. 850.

WILLIAMSON'S ETHERIFICATION THEORY. 329

of ether has played a most important part in the development
of our theoretical views ; the recognition of its truth has rendered
it possible to explain a large number of similar reactions, and
it has moreover led to the discovery of many new groups of
compounds.

Williamson, adopting the views of Laurent and Gerhardt,
gave to ether the molecular formula C^H^^^O, according to which
this substance contains the radical ethyl twice. But according
to the theory of types^ alcohol is derived from water by the
replacement in it of one atom of hydrogen by ethyl, and hence
ether, according to Williamsons view, must be regarded as
alcohol in which the second atom of hydrogen is replaced by
ethyl. To prove the truth of this he made the following experi-
ment. By dissolving sodium in alcohol he first prepared sodium
ethylate, or, as he termed it, ethylate of soda ; and upon this he
acted with ethyl iodide, by which reaction he obtained pure
ether :

Naj"+C,H,J-C,H5J*'+Na /•

This proof, however, did not satisfy him, for, according to the
old theory, it might happen that in this reaction two molecules
(or atoms as they then were termed) of ether, each containing
half the number of carbon atoms, had been. formed. Williamson,
therefore, acted with ethyl iodide on sodium methylate, and with
methyl iodide on sodium ethylate, and in both cases he obtained
a single compound, viz. methyl -ethyl-ether, and not a mixture
of two compounds, viz. methyl-ether and ethyl-ether. In a
similar way he obtained amy 1-ethyl- ether or the seven-carbon

ether, J^^JJ^ ] ^

The formation of ether from alcohol and sulphuric acid could
now be readily explained. Ethyl sulphuric acid is, in the first
place, formed, and alcohol acts again upon this substance :

(1) %^ } o - J{ j so, = ^'^JJ-. I so, + « } o.

(^)clJo-^''^S^)«'^-c!ll:^--3iso,.

Water and ether distil over, whiUt the sulphuric acid which is
reproduced yields ethyl sulphuric acid again on contact with

3o0 THE ETllYL GROUP.

more alcohol, and bcuce the formation of ether becomes con-
tinuous. That tliis is the true explanation of the process was
clearly proved by Williamson by first preparing amyl-sulphuric
acid and then treating this \s'ith common alcohol as in the
ordinary continuous process. At first amyl-ethyl-cther distils
over, then common ether, and the residue no longer contains
amyl-sulphuric acid, but consists entirely of ethyl-sulphuric
acid. As a further proof of the truth of his theory, Williamson
used a mixture of ethyl and amyl alcohols and allowed this
to act on sulphuric acid exactly in the same way as common
alcohol is used in the ordinary preparation of ether, when, as
he predicted, he obtained a mixture of amyl-ethyl-ether and
amyl-ethor.

Further confirmation of the correctness of Williamson s Wews
was afterwards given by Berthelot.^ By heating 222 grams of
ethyl bromide with alcoholic potash, this chemist obtained
12 grams of ether ; whilst if according to the old view the ether
had been obtained by a simple replacement of bromine by
oxygen, only 7'o grams could have been produced. Hence it
is clear that alcohol must take a part in the reaction :

Br f + H J ^ ^ U / ^ " CM, / ^ ^ H / ^ ^ Br I

According to this equation 15 grams of ether should have been
formed, lut owing to the nature of the experiment it was
impossible to avoid a certiiin amount of loss.*

2i8 Ether can be prepan»d by a great number of other
processes. Thus, for example, it is formed with evolution of
heat by the action of ethyl iodide on dry silver oxide :

2 C,H,I + Ag.O = (C.H,),() + 2 Agl.

Til jJace of silver oxide, so<rium oxide, Na^O, may be used.
The reaction then does not occur until a temperature of 180* is
reaclKMl.^

Ktluris also formed when a haloi»l ethereal salt is heated
with alcohol, or with a small quantity of water under pressure.
If, however, the water be present in excess, al(M>hol is produced.

The action of the hytlracids of the chlorine group on alcohol

' Jiiunnil iff P/niriintrir^ {:lj^ xxvi, 2'»,

' Wmtz, AnH. fhihi. rhus. (:i], xlvi. *1'1'1.

• t.r.i'iH'. liiiU. >'.-■. Chint. I'J), xxix. I.'i»».

PREPARATION OF ETHER. 331

also gives rise to ether, but this only when the latter is present
in excess, as in the opposite case the haloid ethereal salts are
formed. This reaction serves as an excellent example of the
action of mass, to which Bertholet, in his classical Essai de
Statique Chiniique,^ first drew attention. When two bodies act
chemically upon one another they may give rise to various
products according to the quantitative relations in which they
stand to one another. And hence reactions which take place
under certain circumstances may under other conditions be even
reversed. Thus, for example, alcohol when heated with an
excess of hydriodic acid yields water and ethyl iodide, but if a
large excess of water be allowed to act on ethyl iodide, alcohol
and hydriodic acid are formed :

aH.oH 4- HI = an J + h,o.

^'■■B^-^^ ' ^^* ^2"6

If, in the first case, the quantity of alcohol be largc^ the ethyl
iodide acts upon it t^o form ether :

When ethyl iodide is heated with a small quantity of water,
alcohol is first formed, and this is then converted into ether.

From the foregoing it is distinctly seen that a small quantity
of a haloid ethereal salt or its corresponding acid is able to
convert a large quantity of alcohol into ether, and moreover
that the water which is constantly formed will gradually retard
and ultimately stop the reaction, inasmuch as the various
products will then be held in a condition of equilibrium.

Many chlorides, bromides, and sulphates convert alcohol
into ether,^ but usually only at a high temperature. In this
case the free acids doubtless are also fonned, together with
basic salts ; and it is these acids which then act in the manner
already described in the process of etherification, this reaction
being brought to an end by the presence of the water which
is formed, and the acid again uniting with the basic salt.

The change of alcohol into ether can also be brought about
by phosphoric and arsenic acids. The reaction is in this case

» Paris An. xi. (1803).

* Mnsson, yinv. Cheni. Phnrm. xxxi. 63 ; Knhlmann, ih, xxxiii. 97 and 192 ;
Keyuoso, Ann, Chim. Phys. [3], xlviii. 386.

;i;U THE ETHYL GliOUP.

I'Kiully llic Siuiif us that of sulpliunc iioiil. In coiiseqiieiicc of
Uhm iiiiiIkkI i>f i>R'piUiiti.)ii ctlier was at one time also termed
nixi'iiii- mill jiliosptioi'ic ether.

aig Mit nil I'll rltirt <\f Klhcr hij the Guniinnons Process. — For the
[>ri')Hii'!ili<iii ><f I'lhtT on the hu^e or small scale the method
i;iiijiliiyiiil hy BimHay 13 always adopted. A misture of sul-
jilniiif iLi'iii and al-uhol is made hi such proportions that the
lii]iiiil bulls at about 140°, the lulatioii varying accoriliug to

lhl<»IIVll-lh ..t

il,>> .« nstiimmt.. A 1

ixmii' of .') parts of

1111 |K'. .vnl,„

nil niili !> {Kirls nf (miii'i.-ii

ralL'il snlplmrif a(;id

i« H vi'iv ii'O-

i.i,-. Till.- is l.catnl it,

!i H:isk or L-ast-intn

U.il..r. Tl..' .1

■.■k ..fll>.. iK-k (Ki-. S7, "

till' opi'niii^' of the

Uiilvt 1- I'nriuK

»:\ niih lh|-.'.-4ulH'S. Into

oiiL'.if tlK'soa tuh.<-

tw\\\v\ iH littfi

I lli.'i' is <-i>iiiii'<'I<m1 with

a niiidi'iisiiii,' app:i-

tikUH. winl-i

1 Mil- third iiiK'nin:.; a thi

riioniotcr is plai-iil.

PUOPERTIES OF ETIIKK. 3?,3

which must dip into the liquid. The mixture is then heated
to the boiling-point, and alcohol allowed to flow from the bottle
(e) through the tube-funnel (which must also dip into the liquid)
in such jjuantity that the temperature remains nearly constant.

According to theory an unlimited quantity of alcohol can be
thus converted into ether. Practice has, however, shown that
the operation must be interrupted when a quantity of alcohol
about six times the volume of that originally contained in the
vessel has been added. This depends chiefly oh the fact that
the materials used are never anhydrous, and therefore, that the
mixture in the retort becomes after a while so diluted with
water that the reaction comes to an end. Besides, the liquid
does not wholly consist of sidphovinic acid, but always contains
free sulphuric acid, and this gives rise to secondary reactions,
blackening occurs, sulphur dioxide and water are formed, and
the presence of this latter exercises a further retarding influence
on the reaction.

The distillate, which, together with ether and water, contains
alcohol and sulphur dioxide, is then treated with milk of lime
or caustic suila, and rectified from a water-bath, when the ether
first passes over, still, however, containing some alcohol and
water. To remove these, the distillate is allowed to stand over
fused chloride of calcium, a method described by Lowitz in the
year 170(5. The ether is then poured otf from the chloride of
calcium and again rectified, when it is found to be pure enough
for all technical purposes and for general laboratory use, although
it still contains sniall traces of water and alcohol. This latter
is extremely ditiicult to remove, and can only be completely got
rid of by repeatedly shaking the ether with a small quantity of
water, and continuing this operation until the wash-water no
longer gives the iodoform reaction. It is then dried over
calcium chloride, and the liquid poured off from this treated
with sodium until no further evolution of hydrogen takes place,
and again distilled from a water-batli. In this purification of
ether a considerable quantity dissolves in the wash-water.
This may, however, be regained by rectification.

220 Properties. — Ether is a very mobile liquid having a pecu-
liar odour which affects the head, and a burning taste. It boils
at 84"0 (Kopp, Andrew^s) ; at O"" it possesses a specific gravity
of 07:35(18, and at 15*" of 070240. It volatilizes quickly not
only at the ordinary temperature, but at a much lower ix)int.
The tension of ether vapour is as follows: —

3i.^4 rzz 5

^^"

:::u5 'L^zi^. "T.-r Tic^iir. Trli-.-c. frrzi it* Lizt jpecinc ffiavity
n:.iy >: r<-:ril rr.ii :::-* ^frj^ifl z-: iH-.Tl-ir li^e '."sirboQ dioiide,
!,r:v.<. t*"1:l .ir i :J,':/.t rirli-jf^r r-iirirr. ir.«i care is needed
::; w.;"k.:::_- '^i'.'z, lirj-r ^-iii.::::-f:f :: rth-rr. r:o llaaie bein^ per-
!..:::^' ::. i> :i-.i,:.>. irl -liL I: i -i^^^ ^riii: wiry vf ether be
:i.l- w^ i :. -I'-ii* ri:- :- \ •:'. ^-l 5T*A»->r a i^Lx:urr is obtained
w :;:j-. tl \t ^« tr-s - ::L :lv :'. : >. ■: : r"--!:*- "^ i-rr. Tr.e hi^h specific
cni^i^y v! 1:: -r Vij- -.7 :.. .j :*..- >:rik:=.^"v iL:-*"!: is f-.UowsL A
sn.:vr. viUA'-:iv.- :" r::-rr :- :r "iji.: :-:: ;% iksk al-I :be short end
of a i:'-^>> svr.':. i. 15 :r. i/:.: lv x-nTiriLrvr ic*:Te the surface
of iho liiiuivi. I: 'l-r .ir-:?::^ ir.i I :i^ ol..: t :Lt: syphon be
i:o\\ svwkvl '. u:. v::.-.r v;.T-:ur -A-ill :::"»■ i.-.v^ iri a continuous
Mucuu. auvl a >::.^11 rv':i..iTr nv^v j>r r:l!«:i "v with it and the

Kv»urv'ivY aiiii Vm; ^ivliL .<:^:^- rh'i* other when exiled to — 31*

snstiUtiA s in Ion J wL:>:- ^'ii^tvi^ih^' tAo- :>. which, at — 44" form

ii ^viiliuuvms s^uiJ crystal -iiic- ma?s, ThvL;irJ aiui )[itchell were

\iiuMc 10 ivnrinn tl.is ?rai«.i:i-nt, aT.i 'Ax- latttr f un I that

i»uiv othor rv^muins li«|ui»l a^ — '.t.V.i TLi- .fustir.n has lately

twu iuvoslis:?^tod by Fran-Iiirn-'Ut,- and hi< «v.nohisioDs agree

\fcUh Uuv^* ^*^ ^'*^* ^^^'^ latter ch».iiii>t<. H..- f..und that moist

^hci\ ^lu*»^ i\H4od, dep<.»sit< crystals, ]»roba]i!y c«iii>isting of ii^e,

huA be vli>l u\U obtain a solid mass at - 44 . This may be

MVM^tK\l b^ the f:u't that not eiK.uJi watur was present, as,

,^^^^w. ^^* Oiuthno, otlRT unites with ice t" torm a «^ryuhydrate.

;j^^ A v\^4vwml. having the formula C\H,.p + i>H^O, was

\|^ii^^^ Hv Vnurx^t by quickly evaporating eilior on filter paper.

% :w J -- J"^ ^. whicli is the minimum temperature obtained

•, xxii. 259 • Brr. IkHtavh, Ckem, Gff. x. 830.

• iym^fn Ii^ndu% Izxxvi. 7^>.

DECOMPOSITIONS AND USES OF ETHER. 335

It was formerly believed that ether, like oil, is insoluble in
water, until Lauragnais showed, in 1 758, that ten parts of water
was sufficient to dissolve the ether completely. According to
Boullay, on the other hand, one part dissolves in fourteen parts,
whilst Draper states that ten volumes of ether dissolve, in 100
parts of water, at 11°. Concentrated hydrochloric acid dissolves
it in much larger quantities than water. ^ On the other hand,
one part of water dissolves in about thirty-four parts of ether.
Ether is miscible with alcohol and wdth almost all other hydro-
carbon derivative compounds as well as with carbon dioxide.
Many solid bodies, such as resins, fats, alkaloids, &c., dissolve
easily in ether. Some of these are soluble in aqueous ether but
not in absolute ether. This is the case with gallic acid, and this
reaction is so characteristic that it may be employed to ascertain
the presence of water in ether. If the latter liquid contains only
a little moisture the dry powder balls itself up ; if more be pre-
sent it deliquesces to a thick syrup, which does not mix with
the layer of ether above, and consists of a solution of tannic
acid in aqueous ether.'* Many inorganic substances are soluble
in ether; thus sulphur dissolves slightly, and phosphorus dis-
solves in rather larger quantity. This latter solution, which
becomes yellow on exposure to light, was formerly known as
JEthcran phofqifwratus. Ether dissolves iodine and bromine in
larger quantity, as well as chromium trioxide, ferric chloride,
mercuric chloride, auric chloride, platinum chloride, several
other chlorides and iodides, and some few salts. Various gases
are also absorbed by ether, such as ammonia, which is taken up
in considerable quantity, other gases being less soluble. Accord-
ing to Regnault, ether undergoes a change when preserved even in
well- closed vessels, assuming a different vapour- tension. If ether
be contained in a flask with air, acetic acid is formed after some
time ; this change taking place more quickly in presence of
an alkali. On the other hand, Lieben states that pure ether,
either alone or in contact with potash, lime, or sodium, does not
undergo any alteration on standing, but that if water or fused
sodium chloride, or calcium chloride, or anhydrous sulphate of
copper, be present, a slow change takes place, the liquid
exhibiting the iodoform reaction.'^

221 Drrrmfpoaitioiis of Ether. — When ether is heated with
water and a trace of sulphuric acid to a temperature of 150

-> g\0

^ Draper, Chrm. x\>?r^, xxxv. 87. ' Bolley, Ann, Chenu Pharm. cxv. 63.

■•* Brr. Dcutsch, Chrm. iv. 75S.

i. ziz. r. x.iii. ' sLm .■

-.' IS.' :: := L-rr-^i :l:. \I lL-/ I: ^:L^.t W tr^rauJ with
7 In .:. I : : ^:^ i: a T-rL.r-rr^vire o: '/ to 4\ ale. hoi an«l

T -

< ;H. I ■ * I I - "Hi* * ■ I)^-

Mis-:; c.L-ts ir-.- 'iiv::..:^- v i ::i i siriiilai 'K^ay. the ra^lical

c I." if:.::, J ::.r r.. ?: -.Xirl. :. ' ►ri:.^ cori-.vrred iniv* an aloohol.^
Iv.l.yl :.::':- i-? .:>> :-.r:..rl ::. :i vileii: rc:iotivu, pr.ibably

r ::-.•.":. r vi-h xvvtiivl ,il :::.::/. -jiii i...i:.!v. '.\Kfch Li5 alreaJv

- • • •

]■•-:!. >::'-:T' i • 'Ah.:-!: vri.rr :* l-r-'irht :n .■■»ut:u-t with ic^.liue

fll. I. r.K. i ...

Ti.v '.r :::* rv . x: iiziii,' .i::on:s ;:':vrr '.vitliotlirr tho <amv prixhirts
ft- *A :*h a!:- 1. i. I: - •:.:•:- ».rli'. r h- -ir. pi»*:-ii . .-i ro plaiinuiii-blaok,
i.Tii": li t;.k'- j: - •, rii; i •.vK* n ■■: rV--^- -ir. p- r»r'.- ail" we* 1 to t-vajMj-
r:^.- ::i :i b-:.'ik':r-_li-s : :;'i ri i: : 5|.iral of i "lit mum wire place J
::!'■*>: iv T.liO hjiir i ' 'litiiiii'-s •• u'^'W. a ]>!i"sph«.«rtr>«:-fnt light
b'.iii.' ii"tiO''l •-v-r III': vrirr iii tri-- ■i:trk ;is so<'!ias tIil- ^'low ceases
H. I.)iivv . Wl^.rii MZ'-Liz- '1 •iX\\:in is !c.l into ether, each
bubljli.- I Tijilii'*-.- u vi'.l»,iit P.-: -t: li. :iii«l a soluTiijii is thus ob-
tain*:-1 r'.'rit^iiniii,' r-xrili*; fui'l. '.«••■ io a' i^i, liV'.lri'.rfii ilioxidf. ami
a small quaiitit.y •-f tniiiji'- a«i'l 'A. W. Wrii^'Iit".

If ethor v;ip.iur l»'j p't.--;l «jVi-r ]uMti:«l ptitash, lime, or
carbonate "f pMr-H-iuni, uiar.-li uas and livilrogeu are formed,
but neither rH*ti«- :i'i'l n-T furniio a* i«l l>unias and Stas).
This r«acti"ii i- ]iiol.iably ilu«- ti tii«- ]irrviuus f«.»rmation of
}X)tassiuni aretnt-- a«'«'ordinu' t'» tliO »iju;in«'n :

C.H.J ) -r '1 K( »H ^ H/) - iM '..H K( », - 4 H.,

and this ai ••tato is tlicn d«iMnip<>s*.d int • carbt-naie and marsh
uas in the presence <»f alkali.

222 fVx. — Ether is kir-tlv u>fd m the labomtorv ns well as
in the arts and m:inufa'ture.s n-: a polwiu, f^r the prej)aration
of 4*olKKlion, the extract inu nf tannic acid. \*c. Fmni its <:jreat
volatility it has also I i-en usi-d in the manufacture of 'ww If
bn.night in the form uf a tinr spray upon tlic skin it produces
such a degree of cold a-^ to in»luie cotuplt'te in^^rnsibihty, anil
L»£Sice the employn\ent of the ether-spray has been projnjsed
5 r effevlins; lo.^al ana-sthosia.

^Ler va|¥>\ir when inlialnl jiroduci-s simil:ir etVccts to nitn»us

* Fjl*nmever ami Tm Inpi"'. /■ /'>■•/.. c'A. «». I *»•;<. \\{'\.

DECOMPOSITIONS AND USES OF ETHER. 537

oxide. This appears to have been first observed in 1818 by
Faraday who was investigating the subject. The introduction
of ether as a general anaesthetic agent is due to Dr. C. Long of
the United States in 1842. He did not however publish any-
thing until three years later, when two dentists, Messrs. Morton
and Jackson, made independent observations on the subject, and
suggested the employment of ether for this purpose* The
inhalation of ether was soon widely adopted in medicine. In
Europe Sir James Simpson of Edinburgh was especially active
in its introduction, and he showed that this body under certain
conditions might be employed without any danger, especially in
obstetric cases. The employment of this and other anaesthetics
met with much opposition from a certain class of persons, but
all such objections were successfully overcome by Simpson's
energy and determination.

223 Ether unites with bromine to form the compound 2C^HjqO
+ 6 Br, when the two liquids are brought together in the cold.
This compound is a crystalline mass somewhat resembling
chromium trioxide, possessing a strong smell, and being decom-
posed by water into its constituents. It is a very unstable
compound, and on standing decomposes spontaneously with
formation of water, hydrobromic acid, ethyl bromide, tribromal-
dehyde, C2HBr30, &c.^ Various metallic chlorides and bromides
also form compounds with ether. One of the first of these was
obtained by Kuhlmann by bringing together anhydrous ether
and stannic chloride. It forms a feathery crystalline mass of
the composition 2 C^Hi^O + SnCl^, which distils at 80**, yielding
glistening rhombic tables which are decomposed by water.*
Various other compounds of ether with metallic chlorides and
bromides have been obtained by Nicklfes.^ These are mostly
crystalline, and some are volatile without decomposition, as for
instance AlgBr^ + 2 C^HjqO, which sublimes in yellow needles.
The trichloride and tribromide of antimony and of arsenic form
similar compounds. Ether combines with antimony penta-
chloride to form a greyish white crystalline mass, SbClg + C^Hj^O,
a very unstable compound.* With titanium chloride it also
forms the body TiCl^ + G^-^qO, crystallizing in small yellow
tables melting at 42*^ to 45°, and boiling at 118" to 120.** Ether

^ Schutzenberger, Compt. Bend. Ixxi^lSll.

' Lewy, Canipt. Rend, xxi. 371.

» Ann, Chim. Phys, [3], Ixii. 280 ; Campt. Rend, lii. 306; iTiii, 537 ; Ix. 800.

* Williams, Joum, Chem. Soe^ 1876, ii. 468.

VOL. III. Z

338 THE ETHYL GROUP.

al:^|^ cuiiiLincs >vitli vanadium oxychloride. By distilliog the
produL-t under dimiuished pressure large steUated crystals
having the formuhi C^H^^O + VOCl, are obtained, appearing
redJish-hrowu by tnmsniitted but green by reflected light.
Thoy melt below 100^ and are decomposed by water into ether,
hydrochloric acid, and vanadium pentozide.^

Chlorine SrBSTrruTioy-PEODUCTS of Ether.

224 Clilorino acts violently upon ether. If a few grams of
othiT b? jKMirod into a flask filled with chlorine gas white fumes
aro after some time given off, and then an explosion takes place,
M» ^N^m|uni«.'J by tlame and considerable deposition of charcoal
{ 'mik>h:r.;k\ If chlorine gas be led into ether, every bubble
M t-i lire t«^ the ithor. which becomes heated throughout, and is
nlniu.»tt'i\ *vn\ erte^l into a black tany mass. If, however, chlorine
|i.. iM.M\l. v>iH vi.r.ly in the dark, into ether, very well cooled,
1. ,. u ur..M\ i^v, il;;^''s arc f^Tnu-d. These have been investigated
U^ I 0 '.M K.i:nault/ Malaguli/ Lichen,^ Abeljanz,* and

■*', ' . .V : ; ir:.,V or MomKhlorcthcr, C.HoClO. This,

, ,,, .1 ^, .^^s^u. is the first pro^luct of the reaction, and

"'.|\„.. ,1 ^^^^\^ ^\w .vmivunds which FrapolU and Wurtz»

\ \^ ,, \y ..1m »iu, ,i 1^\ :i»c a.iiou of hydrochloric acid on a
[\\,,[, , ,1.. U.S. /i,,.V./.a:Kl:.LK!.yae, and which they believed

I", , ...J 1 ..»,!„ :»:;rrsubs:ancv with ethyl chloride. It

,, , i, »,,.n iU '^ i." '.^S.x\hioh is decomi»sed by sulphuric

,',! ,.,,u i. ,.i .. .1 V;,iJ.xdc. Imlnvhloric acid, and ethyl

^^, I,,,,, ., 1 1 ^^\..l■^ yx u\x s^sliv.m othvLue it yields acetal,
J ,1 '» ll^»n II ., U...U ,i.-.M?lva undiT the ethidene com-
.,.^,,,1. II,. .. »,.».*!. n.u A m.u.vl;lorothyl oxide as well as
„.n,,.i. .1 I. r...ui /..^!;xa.^^U;i.'h is ethidene oxide, is

\\\'\ I u»M ji, f I III no - ^ll,^llO^ ^_ ,1^,

CHLORINE SUBSTITUTION-PRODUCTS OF ETHKR B30

Dicldor-Ethyl Oxhide, C^HgClgO. For tho preparation of this
compound Lieben recommends that chlorine should be passed
into ether cooled to 0** and the temperature giadually allowed
to rise to 20^ It is then distilled off on the water-bath and the
distillate again treated with chloriDe. By repeating these
operations, the above compound is at last obtained as a strongly
smelling liquid which boils with decomposition at 140** to 145**
and has a specific gravity of 1*174 at 23° and burns on ignition
with a luminous green-mantled flame. By the moderate action
of zinc ethyl on dichlorinated ether, ethyl chlorinated ether,
C^HgCl(C2H5)0, is obtained. This possesses a pleasant ethereal
smell, boils at 141**, and has a specific gravity of 0*9735 at 0^
Heated with an excess of concentrated hydriodic acid in closed
tubes to 100** it forms ethyl iodide and secondary butyl iodide.
The formation of this compound shows that substitution has
not taken place in both of the ethyl groups, as was originally
supposed ; and Lieben explains this by the following equations :

CjHgClCC^I^) I o + 2 HI = CgHjCKCgHJI + C^H^I + lip.

C3H3C1(C,H,)I + HI = C,H3C1(C2H,)H + I,.
C2H3C1(C2H5)H + HI = C2H,(C.H5)I -t HCl.

By the further action of zinc ethyl on ethyl chlorinated ether

or more simply if iodide of ethyl and zinc be heated with it^

the so-called di-ethyl ether, C^H3(C2H5)20.C2H5, is obtained, a

body which boils at 131** and is a compound ethyl hexyl ether,

yielding, on heating with hydriodic acid, ethyl iodide and

secondary hexyl iodide. By the action of sodium ethylate

on dichlorinated ether, etliTjl-ojcide-chlorinatcd-ethcr is formed.

This is identical in composition with monochloracetal, CHgCl.

CH(OC2H5)2, and for this reason dichlorinated ether" must

.1 •■• GHoCrCHCl ) r\

possess the composition ^ (Ml i

TricMor-Ethyl Oxide, C^HyCljO, is not known in the pure
state. If the residue boiling above 153** obtained in the pre-
paration of dichlorinated ether be heated with sodium ethylate
it dissolves, and from the product of the reaction dichloracetal,
CHClyCHCOC^Hg),, separates out, and hence it would appear
that a trichlorinated ether exists having the composition
CHCUCHCl ) ^

z 2

340 THE ETHYL GROUP.

Tetrachlor-Ethyl Oxide, C^H^Cl^O. This body was discovered
by Malaguti, and first termed chlorinated ether and afterwaids
bichlorinated ether. It is formed by the continued action of
chlorine upon ether, when the liquid is gradually heated to 100'.
The chlorine is absorbed quickly to begin with, then, however,
a stormy evolution of hydrochloric acid takes place, so that the
liquid requires to be cooled. After this chlorine is again led in,
and then the whole heated to 140** until the mass begins to
blacken. It is then mixed with water, dried in a vacuum over
lime and sulphuric acid, and thus a thick liquid is obtained
which has a pungent smell and a specific gravity of 1 5. It has
no constant boiling point, but decomposes when heated. Alco-
holic potash yields acetic acid together with other products,
and on heating with sulphuric acid, trichloraldehyde or chloral,
CCI3.CHO, is formed, and from this it appears that Malaguti s
chlorinated ether is a mixture which contains the compound

This latter body was first prepared in the pure state by
L. Henry,* by the action of phosphorus pentachloride on the
so-called chloral alcoholate (see Ethidene Compounds) :

CC1,CH(0H) J Q ^ p(,,^ ^ CCI3.CHCI I Q ^ pQ(.,^ ^ jj(,j

The same compound is likewise formed when chlorine is
allowed to act on the monochlorinated ether obtained from
aldehyde.^ It boils at 188"* to IOC*', possesses a specific gravity
at 15** of 1*4211, and has a sweetish-bitter taste and a pungent
camphor-like smell.

rcntachlor-Ethyl Oxide, C^HgClgO, is obtained, according to
Jacobsen, by the further action of chlorine on Malaguti's com-
pound. It is a thick liquid having a specific gravity of 1*645,
which is probably, however, a mixture. It gives ethyl com-
pounds by various reactions, and probably, therefore, contains the
compound C2Cl5(CjH5)0. This latter compound is also obtained
from the last described tetrachlorinated ether ; by the action of
alcoholic potash the compound CCij = CCLOCjHg is produced,
and this unites with chlorine directly to form pentachlorinated
ether, a liquid boiling at 190"* — 210** with partial decomposition
being obtained.

* Ber, Deuisch. Chim. Gts. iv. 101. 435; vii. 762; Comptfs Rendut^ xlvil 418.

* Vogt and Wurtz, Comp. Reml Ixxiv. 777.

CHLORINATED ETHER. 341

The bromine compound, CCloBr.jCClBr.O.CgHg, is obtained
as a colourless, heavy liquid having a pleasant smell, by the
action of bromine on the latter body, and this on cooling crys-
tallizes in large clear crystals, which melt at IT*} An isomeric
pentachlorinated ether was obtained by Henry * by acting with
phosphorus pentachloride on a compound also belonging to the
ethidene series obtained by the union of chloral and ethylene
chlorhydrate (monochlorethyl alcohol).

This latter compound corresponds to the above-mentioned
chloral alcoholate.

This pentachlorinated ether is a colourless, thick liquid, pos-
sessing a sweetish taste and a strong camphor-like smell. It

possesses the constitution pyT pi prj \ 0.

Fcrchiarinated Ether, C^ClioO, is the last product of the action
of chlorine on ethyl oxide, and is formed only in the sunlight.
It is a solid body, possessing a penetrating camphor-like smell,
and crystallizes from alcohol in orthorhombic crystals which
melt at 69", and have a specific gravity of 1*9. In its pre-
paration, hexchlorethane, Cg^l^,, and trichloracetyl chloride,
CCljj.COCl, are usually formed, and the perchlorinated ether
decomposes completely into these compounds on heating to 300^
By the action of an alcoholic solution of potassium sulphide^ a
compound is formed termed by Malaguti chloroxcthosc :

cSy0 + 2K,S=gg}0 + 4KCH-S,

This is a liquid boiling at 210°, which unites with chlorine
in the sunlight to form perchlorinated ether, and with bromine
to yield the compound C^doBr^O. If chlorine be allowed to act
in presence of water on chloroxethose, trichloracetic acid is
formed as follows :

CCr=CCl } O + 2 Cl. + 3 HOH = 2 CCI3.CO.OH + 4 HCl.

CH I . . .

Mcthyl'Etlujl'Ether, p t| > 0, is a liquid possessing a smell

resembling that of ethyl oxide, and boiling at 11*. It is best
obtained by the action of ethyl iodide on sodium methylate.
This compound is also produced by treating sodium ethylate
with methyl iodide (Williamson), and it was originally termed

* Busch, Ber. Ikutsch, Chem. Gca, xi. 445. * Ih. vii. 762.

342 THE ETHYL GROUP.

by Lim the three-carbon ether. It may also be obtained by
distilling together potassium ethyl sulphate and potassium
methylate,^ and by the action of dry silver oxide on a mixture
of the iodides of ethyl aud methyl (Wurtz).

THE ETHEREAL SALTS OP ETHYL,
OR ETHYL COMPOUND ETHERS.

Ethyl Chloride, C^H^Cl.

225 This compound was first obtained in alcoholic solution by
Basil Valentioe, who thus describes its preparation : ^ " This I
also say that, when the spirit of common salt unites with spirit
of wine, and is distilled three times, it becomes sweet, and loses
its sharpness.*' In his Last Testament he also says :* "Take of
good spirit of salt which has been well dephlegmated and
contains no watery particles one part ; pour to this, half a part
of the best and most concentrated spiritus vini which also
contains no phlegma or vegetable mercury." He goes on to
state that this mixture must be repeatedly distilled, and then
"placed in a well-closed bottle, and allowed to stand for a
month or until it has all become quite sweet, and has lost its
acid taste. Thus is the spirit us salts et vini prepared, and may
be readily extracted."

The mixture thus obtained of alcohol and ethyl chloride, or
sweet spirit of salt, was well known to the later chemists.
Thus Glauber speaks of it in 1648 in describing strong hydro-
chloric acid : " When dephlegmated spirit of wine is poured
into such strong spirit of salt and digested for a long time, the
spirit of wine makes a separation and kills its sal volatxU, bo
that a fine clear oleum vini swims on the top, which is not the
least potent of the cordials."

Pott then showed in 1730 that this sweet spirit of salt could
bo obtained by the action of butter of arsenic or butter of
antimony on 8i)irit of wine, and other chemists found that
other metallic chlorides may be employed for the like purpose.
Ludolf, in his work on Medical Chcmistnj, states in 1749, that
on heating spirit of wine with sulphuric acid and common salt a
distillate is obtained which when treated with lime yields an ether,

* C-hancc1, Conij>f. Jir,id. xxxi. 621.

• Winirrftnhtn^ ilrn 7rf»*w« Sf*'inji drr urtiftrn /fV /V/i, cJ. Petracus, p. 72.
' Sasilius J'ulciitinHs, ed. Petracus p. 73'».

THE ETHEREAL SALTS. 343

but ho vainly endeavoured to obtain a similar compound by the
action of muriatic gas on spirit of wine. Beaum^'s experiments
in this direction also did not succeed, but Woulfe * obtained
hydrochloric ether in this way, and it was afterwards prepared
and sold by an apothecary in Germany and known as Bassets
hydrochloric ether. This same compound was afterwards termed
light liydrochloric ether, in order to distinguish it from the
BO-called heavy hydrochloric ether obtained by heating alcohol
with common salt, manganese dioxide, and oil of vitriol. This
latter body, which was prepared in 1782 by Westrumb, and after-
wards observed by Scheele, is however a mixture of various
oxidation-products.

Colin and Robiquet- were the first to point out the true
composition of ethyl chloride. The above-mentioned method
of distillation has been used until recently in order to obtain
this compound, although it is not in every respect satisfactory.
Boullay found that, when obtained by means of common salt
and sulphuric acid, the product usually contains a small quantity
of ethyl oxide.

Pure ethyl chloride is" prepared by passing hydrochloric acid
gas into strong spirit of wine. The saturated solution is allowed
to stand for some time, and then distilled oflf on a water-bath.
The yield is, however, not more under the most favourable
circumstances than corresponds to 15 per cent, of the alcohol
employed. The alcohol may, as Groves^ has shown, be com-
pletely converted into the chloride, if zinc chloride be added
and hydrochloric acid gas passed into the boiling solution; this
gas is then completely absorbed, and when the liquid has
become saturated, pure ethyl chloride is evolved, the reaction
going on until the whole of the alcohol has been converted.

According to the experiments of Krllger,* ether is likewise
formed in this process when the mixture is heated to begin
with. This can be avoided by saturating the solution of one
part of zinc chloride, and 82 parts of spirit with hydrochloric
acid in the cold, and then heating to the boiling-point, the
gas being passed in so long as ethyl chloride is formed. The
evolution-flask must, of coui-se, be connected with an inverted
condenser in order to retain the alcohol vapour, whilst the more
volatile chloride of ethyl passes into a vessel surrounded either
with ice or a freezing mixture, where it is condensed. In this

* Phil Trans. 1767, p. 520. • Ann. Chim. Phys. i. 848.

* Joum, Chcm, Soc, 1874, 636. ** Joum. Prakt. Chein. [2], xiv. 193.

344 THE ETHYL GROUP.

^ay it is easy to obtain a kilogram of the compound in a few
hours, and this method serves admirably as a lecture illustration.
The action of hydrochloric acid on alcohol is explained by the
following equation :

CgHg.OH + HCl = CaH^Cl + H^O.

Hence the conclusion that zinc chloride simply acts as a strong
hygroscopic agent would not appear improbable, but this is not
the case, inasmuch as it cannot be replaced by other equally
efficacious hygroscopic agents such as chloride of calcium or
sulphuric acid. Its peculiar action depends upon the fact that
the alcohols very easily decompose, with elimination of water, into
the defines, that is the hydrocarbons of the series CjfH2n, which
unite with hydrochloric acid to form the monochlorides. Accord-
ingly, in the preparation of ethyl chloride according to Groves s
method two reactions take place ; one part is produced by the
direct action of hydrochloric acid on alcohol, and the other part
by the union of ethylene in the nascent condition with hydro-
chloric acid. The truth of this explanation is proved by the
fact that when amyl alcohol is thus treated, a considerable
quantity of the s^coudary chloride is found, together with the
primary chloride, and this, as we know, can only be obtained
from the olefine amylene CgHj^,. *

Ethyl chloride is also formed by the action of phosphorus
pentachlorido on alcohol (Wurtz), and, together with other
products, when alcohol is treated with chlorine, and this accounts
for the production of this substance in considerable quantity
in the manufacture of chloral.

226 Fropcrtics, — Ethyl chloride is a colourless mobile liquid
having a peculiar and pleasant odour, and a sweetish, burning
taste. It does not solidify at — 29°, boils at 12°*5 (Regnault), at 0*
possesses a specific gravity of 0*9214 (Pierre) and its vapour density
is 2*219 (Thenaid).* It is but slightly soluble in water, though
dissolving readily in alcohol, strong spirit taking up half its weight.
This solution may easily be kept in well-stoppered bottles, and
chloride of ethyl may readily be separated out from such a
solution by gently warming it and freeing the gas from alcohol
vapour by passing it through sulphuric acid (Groves).

Ethyl chloride is easily combustible, burning with a luminous
green-mantled flame. When its vapour is passed over heated

* Seborlemmer, Joum, Chtm. Soc, 1875, 808. • Ann, Chim, Ixiii. 49.

ETHYL CHLOniDE. 345

80<j&-liine, oleEaQt gas is formed, according to Stas, whilst
h. Meyer ' finds that in this reaction a mixture of hydrogen
and marsh gas is obtained together with sodium acetate and
carbonate :

(«) C.H5CI + 2 KOH = C2H3KO, + KCH- 2 Hy
(i) C»HjKO, + KOH = KjCO, + CH..

Substitution-products are formed by the action of chlorine on
ethyl chloride. Tbese will be described hereafter.

Tho appamtus shown in Fig. 88 serves to exhibit, in the case
'-,<itit. Chem. Fham. ciisix. 28B.

S40 THE ETHYL GEOCP.

of ethyl chloride, the passage from the liquid to the gaseous
state, and rice rtrtd.^ In order to liqaefy the gas contained in
the shorter and stoppered limb of the syphon tube, mercuiy
must be poured into the longer limb and the compressed gas
cooled by pouring some ether over the shorter limb. On allow-
ing the temperature to rise, and on permitting the mercuiy to
run out by the lower stop-cock, the liquid will be seen to boil,
and the whole again assume the gaseous condition.

227 Ethyl Bromide, C^H^Br, was first prepared by SeruUas' in
1827 by gradually adding bromine to a miicture of alcohol and
phcsphorus. It is also formed, together with other products,
by the action of bromine on absolute alcohol (Lowig), as well as
by heating spirit of wine with strong hydrobromic acid and by
various other reactions. In order to prepare it, Personne's*
method is probably the best. For this purpose 40 parts of
amorphous phosphorus and IGO parts of absolute alcohol are
brought into a flask connected with a reversed condenser, and
gradually 100 parts of bromine allowed to flow in, the flask
being first well cooled in order to moderate the violenoe of the
reaction. As soon as this has been added, the mixture is
distilied on a water-bath, the distillate being shaken up with
water and the bromide which separates out being then dried
over chloride of calcium or potassium carbonate and afterwards
purified by distillation.

Ethyl bromide is a liquid resembling the chloride in its
smell and taste, boiling at 38°'37 (Regnault), and having at 0**
a specific gravity of 1*4733 (Pierre), whilst at 15** it is 1*4189
(Mendolc jeff;. Its vapour density was ascertained by Marchand *
to 1)0 3 754. It bums, when ignited, with a fine green smoke-
less flame, evolving vapours of bromine.

228 Ethyl Iodide, CgH^I, was discovered by Gay-Lussac*
in 1815, and is formed by heating together spirit of wine and
hydriodic acid, as well as by the simultaneous action of iodine
and phosphorus on alcohol ^ (Serullas) :

5 CjH/JH + 5 1 + P = 5 G,H,I + H^PO^ + H,0.

This last reaction is now always employed for the preparation
of this import!int substance. It is largely used in the arts and

* Hofmftnn, Der. Dentwh. Chem, Ge», xii. 1123.

■ Ann. Chim. Phftn. xxxiv. 99. ' Cmnpt. lUnd, Hi. 468.

* Joum, Pntki. t'hrm, xxxiii. 186. * Ann.Chim, Phys. xcL 89.

* /»«JUY. 3*23; xlii. 119.

ETHYL BROMIDE. 347

manufactures, and for the preparation of other ethyl compounds.
Formerly, of course, common phosphorus was employed, and
a number of receipts were given for this purpose. In all of
these, precautions had to be taken to avoid explosions due to the
violence of the reaction, and to prevent loss of substance.

Personne ' was the first to suggest the employment of
amorphous phosphorus, and Beilstein and Rieth,^ who especially
worked out this method, found the following proportions to be
the best. Ten parts of red phosphorus and 50 parts of spirit
are brought into a tubulated retort connected with a Liebig'a
condenser, and to these 100 parts of iodine are gradually added.
After standing for 24 hours, the ethyl iodide is distilled oflF. Of
course the iodine and spirit may be mixed to begin with, and
the phosphorus then added from time to time, and in this case
G7 parts of this latter body are sufficient. The distillate is
washed with dilute caustic soda and water, and the iodide of ethyl
which separates dried over calcium chloride. The residue in
the retort consists chiefly of ethyl phosphoric acid, and, for this
reason, an excess of alcohol, as is shown in the above pro-
portions, must be used.

Ethyl iodide is also formed when potassium iodide is distilled
with a saturated solution of hydrochloric acid in spirit of wine,*
or when concentrated hydriodic acid is heated under pressure
together with ethyl chloride.* Another remarkable reaction
is its formation on heating ethyl nitrate with potassium iodide.*

Ethyl iodide is a colourless, strongly refracting liquid, possess-
ing a peculiar ethereal and somewhat pleasant smell, boiling at
71**'3 (Andrews), or at 7l"'6 (Frankland). Its specific gravity at
0° is 1-9755 (Pierre), and at 15", 1-9309 (Mendelejeflf) ; whilst
its vapour density was found by Marchand to be 5'417. Ethyl
iodide is almost insoluble in water, but is miscible with alcohol
and ether. It is only difficultly inflammable, burning with evolu-
tion of iodine vapours. When heated with fifteen times its
weight of water to 100^ it gradually dissolves with formation of
alcohol. Chlorine decomposes it with formation of ethyl chloride
and separation of iodine, and, like many other organic iodides,
it is also decomposed when exposed to the action of light, iodine
being set free and the liquid becoming gradually red and after-
wards brown. This decomposition takes place especially quickly

* Compt. Rend. lii. 468. ' Ann. Chem. Pharm. cxxvi. 250.

' De Vrij, Joum. PJunvrn. xxxi. ir>9. * Lichen, Zri/sr/i, Chcm, 1868, 712.

• Jnucadella, Cmnpt. Rend, xlviii. 315.

ETHYL IODIDE. 349

231 Ethyl Sulphite, (CgHJoSOg, was first prepared by Ebelmen
and Bouquet^ in 1845 by acting on absolute alcohol with
sulphur monochloride. It is also formed when thionyl chloride is
brought in contact with alcohol.- For the purpose of preparing
this substance, an excess of absolute alcohol is added to well-
cooled chloride of sulphur or thionyl chloride, the product being
purified by fractional distillation. Its formation* from thionyl
chloride is explained by the equation :

SO { cl + 2 HO.C2H, = SO I ^g^Hs ^ 2 HCI.

When alcohol is treated with chloride of sulphur, thionyl
chloride appears to be first produced, and this acts again on the
ethyl hydrosulphide formed at the same time :

(1) S,Clj + HO.C.Hj = SOClj + HS.C2H5.

(2) 3 SOCU + 4 HS.CjH5 = SOCOaHj)^ + 2 C^H^Cl + 4 HCI

+ 2Sj.

According to this reaction the sulphur monochloride may be
regarded as a sulpho-thionyl chloride (Carius).

Ethyl sulphite is a mobile liquid which smells of peppermint,
and has at first a cooling but afterwards a burning sulphurous
taste. It has a vapour density of 478 (Ebelmen and Bouquet)
and a specific gravity of I'lOGS at 0°, and boils at ICl^'-S.^ It
is combustible Avith diflSculty, and can be inflamed only when it
has been previously warmed.

Ethyl Sulphurous Acid, H(C2H5)S03, is not known in the
free state, and of its salts, potassium ethyl sulphite is the only
one which has been prepared. This is formed when a solution
of caustic potash in five parts of water is gradually added to well-
cooled ethyl sulphite, so that the liquid always remains colour-
less. The mixture is then allowed to stand until the whole of
the ethyl sulphite is dissolved, and the solution next saturated with
carbon dioxide and the whole allowed to evaporate in a vacuum.
The residue is dissolved in 90 per cent, spirit, this evaporated,
and the residual salt crystallized from boiling absolute alcohol.
It forms delicate silky glistening crystals easily soluble in water.
The yield is only small, as the body is very readily decomposed,

' Ann. Chim, Phys, [3], xvii. 06,
' Carius, Ann, Chem. Pharm. cxi. S3.
3 Carius, Journ, Prakt. Chem, [2], ii. 285.

360 THE ETUYL GROUP.

and much potassium sulphate is formed during its preparation.
Freshly prepared, it is odourless, but after some time it acquires
the smell of ethyl sulphite, and the aqueous solution contains
potassium sulphate.^

Hydrogen Ethyl Sulphate or Ethyl Sulphuric Acid

H(C,HJSO,.

232 The calcium and barium salts of this acid were obtained
in 1802 by Dabit from the residues of the preparation of ether.
These were, however, regarded as salts of an acid having
a composition intermediate between sulphurous and sulphuric
acids. These observations remained unnoticed until 1819, when
Sertlimer remarked, from experiments made in 1806, tliat spirit
of wine unites with sulphuric acid, forming a compound to
which he gave the name of sulphovinic acid. He showed more-
over that other acids were also able to form similar vinic acids.
Vogel,^ in 1819, then investigated sulphovinic acid and its salts
more accurately, and came to the conclusion that the acid pre-
pared by Sertumer's method may be considered as a compound
of hyposulphuric acid with a heavy ethereal oil, and is identical
with Dabit's acid. Gay-Lussac, in 1820, came to the same
conclusion, and so indeed did BouUay and Dumas, whilst
Hennell looked upon it as a compound of sulphuric acid
with a hydrocarbon, having the composition of olefiaiit gas.

In 1828 SeruUas proved that the compound might be re-
garded as an acid sulphuric ether, and its salts as compounds of
sulphates with the then unknown normal ethyl sulphate. This
view was adopted by the supporters of the radical theory, by
whom ethyl sulphuric acid was considered as a compound
analogous to bisulphate of potash containing as its constituents
sulphuric acid and neutral sulphate of ethyl oxide :

KO.SO^-\-nO,SO^.
KO.SO.^ + C^ff^O,SO^.

Preparation. — In order to prepare ethyl sulphuric acid, con-
centrated oil of vitriol is quickly but carefully mixed with
strong alcohol, and the mixture heated for some time on a
water-bath :

SO, 1 2 + C,H,.OH = SO, I J? j^ + H,0.

» Warlitx, Ana. Chem. Pharm, cxliii. 72. • Gill. Ann. Ixiii. 81.

ETHYL-SULPHURIC ACID. 351

The product always contains free sulphuric acid and unaltered
alcohol, both when equal molecules are employed or when an
excess of either compound is used, and even if the hcatin::^ be
carried on for any length of time. Hennell,^ who used equal
parts by weight of alcohol of specific gravity of 0*82 and oil of
vitriol, found that 56 per cent, of the latter is converted into
ethyl sulphuric acid. Berthelot,* in mixing equal molecules of
acid and alcohol of 94 per cent, strength, obtained the following
yields :

After 40 hours 56 per cent.

„ 90 „ 57-4

„ 20 days 59 „

„ 147 „ 58 8

When alcohol containing 20*7 per cent, of water was employed,
the production of the acid weot on much more slowly, and after
a lapse of 147 days the liquid contained only 54 8 per cent, of
ethyl sulphuric acid. Oa the other hand, by using absolute
alcohol, the yield can, according to Claesson,' be raised to 77'4
per cent. This last-named chemist heated a mixture of alcohol
and pure sulphuric acid on the water-bath, and employing, to
one molecule of acid, varying quantities of alcohol, expressed in
molecules, obtained to 100 parts of sulphuric acid the yields as
noted below :

0-5 1 1-5 2 2-5 8 4

731 571 596 65 72 77*4 774.

From this it appears that, when equal molecules of acid and
alcohol are employed, 57 1 per cent, of ethyl sulphuric acid is
formed. This yield increases, however, with an increase in
the quantity either of acid or of alcohol.

Ethyl sulphuric acid is also formed when sulphuric acid,
warmed on a water-bath, is saturated with ether vapour :

2 SO, { g 4- (C,R^f> ^ - SO, { ^ jj -f- H,0.

In order to prepare ethyl sulphuric acid from the product
obtained by one or other of these reactions, the mixture is
allowed to cool completely, then several times its volume of
water is added, and the whole is neutralized with barium

* Phil. Trans, 1828, ii. 365. ' Bull. Soc. aiim. xix. 227.

" Joum. Prakt, Chem. [2], xix. 246.

352 THE ETHYL GROUP.

carbonate or white-lead. In all these operations a rise of tem-
perature must, as much as possible, be avoided. The soluiioii
of the barium salt is then carefully acted upon with the requisite
quantity of sulphuric acid, or the lead salt is decomposed with
sulphuretted hydrogen, and the filtered liquid evaporated in a
vacuum over sulphuric acid. A colourless, oily, very acid liquid
.is thus obtained which has a specific gravity of 1*035 to
1*037. This is insoluble in ether, and is decomposed on long
continued exposure to sulphuric acid in a vacuum. On heating
a little ether is given off (Hennell, Sertiirner). This is explained
by the fact that the acid cannot be obtained quite anhydrous,
inasmuch as some alcohol is formed, and this acts in the usual
way on the ethyl sulphuric acid.

Its dilute aqueous solution decomposes slowly on standing,
and quickly when warmed or boiled, into sulphuric acid and
alcohol.

Anhydrous ethyl sulphuric acid is obtained, according to
Claesson, by slowly dropping chlorsulphonic acid into well-
cooled alcohol. Like the corresponding methyl compound, it is
an oily liquid which does not adhere to the suiface of glass.

The Ethyl Sulphates.

233 Ethyl sulphuric acid is a monobasic acid forming a series
of salts, all of which are soluble in water, and usually crystallize
well. Some are very stable compounds, whilst others decom-
pose on standing. Their dilute solutions can be boiled without
decomposition, but in concentrated solution they decompose with
formation of alcohol, sulphuric acid, and a sulphate. This
decomposition does not take place in the cases of the salts of
the alkalis or alkaline earths, provided an excess of alkali be
present.

Potassium Ethyl Sulphate, K,{Cfi^^O^, is obtained from
the barium or calcium salt by double decomposition with
potassium carbonate. It is usually obtained in tablets closely
resembling those of boric acid, but when slowly crystallized, it
yields large transparent monoclinic tables. At 17** it dissolves
in 0 8 part of water. It is also soluble in spirit, but not m
absolute alcohol, and deliquesces on exposure to moist air
When fused with caustic potash, alcohol is formed, and, on
heating with dilute sulphuric acid, ether is produced. This
salt is frc([uently employed for the preparation of other ethyl

THE ETHYL SULPHATES. 353

compounds, because this, as well as other ethyl sulphates, when
heated with salts of other acids, yields a new ethereal salt by
replacement of the metal by ethyl.

Sodium Ethyl Sulphate, Na(C2H5)SO^ 4- HgO, is formed as
a cauliflower-like deliquescent mass, which is soluble in alcohol.

Amraonium Ethyl Sulphate is easily soluble in water, alcohol,
and ether, depositing from solution in lar^e, colourless, deli-
quescent crystals, which fuse without decomposition at G2°.

Calcium Ethyl Sulp)iate, (^di(fl^\i^^O^\ + 2H2O, is obtained
by saturating crude ethyl sulphuric acid with chalk. The
solution thus obtained, which contains gypsum, may be con-
veniently used for the preparation of the foregoing salts. It
crystallizes in tablets, and also in transparent monoclinic crystals,
which are unalterable in the air and easily soluble in water.

Barium Ethyl Sulphate, ^di{G,^^0^^-\-2Hfi, is isomorphous
with the calcium salt, and crystallizes in colourless glistening
tables or prisms, which dissolve at VJ"" in 0*92 part of water,
and is also soluble in spirit, but not in absolute alcohol, which
on boiling removes from the salt one molecule of water.

Lead Ethyl Sulphate, Pb(C.,H5S0J., -f- 2H.3O, crystallizes in
large colourless tables, soluble in water and spirit. These lose
water easily, and decompose slowly on keeping, with formation
of lead sulphate, sulphuric acid, ether, and ethyl sulphate, for
which reason the salt attains a pleasant smell. When its
solution is saturated with lead hydroxide, a liquid having a
neutral reaction is obtained, and this on evaporation in a
vacuum leaves a residue of a basic salt, (PbCgHgSOJgO, as an
amorphous mass. This is much more permanent than the
normal compound, although very hygroscopic and easily soluble
in water.

Silver Ethyl SulpJiate, Ag (05115)804 + HgO, forms small
glistening tablets, readily soluble in spirit.

Besides the compounds above described, various other ethyl
sulphates are known.

Normal Ethyl Sulphate, (C^H^gSO^.

234 This compound was examined by chemists in the last

century, but its nature has only quite recently been ascer-

'tained. Formerly this ether was prepared by distilling spirit

of wine with oil of vitriol. This operation was conducted

in a retort heated in a sand-bath, and as soon as the ordinary

VOL. HL A A

354 THE ETHYL GROUP.

ether had come over, the receiver was changed and normal
ethyl sulphate, or, as it was termed, wine-oil or oleum vttrolii
duke, collected. Concerning the formation and composition
of this body, very different views were held. Towards the
end of the last century it was generally assumed that wine-
oil is ether rendered impure by the presence of a large
quantity of sulphuric acid, for Wiegleb stated that common
ether is obtained in large quantities when this substance is dis-
tilled with caustic potash. In the year 1797 the difference
between wine-oil and common ether was distinctly pointed out
by Fourcroy and Vauquelin, who assumed that the first com-
pound stood in the same relation to ether as ether does to
alcohol. This view was generally adopted until Hennell, in
1826, proved that the compound contains sulphuric acid, and
that it is to be considered as a compound of this acid with
carbon and hydrogen, in which the latter elements are present
in the same relative quantities as in ether itself. He also
showed that, when wine-oil is heated with water or with alkalis,
sulphovinic acid is formed, whilst a liquid hydrocarbon is
liberated. This in some cases crystallizes, and possesses the
composition of olefiant gas. These facts were fully confirmed
by the subsequent investigation of Sorullas,^ Marchand,^ and
Liebig.' Serullas found that, when wine-oil undergoes distilla-
tion, it yields the salts of ethyl sulphuric acid, and liebig
gavo to it the formula (02115)2804 + C^HgSOj, and termed it
sulphovinate of wine-oil.

According to the recent experiments of Claesson,* wine-oil
consists chiefly of ethyl sulphate, generally mixed with a larger
or smaller quantity of the polymers of ethylene, a fact already
observed by Hennell ; this latter chemist distinguishing
between wine-oil, a liquid boiling at 280^ and etherin, a solid
crystalline mass obtained when the wine-oil is allowed to stand
for some days.

The first attempt to obtain pure normal ethyl sulphate was
made by Wetherill,* who passed the vapour of sulphur triozide
into ether or alcohol He thus obtained a colourless liquid
smelling like peppennint which decomposes on heating, and

which, as Krlenmeyer afterwards showed, is a mixture of normal

( OH

ethyl sulphate and ethyl isothionate, C^H^ -j ^.^ p „

* Ann. Chitn. Phy.n. xxxix. ir»8. ■ Joum, Pmki. Ch^n, xr. 8.

■ Poyg, Ann. xxi. 40. « Jaum, Pmki. Chfm. [2], xix. 265.

* Ann, Chevi. Pttarm. Ixvi. 117.

NOIIMAL ETHYL SULPHATE. '355

Ethyl sulphate was first obtained iu the pure state by Claesson
in acting on alcohol with ethyl chlorsulphouate, a body which
will be described immediately. Ho also prepared it by the
action of sulphuric acid on absolute alcohol. If ice and then
water be added to the cold mixture and the liquid shaken up
with chloroform, the sulphate is dissolved and left behind on
evaporation. Ethyl sulphate is also formed when silver sulphate
is heated with ethyl iodide to 150^^ Claesson obtaining a
satisfactory yield in this way.

Ethyl sulphate is a colourless liquid, insoluble in water,
possessing a pleasant peppermint-like smell ; it boils at 208"
with slight decomposition, but may be distilled unaltered under
diminished pressure. At 19"* it possesses a specific gravity of
11837. It is only very slowly decomposed by cold water, but
boiling water decomposes it more or less quickly according to
the amount present, alcohol and ethyl sulphuric acid being first
formed. If ethyl sulphate be heated with alcohol, the following
reaction takes place : ^

^^* t c.H, + rf r ' \ C2H5 + an, / ^•

Hthyl CMorsulphonatc, CI.SO.2.OC2H5, was first prepared by
Kuhlmann,^ and afterwards more carefully examined by William-
son* and Purgold.* According to the latter chemist, the com-
pound is an oily, strongly smelling liquid, which can be distilled
in a vacuum. The same compound is obtained purer and more
readily, as was found by Miiller,® by leading ethylene gas into
chlorsulphonic acid. In order to purify the crude product, it is
either distilled in a vacuum or mixed with ice-cold water and
dried over anhydrous copper sulphate. The pure compound
boils under ordinary pressure with slight decomposition at from
151° to 154° (Claesson). It has a penetrating pungent smell,
and acts very violently upon the eyes. When absolute alcohol
is allowed slowly to run into this compound, a violent reaction
occurs, which, according to Claesson, may be represented as
taking place in two directions :

* Stempnewsky, Bcr. JJcutsch, Chem. Ges. xi. 514.
' Erlenmeyer, Ann. Chem. Pharm, clxii. 373.

' Ann. Cfiem. Pharm. xxxiii. 108.

* Quart. Jcum Chem. Soc. x, 97.

* Ber. Deutsch. Clwm Gca. vi. 502.

* Ikid. vi. 227.

A A 2

2SA THE ETHYL GROUP.

'' ^'^ [S;,H, + ^'AOH = S0,{ gJ?H^+ C3.CL

If alcohol bo added to ethyl chloreulphonate, ethyl chloride,
hydrochloric a^nd, and a small quantity of ethyl ether is formed,
and a considerable quantity of ethyl sulphate :

^r { OC,H, + «0^'*H* = SO^ { 00:2: + HCL

235 Jlydrogen Ethyl Srlemtc, H(C2HJSeO^ is formed when
equal parts of spirit of wine and concentrated selenic acid arc
heated together for some time to 100^ In order to purify the
pHNlnct, it is diluted with an equal volume of water, neutralized
with lead carbonate, and allowed to evaporate to one-half in a
vacuum. Tlie greater portion of tlie lead is then thrown down
in combination with selenic acid, and the rest precipitated as
sulphide with sulphuretted hydrogen, and thus an aqueous,
strongly acid liquid, containing ethyl selenic acid, is obtained.
It very roa^lily decomposes, and forms a series of salts which are
aUo very prone to decomposition.*

Potasaium Ethyl Selenate, K(C2H5)SeO^ forms small talc-like
tablets which possess a sweetish saline taste.

Lead Ethyl Selenate also crystallizes in tablets, and is so
unsUible that it has not been analyzed. If a solution of
lead ethylsulphate be added to its solution and the mixture
cvajKiratcd in a vacuum, tablets having the composition

3 [Pb(C,H,SO,)j + 2 H,0] + 2 [Pb;C,H,SeOjj + 2 H,0]
are dep^jsited. The normal ethyl selenate is not known.

Ethyl Nitrite, C^HgNOg.

236 Ruynioud Lully is generally said to have been the dis-
coverer of this compound, which was formerly known as nitric
ether, and it is certainly true that ho was acquainted with the
violent action which nitric acid proiluces on alcohol, but in his
process he allowed the ether to escape. Later chemists who speak
of the ftjnritus nitri dulcis s.dnlcijicatus, understood by this term
the residue which n.'mains behind after the reaction. Hugens

* Faliinn, Ann. ('firm. Pharm. Suppl. i. 241.

ETHYL NITRITE. 357

and Papin^ showed that when alcohol and nitric acid are mixed
together under the receiver of an air-pump, an elastic fluid
is formed, Kunkel,^ however, was the first to observe that
a liquid which swims on the surface of water may be obtained
from such a mixture. This observation remained unnoticed,
because the so-called nitric ether, largely used as a medicine,
was obtained by distilling a considerable quantity of alcohol with
a small quantity of nitric acid, and was, therefore, only obtained
in dilute alcoholic solution. Navier, a physician at Chalons
sur Mame, observed in 1742 the fact already noticed by Kunkel,
namely, that an ethereal smell is perceived when nitric acid and
spirit of wine are mixed together, and that when a mixture of
equal volumes of these liquids is placed in a vessel and allowed
to stand for ten days, an ethereal liquid swims on the top.
This fact was communicated to the French Academy by Duhamel
in the above year, and the liquid thus produced was believed to
be closely allied with Frobenius's ether.

Another method of preparing nitric ether which was after-
wards largely employed, especially by Berzelius, was suggested
by Black in 17C9. It consists in pouring nitric acid, water, and
spirit of wine into a tall vessel, in alternate layers one above
the other, when nitric ether is formed by the gradual mixture of
the liquids. Tielebein, in 1782, stated that the best yield was
obtained when the process of Navier was adhered to, and strong
nitric acid and spirit of wine mixed in the cold, the vessel being
quickly closed. This proposal gave rise to the publication of a
great number of receipts on the best means of preparing nitric
ether, all of which, however, depended on the alcohol being
gradually added to nitric acid, and the separation of the nitric
ether, which is formed, from the rest of the liquid either by
pouring off or by distillation.

The compound formed by this action of nitric acid on alcohol
is, however, not ethyl nitrate as was formerly supposed, but
ethyl nitrite, one part of the alcohol being oxidized, and the
nitrogen trioxide, thus formed, combining with another part of
the alcohol in the following way :

2 C2H5OH + N2O3 = 2 C2H5NO2 + HgO.

Ethyl nitrite thus obtained always contains oxidation-products
of alcohol, especially aldehyde, and this turns alcoholic potash
brown when shaken up with the liquid.

* Phil, Trails, 1676 " FpUtola contra spiritu in vini siitr acido, 1681,

ETUYL NITRATE. 369

penetrating ethereal smell, resembling apples or Hungarian
wine, and a peculiar pungent taste. It boils at 18^, and has
a specific gravity of 0*900 at 15°5 and a vapour density of 2*627
(Dumas and Boullay). When ignited in contact with air it
bums with a bright white flame. The pure ether can be kept
for many years without undergoing any change, but if impure,
and especially if it contains water, it soon becomes acid and
gradually evolves oxides of nitrogen in such quantities that the
bottle containing it frequently bursts. Alkalis, especially in
alcoholic solution, decompose it quickly, with fiarmation of
alcohol. Ammonium sulphide acts violently upon it according
to the following equation :

C.Hg.O.NO -f 3 (NH,).S = CoH,.OH + TNHj + Ufi 4- 3S.

No trace of an ethyl-base is formed in this reaction (E. Kopp ;
Carey Lea).

The alcoholic solution of ethyl nitrite is known under the
name of spiHtus aetlieris 7iitrosi and is used as a medicine.
According to the British Pharmacopoeia it is prepared as
follows : To 1 pint of rectified spirit of wine add 2 fluid
ounces of sulphuric acid, stirring them together : then add in
the same way 2^ fluid ounces of nitric acid. Put the mixture
into a retort into which 2 ounces of fine copper-wire (No. 25)
has been introduced and into which a thermometer is fitted.
Attach a condenser and apply gentle heat ; let the spirit distil
at a temperature from 170° to 175° (Fah.) until 12 fluid ounces
have passed over. Then add half an ounce more nitric acid to
the residue in the retort and distil as before until the whole
product makes up fifteen ounces. Mix this with two pints of
rectified spirit, or enough to bring the specific gravity to 0*845.

In former days this sweet spirit of nitre stood in high repute
amongst physicians, and is now used as a pleasant and mild
irritant.

Ethyl Nitrate, C2H5NO3.

237 It has already been stated that common nitric acid acts
as an oxidizing agent on alcohol, and the more violently the
more nitrous acid it contains. Millon^ showed in the year
1843 that this oxidizing action does not take place, and that
nitric ether is fonned, provided that the lower oxides of nitrogen

» Ann. Chim. Phijs. [3], y\\\. 233.

»> TEE LTEYL GLOUP.

pivaeBt ill th*: Lkric -j^yA W •i-estrovtrtl bv the addition of a
biisSxA quaittity ct urea, iL^: deoi^oipoeidon effected by the iixea

CO NIL,;, ^ 2 HNO. = 3 H.0 n- CO, + 2 >V

lo order to prepare ethyl nitrate accc^rding to Millon's prooesB
a mixture of (?) to 7-5 grams of spirit of specific gravity 0-854,
and a like quantity of nitric acid of sp^?ific gravity 1-4, is dis-
tilled with 1 to 2 grains of nitrate of urea at a gentle heat.
The receiver is charged as s*-.on as ethvl nitrate be<nDS to
distil over instead of aqueous alcohol, and this point may be
recogni-jed by the- peculiar odour of the distillate. When seven-
eighths of this have come over, the operation is stopped, the
distillate mixed with dilute caustic potash and water, and the
ether dried over calcium chloride and rectifie<l.

Carey Lea ^ has improved this method inasmuch as he dis-
solves from four to five times the quantity of urea recommended
by Mill^'U in warm alcohol, adding an equal quantity of nitric
acid of s[Kjr':ific gravity 1*401 and distils the mixture until one-
fifth of the whole has passed over. To the residue, alcohol and
nitric a'^id arc again ad«led, and thtrse operations are repeateil
Foveral times until the whole of the urea is decomposeil.

Acfording to Heintz- the best pr«.»i>ortion is as follows:
SO grams of nitric acid of specific gravity 1*4 aro warmed
with some nitrate of urea, and to this, when it is coM, (10 grams
of hjnrit of specific gravity O'Sl and lo grams of nitrate of urea
are ahh.d, and the mixture distilled to one-eighth. A similar
method has been descnbed by Bertoni^ for the prei>aiation of
large quantities of the nitrate.

Ethvl nitrate is also formed, as Porsoz* has shown, when to
20 grams of j>erfectly pure highly concentrated nitric acid
eooled ill a mixture of ice and siilt, 10 grani:^ of absolute
alcohol an? added drop by drop, the mixture being continually
stirred. In order to sejjarate the other, ice is then added.

Chajunan and Smith * have not found this method advan-
tageous and have suggested the following. Two volumes of
con«'ent.nited sulphuric arid and one volume of fuming nitric
aci<l, of KjHicific gravity 1*30, which has previously been heated

* .ViV/iwi. Amri-, Jnuni. (2), xxxii. 178; xxxiiL 8C.

• Ann, i'li^m. Phinn, i-xxvii. 43. • /At. Drut^tch, Chnn. Ors. ix. 161»2.

* I'nmpf. linut, Iv. [til, * JoHl-H, Cfwtfl. &>C. XX. 5l*l.

ETHYL NITRATE. 361

with a small quantity of urea, are mixed together. To the cold
mixture a few grams of urea are added, and then gradually one
part of alcohol for every three parts of the mixture, the whole
being then well stirred. The nitrate then separates out as a
light layer. Champion ^ states that ethyl nitrate can be more
simply obtained by bringing a cold mixture of one part of strong
nitric acid and two parts of sulphuric acid into a well-cooled
mixture of sulphuric acid and strong spirit.

Ethyl nitrate is also formed by the action of ethyl iodide on
silver nitrate.^

Ethyl nitrate prepared according to one or other of these
various processes, is well washed with water and dried over
chloride of calcium or ignited carbonate of potash. It is a
mobile liquid possessing a pleasant smell which how^ever is
quite diflferent from that of the nitrite. It has a sweet taste,
but a bitter after-taste. It boils at 86°'3, and has a specific
gravity at 0** of 11322 (H. Kopp). When ignited it burns with
a bright white flame. Whilst Millon was ascertaining the
vapour density of nitric ether according to Dumas's method and
attempted to seal the neck of the bulb containing the vapour,
heated above its boiling point, with a blowpipe flame, a violent
explosion took place which broke the bulb. The vapour, when
heated to a lower temperature may, however, be inflamed with-
out explosion. Concentrated caustic potash does not act at
ordinary temperatures on ethyl nitrate, but an alcoholic solution
quickly decomposes it with separation of crystals of nitre.

Phosphites and Phosphates of Ethyl.

238 Hydrogen Ethyl Phosphite or Uthyl Phosphorous Add,
HgCCgH^jPOg, is formed when phosphorus trichloride is allowed
to fall drop by drop into well-cooled spirit of wine of specific
gravity 0'850.^

PCI3 + 2 C.3H,0H -I- H.,0 = H2(C,H5)P03 4- C^H^Cl + 2 HCl.

The solution is then gently heated in order to drive oflF the
hydrochloric acid and chloride of ethyl, and the residue is
allowed to evaporate to a syrupy consistency in a vacuum. The

^ Vompt. Eciid. Ixxviii. 1150.

2 Warster, Bcr Dcutsch. Cfcm. Ga^. v. 406.

« Wurtz, Ann, Vhim. Pkys. [3J, xvi. 218,

362 THE ETUYL GliOUP.

acid thus obtained very readily decomposes into alcohol and
phosphorous acid. The salts, which however do not crystallize
well, are more permanent than the acid. In order to obtain
the barium salt, the acid solution is saturated with barium
carbonate, and filtered from the barium phosphite. The
other salts can be obtained from the barium salt by double
decomposition.

Potassium Ethyl Phosphite forms a thick syrup.

Barium Ethyl Phosphite, Ba < tj^O^H iPO^* ^^ ^^ amorphous
deliquescent friable mass.

Lead Ethyl Phosphite, Pb - urr^H^ipO^* crystallizes in unc-
tuous, shining scales, unalterable in the air. Its aqueous solution
gradually deposits lead phosphite.

Normal Ethyl Phosphite, (C2HJ3PO3. is obtained by acting on
absolute alcohol with phosphorus trichloride, or better by dis-
solving sodium in alcohol, evaporating to dryness, and gradually
adding the calculated quantity of phosphorus trichloride. In
order to diminish the violence of the reaction, which otherwise
takes place with evolution of light, the mixture is diluted with
five volumes of pure ether. The mixture is heated during the
operation to the boiling point of ether, until no further acid
vapours are evolved. The ether is then distilled off on a
water-bath, and the ethyl phos[)hite is obtained by subsequent
distillation from an oil-bath. It is purified by rectification in a
current of hydrogen as it undergoes oxidation in the air.^

Ethyl phosphite is a colourless disagreeably smelling liquid
which boils in an atmosphere of hydrogen at 188"* and in the
air at 191°. It has a specific gravity of 1075 at lo^'o, is easily
inflammable and burns with a bluish-white flame. It is not
only soluble in spirit of wine, but also in water. Heated with
the exactly requisite quantity of baryta it forms alcohol and
barium diethyl phosphite [P03(C2Hg)2].,Ba, which remains as a
deliquescent crystalline mass. Other diethyl phosphites may
be obtained from this by double decomposition ; these are all
soluble and difficultly or non-crystallizable. When diethyl
phosphite is heated with an excess of baryta solution the soluble
barium salt of dibasic ethyl phosphoric acid, PC)3(C2H^)Ba,
crystallizes out. The other salts of this acid do not crystallize.
The existence t^f two ethyl phosphoric acids, the one monolxi.sic

* Hailtoii, C/u/n, Soe. Joum, vii. 210.

PHOSPHITES OF ETHYL. 363

(Wurtz) and the other dibasic (Railton), can be explained by the
following formulae ;

Wurtz's Acid. Ilailton*s Acid.

/H /C2H5

O = P-OH O = P-OH

NOCgHj, \0H

According to this, the latter acid should be identical with
ethyl phosphinic acid obtained by oxidizing ethyl phosphine, but
this is not the case. Whilst the latter is a very stable compound,
the dibasic ethyl phosphoric acid cannot be isolated, and if the
barium salt be boiled with water, barium phosphite and alcohol
are formed.- These compounds require re-investigation.

Chloride of Ethyl Phosplwrous Add, P(0C2Hg)Clg, is formed
when absolute alcohol is allowed to run into the calculated
quantity of phosphorus trichloride.^ It is a strongly refracting
fuming liquid, boiling at 117® and having a specific gravity
at 0° of 1*31G. Water acts violently upon it with formation
of phosphorous acid, hydrochloric acid and alcohol. By the
further action of alcohol it is transformed into the compound
P(0C,H^,C1.

The three compounds obtained by the action of phosphorus
trichloride on alcohol, yield with chlorine or bromine, the ethyl
group in the form of haloid salt :

P(OC2H,)3 4- CI2 = PO(OC2H,)2Cl -f CgH.Cl.

In this case the chloride of diethylphosphoric acid is ob-
tained, whilst the chloride of diethylphosphorous acid yields
dichloride of ethyl phosphoric acid, PO(C2H50)Cl2, and the
chloride of ethyl phosphorous acid is converted into phosphorus
oxychloride.*^

Acid Ethyl Pyrophoffjyhite, O < p/rjp^xj'*N(-\fi» is not known in

the free state, but its zinc salt is produced together with other
products when zinc ethyl is heated to 140° with phosphorus
pentoxide. The barium salt has the composition P205(C2H5)2Ba.^
239 Fhosphaies of Ethyl, Tribasic orthopho.^^phoric acid forms
three ethyl compounds, two acid and one normal.

( OH C OH ( OC2H.

po ' OH po \ ocH. po I oan

' Mentschutkin, Ann, Chcni. PJiarm. exxxix. 313,
- W^ichelhaus, Ann. Chnn. Phann. Sum)!, vi. 257.
^ Dilling, ^cifsch. Chan, [2], ui. 266.

36 1 THE ETHYL GROUP.

Ethyl Fhogphoric Acid, VOfifi^{OW)^ was discovered in
1820 by Lassaigne^ and afterwards investigated by Pelouze*
and Liebig.^ In order to prepare it, equal parts of vitreous
phosphoric acid and strong spirit are heated for some minutes to
from GO** to 80^ After standing for twenty-four hours the liquid
is diluted with eight vohimes of water, neutralized with barium
carbonate, and boiled in order to drive oflF the excess of alcohoL
When the liquid has cooled down to 70", it is filtered and allowed
to stand in order that the barium salt may crystallize out The
aqueous solution is then decomposed with the requisite quantity
of sulphuric acid. The lead salt may also be prepared, and
this decomposed by sulphuretted hydrogen. The filtrate is
first evaporated over a lamp, and is then concentrated by stand-
ing over sulphuric acid. An oily odourless liquid is thus
obtained which possesses a biting acid taste. When heated,
it evolves the vapours of alcohol and ether, and afterwards
ethylene gas. Its aqueous solution may be concentrated by
boiling up to a certain point without decomposition ensuing.

Ethyl phosphoric acid is also formed when ether is treated
with concentrated phosphoric acid.* It may also be prepared
by acting with phosphorus oxychloride on aqueous spirit (Schiff),
as well as by the action of iodine and phosphorus in the
preparation of ethyl chloride (Reynoso).

The ethyl phosphates of the alkaline metals are deliquescent,
and crystallize imperfectly.

Barium Ethyl Phosphate, BaCgH^PO^, crystallizes in short
quadratic prisms or six-sided tables, and possesses an unpleasant
bitter saline taste. It loses its water of crystallization at 120^
Its solution saturated at 40° deposits crystals both on cooling
and on heating.

Lead Ethyl Phosphate, PbC2H5P04 + HgO, is the least soluWe
of all the ethyl phosphates, and is therefore easily obtained by
precipitating the foregoing salts with sugar of lead. It can be
obtained in the crystalline state from solution in boiling
water.

Anenic Ethyl Phosphate, As2(C2HgP04)3, is formed by dis-
solving arsenic trioxide in a boiling solution of the acid, and
forn)8 fine feathery needles.

Chloride of Ethyl Phosphoric Acid, P02(C2H5)Cl2, is not only
formed by the methods above described, but also when equal

> Ann. Chhn. PhyH. [2], xiii. 294. • Ih. Hi. 87.

' Ann. Phnnrt. vi. \A\), * Vugeli, Ann. Chrm, Pharw, Ixix. 180.

PHOSPHATES OF ETHYL. 365

molecules of alcohol and phosphorus trichloride are allowed to
act upon one another. It is an oily, readily decomposable sub-
stance, which, when distilled in a current of hydrogen, boils
pretty constantly at 167^

Diethyl Phosphoric Acid, 11(02^^5)2^04. In order to pre-
pare this acid, phosphorus pentoxide is allowed to deliquesce
under a bell-jar in the vapours of anhydrous alcohol or ether.
After one or two weeks a syrupy liquid is formed which con-
tains the above compound, together with phosphoric acid, ethyl
phosphoric acid, and frequently traces of triethyl phospliine.
The easily soluble lead diethyl phosphate Ls then prepared, and
this decomposed by sulphuretted hydrogen, the filtrate being
allowed to evaporate in a vacuum over sulphuric acid, when the
acid is obtained as a non-crystallizable syrup. The diethyl-
2)hasphates are soluble in water and easily crystallizable.

Lend Diethyl Phosphate, Pb(C2H5)4(P04)2. If the impure
acid obtained as above described be saturated with white-lead,
and the filtrate evaporated, tablets of a difficultly soluble lead
salt first separate out, and the solution becomes acid. If this
be again neutralized with white-lead, an insoluble lead pre-
cipitate is thrown down, and the filtrate yields on evaporation
crystals of lead diethylphosphate, which may be purified by
recrystallization. The salt is deposited in needles easily soluble
m water and in hot spirit. They melt at 180% and the fused
salt cools to a stellar crystalline mass.

Chloride of Dicthylphosphoric Acid, P03(C2H5)2C1, has been
already mentioned (see p. 363). It is formed by the action of
phosphonis oxychloride on the calculated quantity of alcohol,
and is a liquid decomposing on distillation.

Normal Ethyl Phosphate, {O^^^O^, was first obtained by
Vogeli by heating lead diethyl phosphate to 190° :

Pb(C,H,),(PO,), =. (C2H,),(P0,) + PbC,H,PO,.

It is also formed when silver phosphate is heated to 100**^
with ethyl iodide, as well as when phosphorus oxychloride,- or
pentachloride * acts on sodium ethylate or absolute alcohol : *

POCI3 + 3 HO.C2H5 = PO(OC2H5)3 + 3 HCl.
It has already been stated that small quantities of these

1 Clermont, Ann, Chim. Phys. [3]» xUv. 330.

* Linipricht, Ann. Chcm. Pharm, cxxxiv. 347.

* Geuther and Bischoff, Joum, PrakL Chtm [2], vii. 101.

* Schiff, Ann. Chrm. Pharm. ci. 299.

366 THE ETHYL GROUP,

compounds are also formed when alcohol vapour acts upon
phosphorus pentoxide. If the reaction be allowed to take
place quickly, a considerable quantity is formed. According to
Carius^ the pentoxide should be mixed with three or four times
its volume of anhydrous ether, and then half the theoretical
cjuantity of alcohol added, and the ethyl phosphate separated
from the diethylphosphoric acid by distillation.

Ethyl phosphate is a colourless liquid possess! n<^ a peculiar
pleasant smell and a burning taste, having at 12° a specific
gravity of 1072 and boiling at 215°, though towards the end of
the distillation the boiling-point reaches as high as 240^ and a
black acid residue remains. In a current of hydrogen, on the
other hand, it boils constantly at 203** (Wichelhaus). It is
miscible with water, and the solution soon becomes acid with
formation of diethylphosphoric acid (Carius) ; this decomposition
\akes place, however, very slowly (Limpricht).

Ethyl Pyropliospliate, {G^^^jd^, is obtained by heating
silver pyrophosphate with ethyl iodide to 100°, as an oily liquid
possessing a peculiar smell and a burning taste. It is soluble
in water, alcohol, and ether, and its aqueous solution soon
becomes acid.*

The Arsenites, Arsenates, and Borates of Ethyl.

240 Ethyl Ar senile, {C^^^PisO^, is formed by the action of
ethyl iodide on silver arsenite, as well as by heating together
ethyl silicate and arsenic trioxide to 200°, when silica or an ethyl
polysilicate separates out. It is, however, best obtained by
treating arsenic tribromide with sodium e thy late, an excess of
the latter substance being carefully avoided, as it acts at once
upon the ethereal salt with formation of common ether. In
order to decompose the excess of arsenic tribromide, the re-
sulting material is treated with dry ammonia, which unites with
the bromide to form a compound insoluble in spirit and in ether.
It is then filtered off, and the arsenite purified by distillation.
It is a colourless liquid boiling at IGa** to 1 GG*', and having a
specific gravity of 1224 at 0^ It is quickly decomposed by
water, with separation of arsenic trioxide.'

^ Carins, Ann. Chem. Pharm, czxxWi. 121.

• Clemiont, Ann, Chem Pharm. xci. 376.

* Clennont, Bull. Soc, C'Aim. [21 viii. 20^; xiv. ^9

ARSENITES, ARSENATES, BORATES OF ETHYL. 367

Ethijl Arsenate, (CgHJgAsO^, is obtaiaeJ by beating silver
arsenate to 100'* with the calculated quantity of iodide of ethyl
diluted with ether. It is a colourless liquid, which boils under
the ordinary atmospheric pressure, with slight decomposition at
235° to 238**, but may be distilled in a vacuum without de-
composition. It dissolves in water with decomposition, the
solution yielding all the reactions of arsenic acid.^

Ethyl Orthoborate, (0.2115)3603, was discovered by Ebelmen in
1845, and investigated by this chemist and Bouquet. They
obtained it by saturating alcohol with gaseous boron trifluoride.^
These experiments were afterwards corroborated by Bowman,'
and H. Rose noticed that ethyl borate could also be easily pre-
pared by distilling a mixture of two parts of anhydrous borax
and three parts of potassium ethyl sulphate.* Frankland em-
ployed this reaction in his investigation on the organic com-
pounds containing boron,^ and found that from the distillate,
which contains a large quantity of alcohol, ethyl borate could
be best separated by the addition of one-fourth part its weight
of fused calcium chloride ; after this has dissolved, two layers of
liquid make their appearance, of which the upper one contains
the whole of the ethereal salt, and this can be purified by
fractional distillation. It also is formed by heating boron trioxide
with alcohol for some time to 120°, and may be readily obtained
from the portion of the distillate coming over above 100°, by
addition of a small quantity of sulphuric acid.

Ethyl borate is a thin colourless liquid boiling at 120°, having
a specific gravity of 0 8G1 at 26°'5, a vapour density of 5*14,
j\nd burning with a green flame. It has a peculiar pleasant
smell and a hot bitter taste. It is easily decomposed by water,
with separation of boric acid. When heated with boric trioxide,
ethyl metabarate, (CaHJ^BaO^ is formed as a thick colourless
liquid, converted at 200° into orthoborate and ethyl tribarate,
C2H5B3O5. This latter is a gummy mass, which, like the other
borates is decomposed by water, with separation of boric acid.*^

» Clermont, Bull. Soc. Chim. [2], viii. 206 ; xiv. 99.

* Ann. Chim, Phys. [3], xvii, 65.
3 Fhil, Mag. [3], xxix. 546.

* Fogg. Ann. xcviii, 245.

» Ann. Ghem. Pharm. cxxiv. 129 ; Phil. Trans. 18C2, 1C7.

* Scliiff, Ann. Chcm. Pharm, Sappl. v, 154.

36ft THE ETHYL GROUP.

compounds arc also formeil when alcohol vapoar acts apon
phosphorus pentoxide. If the reaction be alloweil to take
place quickly, a considerable quantity is formed. Acconling to
Carius^ the pentoxide should be mixed with three or four times
its volume of anhydrous ether, and then half the theoretical
r|uantity of alcohol added, and the ethyl phosphate separated
from the diethylphosphoric acid by distillation.

Ethyl phosphate is a colourless liquid possessing; a peculiar
pleasant smell and a burning taste, having at 12"* a specific
gravity of 1072 and boiling at 215**, though towards the end of
the distillation the boiling-point reaches as high as 240", and a
black acid residue remains. In a current of hydrogen, on the
other hand, it boils constantly at 203"* (Wichelhaus). It is
miscible with water, and the solution soon becomes acid with
formation of diethylphosphoric acid (Carius) ; this decomposition
\akes place, however, very slowly (Limpricht).

Ethyl Pyrophosphate, (CjHj)^?^©^, is obtained by heating
silver pyrophosphate with ethyl iodide to 100°, as an oily liquid
possessing a peculiar smell and a burning taste. It is soluble
in water, alcohol, and ether, and its aqueous solution soon
becomes acid.-

The Arsenites, Arsexatks, and Borates of Ethyl.

240 Ethyl Arsenitc, (C2H5)3As03, is formed by the action of
ethyl iodide on silver arsenite, as well as by heating together
ethyl silicate and arsenic trioxide to 200°, when silica or an ethyl
polysilicate separates out. It is, however, best obtained by
treating arsenic tribromide with sodium ethylat^, an excess of
the latter substance being carefully avoided, as it acts at once
ujKm the ethereal salt with formation of common ether. In
order to decompose the excess of arsenic tribromide, the re-
sulting material is treated with dry ammonia, which unites with
the bromide to form a compound insoluble in spiiit and in ether.
It is then filtered off, and the arsenite purified by distillation.
It is a colourless liquid boiling at 165° to 1 GG°, and having a
specific gravity of 1*224 at 0°. It is quickly decomposed by
water, with separation o'f arsenic trioxide.^

' TarinR, Ann, Chem. Pharm, czxzvij. 121.

• <'liTmont, Ann. Chnn Pharm, xci. S76.

* i'lennont, HulL Soc, Chiin. [2], viii. 20^; xiv. ^9

ARSENITES, ARSENATES, BORATES OF ETHYL. 367

Ethyl Arsenate, (C2H5)3AsO^, is obtaiued by beating silver
arsenate to 100'' with the calculated quantity of iodide of ethyl
diluted with ether. It is a colourless liquid, which boils under
the ordinary atmospheric pressure, with slight decomposition at
235° to 238°, but may be distilled in a vacuum without de-
composition. It dissolves in water with decomposition, the
solution yielding all the reactions of arsenic acid.^

£thyl Orthohorate, (02115)3608, was discovered by Ebelmen in
1845, and investigated by this chemist and Bouquet. They
obtained it by saturating alcohol with gaseous boron trifluoride.*
These experiments were afterwards corroborated by Bowman,'
and H. Rose noticed that ethyl borate could also be easily pre-
pared by distilling a mixture of two parts of anhydrous borax
and three parts of potassium ethyl sulphate.* Frankland em-
ployed this reaction in his investigation on the organic com-
pounds containing boron,^ and found that from the distillate,
which contains a large (Quantity of alcohol, ethyl borate could
be best separated by the addition of one-fourth part its weight
of fused calcium chloride ; after this has dissolved, two layers of
liquid make their appearance, of which the upper one contains
the whole of the ethereal salt, and this can be purified by
fractional distillation. It also is formed by heating boron trioxide
with alcohol for some time to 120°, and may be readily obtained
from the portion of the distillate coming over above 100°, by
addition of a small quantity of sulphuric acid.

Ethyl borate is a thin colourless liquid boiling at 120®, having
a specific gravity of 0 8G1 at 26°*5, a vapour density of 5*14,
i^nd burning with a green flame. It has a peculiar pleasant
smell and a hot bitter taste. It is easily decomposed by water,
with separation of boric acid. When heated with boric trioxide,
ethyl mctaborate, (CoHJ^BgO^, is formed as a thick colourless
liquid, converted at 200° into orthoborate and ethyl triborate,
C2H5B3O5. This latter is a gummy mass, which, like the other
borates is decomposed by water, with separation of boric acid.*

» Clermont, Bull. Soe. Chim, [2], viii. 206 ; xiv. 99.
^ Ann. Chim. Phys. [3], xvii, 65.
8 phii^ jijag. [3], xxix. 546.

* Fogg. Ann. xcviii. 245.

» Ann. Chem. Pharm, cxxiv. 129 ; Phil. Trans. 18C2, 167.

• Scliiff, Ann, Chem, Pharm, Snppl. v. 154.

368 THE ETHYL GROUP.

Ethyl Silicates.

241 Ethyl Orthosilicatc, (CgHJ^SiO^, is formed, as Ebelmen*
has shown, by the action of silicon chloride on absolute alcohoL
It is a mobile pleasantly smelling liquid, having a strong taste of
peppermint, boiling at 165°-5, and having at 0° a specific gravity
of 0 967(). This ethereal salt is easily inflammable, burning
with a brilliant white flame, depositing clouds of very finely
divided silica, which is insoluble in alkali. It is slightly
attacked by water, in which it is insoluble. On exposure to
moist air, it gradually decomposes, and a small quantity which
Friedel and Crafts^ had kept for three years in a badly stoppered
bottle was completely converted into a mass of silicic acid,
which was so hard that it scratched glass. Absolute alcohol
dissolves this ethereal salt without alteration, and aqueous
spirit decomposes it quickly, with formation of ethyl polysiU-
cates. When ethyl silicate is heated with silicon chloride in
a closed tube to 150^ one or other of the following chlorhydrins
are formed, according to the quantities of the constituents
present :

Boiling-point.

Si(OCjH5)3Cl .... 155°-7 to 157°
SiXOCjHJ^CIj. . . . 136° to 138°
Si(0CjH5)Cl, .... 103° to 105°

These compounds are colourless liquids, easily decomposed by
water, and converted by the action of ethyl alcohol into ethyl
silicate, whilst the other alcohols give mixed ethers, as, for
example, the following:

Boiling-point.

SiCOC.HJgOCHs. . . . 155° to 157
Si(0CJHj)j(0CH3), . . 143° to 147
Si(OCjH5)(OCHj32. . . 133° to 135

■»NwO

Ethyl Disilicate, (CgHJ^SijOy, is formed by the action of
silicon chloride on alcohol containing a small quantity of water,
and is hence usually formed in the preparation of the ortho-
silicate :

2 SiCl, + 6 HO.CgH, + H.0 = O I ||[oc'h'J' + ^ "^'•

^ Ann. C^im. Phyt, [3], xvi. 144. * Bulh S(*e. Chim. v. 174, 288.

ETHYL OXALATE. 369

It is an oily liquid, resembling the orthosilicate in its smell ;
is easily inflammable, boils between 233** and 234'', and possesses
at 0** a specific gravity of 10196 (Friedel and Crafla).

Ethyl MetdsiliccUe, (€2115)28108. This is formed, according to
Ebelmen, by the action of silicon chloride on aqueous alcohol.
It is a slightly smelling liquid, which boils at 350'', and is de*
composed by water. Heated with a small quantity of water, a
gummy mass is obtained, which on cooling forms a glassy solid,
and is said to have the composition (02115)281^0^. Friedel and
Crafts were unable to obtain this compound

Ethyl Carbonates.

242 Hydrogen Ethyl Carbonate or Ethyloarbonic Add,
H(C2H5)C03. This compound is not known in the free state, but
its corresponding potassium salt has been obtained by Dumas
and Feligot* by passing dry carbon dioxide into a solution of
caustic potash in absolute alcohol, the solution being well cooled :

CO2 + C,H,.OH + KOH = CO { Q J^j + H2O.

At the same time both normal and acid potassium carbonate
are formed. In order to separate these^ the liquid, as soon as a
considerable quantity of precipitate has been formed, is shaken
with an equal volume of ether and the solid mass collected on a
filter. From this mass absolute alcohol dissolves only the ethyl
potassium carbonate, and this may be obtained, on addition of
ether, in the form of a pearly crystalline precipitate, which is
decomposed slowly by aqueous alcohol, but quickly by water :

CO j ^^^j + H2O = CO-f ^5 + HO.C2H5.

The corresponding sodium compound is formed, according to
Beilstein, as a white precipitate, when carbon dioxide acts, on an
alcoholic solution of sodium ethylate,^ and when normal ethyl
carbonate is heated with sodium ethylate to 120** (Geuther) :

Norninl Ethyl Carbonate, (G^^\CO^. This body was dis-
covered by Ettling' in 1836, and obtained by him,

Ann, Chim. Phya, Ixxiv. 9. ' Ann, Chefn, Pharm,

' Ann. Phartn, xix. 17.

VOL. in. B

370 THE KTHYL GROUP.

with carbon monoxide and other products, by heating pure ethyl
oxakte, (€2115)20204, with sodium. Cahours^ then showed that
it was also formed when the metal potassium was employed.

This peculiar reaction has not as yet found any satisfactoiy
explanation. Ethyl oxalate is indeed distinguished from ethyl
carbonate by an increment of CO, but as in the formation of
this latter compound the alkali metal disappears, the decompo-
sition cannot, as Gmelin^ remarks, be explained by the supposi-
tion of a catalytic action. Hence it is probable that the following
reaction takes place :

2 (Cfi^^Cp^ + Nag = (CjH^aCOa + 2 CoH^ONa + 3 CO.

The other products which have been observed are formed by
the action of sodium ethylate on ethyl oxalate. Geuther,' who
has investigated this subject carefully, states that oxalic ether
can also be converted into ethyl carbonate when it is treated
with sodium ethylate, and Dittmar and Cranston* came to the
same conclusion, finding that, when one molecule of sodium
ethylate was used with four molecules of ethyl oxalate, three
molecules of ethyl carbonate, and three molecules of carbon
dioxide, together with about 0*4 molecule of alcohol, as well
as other products not exactly examined, w^ere formed. Accord-
ing to Geuther, ethyl formate is also produced, as well as a
small quantity of a crystalline acid and two different brown
amorphous bodies having an acid character.

Ethyl carbonate is prepared by distilling a mixture of ethyl
potassium carbonate and ethyl potassium sulphate,* as well as
by acting on ethyl iodide with silver carbonate.^ It is a colour-
less, pleasantly smelling liquid, boiling at 120**, and having a
specific gravity of 0 9998 at 0° (Kopp) and a vapour density of
4*09 (Cahours). It is easily inflammable, burning with a blue
flame. Treated with chlorine, it yields substitution-products, of
which the last is perchlorethyl carbonate, (02015)2005.' This
crystallizes in small white needles; which haTe a faint smell, melt
at 85** — 8G^ and may bo partially distilled without decomposition,
though yielding at the same time carbon dioxide, hexchlore thane,
and trichloracetyl chloride.^

* Jnn. Phafm. xlvii. 291. • BandboitJc, ix. 182.

> Zeitsch, Chem, 1868, 662. * Joum, Chrm, Soe. (2J, vil 441.

» Chancel, Compt, Rend, xxxii. 687. • Clennout, ib, xxxix. 338.

" Cahoura, Ann. Chem, Pharm. xlvii. 291.

' Malaguti, Ann. Chim, Phys, [3], xvi. 80.

ETHYL OBTHOCARBONATE. 371

CO { qS'cJ' = CjCl, + CO, + CClj^CGCl.

X 2 5

Ethyl OrtJuHXLrbonate, CiOG^H^)^ was discovered by Basset,^
who prepared it by the action of sodium on a solution of chloro-
picrin in absolute alcohol :

4NaOC2H^ + CCI3.NO, = CCOCjHg), + 3NaCl + NaNO^

It is an aromatic-smelling liquid, boiling at 158** — 159^ and
easily decomposed by alcoholic potash, with formation of potas-
sium carbonate. When heated for six hours with boron trioxide
to 100®, the following reaction takes place : ^

(C^H^.CO, + 2 B,03 = (C^H^gCOs + {G.U^^Bfir

( CI
Hthyl Chlorocarbonate, CO -J Qp tt . This compound was

first obtained in 1833, by Dumas,* by the action of carbonyl
chloride on absolute alcohol :

C0{ g[ + HOC,H, = CO { gJ.^H^ = HCl.

It is a colourless mobile liquid, boiling at 94^ and having a
specific gravity of 1*133 at 15^ It possesses a suffocating and
irritating odour, but if the vapour be mixed with a large quan-
tity of air, it possesses a pleasant smell. In contact with warm
water, partial decomposition occurs, with formation of hydro-
chloric acid, and with alcohol it decomposes slowly, with forma-
tion of ethyl carbonat^.^ This last ether is also formed when
ethyl chlorocarbonate is treated with sodium :

2C0 { gi^^H, + ^S = CO { gg;H» + CO + 2 NaCl.

A similar reaction also occurs when this chloro-ether is acted
upon with sodium ethyl carbonate : *

CO { OC,H, + CO { ggf * = CO { gg;«; + CO, + NaCl.
243 Ethyl Carbamate, QO < Qptx was obtained by Dumas,^ in

* Joum, Chem, Soc, [2], ii. 198 ; Ann, Chem. Phamu czxzii. 54.

* Ann. Chim. Phys, [2], liv. 226 ; Ann, Phamu x. 277.
' Batlerow, Zeitsch, Chem, 1863, 484.

* Wilm and Wischin, Ann. Chem, Pharm, cxivii. 160.

* Wyss, Ber. Deutsch. Chem. ties. ix. 847,

* Ann, Chim, Phys. liv. 225.

BBS

372 THE ETHYL GROUP.

1833, by acting with ethyl chlorocarbonate on ammonia, and he
termed it urethane, because it may be considered as a compouad
of urea with ethyl carbonate. This name was afterwards changed
in accordance with the usually adopted nomenclature for the
carbamine salts. Ethyl carbamate is also formed when the
carbonate is allowed to remain in contact with cold ammonia,
whilst when heated, urea is formed.^ It is also produced by the
action of cyanogen chloride on alcohol.*

CICN 4- 2 C^H.OH = C0H5CI + (. 2 O* } ^^•

Ether may be also employed instead of alcohol, the reaction
then taking place slowly.^ It is also formed together with ethyl
allophanat^, when the vapour of cyanic acid is passed into
alcohol or ether : *

HO.CN + C.,H,.OH = ^ ^^ \- CO.

_ NHa
- C AO 1

In order to prepare this compound, ethyl carbonate is allowed
to remain in contact with an equal volume of aqueous ammonia
until the ether has all dissolved, and then the liquid is allowed
to evaporate in a vacuum. In this way fine transparent crystals
are obtained, easily soluble in water and alcohol. Ethyl carba-
mate melts below 100^ and on cooling, again soli<lifies to a
spermaceti-like mass. When perfectly dry, it boils without
decomposition at 180°, subliming, however, at a lower tempera-
ture. In the moist state it partially decomposes on heating,
with formation of ammonium carbonate.

Ethylamidomcihyl Carbonate , CO i ^i/ it , is formed by

acting on ethyl chlorocarbonate with a strong aqueous solu-
tion of methylamine. It is a colourless not unpleasantly
smelUng ethereal liquid, lighter than water, and boiling at l70^
The ether produced in a corresponding way from ethylamine is a
ver^ similar body, boiling between 175-G°.*

' Cahoum, Compt, Rend. xxi. 121>.

« Wtirta, Compt. Rrnd. xxii. 503.

» Oqoz, JnsL 1857, 207

^ Licbi^ nnd Wohler, Ann. Vhem. Pharm. liv. 870 ; Iviii. 260.

' Schn>inrr, Joum. PmU. Chem. (2|, xxi 1:J1,

ETHYL ALLOPHANATE. 373

Ethyl Allophanate, C2N2H3O8.C2H5.

244 This ether was first obtained by Liebig and Wohler, in
1830, by passing the vapour of cyanic acid into alcohol, and
described by them under the name of cyanic ether.^ Fifteen
years later they found that this compound contains neither
cyanic acid nor cyanuric acid, but a new acid, for which they pro-
posed the name of allophanic acid, because it is a substance
different from that which from its mode of formation might
have been expected.^ Absolute alcohol absorbs the vapour of
cyanic acid with such avidity that the liquid begins to boil.
Hence it is best to dilute the alcohol with an equal volume of
ether, and to allow the saturated liquid to stand for twenty-
four hours, when the compound crystallizes out in fine prisms,
having a pearly lustre. These are best obtained by saturating
ether with cyanic acid, evaporating, and then adding 95 per
cent, spirit, and allowing the solution to stand.

Ethyl allophanate is also formed when a solution of potassium
cyanate in aqueous alcohol is acidified,^ as likewise, together
with ethyl carbonate, when ethyl chlorocarbonate is brought
into contact with potassium cyanate and absolute alcohol : *

2 CICO2C2H5 + 2 KOCN 4- 3 HOC2H, = 2 KCl
+ 2 (C,Ufi)fiO + C2H3N3O3C2H,.

Ethyl allophanate is tasteless and odourless, only slightly
soluble in cold water, alcohol, and ether, but more soluble in the
warm liquids. It also dissolves without alteration in hot nitric
acid and dilute sulphuric acid. It melts at 190-1*, and decom-
poses when it is allowed to stand at this temperature for some
time, with formation of alcohol and cyanuric acid (Amato). Its
constitution is recognised by the fact that it is also formed when
ethyl chlorocarbonate acts upon urea : ^

/NH^ /NH2

CO + CICO.OC2H, = CO + HCl.

NNH^ \NH-CO.OC2H5

It is also formed by the direct union of cyanic acid and ethyl

• Fogg, Ann. xx. 396. ' Aiui. Chem. Pharm. lix. 291

• Amato, Oatz. Chim. Ital. iii. 469. * Wilm, Lkbig's Ann, czcii. 24

• Wilm and Wischin, Ann, Chan. Pfutrtn, cxlvii 150.

374 THE ETHYL GROUP.

carbamate, which is the first product of the action of cyanic
acid on alcohol (par. 243).^

/NH- /NH-CO-NH,

CO + NCOH = CO

\OC2H5 XOCjH^.

On the other hand, the allophanate is decompoeed into two
molecules of ethyl carbamate by heating it with spirits of wine
to 160°. If ethyl allophanate be heated with ammonia to 100*
biuret is formed :

/CO.NIL /CO.NHL

NH + NIL = NH + HO.C.H,.

\CO.OC0H5 \CO.NH,

Hence biuret (Vol. I. p. 652) is the amide of allophanic acid,
a substance which does not exist in the free state, although a
series of ethers and a few unstable salts are known. These
latter are obtained by the action of alkalis and alkaline earths
upon the ethers, and their aqueous solutions decompose very
easily on heating with formation of urea.

Diethyl CijanamidocarboncUe, N(CN)(CO.OC^5)2, is formed
by the action of ethyl chlorocarbonate on sodium cyanamide
(Vol. I. p. 676). It is easily soluble in alcohol, separating
from the solution in large glistening crystals. When heated
with sodium ethylate the sodium salt, N(CN)(C0.0C2HJNa, is
formed, crystallizing in glistening crystals which melt at 241®.
Concentrated sulphuric acid acting upon this latter compound,
yields the monethyl ether, N(CN)(CO.OC2H5)H, a yellowish
syrupy liquid having an acid reaction and a burning taste. This
is decomposed by boiling water into carbon dioxide and alcohol
If the sodium salt be heated with ethyl iodide, an ether is
formed, having the composition N(CN)(CO.OC2H5)C2H5; this
is an oily liquid boiling at about 213°.*

Diethyl Guanidine Carbonate, CNHCNH.CO.O.CjHj),, is
formed by the action of ethyl chlorocarbonate on guanidine
(Vol. I. p. 680) :

NH- NH.CO.OC.H.

I I

C=NH + 2CICO.OC0H, = C-NH + iHCl.

Hj NH.CO.OC2H5.

* Hofmnnn, Ber, l>ufitrh, Chem. Gen. iv. 262.
3 Ranler, Journ. Pnkt. Chrm, [2], xvi. 120.

ETHYL FORMATE. 375

This compound is insoluble in water, but dissolves readily in
alcohol, crystallizing in colourless crystals melting at 162°.
When heated with alcoholic ammonia to 100^ the monethyl
compound of urethane is produced :

NH.CO.OaH, NR

'2"5 -J' "2

C=NH + NH3 = C=NH + NH2.CO.OC2H5

NH.CO.OaH. NH.i

..^.CO.OC,H,.

This monethyl ether is a powerful base, crystallizing from
aqueous solution in rhombic tablets and forming a series of
"well-crystallizable salts.^

Ethyl Formate, C2H5CHO2.

345 In the communication already referred to under formic
acid, Arfvedson, in 1777, states that when formic acid is distilled
with spirit of wine, oily drops of a liquid appear, the properties
of which he did not further investigate. Five years later
Bucholz obtained this ether in the same way, separating it from
the alcoholic distillate by means of water.

According to Kopp^ ethyl formate is best prepared by
bringing 8 parts of anhydrous sodium formate into a retort and
pouring on it a mixture of 7 parts of 88 per cent, spirit and
11 parts of sulphuric acid, so much heat being evolved that the
ether distils and may be collected in a well-cooled receiver.
This ether is also formed as a by-product in the preparation of
ethyl oxalate (Lowig), and also by heating hydrogen ethyl
oxalate, (C2H5)HC204, with glycerin to 100^ the reaction which
here takes place being exactly analogous to that of the formation
of formic acid from oxalic acid. It is not necessary for this
purpose to prepare pure ethyl oxalic acid, but the crude product
obtained by heating oxalic acid for a long time with alcohol
may be employed.^ A still more simple method is to heat
anhydrous glycerin with equal molecules of alcohol and oxalic
acid, connecting the flask with a reversed condenser until com-
plete decomposition has occurred ; the oxalic acid then requires
to be warmed and the ether distils over.*

' NeiK'ki, Bf-r. Dfutsrh, Chrm. Ges. vii. 1588 ; Jourti. Pralt. Cluia, [2], xvii.
237.

' Ann. Chein, PhannAv.no. - Church, /*/(?/. i/r/y. [4 J, xi. 527.

* Lorin, Bull, Soc, Chim \2\, v. 12

366 THE ETHYL GROUP.

compounds are also formed when alcohol vapour acts upon
phosphorus pentoxide. If the reaction be allowed to take
place quickly, a considerable quantity is formed. According to
Carius^ the pentoxide should be mixed with three or four times
its volume of anhydrous ether, and then half the theoretical
quantity of alcohol added, and the ethyl phosphate separated
from the diethylphosphoric acid by distillation.

Ethyl phosphate is a colourless liquid possessin<( a peculiar
pleasant smell and a burning taste, having at 12** a specific
gravity of 1072 and boiling at 215°, though towards the end of
the distillation the boiling-point reaches as high as 240°, and a
black acid residue remains. In a current of hydrogen, on the
other hand, it boils constantly at 203° (Wichelhaus). It is
miscible with water, and the solution soon becomes acid with
formation of diethylphosphoric acid (Carius) ; this decomposition
\akes place, however, very slowly (Limpricht).

Etkyl Pyrophosphate, {G^^^fi^, is obtained by heating
silver pyrophosphate with ethyl iodide to 100°, as an oily liquid
possessing a peculiar smell and a burning taste. It is soluble
in water, alcohol, and ether, and its aqueous solution soon
becomes acid.*

The AnsENiTRs, Arsenates, and Borates of Ethyl.

240 Ethyl Arsenite, (C2H5)3As03, is formed by the action of
ethyl iodide on silver arsenite, as well as by heating together
ethyl silicate and arsenic trioxide to 200°, when silica or an ethyl
polysilicate separates out. It is, however, best obtained by
treating arsenic tribromide with sodium ethylate, an excess of
the latter substance being carefully avoided, as it acts at once
upon the ethereal salt with formation of common ether. In
order to decompose the excess of arsenic tribromide, the re-
sulting material is treated with dry ammonia, which unites with
the bromide to form a compound insoluble in spiiit and in ether.
It is then filtered off, and the arsenite purified by distillation.
It is a colourless liquid boiling at 165° to 166°, and having a
specific gravity of 1*224 at 0°. It is quickly decomposed by
water, with separation of arsenic trioxide.*

' Tarini, Jnn, Chem. Pharm, cxxxvii. 121.

• ('h'rniont, Ann, Chem Pharm, xci. 376.

* C'lrnnont, Huil. Soc, Chitn, [2], viii. 206; xiv. j)9

ARSENITES, ARSENATES, BORATES OF ETHYL. 367

Ethyl Arsenate, [C^^^PisO^, is obtaiQed by heating silver
arsenate to lOO** with the calculated quantity of iodide of ethyl
diluted with ether. It is a colourless liquid, which boils under
the ordinary atmospheric pressure, with slight decomposition at
235** to 238**, but may be distilled in a vacuum without de-
composition. It dissolves in water with decomposition, the
solution yielding all the reactions of arsenic acid.^

Ethyl Orthoborate, (02115)3603, was discovered by Ebelmen in
1845, and investigated by this chemist and Bouquet. They
obtained it by saturating alcohol with gaseous boron trifluoride.^
These experiments were afterwards corroborated by Bowman,*
and H. Rose noticed that ethyl borate could also be easily pre-
pared by distilling a mixture of two parts of anhydrous borax
and three parts of potassium ethyl sulphate.* Frankland em-
ployed this reaction in his investigation on the organic com-
pounds containing boron,^ and found that from the distillate,
which contains a large quantity of alcohol, ethyl borate could
be best separated by the addition of one-fourth part its weight
of fused calcium chloride ; after this has dissolved, two layers of
liquid make their appearance, of which the upper one contains
the whole of the ethereal salt, and this can be purified by
fractional distillation. It also is formed by heating boron trioxide
with alcohol for some time to 120°, and may be readily obtained
from the portion of the distillate coming over above 100°, by
addition of a small quantity of sulphuric acid.

Ethyl borate is a thin colourless liquid boiling at 120*", having
a specific gravity of 0 8C1 at 2G°'5, a vapour density of 514,
ivnd burning with a green flame. It has a peculiar pleasant
smell and a hot bitter taste. It is easily decomposed by water,
with separation of boric acid. When heated with boric trioxide,
ethyl meiahoi^ate, (02115)2620^, is formed as a thick colourless
liquid, converted at 200° into orthoborate and ethyl triborate,
C2H5B3O5. This latter is a gummy mass, which, like the other
borates is decomposed by water, with separation of boric acid.^

* Clermont, Bull. Soe. Chim. [2], viii. 206 ; xiv. 99.
^ Ann. Chim. Phys. [3], xvii. 55.

3 Phil, Mag. [3], xxix. 546.

* Pogg. Ann. xcviii. 245.

« Ann, Chem, Pharm. cxxiv. 129; Phil. Trans. 1862, 167.

* Schiir, Ann, Chem, Phann. Suppl. v, 164.

378 THE ETHYL GROUP.

SULPHUR COMPOUNDS OF ETHYL.

246 Ethyl ffydrosiUphide or Ethyl Mercaptan, CgH^JSH. This
compound was obtained by Zeise in 1833 by distilling caldom
ethyl sulphate with a solution of barium hydrosulphide :

CaCSO.CjHg), + Ba(SH)2 = 2 C,HySH + CaSO, + BaSO,.

Mercaptan, as Zeise named this substance, is also formed when
an alcoholic solution of potassium hydrosulphide is saturated
with ethyl chloride and then the product distilled, the current of
ethyl chloride being continued.^ According to Liebig,* it is
best obtained by saturating caustic potash of specific gravi^
IS with sulphuretted hydrogen, adding an equal volume of a
solution of calcium ethyl sulphate of the same specific gravity
and distilling. It is likewise easily obtained by acting with
phosphorus pentasulphide on alcohol.^ For other methods of
preparing mercaptan the original memoirs may be consulted.*

In order to purify the crude product it is first separated from
water, dried over chloride of calcium, and distilled. The first
portions passing over consist of almost pure mercaptan, whilst a
quantity of ethyl disulphide formed at the same time remains
behind. This latter substance is not formed when the mercaptan
is prepared according to Regnault's method.

In order to free it from sulphuretted hydrogen, which is
difiicult to remove, it is best to rectify it over mercury mercap-
tide. It may also be obtained in the pure state by the decom-
position of this same compound, a description of which will be
found in the sequel (Zeise).

Ethyl hydrosulphide is a colourless liquid having a penetrating
garlic-like smell, and unpleasant taste. It boils at 36**2, has at
21** a specific gravity of 0835, and possesses a vapour density
of 2" 188 (Rcgnault). A drop solidifies on a glass rod exposed
to a current of air, yielding a white mass which soon melts and
evaporates (Liebig). When mixed with water, and the mixture
cooled to + 2°, crystals are formed which melt again at 12',
decomposing into mercaptan and water. ^ The.se jwssess the
composition CjHgS + I8H2O (Clae.sson). Mercaptan forms

* Regnault, Ann. Chim, Phys. [2], Ixxi. 8ftO.
' Ann, Pharm, xi. 14.

' Kekale, Ann. Chtm. Pharm. xc, 810.

* Sace, Ann. Chcm. Pharm. li. 348 ; E. Kof.p, ih. Ixiv. 320 ; Delui^ fh. Ixxii.
18 ; Ixxv. 121 ; Carius. ih. ixii. 190 ; Schiff, ib, oxviii. J>0.

» H. Miillcr, Arch. Pharm. [2J, cl. 147,

ETHYL MERCAPTAN. 379

two compounds with titanium chloride, of which the first,
TiCl^ -I- CgHgS, is deposited in blackish-red crystals, whilst the
other, TiCl4 + 2CjHgS, has a bright scarlet-red colour, and
crystallizes well.^ Mercaptan is easily inflammable, burning with
a blue sulphur-like flame. Nitric oxide is quickly absorbed by
this substance giving rise to a dark blood-red solution. Ethyl mer-
captan, both in the pure state and in solution in water, possesses
a neutral reaction. The hydrogen which is combined with the
sulphur may readily be replaced by metals with formation of
compounds termed mercaptides.

Potassium Mercaptide, CgH^SK, is formed with evolution of
hydrogen, when potassium is dissolved in mercaptan; and it
remains behind, when the excess of the volatile liquid is evapo-
rated, in the form of a granular mass, which, when heated,
undergoes decomposition.

The sodium compound, prepared in a similar way, forms a
snow-like mass.^

Lead Mercaptide, (C2H5S)2Pb, is thrown down on mixing
idcoholic solutions of mercaptan and lead acetate as a yellow
crystalline precipitate, which dissolves in an excess of lead ace-
tate and crystallizes from solution in needles. It is unaltered
by caustic potash.

Capper Mercaptide, (C2H5S)2Cu, is a pale yellow precipitate
obtained when a solution of potassium mercaptide is brought in
contact with one of copper sulphate.

Silver Mercaptide, Cg^^S Ag. Mercaptan acts upon silver oxide
so violently, even when it is diluted with alcohol, that ignition
may take place. Mercaptan produces a snow-white precipitate
in solution of silver nitrate, but this precipitate appears always
to contain nitric acid.

Mercuric Mercaptide, (C2H5S)2Hg. Mercaptan acts violently,
with evolution of heat, on solutions of mercuric salts yielding
a precipitate of the above compound. In order to prepare it,
mercury oxide is added in small quantities to ethyl hydrosul-
phide well cooled with ice, and the mass thus obtained
recrystallized from boiling alcohol. Glistening, colourless,
transparent tablets are obtained, which melt at 80°, and then
solidify to a solid mass. This compound is decomposed above
130® with formation cf vapours which attack the eyes power-
fully. It dissolves in concentrated hydrochloric acid without

^ Demaryav, BuU. Soc. Chim, [2], xx. 127.

2 Claes»on,' Bull Soc. Chiia, [2], xxv. 184 ; Joarn, Frakt, Chem. [2], xv. 193.

380 THE ETHYL GROUP.

decomposition, and on cooling the dilute boiling acid, it separates
out in glistening crystals. It is also unattacked by caustic
potash. It forms a difficultly soluble compound with meivaiic
cliloride (C2H5S)2Hg + HgClj, obtained in the form of glistening
tablets from boiling alcoholic solution.

Bismuth Afercaptide, (CgH^S^jBi, is obtained by the actkm
of bismuth nitrate, and crystallizes in elastic yellow needles
easily soluble in acids and alcohol, and precipitated when the
acid solution is neutralized (Claesson).

Gold Mercaptide, CgH^SAu. Mercaptan does not act upou
gold oxide so violently as upon silver oxide. If dilute aqueous
solutions of aur'c chloride and mercaptan are mixed, a semi-
solid mass of aurous mercaptide is formed, the chlorine which is
evolved decomposing a portion of the mercaptan. This com-
pound, when dried, forms a light amorphous mass resembling
aluminium hydroxide.

Platinum Mercaptide, (C2H5S)2Pt, is a pale yellow precipitate,
which on exposure to air becomes heated nearly to incandescence,
leaving a black residue of sulphide of platinum.

Ethyl Sulphide, {C^^^.

247 This was first obtained in 1833 by Dobereiner,' and
afterwards more fully examined by Regnault.* In order to
obtain it, gaseous ethyl chloride is passed into an alcoholic
solution of potassium hydrosulphide, and the operation conducted
exactly as described under methyl sulphide. It may also be
easily prepared by distilling an alcoholic solution of potassium
monosulphide with potassium ethyl sulphate.^ It is further
obtained by the action of phosphorus pentasulphide on ether,*
and, together with mercaptan, when the pentasulphide is
allowed to act upon alcohol. The metallic sulphides, which
are decomposed by hydrochloric acid, also yield this compound
when they are heated with the haloid ethyl ethers,* and some
ethyl sulphide is likewise formed when these sulphides are
brought together with a mixture of hydrochloric acid and
alcohol.*

' Srhurifjij, J^urn, Jxi. 377.

* Ann. Chim. PKyn. [2J, Ixxi. 387.

* Holwon, Quart, Joum, Chin. Hfc. x. 56,

* RGckmanii, Journ, Prali, Chem. [2], xvii. 4M.
" Kei^iiault, /or. eit.

* Loir, Jnn, Chim, Phtfn. [3], xxxix 441 ; liv. 42.

ETHYL SULPHIDE. 381

To prepare pure ethyl sulphide the crude liquid is washed
with water, dried over chloride of calcium, or, better, over
phosphorus pentoxide, and then carefully distilled. It is a
colourless liquid, having a strong garlic-like smell, but some-
what less unpleasant than mercaptan. At 0° its specific gravity
is 0*8367 ; it boils at 92**,^ and its vapour has a density of 3*10.
(Regnault.)

If chlorine be passed into cold ethyl sulphide in the dark,
substitution-products are formed, which have been investigated
by Regnault* and Riche.^ Ethyl sulphide also combines with
many metallic chlorides and iodides.*

Ethyl StUphide Mercuric Chloride, {C^Ii^^S,lIgC\2, is obtained
as a white crystalline mass, when an aqueous solution of corro-
sive sublimate is shaken up with ethyl sulphide. It is soluble
in alcohol and ether, and crystallizes from solution in the latter
solvent in fine monoclinic prisms melting at 90°, and possessing
an aromatic smell. These lose ethyl sulphide on exposure to
air, alid become opaque.

£thyl Sulphide Mercuric Iodide, (03115)28. Hgig, is formed by
heating the foregoing compound, or mercuric sulphide, with
alcohol and ethyl iodide to 100° for several' hours. It is depo-
sited in yellow needles soluble in alcohol and ether, melting at
110** and decomposing at 180°.

Ethyl Sidphide Titanium Chloride, 2(C2H5)2S.TiCl^, forms fine
dark-red crystals. Another compound of a similar constitution
is known, which does not crystallize well, and has a rose-red
colour, (02^5)2^ + TiCl, (Demar(;ay).

Ethyl Sulphide Platinum Chloride, SCCaHJgS.PtCl^, is ob-
tained in a similar way to the mercury compound, and
crystallizes in yellow needles.

Ethyl Methyl Sulphide, 03115(0113)8, was first obtained by
Carius^ by heating ethyl dithiophosphate with methyl alcohol
to 150*. It is also formed when the alcoholic solution of
sodium ethyl mercaptide is heated with methyl iodide.^ This
compound is a disagreeably smelling liquid boiling at 68°, and
forming a crystalline compound with mercuric chloride.

« Beckmann, loc. at. « Ann. Chirn, Phys [2], Ixxi. 387.

' lb. [3], xliii 2S3 * Loir, loc, cii,

* Ann. Chem, Pharm. cxix 313.

• Kruger. Journ Prakt. Oicm. [2], xiv. 206

382 THE ETHYL GROUP.

Ethylsulphine Compounds.

248 Diethylsulphine Compounds. When ethyl sulphide is
added drop by drop to well-cooled nitric acid of specific gravity
12 it dissolves, and forms a nitrate corresponding to the methyl
compound. This is a thick liquid. The compound has not been
obtained in the pure state. By the action of barium carbonate
on its aqueous solution, diethylsulphine oxide, {fi^^^O, is
obtained.

This is a thick colourless liquid soluble in water, alcohol and
ether, which on cooling yields a crystalline mass, and decomposes
on heating.^ When treated with hydriodic acid, or with adnc
and sulphuric acid, it is reduced to ethyl sulphide, and when
warmed with fuming nitric acid it is partially converted into
diethylsulphoiie, (02115)2802. This latter compound may be
obtained in the pure state by shaking ethyl sulphide with a
solution of potassium permanganate.* It forms rhombic tables
soluble in water and alcohol, melting at 72^, and subliming at
100"*, though not boiling till 248°.^ On treatment with zinc and
sulphuric acid it remains unaltered, and is likewise unacted upon
by hydriodic acid and phosphorus pentacliloride (Beckmann).

Triethylsulphine Compounds. These bodies were discovered
by Oefele,^ and afterwards investigated more carefully by Dehn*
and Cahours.* The iodide is easily formed by heating ethyl
sulphide with ethyl iodide.

Triethylsulphine Hydroxide, (02115)38011, is obtained by the
action of freshly precipitated silver oxide on an aqueous solution
of the iodide. The solution when dried in an exsiccator leaves
a crystalline extremely deliquescent mass. This possesses a
strongly alkaline reaction, attacks the skin like caustic potash,
decomposes ammoniacal salts, precipitates the solutions of
metals, and dissolves aluminium hydroxide.

Triethylsulphine Chloride, (02115)3801, is obtained from the
hydroxide by saturation with hydrochloric acid. It crystallizes
in deliquescent needles difficultly soluble in alcohol, and com-
bines with a number of metallic chlorides to form double salts
such as 2(03115)3801 + PtOl^. This latter is deposited from
solution in hot water in yellowish-red monoclinic prisms.

> Beckmann, Joum. Praki, CTtem, [2], xvii 452.

* Oefele, Ann, Chtm. Pharm. cxxWi. 370 ; cxxxU. 82.

» lb. cxxxii. 88. * Loe. cU,

» Ahh. Ch£m. Phann, Suppl. iv. 85. • Ann, Chim. Phtft. [5], x. 18.

ETHYL SULPHINB COMPOUNDS. 383

Triethyhulphiru Bromide, (C2H^)3SBr, is obtained on heating
ethyl bromide with ethyl sulphide to a temperature of 130** —
140^ It forms colourless rhombic crystials, easily soluble in
water and difficultly soluble in alcohol.

Triethylsulphine Iodide, (€2115)381, is easily formed by heat-
ing ethyl sulphide with ethyl iodide in a flask connected with
an inverted condenser. It is easily soluble in water and boiling
alcohol, and crystallizes in colourless and odourless rhombic
crystals which have a disagreeable taste.

TriUhylsulphine Nitraie, (C2H5)3SN03, is obtained by decom-
posing the iodide with silver nitrate. It crystallizes in extremely
deliquescent needles, and forms with silver nitrate the double
salt {G^^^l^O^ + AgN03. This latter compound crystallizes
in tablets difficultly soluble in alcohol.

Triethylsulphine Sulphate, [(C2H5)8S]2SO^, crystallizes imper-
fectly and is easily soluble in water, but dissolves with difficulty
in alcohol.

Triethylsulphine Cyanide, (CgHgjgSCN, is obtained by heating
a solution of the iodide with silver cyanide, and forms, on con-
centration, a thick syrup, which on long standing in the
exsiccator yields deliquescent needles. Caustic potash decom-
poses it into ethyl sulphide, propionic acid, and ammonia.^
Several triethylsulphine salts of organic acids are known.
JHethylmethylsulphine Compounds. When ethyl sulphide is
heated with methyl iodide, diethylmethylsulphine iodide is
formed. This is not crystallizable, and decomposes easily with evo-
lution of ethyl sulphide. When its solution is heated with moist
silver chloride the corresponding chloride is obtained, and this is
also a very unstable compound. Its solution evaporated in a
vacuum yields a thick sjrrup. The hydroxide obtained from the
iodide by means of silver oxide does not crystallize, and the salts
obtain^ by the action of acids are also mostly non-crystallizable.
On the other hand, the chloride yields well-defined double salts.
Diethylmethylsulphine Platinic Chloride, 2(C2H5)2CH3SC1 +
PtCl^ crystallizes from water in bright yellow cubes, octohedrons,
tetrahedrons, and other forms of the regular system. These on
drying fall to a yellow powder, and they melt at 214'' with
evolution of unpleasantly smelling vapours.

Diethylmethylsulphine Mercuric Chloride, (C2H5)2CH3SC1 -f
6HgCl2, forms colourless apparently hexagonal crystals which
melt at 198°.

1 Ciaiitre, ZeiUcK Cluim. 1868, 622.

384 THE ETHYL GROUP.

EthyhntthyUthyhulphine Compounds, The iodide, CsHj(CH^
C2H5SI, is obtained by the union of ethyl iodide and methjl
ethyl sulphide, and crystallizes in long, very deliquescent needln^
and yields a non-crystalline chloride.

Etkylmethylethylsulpkine Platinie Chloride, 2C^lL^{Ctl^
CgH^SCl + PtCl^, is a dark-red precipitate insoluble in alcobtd.
It crystallizes from aqueous solution in long, apparently mono-
clinic prisms which on drying fall to a rose-red powder, melting
with decomposition at 186°. If crystallized frequently from
water, or warmed for a long time on the water-bath, this com-
pound is converted into the isomeric diethylmethyl compound,
which, however, cannot be reconverted into the compound under
discussion.

Ethylmethylcthylsidphine Mercuric Chloride, C^^{j(!^H^
CgHgSCl -f 2HgCl2, is a difficultly soluble white precipitate
crystallizing from hot water in rhombic tables melting at 112*.

Besides these, other double salts belonging to both series are
known.^

Ethyl-thiocarhamide Iodide, CS(NH2)2C2H5l, may be con-
sidered in connection with the triethylsulphine compounds. It is
obtained by heating ethyl iodide with sulphur-urea (VoL I. p.
G54), and yields with water and silver oxide a strongly alkaline
solution from which rhombic crystals separate on addition of
hydrochloric acid and platinie chloride.*

Constitution of the Sulphine Compounds. — Two explanations
have been given respecting the constitution of the sulphine
compounds According to one of them, these compounds are
to be regarded as built up of two molecules, and the isomerism
of the two groups above mentioned can in this way be readily
explained. Moreover this explanation is in accordance with
the fact that triethylsulphine cyanide on heating with alkalis
acts as if it were a compound of ethyl sulphide aiid ethyl
cyanide.

According to the second hypothesis, these bodies arc not mole-
cular compounds, but contain tetrad sulphur. Much may bo
said for this view. If the iodides are heated, they do not
decompose into the constituents from which they were obtained.
One part volatilizes without decomposition, but the larger
portion decomposes with formation of free iodine, hydriodic
acid, and other products.

* KriigtT, Journ. PnU't, C/rw. [2J, xiv. 193.

■' ncrntbscn and Kl»n.«»«»r, Ber. IhutKh. Chem, Or». xi, 492.

ETHYL DISULPHIDE. 386

If the first view of their constitution he accepted, the hydr-

ddes must he regarded as compounds of a sulphide with an

icohol, and they, therefore, ought easily to decompose into these

^hen heated. This, however, is not the case ; they yield, on the

x>ntrary, various other products of decomposition, which as yet

aave not been properly investigated. If the sulphines are

regarded as atomic compounds, we must assume that the four

combining units of sulphur are unsymmetricaL On this point

the subsequent chapters on theoretical chemistry must be

consulted.

Ethyl Bisulphide, (G^^^\S^.

249 This compound was obtained first by Zeise ^ by distilling
calcium polysulphide with potassium sulphovinate, and was
termed by him thialoL It is also formed by various other
reactions, of which the most important theoretically is the action
of iodine on sodium mercaptide . ^

+ 2 Nal

Ethyl disulphide is also formed when mercaptan is heated for
six hours at ISO"* with the requisite quantity of sulphur :^

2 CjH,SH + S, = {C,ll,)^S, + SH,.

In order to prepare it a mixture of 2 parts of potassium disul-
phide, 3 parts of potassium ethyl sulphate, and 5 parts of water
are distilled, water being added from time to time so long as
any oily drops are carried over. It is a colourless liquid having
a strong garlic-like smell, boiling at 151"*, and possessing a
vapour density of 4*270 (Cahours). When heated with dilute
nitric acid it forms diethyl-disuljyJiO'dioxidc, (0.2115)28202, a
body which is the first oxidation-product of mercaptan, and is a
colourless oily liquid possessing a penetrating smell and volati-
lizing in presence of aqueous vapour, (\austic potash decomposes
it into ethyl disulphide, ethyl sulphonicacid, and ethyl sulphinic
acid * (pars. 254-5), and if it be treated with zinc-ilust and water

* Ann. Pharm. xi, 1.

* KekuU and LiDncmann, Amu Cliem. Pharm, cxxiii. 273.
^ M. Muller, Jaum. l*rakt. Ckem. [2], iv. 39.

* Pauly and Otto, Ber. DeutHch. rhem. Grs. xi. 2073.

VOL. III. c (

NaSCjH,

SCjHj

+ I2

= 1

NaSCjHj

SCJgH^

38G THE ETHYL GROUP.

the zinc compound of mercaptan and ethyl sulphinic add ve

obtained :

2 ^*2»sO } S + 2Zn - (C,H,S)^ + (C^jSO,)^
Ethyl Tliiomljyhuric Acid, SOj •{ en tt » is J^o* known in the

V So

free state, but salts of this acid are known. The sodium com-
pound, SoOgNaCgHj, is obtained by heating ethyl bromide with
an aqueous solution of sodium thiosulphate. It crystallizes in
thin six-sided tablets, and when the aqueous solution is wanned
with hydrochloric acid, sodium sulphate and mercaptan aie
formed :

SO2 1 SC H "^ ^2^ ^ ^^* { OH^ "^ HS.C2H4.

The silver and mercury salts are difficultly soluble precipitate^*
which quickly blacken. If the sodium salt be added to barium
chloride decomposition tiikes place in a few hours, common salt,
barium dithionate, and ethyl disulphide being formed.*

Ethyl Trisulphidc, (ColIJg^S' ^^ obtained by Cahours* in
the impure state by distilling potassium trisulphide with potas-
sium ethyl sulphate. It is also formed when the disulphide
is heated with sulphur (M. Miiller). It is an unpleasantly
smelling liquid which decomposes on heating, but may be
distilled in presence of water.

Ethyl TctrasiUjjhide, {0^11^)25^, is obtained by the action of
sulphur chloride on mercaptan :

2 CJTj.SH + S^Clg = (C,HJ,S, + 2 HCl.

It is a heavy colourless oil having a most unpleasant smell and
decomposing on heating into sulphur and the disulphide.

Ethyl Pejiiasidphide, {CJilr^,Ji^, is f )rmed when the foregoinir
compound is heated with sulphur to 150^ It is said tt) be an
elastic mass, but it has not been obtained in the pure stjito.*

Ethyl Thwphosphite, (021158)3?, is obtained by the action of
phosphorus trichloride on mercaptan. It is a heavy oily liquid
possessing a jx?netr:iting and unplejisant smell, and on heatlnj
splitting up into pliospln>rus and ethyl disulphiile.^

^ Bunte, Ber. Dnitvh. CJinn. Orn. vii. r,4»l.

* Hiinisav, Journ. Ch^m, Siic, xxviii. 687.
' /;////. .SV. Cfiim. [-2]. XXV. 181.

* riai-«son, null, SiK. ChiM. [2], xxv. IS.".. » /■■/'./.

f
o

ETHYL THIOPHOSPHATES. 387

Hthyl Tetrathiophosphate, (C2H5S)3PS, is formed by the action
of phosphorus pentasulphide on mercaptan :

6 HS.C2H5 + P2S5 = 2 PS(SCaH5)3 H- 3 H^S.

It is an oily liquid having a very disagreeable smell. In small
quantities it may be distilled undecomposed at 200°. Water
decomposes it with formation of sulphuretted hydrogen, mer-
captan, and ethyl thiophosphoric acid. In the preparation of
this thio-ether, diethyltetrathiophosphoric acid, H(C2H5)2PS4,
is formed, a body which is very unstable in the free state,
but which forms a series of crystallizable salts.^

Intermediate between these thio-compounds and the phosphoric
ethers several compounds exist containing both oxygen and
sulphur. These, as well as the foregoing compounds, have been
investigated by Carius, and amongst them we shall here only
mention the normal ethers.

Mhyl TrithiophoispJiatc, (CgH^gPSjO, is formed by heating
mercaptan with phosphorus pentoxide :

roH

5 HS.C2H5 + P2O5 = POCSCgHJa -f PO ^ SCgH, H- 2 H^O.

This compound may be separated from phosphoric acid and from
ethyl dithiophosphoric acid, which are formed at the same time,
by means of water. Ethyl trithiophosphate is an oily liquid,
which has a peculiar alliaceous smell, and decomposes with
violence on heating to loO"*, ether, ethyl sulphide, and ethyl
disulphide being evolved, and an unpleasantly smelling mass
containing phosphoric acid remaining behind. Water decomposes
this compound with formation of ethyl thiophosphoric acid.

£thyl Dithiopho^hate, (CgHJgPSgOg, is formed by the action
of phosphorus pentasulphide on alcohol :

5 HO.C2H5 + PjS, = PO-5 odjH, + PO J Oil % HjO -[. SHj

( SCgHg ( SCgHg.

Ethyl dithiophosphoric acid, formed at the same time, is also
obtained (as has been stated) when mercaptan is brought in
contact with phosphorus pentoxide. It might have been ex-
pected that in these two distinct reactions isomeric compounds
would have been produced, of which the one would contain the

^ Carins, Ann. Chem. Pharrti. cxix. 289.

388 THE ETHYL GROUP.

radical phosphoryl, PO, and the other the radical thiophos-
phoryl, PS ; tliis, however, is not the case, either in this or other
similar reactions.

Ethyl dithiophosphate is a colourless oily liquid possessing a
faint garlic-like smelL When heated or placed in contact with
water it acts like the foregoing compound. When heated with
sulphuric acid eihyl perUathiqpha8pfuite,{C fi^S)^O.S.'PO{SCfi^^
is formed. This compound yields large monoclinic crystals
having a fatty lustre melts at Tl''^, and possesses on warming
an unpleasant smell.

Mhyl Monothtophosphate, {C^^^^O^ is obtained by heating
thiophosphoryl chloride with absolute alcohol. It is a colourless
not unpleasantly-smelling oil, which can be distilled without
alteration in a current of carbon dioxide. This same compound
was obtained by Chevrier ^ by acting on phosphorus thiochloride
by sodium ethylate. It also has an unpleasant smell like decom-
posing turnips. On boiling this with water, ethyl monothio-
phosphoric acid, H(C2H5)2PS03, is formed, and this body may
be obtained in the same way with evolution of sulphuretted
hydrogen from dithiophosphoric acid. If a salt of ethyl mono-
thiophosphoric acid be warmed with phosphorus oxychloride,
an oily, slightly smelling liquid, ethyl dithiopyrophosphate

Ethyl Thioarsenite, (C2HgS)3As, is formed by the action of
sodium mercaptide on arsenic trichloride diluted with ether.
It is a heavy, oily, very unpleasantly smelling liquid, which on
heating decomposes into arsenic and ethyl sulphide.*

Uthyl Tf-ithiocarboneUe, (C2HgS)2CS. This compound was
discovered by Sclnveizer' in 1844, and obtained by acting upon
ethyl chloride with potassium thiocarbonate. It was more care-
fully investigated by Debus.* According to Huscmann,* it is
best prepared by shaking up sodium thiocarbonate with two to
three times its weight of alcohol, and rather less than the
e(iuivalent quantity of ethyl iodide. A reaction then occurs
witlj considerable evolution of heat. In place of the iodide,
bromide of ethyl may also be employed,®

> Bull Soe. Chim, [21. xii. 372.

« Clacsson, Bull, Soe. Chim. [2], xxv. 185.

' Junm. Ihrakt, Chrm, xxxii. 54.

^ Ann. Chem. Pharm. Ixxv. 147.

* Ann. Chrm, Pharm. cxxiii. 66

• Suloiiion, Jtwrn. Prakt. Chan. [2], vi 433.

XANTHIC ACID. 389

Sulphocarbonate of ethyl, as this compound was formerly
called, is a yellow liquid possessing an alliaceous smell and a
pleasant sweetish taste, resembling anise. It is scarcely soluble
in water, and boils at 240°. Ammonia decomposes it with
formation of ethyl mercaptan and ammonium thiocyanate.

£ihyl Orthotetrathiocarhonaie, C(SC2H5)^ is formed by the
action of sodium mercaptide, CgH^SNa (page 379), on tetra-
chlormethane, CCl^. It is a light-yellow, peculiarly smelling
oil, which decomposes on heating.^

Intermediate between these ethers and the ethyl carbonates a
series of compounds exist, which may be divided into two classes
according as they contain the radical carboxyl, CO, or thiocar^
bonyl, CS.2

Xanthic Acid, or Etuyl-Oxydithiocarbonic Acid,

cs { gg^H.

250 The potassium salt of this acid is easily obtained by the
action of carbon disulphide on an alcoholic solution of potash.^
In order to prepare this salt a solution of caustic potash in
absolute alcohol is mixed with an excess of carbon disulphide,
and the crystalline mass which is soon deposited brought on to
a filter, quickly washed with ether, and dried over sulphuric acid.*

Potassium XantliatCy Yi{G.^^G^Jd, forms colourless silky
needles, which become yellow on exposure to moist air. It
possesses a peculiar faint smell and a strongly sulphurous taste.
It is easily soluble in water, more difficultly in alcohol, and
colours the skin yellow. When heated with water this compound
decomposes in the following way :

2 KCCoHJCSgO H- 2 H,0 = K^CSg -h 2 HO.C.H^ + H^S + CO.^

The potassium salt when treated at 0° with dilute sulphuric
or hydrochloric acid yields xanthic acid as a heavy, colourless
oil, which must be- quickly washed with water and dried over
chloride of calcium, and then may be kept in a cold place with-
out decomposition. It has a penetrating smell somewhat re-
sembling sulphur dioxide, and a sharp penetrating astringent
taste. On warming it decomposes into carbon disulj)hido and

^ Claesson, Journ. Prakt. Chan. [2], xv. 193.

2 Salomon. 16. [2], vi. 433.

' Zeise, Schitcig. Journ. xxxvi. 1 : xliii. 100 ; r(>(jg. Ann. xxxv. 487.

* Slice, Ann, Chcm, Pharm, li. 345.

390 THE ETHYL GROUP.

alcohol ; this decomposition begins at 24•^ the liquid becoming
turbid, and at last beginning to boil with evolution of diauljAiide
of carbon. Xanthic acid decomposes the carbonates and fonna
a series of salts, some of which possess a very chaiacteristic
colour, such, for instance, as the fine yellow and very staUe
cuprous salt, (C2H5COS2)2Cuj, from which, indeed, the name
of the acid is derived {J^avdo^. yellow). This is obtained by
precipitating the potassium salt, best in alcoholic solution, by
means of cupric chloride, when a blackish-brown precipitate
falls, consisting probably of the cupric salt, and this soon changes
into fine yellow flocks and other products.

Amongst other salts the following may be described :

Ammonium XanthatCy G^^i^^^CO^^ can be obtained by
double decomposition w^ith other salts, or by satmrating the
free acid with ammonia. The solution yields, on evapora-
tion in a vacuum, glistening crystals, resembling those of urea,
which easily decompose and volatilize in a current of steam
(Debus).

Lead Xanthate, (C2H5.COS2)2Pb, is a crystalline precipitate
insoluble in cold water.

Ferric Xanthate, {CM^.CO^^^q^, is obtained by boiling
ferric chloride with a potassium salt and carbon disulphide. It
forms largo regular glistening black monoclinic crystals, of which
the smallest quantity imparts to carbon disulphide a very deep
colour.

The chromic salt which can be prepared in a similar way
from the violet chromic chloride, forms dark-blue glistening
crystals which dissolve in carbon disulphide, imparting to the
liquid a violet-blue colour.

Arnenic Xanthate, {Q^^CO^^^PiS, is formed by the action of
arsenic trichloride on the potassium salt. It forms large thick
monoclinic tables without colour and odour, which melt easily,
and on cooling yield a crystalline mass.

The antimony salt may bo prepared in a similar way. It is
dejiosited in large glistening, bright-yellow crystals, whilst the
bismuth salt crystallizes in bright golden-yellow tables.^

Ethyl Xanthatc, or Ethyl Oxymlphocarhonatc, Csi^^^'^'is

obtained by the action of ethyl chloride, or better of ethyl
bromide, on the ]>otassium salt. It is a colourless liquid boiling at
£00^ and possesses a strong unpleasant smell and a sweetish ta^te.

^ llliuiwotz, Ann, Chem, Pharm, cxxii. 87.

ETHYL XANTHATE. 891

By the action of ammooia it is transformed into xanthamide or ethyl

monothiocarbamide, CS < ^p Vr , a body crystallizing in modified

monoclinic pyramids, which melt at SC", and are easily soluble
in alcohol, but dissolve with greater diflficulty in water, and on
heating are converted into mercaptan and hydrocyanic acid. By
the action of nitrogen trioxide in presence of water this body is
converted into the compound (Cfi^fi^^^i^* *^ which Debus
has given the name of (xci/'SulpfiocyaniC'Cthyl-oxide.^ It crystal-
lizes in thin white prisms, which melt at 100'', and on boiling
with baryta-water form barium carbonate, ammonia, sulphur,
and alcohol

JCanthic I>i8vJphide, 02028^(02115)2. This compound was dis-
covered by Desains * and examined by Debus,* who termed it
ethyl bioxysulphocarbonate. It is formed by the action of
chlorine or iodine on the xanthates according to the following
equation : ^

OC,H,
CS

OC.H^
CS

^C^,

^C,H,.

2KI.

Xanthic disulphide is insoluble in water, crystalliziDg from
alcohol in glistening white prisms, which do not smell un-
pleasantly, possess a biting taste, and melt at 28°. When heated
to 210* they decompose into sulphur, carbon monoxide, carbon
disulphide, ethyl xanthate, and the following compound.

Ethyl Dioxythiocarbanate, 0S(002H5)2, is a pleasantly smelling,
strongly refracting liquid, boiling at 160°, and converted by
ammonia into alcohol and ammonium thiocyanate :

OS { ^^2^5 4. 2 NH3 = 2 HOO2H5 + NOS(NH,).

251 Ethyl Monothiocarbonic Acid, 00(002H6)SH. This com-
pound is not known in the free state, but its potassium salt is

' Ann. Chew. Pharm. Ixxxii. 270 ; Chem. Soc. Joum. iii. 84.

« lb. Ixiv. 325. > Ih. Ixxii. 1 ; Ixxv. 121 ; Ixxxu. 255.

* Kekulu and Liiincmano, Ann. Chem Phann, cxxiii. 273.

Sta THE ETHVL GirOCP.

fonneii by the aini:>a of alcjbi>Iic piHash on ethyl y^ntKat^
fJjehus^, when the folio wixig peculiar acdcm oocurs :

CS[^?A. 2KOH = CO-f^A+HO.CA + KSH.

It is soluble in waierand alcohol, and appears to be isomoTphoos
with potassium xanthate. Acids decompose it into alcohol, car-
bon dioxide, acd sulphoietted hydrogen, and when its aoluticHd
:5 bjiIe*J. alcijhol. carbonyl sulphide, potassium sulphide, and
potasidum carbonate are formed.^

\^lien a 5«jlution of lead acetate is added to its solution, a white
precipitate of lead ethyl monothiocarbonate, (COj-CjH^^jSjPhi
is formed, and this crystallizes from hot alcohol m needles.
Ic^iine acts up^n these salts as it does on the xanthates
with the furmation of the ethyl ether of dithiocarbonic acid or

fUdhi/learhoxydistdjJti'U, < c poOO'H* '^^ w acolourless^

strongly refracting oil, heavier than water.*

The monosulphide, S^COj-C.HJj, corresponding to the former
compound, was obtained by Victor Meyer by acting on ethyl
cliL^rocarlxinate with sodium sulphide. It was termed by him
etliyl dicarbothiunate. It is a colourless liquid, boiling about
180\ and possessing a peculiar, but faint smelL*

£thi/l Thio,cijcarhoivitt\ COlOC^H^iSC^Hj, is obtained by
acting with ethyl bromide or potassium ethyl monothiocarbo-
nate, and also when sodium mercaptide is treated with ethjrl
chlorcarbonate :

CO I ^['2^5 + NaSaH, = CO | g J^^s + NaCl.

It is a colourless, strongly refracting iiquid, boiling at 156'. It
IK)sses8es a smell like that of decaying fruit, and has an aromatic
Uiste. Cold ammonia decomposes this compound, which is
isomeric with ethyl dioxythiocarbonate into mercaptan and
urethane :

On heating with water to luir, alcohol, carbon dioxide, and
mercaptan an; formed/

> TWn<U>r, Ann, Chfitu Pharm. cxiviii. 137.

' Debus, Ann. Chan. Pharm,

» lUr. Dfuttifh. Chcux. Oes. ii. 297.

* ::Valomoii, Joum. Prukt. Ckem. [2], \l 433.

ETHYL THIOCARBONATES. 893

JEthyl JDithioxycarbonate, CO(SC2H5)2. This compound, iso-
meric with ethyl xanthate, was discovered by Schmitt and Glutz,^
and obtained by the action of sulphuric acid on ethyl thio-
cyanate, and termed by the discoverers carbonyl disulphodiethyl.
It is also formed by the action of sodium mercaptide on
carbonyl chloride : ^

CO { ^} + 2 NaS-C^Hg = CO { |§«^5 + 2 NaCl.

In this reaction the chloride, COC^SCgHg), a liquid boiling
at 136^ is first formed. Ethyl dithioxycarbonate is a strongly
refracting liquid possessing a garlic-like smell, and boiling at
196^ Ammonia decomposes this ether into mercaptan and urea.

252 The following table exhibits the composition of the thio-
carbonates compared with ethyl carbonate :

Ethyl Carbonate. B.P.

Ethyl Thioxycarbonate. B.P. Ethyl Dioxythiocarbonate. B.P.

Ethyl Dithioxycarbonate. B.P. Ethy^i%fuh&o°nate. ^■^^

C0{|S«5s 196' ^^{ocfl^ 2^^"

12 6 ^25

Ethyl Trithiocarbonatc. B.P.

CSJiS^H" 240°

V 2 6

Some similar compounds of the methyl series are also known,
as well as others which contain both methyl and ethyl.^

NH.

/ .

253 Ethyl Thiocarhaniate, CS , is formed by the action

of xanthic ether on ammonia :

o.an. NH,

CS + NH, = CS + C,H,.HS.

\ \

S.C2H5 O.CgHij

* Bcr. Vcutsch. Chem. Gcs. i. 16C.

' Salomon, Jouni. Pra\t. Chcm. [2], vii. 252.

' Salomon aud Mnuitz, Joum. Prakt, Chcm, [2], vili. 114.

394 THE ETHYL GROUP.

It is a crystalline compound, and combines with many salts
of the heavy metals. On warming it splits up into mercaptan
and cyanic acid, and, on boiling with alkalis^ into alcohol and
thiocyanates.

Ethyl TkioallophancUe, CgHjNgSgO.CjHg, is formed by the action
of hydrochloric acid on a hot concentrated alcoholic solution of
potassium thiocyanate, thus :

2 CNSK + 2 HCl + CH5.OH = C0.SC2H,(NH)CS.NH^

Ethyl ThioallophanAte.

Recr}'stallized from hot water and ether, this compound forms
white needle-shaped crystals, which are odourless, possess a
bitter taste, and melt with decomposition between 170** and
175^1

By the action of ammonia, in the cold, on ethyl thioallo-
phanate the foUowmg decomposition takes place, furnishing the
clue to the constitution of this ether :

SCjjHg

NH +2 NH.

NH,

= do +

CS +

/
CS.NH,

\h.

^Hy

4" HS.CoHj

8**6

Ethyl Sulphonic Aero, (CjHJSOjH.

254 This was discovered by Lowig and Weidmann* in 1839,
and prepared by the oxidation of ethyl mercaptan with nitric
acid. It was aften\'ard8 more fully investigated by H. Kopp.*
It is also formed by the oxidation of ethyl disulphide, as well as
of the higher sulphides of ethyl, and also of ethyl thiocyanate.*

In order to prepare it, liver of sulphur, obtained by fusing
potashes with sulphur, is distilled with solution of potassium
ethyl sulphate, and the impure disulphide thus obtained oxi-
dized with an equal volume of nitric acid.* This reaction is
best carried out in a retort of which the neck is placed in an
upward position and connected with the lower part of an in-
verted condenser The reaction is, to begin with, extremely

* Blankenhoni, Joum.. Pntlct. Chem, [21, xvi 358.

* Pitijij Ann. xlvii. 153; xlix. 329 ; Li>wi;r, An%, Chtm. Pharm. Ixxv 349.
^ Ann. Chcm. Phami. xxxv. 343. * Muspratt, CKem, Sue. Joum, i. 45.
'" M. Miiller. Journ, J'rukL C/um. [2], iv 39.

ETHYL SULPHOXIC ACID. 396

violent, but afterwards it must be aided by warmth, and lastly,
the mass must be gently boiled until it is all dissolved. The
product is heated on a water-bath, to drive off nitric acid, until
it possesses a syrupy consistency. The residue is dissolved in
water, and neutralized with lead carbonate in order to separate
the excess of sulphuric acid formed. The amount of this, how-
ever, if the sulphuric acid be not too strong, is not large. The
filtered solution is then evaporated, and the ethyl sulphonic
acid is thus obtained as an oily liquid of specific gravity 1'3,
and crystallizing in the cold. It rapidly absorbs water from the
air, is odourless, has a strong acid taste, and on heating to a
high temperature decomposes with evolution of vapours of
sulphuric acid and sulphur dioxide.

Ethyl Sidphonic Chloride, C2H5SO2CI, was discovered by
Gerhardt and Chancel,^ ^^nd is formed by the action of
phosphorus oxycliloride or phosphorus pentachloride on ethyl
Bulphonate :

2 SO2 1 ^^^ + 2 PCI5 = 2 SO J §^«4- 2 NaCl + 2 POCly

It is a colourless liquid, smelling like mustard-oil, boiling at
l7T'o,^ and having a specific gravity of 1*357 at 22'''5. It
fumes slightly in the air, and is slowly decomposed by water
with formation of ethyl sulphonic acid and hydrochloric acid.
Nascent hydrogen converts it into mercaptan.^ When heated
with phosphorus pentachloride to 120^ phosphorus oxychloride,
ethyl chloride, and thionyl chloride are formed :

fan

2 1 qI "« + PCI5 = POCI3 + C^H.Cl H- SOCI2.

When kept for any length of time it decomposes into sulphur
dioxide and ethyl chloride.*

Ethyl sulphonic acid forms a series of stable Siilts, oLtaiued
by neutralizing the free acid with an oxide, as well as by other
methods.

Potassiiim Ethyl Sulphoiiatc, C2H5SO3K -|- HgO, crystallizes
in hygroscopic tablets, which lose water on heating, melt at
120°, and on cooling yield the anhydrous salt in the form of a
crystalline mass. If it be more strongly heated it becomes

* C(mipL Jknd. xxxv. fiOO. ' Carius, Jaum, Prakt, Chevi. [2], ii. 262.

* Vojrt, Ann. C%m. Ph/tnn. cxix, 152; Kndemann, ib, cxI. 333.

* Carius, Ann. Chcm. riuirm. cxi. 93 ; cxiv. 140,

396 THE ETHYL GROUP.

■^

brown, evolves unpleasantly smelling vapours, and leaves a
residue of potassium sulphide.

Sodium Ethyl SulpJumate, CgHgSOjNa, resembles the potas-
sium salt, and is very deliquescent It contains water of
crystallization which it loses at 100°, and when a concentrated
solution of sodium sulphite is heated with ethyl iodide to from
ISO** to 150", the double salt 4C2H5S05Na + Nal is formed.
This crystallizes from alcohol in silky needles.^

Avimoiiium Ethyl Sulphonaie, CgHgSOjNH^, is a crystalline
deliquescent mass, obtained by boiling ethyl iodide with a
solution of ammonium sulphite. This reaction is well suited
for the preparation of ethyl sulphonic acid. The product of this
reaction is boiled with lead oxide as long as ammonia is evolved,
and the solution filtered and decomposed with sulphuretted
hydrogen.'^

Barium Ethyl Sulphonaie, (C2H5S03)jBa + H^O, crystallizes
in oblique rhombic tables which effloresce readily, and have an
unpleasant taste.

Lead Ethyl Sulphoiiate^ (C2H5S08)2Pb+H20, is soluble in
water and alcohol, crystallizing from hot aqueous solution in
tablets.

Silver Ethyl Salplwnate, CgH^SOjAg, crystallizes from hot
water in scales. It is also soluble in alcohol, melts when
warmed, and may be heated to a tolerably high temperature
without undergoing change.

Besides these, various other ethyl sulphonates have been
prei)ared.

Methyl-Ethyl Sulplionate, C2H5SO3CH3, is obtiined by acting
on ethyl sulphonic chloride with sodium methylate. It is a
colourless, slightly smelling liquid boiling between 197° 5 to
200°-5.

Diethyl Sulpkoiiatey or Ethyl Sulphonic Ethyl Ether,
C2H5SO3.C0H5, is prepared in an analogous way to the fore-
going compound, and has a smell not unlike its isomeridc, ethyl
sulpliitc.'* It is also formed when ethyl iodide is allowed to
act on silver sulphite.* It boils at 213°.

255 Ethyl Sulphinic Acid, CgH^SOj;!!. By the action of sul-
phur dioxide on zinc ethyl Hobson * obtained the zinc compound
of an acid to which he gave the name of ethyl trithiouic acid,

* [kndcr, Ann. Chrm. Pharm. oxlviii. 90. ' lleniilian, 1^. clxviii. 145.

=» Carins Journ. PrakL Chnn, [2], ii. 262.

* Kurbatow, Bcr. Dculxh, Chem, 6«. vi. 197. * Chctn, Sue Jonrn. x. 58.

ETHYL SELENIDE. 397

and, according to his analyses, it possessed the formula, CgH^SgOg.
Neither Wischin^ nor Zuckschwerdt ^ could obtain this com-
pound, bnt when the experimental conditions were somewhat
altered, zinc ethyl sulphinate, (C2H5S02)2Zn, was obtained.

This is difficultly soluble in water, and may be obtained in
soft pearly scales from alcoholic solution. The same salt is also
formed when ethyl sulphonic chloride is brought in contact with
zinc-dust and water.^ By decomposing with baryta-water
barium ethyl sulphinate, (C2H5S02),Ba, may be obtained. This
18 easily soluble in water, and on evaporation in a vacuum is
deposited in crystals. Besides these, other crystalline com-
pounds have been prepared. When a solution of the barium
salt is treated with sulphuric acid ethyl svlphinic add is obtained.
This has a pleasant sweet taste, and remains, on evaporation
in a vacuum, as a syrupy liquid. If the acid or the zinc salt
be oxidized with nitric acid a crystalline compound is obtained,
together with ethyl sulphonic acid, and this crystallizes from
hot alcohol in large glistening tablets melting at 81°*5 and which
when carefully heated may be sublimed without decomposition.
This body possesses the formula CgHjgSgOyN, and when boiled
with alkalis, or heated with hydrochloric acid, it is converted
into ethyl sulphonic acid and ammonia, some sulphuric acid
being always formed. Hence this body is tmethyl sulphonic
nitric oxide, (C2H5S02)3NO, which probably decomposes in
contact with water into sulphonic acid and hydroxylamine,
NOH3, and this latter compound acts as an oxidizing agent and
ammonia is reduced.

COMPOUNDS OF ETHYL AND SELENIUM.

256 Ethyl Hydrosehnidcy CoH^SeH, was discovered by
Siemens,* who prepared it by distilling a solution of potassium
hydroselenide with potassium ethyl sulphate. It is a colourless
liquid boiling below lOO*', and possessing a most unpleasant
smell resembling that of cacodyl, which is doubtless caused by
the presence of a small quantity of ethyl diselenide. It forms
with mercuric oxide a yellow amorphous selenium mercaptide.

* Ann. Chein, Pharm. cxxxlx. 364. ' Ber. Deutsch, Chem. Gen, vii. 292.

• Fauly, Ber, Deutsch. Chcm. Ocs, x. 941. * Ann. Chcm. Pharm, Ixi. 860.

398 THE ETHYL GROUP.

Ethyl Sclenidc, (02115)286, was first prepared by Lowig^ in
1830 by distilling ethyl oxalate with potassium selenide, and
afterwards more accurately examined by Joy ^ who obtained it
by distilling potassium ethyl sulphate with potassium selenide.
He was, however, unable to complete his experiments owing
to the intolerable odour which the body possesses. This, as was
afterwards shown by Rathke,^ is due to the presence of a small
quantity of ethyl diselenide. In order to prepare the mono-
selenide, the best plan, according to this latter chemist, is to
take a pure solution of caustic potash and distil it with
potassium ethyl sulphate, to which a small quantity of selenium
phosphate is added, which, however, must contain no free
selenium. In this way potassium phosphate and potassium
selenide are formed, and on distillation a mixture of mono-
selenide and diselenide is formed, the latter being formed by
the action of oxygen on the former compound. They may
be then separated by fractional distillation. It is, however,
simpler to treat the distillate again with half the quantities
of potassium ethyl sulphate, caustic potash, and water, which
were originally employed, and to add to this a small piece
of ordmary sulphur. On distillation for several hours with
a reversed condenser this compound is obtained in the pure
state.*

Ethyl selenide is a colourless, easily mobile, strongly re-
fracting liquid, boiling at 108**, and having a peculiar but
not unpleasant smell. It dissolves easily in dilute nitric acid
with formation of the nitrate (02H5)2Se(OH)N03, which is
decomposed on concentration. Hydrochloric acid precipitates
ethyl selenium dichlorido, (02H5)2SeOl2, as a yellowish oil,
slightly soluble in water, but rather more soluble in hydro-
chloric acid. Aqueous ammonia converts it into ethyl selenium
oxychloride, (02H5)^Se200l2, which crystallizes from alcohol in
glistening colourless cubes, and is converted, in presence of
hydrochloric acid, into the original compound. Hydrobromic
acid precipitates ethyl selenium bromide, (02H5)2SeBr2, from
solutions of the nitrate, in the form of a light yellow coloured
soluble oil ; the iodide prepared in a similar way is a yellow
lustrous liquid somewhat resembling bromine.

* P<>00- -^^n. xxxvii. C/>2.

• Ann, Chern^ Pftann. Ixxxvi. 35.

• Anit. Cfinn. Phamu clii. 210.

* rieverling, LUb. Ann. clxxxv. 331 ; Ber. Deutsth. Chnu, Oes. ix. 1460.

ETHYL TELLURIDE. 399

TrUihyl Seleniodide, (C2H5)3SeI, is fonned by the combination
of the foregoing compound with ethyl iodide.^ It forms glistening
Yrhite crystalline needles closely resembling Epsom salts, and very
soluble in water. They decompose, on heating, into their consti-
tuents which on cooling gradually again unite with one another.
Moist silver oxide acts on the solution of this body as it does
on the corresponding sulphine iodides. The hydroxide thus
formed is left on evaporation in a vacuum as a syrupy liquid,
which is as alkaline and caustic as potash. Its salts are, most
of them, deliquescent, possessing an alliaceous smell, and having
a bitter and burning taste. The platinichloride, (CgHJ^SegPtCl^
crystallizes on evaporating the hot saturated solution in glistening
red acute rhombohedrons with basic terminal faces (Pieverling).

Ethyl IHseknide, (02115)2862, which is formed as a by-product
in the preparation of the above-mentioned selenium compounds,
was first obtained by Wohler and Dean,^ mixed with some
monoselenide, by heating potassium selenide (obtained by
heating potassium selenite and carbon together) with potassium
ethyl sulphate. Rathke has however shown that when a selenite
is heated with carbon, polyselenides are formed, scarcely any
monoselenide being produced, the reaction beginning before the
moisture in the carbon is driven off and this then acting as an
oxidizing agent.

Ethyl diselenide is a heavy brownish-red oil, boiling at 180**,
and having a frightful smell, and acting as a poison (Pieverling).
When it is dissolved in nitric acid, and hydrochloric acid is
added, the compound C2H5SeS02H + HCl is formed, crystallizing
in fine monoclinic prisms (Rathke).

COMPOUNDS OF ETHYL AND TELLURIUM.

257 Hthyl Telluride, (Q^^^e, was first obtained in 1840 by
Wohler' by distilling potassium telluride with barium ethyl
sulphate. It was then prepared by Mallet,* and afterwards more
exactly investigated by Wohler.^ In order to prepare it, one
part of tellurium is treated with 10 parts of ignited cream of
tartar in a porcelain retort to the neck of which a bent glass
tube is attached. When no further evolution of carbon dioxide
takes place, the glass tube is placed in a large flask filled with

' Cahours, Comptcs JiCiuhis, Ix. 620. * Ann. Chcm. Pharm. xcvii. 1.
' yinn, Chcni. Pharm, xxxv. 111. * Chan. Soc. Journ. v. 71.

* Ann. Clicm. PJutnn. Ixxxiv. Gl),

400 THE ETHYL GROUP.

carbon dioxide, in order to prevent the entrance of air into the
apparatus, and then, after the vessel has cooled, the requisite
quantity of concentrated solution of potassium ethyl sulphate
dissolved in water free from air is added, and the whole warmed,
the contents of the retort being brought into a flask filled with
carbon dioxide and the whole distilled in a current of this gaa.
These precautions are necessary in order to prevent the oxida-
tion of the potassium telluride, but in spite of this a quantity
of ethyl ditelluride is usually formed, and this comes over
towards the end of the distillation.

Ethyl telluride is a thick red liquid boiling at 98^^ and
yielding a deep yellow-coloured vapour. It is heavier than
water, possesses a strong, very unpleasant smell, reminding
one at the same time of ethyl selenide and telluretted
hydrogen. Its vapour attacks the lungs and appears to be
poisonous. During the whole time that Wohler was occupied
in this investigation his breath was tainted with the un-
pleasant smell of this compound. When a small dose of
potassium telluride, namely, from 0 04 to 005 gram, is taken,
the breath after a few minutes becomes for a length of time
tainted with this unpleasant odour.* Ethyl telluride is easily
inflammable, and burns with a bright blue flame evolving clouds
of tellurium dioxide. Exposed to the air it soon becomes
covered with a white crust, and the whole mass gradually
changes to a white earthy solid. This oxidation occurs so
quickly in sunlight that the liquid begins to fume, without
however taking fire.

Ethyl Tellurium Oxide, {Q^^^qO, has not yet been obtained
in the pure state. Its solution, prepared by treating the chloride
or oxychloridc with silver oxide, turns turmeric paper brown, and
absorbs carbon dioxide from the air. On evaporation, decom-
position occurs. When saturated with an acid, ethyl tellurium
salts are obtained, the point of departure for which is the nitrate.

Ethyl Tellunum NUrate, T:(i{C^^,{0^)^0^, is formed by
dissolving ethyl telluride in nitric acid. It forms monoclinic
crystals, which on heating deflagrate like gunpowder.

Ethyl Tclluriuvt Chloruk, Te(C2H,)2Cl2, is obtained from the
solution of the nitrate by the addition of concentrated hydro-
chloric acid, when an oily licjuid is formed, possessing an un-
pleasant smell, and volatilizing at a high temperature without

][ Heercn. Chcm. CciUr. 1861, 916.

- liansM.'!), Ann, Chan, Pharm. Ixxwi. 208.

NITROGEN BASES OF ETHYL. 401

decomposition. When it is dissolved in warm ammonia and the
liquid allowed to evaporate, the oxychloride, Te2(C2H5)^OCl2, is
formed in glistening six-sided prisms, which are difficultly
soluble in water but readily so in ammonia and alcohol.

The bromide is a light yellow oil, and the iodide an orange-
yellow precipitate. Treated with ammonia they both yield
crystallizable oxy-compounds.

£thyl TeUurium Sulphate, Te2(C2H5)^(OH)2S04, is obtained by
decomposing the oxychloride with silver sulphate, or by acting
with lead dioxide and dilute sulphuric acid on ethyl telluride.
It crystallizes in colourless prisms.

Hthyl Tellurium Carbonate, Te2(C2H5)^(OH)2C03, is obtained
by saturating the solution of the oxide with carbon dioxide, or by
decomposing the oxychloride with silver carbonate. It forms
small well-defined crystals.

Various ethyl tellurium salts of organic acids are also known.

Ethyl Ditelluride, (C2H5)oTe2, is always formed in the prepa-
ration of the mono*«lluride ; it is a dark-red liquid having a
high boiling point.

Triethyl Tellurium Iodide, (C2H5)3TeI, is a crystallizable body
obtained by the combination of ethyl iodide with ethyl telluride.i
It crystallizes from aqueous solution in a vacuum in bright yellow
monoclinic prisms, which melt at 90** — 02°. On distillation it
decomposes into its constituents which after some hours unite
together on standing (Pieverling). J3y treating the aqueous
solution of this body with silver oxide, a liquid having an alka-
line reaction is obtained, and this, when saturated with hydro-
chloric acid and treated with platinum chloride, yields an
orange-yellow crystalline precipitate of [(C2H5)3Te]2PtClg.^

NITROGEN BASES OF ETHYL.

The Ethylamine Compounds.

258 Ethylamine, NH2C2H5, was first prepared by Wurtz ^ in
1848, by distilling ethyl isocyanurate with caustic potash, and
Hofmann * soon afterwards obtained the other ethyl bases.
These discoveries not only exerted a great influence on the

' Cabours, Ball, Soc. Chim. [2], iv. 40.

* Becker, lAehig'g Ann. clxxx. 262.

' Comptes JRejidvSj xxviii. 22.3 ; Ann, CJiim. Phi/s [3], xxx. 443.

* P?i)l. Trans. 1850 [1], 93; Ann. Chem. Pharm. Ixxiii. 91.

VOL. II r. D D

402 THE ETHYL GROUP.

progress of theoretical chemistry but also on the industrial
application of the science, inasmuch as by their means an
important branch of the manufacture of aniline colours was
called into being. In order to prepare the ethyl bases, a
haloid salt of ethyl is heated with ammonia. The ethyl
ethers of other inorganic acids, such for instance as the
nitrate (Juncadella), the sulphite (Carius), the sulphate
(Strecker), and the phosphate (Clermont), are attacked in a
similar way by ammonia, but in all these cases the three other
bases are formed together with the primary base.^

In order to prepare large quantities of these compounds, the
method proposed by Hofmann^ is the best. For this purpose
the crude ethyl chloride obtained as a by-product in the prepa-
ration of chloral is employed. This contains higher substitution-
products, but these may afterwards be readily separated. One
part of this crude ethyl chloride is digested with three times its
volume of spirit, containing 95 per cent, of alcohol, previously
saturated with ammonia at 0**. For this purpose a wrought iron
digester is usually employed, the whole being heated for an hour
in boiling water. On cooling, the liquid deposits sal-ammoniac,
this is filtered off, and the liquid distilled on a water-bath. The
higher chlorinated chlorides of ethyl pass over first, and then al-
cohol containing ammonia, which after a further saturation with
ammonia may be used in a second preparation. As soon as the
distillation is complete, the residue left in the retort is evapo-
rated m a basin until all the alcohol is removed. On cooling,
the liquid solidifies to a feathery crystalline mass of the ethyl-
amine hydrochlorates, with which a small quantity of sal-
ammoniac is mixed. Concentrated caustic soda is now added,
and the liquid layer which separates out, consisting of a
mixture of the three bases, is drawn off and dried over solid
caustic soda. Although the boiling points of the three bases
differ very considerably, they cannot be separated by fractional
distillation, and in order to obtain them in the pure state a plan
similar to that adopted in the case of the methyl compounds
must be employed. The product is, therefore, treated with ethyl
oxalate, when the triethylamine remains unaltered, and may
be distilled off from the water-bath. The residue consists of a
mixture of solid diethyloxamide, Cp,(NH.C3H5)j, and liquid
diethyl oxamic ethyl ether, C202N(C,H5),OC,H^ which is then

> Hofmann, Proc. Roy. Soc, xi. S6, Carer-liet, Siliim. Am. Journ, [2], xxxiL
26 ; xxxir. • Ber. DeuUek. Ckem. Ot$, iii. 109.

RTHYLAMINE. 403

washed and mechanically separated, and then purified as hereafter
described.^ Duvillier and Buisine have described a modification
of this method of separation.^

Ethylamine, CgHg.NHj.

259 In order to obtain this compound pure, diethyloxamide is
recrystallized from hot water and then distilled with caustic
potash :

CjOj(NH.C2H,), -f 2 HOK = 2 NH2.C2H4 + Cj02(0K),.

Pure ethylamine is also obtained by reducing nitroethane.

It is a mobile liquid boiling at 18°*7, and having a specific
gravity of 0*6964 at 8^ It possesses a strong ammoniacal smell
and a powerful caustic taste. It is miscible in all proportions
with water with evolution of heat, and when ignited it bums
with a yellow flame.

Ethylamine is also formed when sal-ammoniac and ammonium
iodide are heated with alcohol to 400°,* as well as when sal-
ammoniac is fused with crystallized sodium ethylate.*

Ethylamine is so powerful a base that it decomposes ammoniacal
salts, and, like ammonia, throws down many metallic hydroxides.
It is, however, distinguished from ammonia by the fact that
precipitated aluminium hydroxide redissolves in excess of
ethylamine. This base may, therefore, be employed for the
separation of ferric oxide and alumina.^ Other points of
difference are that cupric hydroxide dissolves only with diflB-
culty in excess of ethylamine, whilst the salts of cadmium,
nickel, and cobalt yield precipitates which are insoluble in
excess.

Ethylamine Hydrochloride, or Ethylammonium Chloride,
N(C2H5)H3C1, crystallizes from water in fine very deliquescent
prisms, and from hot alcohol in tablets. Stas obtained it in
large crystals by allowing a mixture of ethyl chloride and an
ethereal solution of ammonia to stand for some time exposed to
the action of the sun's rays.' According to Groves this salt is
best obtained by heating a mixture of one volume of ethyl

* Hofmann, Proc Roy. Soc, xi, 66 ; Ber. DcuUch. Chem. Ges. iii. 776 ; Ber.
Berlin. Acad., 1871, 26. * Compi. Rend. IxxxviiL 81,

3 V. Meyer, Lichigs Ann, clxxv. 88.

* Berthelot, Ann, Chim. Phys, [3], xxxviii. 64,

• Kiihler, Ber. Deutsch. Chem. Ges. xi. 2093.

• E. Aleyer, Joum, Praki, Chem. Ixvii. 147. ' Kekule, Lehrbuch, i

D I) 2

404 THE ETHYL GROUP.

chloride and three volumes of strong alcoholic ammonia for seven
hours to 100^^ It melts at 76^ — 80° and on cooling solidifies to
a crystalline mass. Heated from 315" to 320°, it evolves vapours,
and on cooling forms a milk-white amcrphous mass melting at
260°. It forms double salts with metallic chlorides.

The bromide and iodide closely resemble the chloride but
have not been more exactly described. According to Wohler
and Diinhaupt pure ethylamine hydriodide is obtained when
a boiling mixture of equal volumes of ethyl iodide and absolute
alcohol is saturated with dry ammonia and then allowed to stand
until water produces no further turbidity.*

Ethylammonium Sulphate, (NC2H5)2HgSO^ is an uncrystalliz-
able deliquescent mj^ss, easily soluble in alcohol. It forms double
salts with the sulphates of magnesium, copper and aluminium.
Aluminium ethylammonium' alum, A1^(S0^^ + (NCgHJ^H^SO^
+ 24H2O, crystallizes in octohedrons.

Ethylaminmiium Nitrate crj-stallizes only with difficulty in
very deliquescent scales.

Ethylammonium Carbonate is obtained by distilling the anhy-
drous chloride with dry carbonate of soda. It is obtained as
a liquid which solidifies to a cryst-alline mass. It has a strung
smell of ammonia and is deliquescent. Its composition closely
corresponds to that of the normal salt.

Ethjlammonium Carhamatc, CO < oxvfi H ^H ' ^^ ^ W'hite

powdery mass obtained by passing dry carbon dioxide into
ethlyamine. It is soluble in water and its solution precipitates
calcium chloride on stan<Ung.

Ethylammonium Cliloraiiratc, N(C2H..JH3AuCl^, is obtained
by evaporating a solution of the hydrochloride with gold chloride,
and crystallizes in fine golden-jellow prisms, soluble in water,
alcohol, and ether.

Ethylammonium Plaiinichloride, 'ifj^C^^H r^JI^T tCl^^ is formed
as a yellow precipitate when concentmted solutions of its two
constituents cure mixed and alcohol added. It crystiillizes from
hot water in obtuse rhombohedrons, which were long supposed
to be cubes (Schabus).

riatodiethylammonium Platimchloridi\ Pt(NC.H,Ho)4PtCl^.
This compound, which corresponds to Magnus h green salt, is a
reddish insoluble powder, obtained by Wtirtz by acting on ethyl-
amine with platinous chloride. When it is heated with a

* Quart. Journ. Chrm, »St>c. xiii. 331. - Jun. Chem. Phann, Ixxxn. 371.

ETHYLAMMONIUM SALTS. 405

solution of ethylamine it dissolves, frequently leaving a residue
of an insoluble black powder, and on evaporating the solution,
fine colourless prisms of platodiethylammoniura chloride,
Pt(NC2H5H2)^Cl2 (see Vol. II. Part 11. p. 412), are obtained.

Corresponding palladium compounds are also known,^ and
in addition to those already described, several other ethylamine
salts have been investigated by E. Meyer.-

Ethylammoniurri Hydrosuljphide is obtained by acting with
sulphuretted hydrogen on ethylamine cooled with ice. It forms
fine colourless crystals which become yellow-coloured on exposure
and deliquesce. Its solution dissolves antimony sulphide.

D-icJdorethylamine, ovEthylatcd Chloride of Nitrogen, NCgHgClg.
This singular compound was first obtained by Wurtz,^ by
acting with chlorine on an aqueous solution of ethylamine.
In order to prepare it, 250 grams of bleaching powder are
rubbed up with water to a thick paste and placed in a two-liter
fiask, 100 grams of ethylamine hydrochloride being added in
four portions, a strong evolution of heat occurring. The mix-
ture is then distilled so long as oily drops pass over, and the
product is subjected to a second treatment with bleaching
powder. The distillate is then washed with water, shaken up
with 50 per cent, sulphuric acid, washed with dilute caustic
soda, dried over chloride of calcium, and fractionated.* Di-
chlorethylamine is a strongly refracting golden-yellow liquid,
having a highly penetrating smell resembling chlorpicrin and
hypochlorous acid. It boils at 88°— 89°, and at 5° has a
specific gravity of 1'2397. By the action of zinc-ethyl it is
converted into triethylamine :

\C2H5 ^^2^6 XCgH, \C1-

Wlien kept. It frequently decomposes with formation of
hydrochloric acid, sal-ammoniac, ethylamine hydrochloride,
chloroform, acetonitril, and acetyl chloride.^ This decomposi-
tion, however, only takes place when the body is not perfectly
pure.®

Di'iodoethylamine, CgH^NIg. This ethylated iodide of nitrogen
was obtained by Wurtz, together with ethylamine hydriodide,

' H. Muller, Ann. Chcm, Pharm, Ixxxvi. 367.
' Joum, Prakt. Chem, Ixvii. 147 ; Ixviii. 279. ^ Compt, Bend, xi. 810,

* Tscherniak, Ber. Deutsch. Chem. Ocs. ix, 146. » Kohler, ih, xiL 1869.

« Tscherniak, B^, Deutsch, Cfu:m. Ges. xii 2129.

406 THE ETHYL GROUP.

bj treating an aqueous solution of ethylamine with iodine. It
is a dark blue liquid which decomposes on heating with
carbonization and evolution of iodine vapours.

Ethyl Formamide, N < COH, is obtained by distilling an

aqueous solution of ethylamine formate, and separates from the
distillate on addition of potash.^ If ethylamine be brought in
contact with chloral, a crystalline compound is formed,
which on distillation decomposes into chloroform and ethyl
formamide : -

CCL.CH

CCLH + CH

N(C,HJH

N(C,H5)H.

Ethyl formiimide is a thick, almost odourless liquid, boiling
at 199'' and having a specific gravity of 0*952 at 21''

DiETIIYLAMINE, N(C2H^2H.

260 Diethylamine is obtained by distilling the before-men-
tioned ether of diethyloxamic acid with potash :

<^A { oc^lf'^' + ^ ^^" ■ ^»^« I OK + N(C,H5).H +

H0.C2Hg.

In order to obtain this ether in the pure state, the cnide oil
is cooled to 0°, poured off from the diethyl oxamide which
separates out, and distilled, when the pure ether comes over
at 2G0^

Diethylamine is a colourless liquid boiling at 57'*'5, pos-
sessing a strongly ammoniacaJ smell, and being easily soluble
in water. It is distinguished from ethylamine by the fact that
copper hydroxide dissolves only very slightly in excess, whilst
rinc hydroxide is altogether insoluble (Carey Lea). Its salts
have been but slightly investigated. The platinichlorido,
[^(CjHg^jHJjl^tCljj, forma large orange-red monoclinic crystals
resembling octohedrons (Miiller, Sohabus).

Ifilrosodicthi/laminr, ^^(CgHJjNO, was obtained by Gcuthor

' Liniii'innnn, Wirn. Akad. B^r, 2to Abth. Ix. 44.
s Hnfiiiann, /^*r. ikuUch, Chem, Gea. v. *J47.

DIETHYL AMINE AND TRI ETHYL AMINK 407

by acting on a concentrated solution of potassium nitrite with
a perfecUy neutral solution of diethylamine hydrochloride :

an. + HO.NO = N^ CjH^ + ILO.
H (NO

This compound, to which he gave the name of nitro-diethylin,
and which has likewise been termed diethyl-nitrosamine, is
a yellowish oil having an aromatic smell and a burning taste,
boiling at 177^ and having at 17°*5 a specific gravity of 0*951.
When acted upon by hydrochloric acid in presence of water it
dissolves, and on heating forms diethylamine hydrochloride,
whilst nitric oxide is evolved, produced from the decomposition
of the nitrous acid formed. Dry hydrochloric acid gas also
converts it with evolution of nitrosyl chloride into diethylamine
hydrochloride, and when it is treated with water and sodium
amalgam the following reaction takes place : ^

2 N(C,H,)2N0 + 3 H, .= 2 NCC^H J^H^ + N^O + H,0.

Diethyl Fonnamide, N(C2H5)2COH, is formed by distilling
diethylamine formate, as a thick odourless liquid boiling at
175**- 178^ and having at 19° a specific gravity of 0*908
(liinnemann).

Triethylamine, N(C2H5)3.

a6i This is a colourless, oily, pleasantly smelling, strongly
alkaline liquid, boiling at 91"*, lighter than water, and slightly
soluble in this liquid. It precipitates many metallic salts. The
precipitates are, however, not soluble in an excess of the reagent,
with the exception of silver oxide, which dissolves sparingly,
and of the aluminium and stannic hydroxides, which are readily
soluble, in excess.

Triethylamine Hydrochloride, N(C2H5)3HC1, is an inflammable
substance crystallizing in feathery non-deliquescent scales
which may be sublimed without decomposition. It forms with
platinic chloride the compound [^(C2H5)3H]2PtClg, easily
soluble in water, and yielding, on evaporation, large red rhombic
crystals.

Triethylamine Hydrobramide, 'N (0.271^^1131, forms large
feathery crystals resembling sublimed sal-ammoniac.

The sulphate is a very soluble salt crystallizing with diflSculty.

^ Joum. Prakt. Chem. [2], iv. 435.

403 THE ETHYL GROUP.

Triethylamine Nitrate, N(C2H5)3HN03, is, according to Lea,
uucrystallizable, whereas V. v Lang mentions that it forms
rhombic crystals which are isomorphous with those of nitre.^

The Tetraethylammonium Compounds.

262 TetraethylamTitonium Hydroxide, N(C2H5)^OH, is obtained
by gradually adding freshly precipitated silver oxide to a weak
warm solution of the corresponding iodide. If the filtrate be
evaporated first on a water-bath and then in a vacuum, long
very deliquescent needles are frequently obtained. These
disappear on further evaporation, the compound drying up to
a semi-solid deliquescent mass which in its reactions closely
resembles caustic potash, with the exception that chromium
hydroxide is insoluble in an excess of this reagent.

When heated with ethyl iodide, alcohol is formed :

N(C2H,),0H -h C^H.I = N(C2H^,I + G^YL,,011.

The hydroxide when heated alone decomposes into triethyl-
amine, ethylene, and water.

Tetraethylammonium Chloride, li{(u^^fj\, is obtained by
saturating the hydroxide with hydrochloric acid. It is crystal-
line but very deliquescent, and forms with various metallic
chlorides crystallizable double salts.

The bromide is a very siniiliar body, uniting with bromine to
form the tribromide, N(C2H5)^Br3, crystallizing from alcoholic
solution in bright yellow needles which melt at 78"* without
decomposition.^

Tetraethylammonium Iodide, ^[G^^^. This forms the
starting-point for the preparation of the tetraethylammonium
compounds, and is formed, as has already been stated, by the
action of ethyl iodide on ammonia or on the ethylamines. If
iodide of ethyl be mixed with triethylamine the mixture soon
becomes hot, and, after some days, solidifies to a white crystal-
line mass. The combination takes place more rapidly when the
mixture is heated in sealed tubes to 100^ The iodide is
easily soluble in water, and separates on evaporation in fine
well-formed crystals. When heated it decomposes into ethyl
iodide and triethylamine which distil over separately, but, on
cooling, ngjiin unite. It is insoluble in caustic potash, and

* Z^Uwch. r/,r„u 1867, ^05. » Marquart, Jkr. lk\U9ch. Chem, Ocs. iii. 284.

TETRAETHYLAMMONIUM COMPOUNDS. 409

hence separates out when caustic potash is added to iU sohition,
without undergoing the slightest decomposition. Exposed to
the air, tlie salt changes to the tri-iodide, ^^{C^^)^^, a fact
first observed by Hofmann, but afterwards more exactly
examined by Weltzien.^ This compound is also obtained by
treating the product of the reaction of iodide of ethyl en
ammonia with iodine. It crystallizes from hot alcohol in
feathery needles, but is deposited from a solution in potassium
iodide in quadratic piisms which exhibit a fine blue lustre by
reflected light, and a reddish-brown colour by transmitted light.
On addition of water to the mother-liquor, a brownish oil
separates out, probably the pentaiodide. By the action of
iodine monochloridc on tctraethylammonium chloride, the com-
pound N(C2H5)^Cl2l is formed in fern-shaped crystals like
sal-ammoniac.^

TetrcLethylammonium Chloraurate, N(C2H-)^AuCl^, is a
lemon-yellow crystalUne precipitate deposited from solution in
hot water.

Tetraethylammonium Plallnuhloride, N2(C.»H5)yPtClg, is
exactly analogous to the corresponding potassium compound,
and crystallizes from hot water in octohedrons.

Besides these bodies, a large number of other tetraethyl-
ammonium salts exist. Those have been examined by Hofmann
and by Classen.*

Methyltricthylammonium Iodide, NCH3(C2H5)3l, is easily
formed by the combination of methyl iodide with triethylamine.
It is obtained in crystals which are exceedingly soluble in
water, and which, in chemical reaction, exhibit great analogy
with tetraethylammonium iodide.*

Dimcthyldicihylammonium Iodide, N(CHj,)2(C2Hj2T. is formed
by the prolonged action of ethyl iodide on dimethylamine, as
also by acting on diethylamine w^ith methyl iodide. In its
properties it closely resembles the other ammonium iodides. If
the corresponding chloride be heated it decomposes into methyl
chloride and methyldiethylamine, N(CH3)(C2HJ2.^ Hence we

( CH3 C C2H,

see that the salts, N \ CH, -*- C.,H,C1 and X-^ C2H: + CH.Cl

(C2H, - • (CH3

* Ann. Chnn. Ph/irm. l.xxxvi. 292 ; xci. 33,
2 Tildcn, Jonrn, Chrm. Soc. [2], xix. 145.

' Joum. Prakt, Chm. xciii. -146.

* Hofmann. Phil Trans. 1851 (ii.) 357.

* Meyer an«l Lecco, Antu Ckem, P/utrnt, v\xxx. 173.

410 THE ETHYL GROUP.

are idcDtical and cannot be considered as molecular compounds,
one of which contains ethyl chloride and the other methyl
chloride. Hence it also follows tJiat in all the ammonium
compounds nitrogen acts a^ a pentad}

Ethyl Hydrazines.

263 These compounds (see ante, p. 161) were discovered by
E. Fischer * and carefully investigated by him.

Ethyl Hydrazine, CjHyNgHy Diethyl urea, COCNH.CjH^)^
is the starting point for this compound, being first converted by
means of nitrogen trioxide into the nitroso-compound CON,
(NO)(C2H5)2H. This is next treated with acetic acid and zinc
dust, diethyl semicarbazide being formed, and this, on boiling
with hydrochloric acid, is converted into ethyl hydrazine, carbon
dioxide, and ethylamine :

HN.CjH.
CO + H,0 = COjj + HjN.CjHg +

H,N— N. CgHg. HjN— HN.CjH^.

As soon as the decomposition is complete, the solution is
cooled by ice and saturated with hydrochloric acid, when hydra-
zine hydrochloride separates out as a crystalline mass. Wlien
concentrated caustic potash is added to the dry salt, a solution
of the base is obtaine<l, which separates out as an oily liquid on
the addition of powdered caustic potash. It may be completely
dehydrated by the addition of anhydrous baryta.

Ethyl hydrazine is a mobile colourless liquid possessing an
ethereal slightly ammoniacal smell, and boiling at OO''^ when
the barometer stands at 709 mm. It is very hygroscopic, and at
the ordinary temperature possesses a high vapour-tension, and,
for this reason, it emits thick white fumes on exposure to moist
air. It dissolves in water and alcohol with evolution of heat ;
it is very caustic, in a short time destroying cork and caoutchouc.
With acids two series of salts are formed, of which the hydro-
chloride is the only one hitherto carefully examined. The acid

^ In pars. 34 niid 35 of Vol. I. it is stated that the elements of the nitrogen
group arc trivHlmt, but that they possess the peculiarity of acting as pentads in
certain coniix)un(ls. The facts a))Ove stated, as well as others, such as the existence
of a stable nhosphonis |>entafluoride, prove that these elements do not possess a
constant valency. The coni{K>und8 in which they arc pentads decompose more or
less reailily into two ihdIccuIcs.

' Lifbig a Annate)^ cxcix, *2>1.

ETHYL HYDRAZINE& 411

salty C2H5.N2H3(C1H)2, forms white needles, and its aqueous, as
-well as its alcoholic solution, has an acid reaction. When this
solution is evaporated, or when the dry salt is heated to llO'',
the neutral compound is obtained as a homy deliquescent mass.
The neutral sulphate is very soluble in water, and crystallizes
from hot alcohol in fine glistening tablets or scalea

Ethyl hydrazine is only slowly attacked by oxidizing agents
in acid solution, but it is quickly destroyed in alkaline liquids.
It reduces Fehling's solution in the cold with evolution
of nitrogen mixed with a combustible gaa The oxides of silver
and mercury act in a similar way, the latter with formation of
a small quantity of mercuric ethide. Ethyl hydrazine behaves
like ammonia with respect to the salts of lead, nickel, cobalt
and iron. The cobalt precipitate, however, is prevented from
oxidation by the reducing action of the base, and hence it
preserves its blue colour for a long time, whilst the precipitated
ferric hydroxide is rapidly converted into the black hydroxide
on warming. Heated with alcoholic potash and chloroform
hydrazine gives the carbamine reaction (see p. 413), whilst with
ethyl iodide it forms diethyl hydrazine and other ethylated bases.

Potassium Ethyl Hydrazine Sulphonate, C2H5.NH.NH.SO3K, is
formed by warming the base with potassium disulphate. It
is very soluble in water, and separates out on addition of alcohol
in fine glistening scales. When boiled with hydrochloric acid it
decomposes into the base, and acid potassium sulphate, and
when its concentrated solution is treated with mercuric oxide
potassium diazoethane sulphonatc, CgHgNrrN.SOgK, is formed.
This crystallizes in scales or needles which deflagrate strongly
on heating when dry, and on treatment with zinc-dust and
acetic acid is again converted into the original compound.

264 Diethyl Hydrazine, (C2H5)2N2H2, is obtained by the
action of zinc-dust and acetic acid on an aqueous solution of
nitrosodiethylamine, when at the same time ammonia and
diethylamine are produced :

(C2HJ2N-NO + 2 H2 = (C2H,)2N-NH2 + H2O.

(C2HJ2N-NO + 3 H2 = (C2HJ2NH + NH3 + H2O.

In order to separate it from the diethylamine formed at the
same time, it is converted into the difficultly soluble urea, which
will be afterwards described, and which is decomposed by hydro-
chloric acid into diethyl hydrazine, carbon dioxide, and ammonia.
The base dried over caustic baryta is an easily mobile colourless

412 THE ETHYL GROUP.

liquid which possesses an ethereal and faint ammoniacal odour.
It boils at 96'* to 99° and is easily soluble in water and alcohoL
It is a monacid base, and forms soluble salts which as a rulo
crystallize with difficulty. The platinichloride, (C2H5)^N^Hg
PtClg, separates out in yellow needles on addition of platinic
chloride to the alcoholic solution of the hydrochloride. Fehling's
solution is reduced by the free base only on warming, with
evolution of nitrogen and formation of diethylamine. This
reaction may be employed to detect the presence of a nitros-
amine in aqueous solution. It is heated slowly with zinc-dust
and acetic acid to the boiling point, filtered and warmed with
Fehling's solution after saturation with an alkali. The smallest
quantity of the hydrazine which is formed may be detected by
the precipitation of cuprous oxide. This reaction is only of course
available when no other substances are present which either alone
or by the action of nascent hydrogen act as reducing agents,
such for example as the hydrazine bases, hydroxylamine, and
the nitrogen acids, which latter yield bases. In such cases these
bodies must be removed by distillation, either with an alkali or
with an acid.

265 Truthylazoninm Iodide, (C2HJ3N2H2I. This is formed
by the union of diethyl hydrazine with ethyl iodide. It is easily
soluble in water, and crystallizes from hot alcohol in white
needles, which yield with silver oxide a strong alkaline
hydroxide analogous to tetraethylammonium hydroxide, and
this when heated with water yields diethyl hydrazine and
ethylene. If its aqueous solution be treated with zinc-dust
and -dilute sulphuric acid on a water-bath, triethylamine, hydri-
odidic acid and ammonia are formed. This decomposition is a
further proof that ammonium compounds contain pentad nitro-
gen, for this reaction can only be explained under the supposition
that the iodide possesses the following composition :

N-OJL

H.x/ \c:h,

Tetracihf/l-Te(razon(\ (CjHJ^N^, is formed by the action of
yellow mercuric oxide on a cold aqueous solution of diethyl
hydrazine :

2 (C.Hj)„N-NH4 + 4 1 1 «( ) = * " *^ l| + 2 Hg,0 + 2 H,0.

CYANOGEN COMPOUNDS OF ETHYL. 413

This compouDd is an almost colourless oil insoluble in water
but soluble in alcohol, possessing a peculiar alliaceous smell. It
does not solidify at — 20°. It volatilizes in aqueous vapour but
cannot be distilled by itself, and when quickly heated partially
decomposes with deflagration into diethylamine and nitrogen.
It is easily soluble in acids, but its salts are very unstable. Thus
the hydrochloric acid solution when heated to 70° — 80° decom-
poses with a rapid evolution of nitrogen :

This reaction is remarkable for the ease with which the ethyl
group separates from the nitrogen and is converted into aldehyde,
in order to yield the hydrogen necessary for the formation of the
amine.

The platinichloride, (C.2H5)8NgH2PtClQ, separates out from
alcoholic solution in small golden yellow prisms. It dissolves in
cold water without alteration, but like the chloride, decomposes
on boiling.

Tetraethyl-tetrazone acts as a strong base, decomposing many
salts of the heavy metals. If a solution of this substance be
brought in contact with silver nitrate, an almost instantaneous
evolution of nitrogen takes place with formation of a silver
mirror. Warmed with water and silver oxide the same phenom-
enon takes place, silver acetate being at the same time formed.
When shaken with a solution of iodine in potassium iodide a
dark oil separates out which deflagrates when slightly warmed
under water.

CYANOGEN COMPOUNDS OF ETHYL.

266 Ethyl Carhamine, CN.CgHg. If a mixture of ethylamine,
chloroform, and alcohol be poured into a retort containing
powdered caustic potash the liquid soon begins to boil violently
and ethyl carbamine distils over together with ethylamine,
chloroform, alcohol, and water, the first-mentioned substance
being separated by repeated fractional distillation.^ It is, how-
ever, obtained in the pure state more readily by acting with
one molecule of ethyl iodide upon two molecules of silver
cyanide in presence of some ether, the mixture being heated in
sealed tubes for several hours to 130' — 140^- The crystallized

^ Hofmann, Aim. Chem. Phnnn. cxlyi. 107.

» Gautier, BuU, Soc. Chim. [2 J, viii. 216, 39r>, 400.

414 THE ETHYL GROUP.

compound CNAg + CNCjH^ is then formed, and this is distilled,
after the evaporation of the ether, with half its weight of potas-
sium cyanide and some water, the product being subsequently
dried over calcium chloride and rectified.^

Ethyl carbamine is a colourless liquid having a repulsive
penetrating odour. The inhalation of its vapour produces
headache and giddiness. It possesses a slightly alkaline re-
action, boils at 78** — 80**, and is converted into ethylamine
formate when heated with water for twelve hours to 180^
Anhydrous hydrochloric or hydrobromic acid is absorbed ¥rith
such avidity that a tarry mass is formed. In presence of ether
the salts of ethyl carbamine are obtained, of which the hydro-
chloride possesses the composition (CN.C2H5)2(C1H)3.* It forms
white scales having a bitter taste. It is deliquescent and its
solution quickly decomposes with formation of ethylamine and
formic acid. If, however, it be treated with concentrated caustic
potash in the cold, ethyl formamide is obtained as the chief
product. This is also formed together with acetic anhydride
when the carbamine is mixed with anhydrous acetic acid, con-
siderable heat being evolved :

Ethyl carbamine is also formed in small quantity by distilling
the isomeric propionitril, a body to bo afterwards described, and
it is converted mto this substance when heated in closed glass
tubes to 180°.

267 Ethyl Cyanate, NC.OCaH^ the normal cyanic ether, was
obtained by Cloiiz' by acting with cyanogen chloride on a
solution of sodium ethylate in a mixture of ether and alcohol.
It was called by him cyanetlwlin in order to distinguish it from
the isocyanate which was then supposed to be the tnie cyanic
ether.

It is a colourless oily liquid, possessing an ethereal smell and
a sharp bitter taste, having a specific gravity of 1*1271 at 15°.
Caustic potash decomposes it with formation of alcohol and
potassium cyanurate. If hydrochloric or hydrobromic acid be
passed into the solution, a thick mass is obtained which becomes
solid within twenty-four hours, and on slightly warming yields

* r.autier, Bull Soc, Chim, [2], ix. 211.
• Bull. 8oc. Chim. (21, ii. 212. » Comjd. Rend. xliv. 42S.

ETHYL CARBIMIDE. 416

a distillate of ethyl chloride or bromide, cyanuric acid remaining
behind.^ Ethyl cyanate decomposes easily into a crystalline
mass which is a mixture of the two following compounds : ^

Diethyl amidocyanurate, C3N3(OC2H5)2NH2, crystallizing in
slender white prisms, melting at 97^

Ethyl diamidocyanurate, 03N3(OC2H5)(NH2)2, a white crys-
talline mass fusing above 190°.

268 Ethyl Isocyanate, or Ethyl Carbimide, CO.NC2H5, was
obtained by Wurtz' by distilling a mixture of one part of freshly
prepared and well-dried potassium cyanato with two parts of
potassium ethyl sulphate. The reaction begins at 180'', and is
completed at 250^ The distillate is a mixture of ethyl iso*
cyanate and isocyanurate, and these can be readily separated
by distillation. Ethyl carbimide is a mobile liquid, boiling at
60*, and having a specific gravity of 0 898. It possesses a
suffocating, very irritating smell. It is converted by the action
of water, ammonia, and the amines into the ethylated ureas.

The following reaction takes place when it is heated with
caustic potash :

n|^^6 + 2HOK = CO(OK)2 + N-Jh '

It has already been stated that this was the reaction by which
the amines were first obtained by Wurtz (see p. 401).

Ethyl carbimide combines with anhydrous hydrochloric acid
to form ethyl carhonyl ammonium chloride, N(C0)(C2H5)HC1, a
liquid possessing a penetrating odour, boiling at 98**, and
decomposed by water into ethylamine hydrochloride and carbon
dioxide.* It forms similar compounds with hydrobromic
acid.*

Ethyl Isocyamcrate, C303(NC2H5)3, is easily formed from the
foregoing compound, as also when potassium cyanurate and
potassium ethyl sulphate are heated together to 200*. It
crystallizes from boiling alcohol in rhombic prisms, which melt
at So** and boil at 276° (Limpricht and Habich). When
heated with ammonia it does not undergo change, whereas
on treatment with potash, it decomposes with formation of

* Gal, CompL Rend. Ixi. 527.

' Hohnann and Olshausen, Ber. Deutsch, Chcm, Qes, iii. 269.

* Ann, Chim, Phys. [3], xlii. 43.

* Limpricht and Habich, Ann. Chem. Phami. cix. 107.
» Gal, Bull, Soc. Chim. vi. 439.

416 THE ETHYL GROUP.

ethylamine and potassium carbonate. On the other hand,
boiling baryta- water decomposes it into triethyUhiuret :

CO— N.C2H5 CO— Nac^5

C^H^.N CO + HoO = C2H5.N + CO,

\ / \

CO— N.CaH^ CO— NH.C2H5.

Ethyl isocyanurate is a thick oily liquid, which when heated
yields diethyl-urea and ethyl carbimide.^

IHtthyl'isocyanuric Acid, C303N3(C2H5)2H, is contained in
combination with ethylamine in the crude product obtained by
distilling potassium cyanurate w^ith potassium ethyl sulphate,
and is prepared from the mother-liquors of ethyl isocyanurate
by boiling with baryta-water until ethylamine is evolved.
Carbon dioxide is then passed through the liquid, and the
filtrate evaporated, when triethyl-biuret first separates out
and then the barium salt of diethyl -cyanuric acid ; this latter
is then decomposed by sulphuric acid. The free acid crystal-
lizes in hexagonal prisms or obtuse rhombohedrons. It melts
at 173°, and volatilizes without decomposition. If silver
nitrate be added to a hot ammoniacal solution, the salt,
C303N3(C2H5)2Ag, separates out in needles (Limpricht Mid
Habich).

JUthyl Ferrocyanide, (C2HJ^(C^N3)^Fe2 + I2H2O. When an
alcoholic solution of ferrocyanic acid is saturated with hydro-
chloric acid, the compound (C2H5)g(C3N3)^Fe2 + 4C2H5CI +
I2H2O is formed. This is deposited in colourless crystals which
rapidly become blue on exposure to air. If these be dissolved
in alcohol, and ether added, ethyl ferrocyanide separates
out in pearly crystals which readily turn blue on exposure to
air.^

Ethyl Platinocyayiide, (C2H5)2Pt(CN)^ + 2H2 O, is obtained
by passing liydrochloric acid into a concentrated alcoholic solu-
tion of platinocyanic acid (Vol. I., p. 417). It crystallizes in
quadratic pink needles which easily decompose in the air with
formation of alcohol. When heated on a water-bath they
become lemon-yellow with fonnation of the anhydrous platino-
cyanic acid : ^

(C.H^^PKCN), + 2 H2O = H,Pt(CN),+ 2C2H5.OH.

* Limprirlit and Habieh, loc, eif.

« H. L. Ruff, Ann. (.%'m, Pharm. xci. 2r»3.

* V. Thann, Ann. t%m, Pharw, cvii. 315.

ETHYL THIOCYANATE. 417

Ethyl Cyanamidc, ^{C^^G^H, is formed by passing
cyanogen chloride into an ethereal solution of ethylamine
when a neutral syrupy liquid is obtained which, when dissolved
in water and evaporated, and these operations frequently re-
peatedy is converted into the polymeride, triethyl cyanuramide,
NjHj(C2H5)3(CN)3. This has an alkaline reaction and
crystallizes in needles. When heated with hydrochloric acid
it is converted into triethyl isocyanurate. Both theso
amides decompose when heated, solid ethyl dicyanamidc,
(^C)^^^^^^, being left behind, and dieihylcyanamide,
QiC)JS{C^^2f distilling over.^ This latter is also formed when
ethyl iodide is heated with silver cyanamide (Vol. I., p. 67G).
It is a liquid, boiling at 180", and decomposing when heated
with strong hydrochloric ac^id as follows : -

rex rH

N \ an, + 2 H,0 = N \ C.H, + NH« + CO...

( C0H3 ( c

5 ^ "'''8

2H.

269 Ethyl Tliiocyanate, NC.SCoHg. Cahours ^ first obtained
this compound by distilling a concentrated solution of potas-
sium thiocyanate with potassium ethyl sulphate, and Lowig*
prepared it by the action of ethyl chloride on potassium
thiocyanate. It is also ea.sily fonned by heating ethyl iodide
togetiher with many metallic thiocyanates, of which the mercury
salt is however not one.^ In order to prepare it, an alcoholic
solution of potassium thiocyanate is heated with ethyl iodide.
The compound is separated out by the addition of water, and
washed with a concentrated solution of common salt, as its
specific gravity is very nearly e([ual to that of water. It is then
dried over chloride of calcium.^

It is a mobile liquid possessing a penetrating alliaceous smell
and sweet taste, boiling at 141*" — 2'' when the barometer is at
733"*,^ and having at 0" a specific gravity of 1*033, and a
vapour-density of 3018 (Caliours). P^tliyl thiocyanate is
oxidized by nitric arid with formation of ethyl sulphonic
acid, and on boiling with an alcoholic solution of potassium

• Caboure and Clooz, Compt. liAnd. xxxviii. 354 ; Hofmann, Ber, Deutsch, Ch^m.
0e3. ii. 600 ; iii. 264.

• Fileti and Scliiff. Ber. Deuisch. Client, Oca. x. 427.

» Ann, Chim. I'hys. [3], rv-iii. 264. *• Poriri, Ann. Ixvii. 101.

• SchlagdenhaufTen, Ann. Chini. Phys. [3], Ivi. 207.

• Baudrimont, Bull. Soc. CJiim. ' V. Meyer, Lichig's Ann clxxi. 47.

VOL.. III. E E

418 THE ETHYL GROUP.

sulphide it is converted into potassium thiocyanate and mer-
captan. Caustic potash converts it into potassium cyanide,
potassium cyanate and ethyl disulphide.^
The latter reaction is represented as follows :

2 NC.SCgH, + 2 KOH = j l^^gs + NCK + NCOK + H,0.

V 2 6

270 Ethyl Thiocarbimide, or Hthj/l Mustard Oil, CS.NCjHj.
An alcoholic solution of ethylamine becomes waim on addition
of sulphide of carbon, and fine six-sided tables separate out from
the neutral solution consisting of ethylammonium ethylthiocar^

{NH C H
^n/pVt ^H W^^^ acted upon by caustic soda it

yields, with evolution of ethylamine, the sodium salt of ethyl
thiocarbamic acid. This latter, on addition of hydrocl Joric acid,
separates out hs a clear light oil, solidifying after some time to a
saponaceous crystalline mass, whilst if a larger quantity of hydro-
chloric acid be added it dissolves, carbon disulphide and ethyl-
amine hydrochloride being formed. If the ethyl-ammonium salt
above mentioned be heated under pressure to 110* — 120^ sul-
phuretted hydrogen is evolved, and diethylthio-urea is formed
(see p. 422), which, when heated with phosphorus pentoxide
yields ethyl thiocarbimide : ^

This compound is more easily obtained by boiling the ethyl-
ammonium salt of ethyl thiocarbamic acid and water with silver
nitrate, mercuric chloride, or cupric chloride. The corresponding
metallic salts of the thiocarbamic acid are first formed, and these
decompose with production of a metallic sulphide, 8uphurette<l
hydrogen, and ethyl mustard oil.^ Instead of the metallic salts
an alcoholic iodine solution may be employed :

^^ { SN^b^H^H + ^2 = CS.NC2H, + HI + S + N(C,HJH3l.

As soon as the colour of the iodine has disappeared, the liquid
is distilled and the thiocarbimide precipitated from the distillate
by water.*

* Briining, Jnn, Chem, Pharm. cir. 198.
' Hofmann, Her. DriUsch, Ckem, Ots, i. 25.
> Ber. Jkvtsch, Chcm. Ges, I 1C9.
< 76. u. 452.

ETHYLATED UREAS. 419

Ethyl mustard-oil is also formed when ethylamine is heated
with thiocarbonyl chloride, CSCIg.^

Ethyl thiocarbimide is a mobile liquid boiling at 134"^ and
possessing a very irritating smell, and when dropped on the
skin producing a burning sensation. The specific gravity of
its vapour is 2*98.

Heated with absolute alcohol to 110*' monothioeihylurethanc
is formed :

CS.NCoH, -f HO.C^H, = CSJ^^^^fi)^

This is a liquid possessing an alliaceous smell, boiling at
204"* — 208**, and decomposed by dilute acids with formation of
alcohol, ethylamine, carbon dioxide, and sulphuretted hydrogen.
A compound isomeric with this is obtained when mercaptan
is heated with ethyl isocyanate. It smells like the foregoing
compound, boils at the same temperature, but is decomposed by
dilute acids, as might be expected from its mode of formation,
into mercaptan, carbon dioxide, and ethylamine. Its constitution

is, therefore, CO | g^^^^^^^

When mercaptan is heated together with ethyl mustard oil a
combination takes place, and a body is obtained resembling the
foregoing. This cannot, however, be obtained in the pure state,
as on distillation it decomposes into its constituents. This body

is doubtless dUhioethylur ethane, CS \ o A A ^'

ETHYLATED UREAS.

271 Ethyl Carbamide, CO.N2H3(C2H5), is formed by the action
of cyanic acid on ethylamine, and also by acting upon ammonia

with ethyl carbimide :

CO.NCoH, + NH3 = CO I ^§^2H5)H

In order to prepare this body a solution of ethylamine sul-
phate is boiled down to dryness with potassium cyanide, and
the residue treated with alcohol. Ethyl urea crystallizes in
striated monoclinic prisms, easily soluble in water and alcohol,

* Rathke, Ann. Chem. Pharm. clxvii. 211.

* Hofmann, Bcr, DciUsch. Cfum, Ges, ii. 116.

E E 2

420 THE ETHYL GROUP.

melting at 92°, and decomposing at a higher temperature with
formation of diethyl cyanuric acid (p. 416). When heated with
caustic potash, potassium carbonate, ammonia, and cthylamine
are formed.^ It absorbs hydrochloric acid gas with formation of
the salt CO.N2H^(C2H^)Cl. The corresponding nitrate crystal-
lizes in short thick prisms and, like the oxalate, it is slightly
soluble in water. The hot aqueous solution of the urea
dissolves freshly precipitated mercuric oxide, and on heating
this solution, small needles separate out of the compound

(.Q f N(C,H,)H

"I NH )

r NH i ^o ' which is almost insoluble in cold water.*

^^ { N(C,H,)H.

a-Diethyl Carbamide, CO(NH.C2H5)2, is formed by the
decomposition of ethyl isocyanato by water, as well as by the
union of this substance with ethy lamine. 1 1 crystallizes from
water in flat prisms, and from alcohol in silky needles. It melts
at 112°o and boils at 2G3°. Heated with caustic potash it
decomposes with formation of ethylamine, and combines with
nitric acid to form a deliquescent nitrate (Wurtz).

^'Diethyl Carbamide, CO < ;v/r?iT \ , is formed by the com-
bination of die thy lamine and cyanic acid. The only reaction
of this substance with which we are acquainted is that when
heated with caustic potash it yields potassium carbonate,
diethylamine, and ammonia.

Tridhyl Carbamide, ^^ \ ^tn^ysx , is obtained by dropping

ethyl isocyanate into diethylamine. It forms white crystals, is
soluble in water, alcohol, and ether, mt^lts at 63°, and boils at
223°. It decomposei with alkalis with formation of ethylamine
and diethylamine.*

Tetraethyl Carbamide, CO I ^in^\\^y 's not produced by the

action of ethyl isocyanate upon triethylamine (Hofmann),* but is
formed by passing carbonyl chloride mixed with double or
treble its volume of jxitroleuin-spirit into dilute diethylamine.
It is a pleasantly-smelling licjuid, boiling at 205°, dissolving in
acids, and again separating out on the addition of alkalis.*

* Wurtz, Compt.Rend, xxxii. i\A \ Rfp. Chim. Pure. iv. IflO.

* Lpuckart, JoMm. Pmkt. Chrm. [2], xxi. 1. » Wurtz, lirp. Chim. Pure. iv. 199.

* Hofiiiann, J'hil. Trans. 1851, ii. 370.

* Michler, Ber, DniUch. Chrm, Oca. viii. 1664.

ETHYL SEMICARBAZIDES. 421

ETHYL SEMICARBAZIDES.

272 The Dame azide has been given by Fischer to compourds
formed by the replacement of the hydrogen in the hydrazine
group by acid radicals. The corresponding ureas must, there-
fore, be termed carbazides, and if these contain only one amido-
group they are called semicarbazides.^

Ethyl Semicarhazide, or Ethylhydrazine Urea, CgHg.NH —
NH.CO.NH2. In order to prepare this compound, an equivalent
quantity of pure potassium cyanatc is heated to boiling with
ethyl hydrazine hydrochloride in concentrated aqueous solution.
On cooling, the urea, which is easily soluble in water, separates
out on careful addition of solid caustic potash. The crystallized
mass is dissolved in chloroform, the solution concentrated and
ether added, when the compound is deposited in thin gUstening
tablets melting at 105° — 10G°.^

a-Diethyl Semicarhazide, C.;PL^.^Qsn)^.CO.^{Pfi^)Yi. For
the preparation of this compound, nitrosodiethyl-urea is employed.
This latter body was discovered by v. Zotta,^ but its constitution
was first recognised by E. Fischer."* It is obtained by passing an
excess of nitrogen trioxide into an ethereal solution of diethyl-
urea^ It is a yellow oil insoluble in water, from which solution
transparent tablets separate at a low temperature. It possesses
a burning taste and decomposes suddenly on heating. When
brought in contact with phenol and sulphuric acid it colours the
liquid first brown, then green, and finally a bright blue.^ By the
action of acetic acid and zinc- dust it is converted into diethyl-
hydrazine urea, an oily liquid which is easily soluble in water
and alcohol, and can with difficulty be obtained crystallized.
Its hydrochloride crystallizes in needles, and forms a difficultly
Eoluble platinichloride. When this urea is boiled with con-
centrated hydrochloric acid it at once decomposes into carbon
dioxide, ethylamine, and ethylhydrazine (p. 410).

^'Diethyl Semicarhazide, {C..fi^%'^ - KH. - CO.NHg. This
urea forms the point of departure, as has already been stated, for

* Ber. Deutsch. Ch^m. Ges, ix. 883.

' Fischer and Troschke, Lichiys Ann. cxcix. 294.

' Ann, Chem. Phann. clxxix. 101. * lb. cxcix. 283.

• This reaction depends upon the liberation of nitrou-s a'^id. It was discovered
by Liebcrmann {Ber. Deutsrh. Cfwrn. Gcs. vii. 247, 1008), an<l o(;curs in the case
of almost all nitroso-compounds.

NITRO-COMPOtJNDS OF ETHYL. 423

diethyl carbamide (p. 420) is formed. If, however, ethylamine
be present at the same time triethyl gvAxnidine is formed :

Diethyltbiocarbamide. Ethylamine.
Triethylguanidine.

This latter compound is also formed by the action of sodium
cthylate on ethyl isocyanurate/ and by heating chlorpicrin with
ethylamine. It is very soluble in water. Its solution is
caustic and alkaline, and it solidifies gradually on exposure to
air by absorption of carbon dioxide. At a high temperature
it distils, and partially decomposes with formation of ethylamine
and a-diethyl carbamide. Hence it contains one molecule of
water in very persistent combination, and, therefore, as it is a
monacid base it is probably an ammonium hydroxide.

NITROCOMPOUNDS OF ETHYL.

•

274 Nitroethane, CgHgNOg, was discovered by V. Meyer, and
Stuber,* who obtained it by the action of ethyl iodide on silver
nitrite, when together with this nitro-com pound about the same
quantity of isomeric ethyl nitrite is produced. In order to
prepare it on the large scale the foUowmg process may be
adopted : 2090 grams of dry silver nitrite are brought into a
large flask connected with a reversed condenser, and to this
1700 grams of ethyl iodide are gradually added by means of
a stoppered funnel, so that the liquid boils quickly but not too
violently. As soon as all the ethyl iodide is added, the liquid
is heated for some time on the water-bath, and then the
condenser is turned round and the liquid distilled in the water-
bath as long as any liquid comes over. It is next heated in
an oil-bath, and the distillate collected separately. The residue
in the flask, which consists of silver iodide and silver nitrite,
is then finely powdered, and, on to this residue, the distillate
which came over at 100° is poured, and the whole again digested
in the manner described, when a further quantity of nitro-
ethane is obtained. This is now added to the first portion,

' Hofmann, Proc, Roy, Soc. xi. 281.

' Brr. Deutsche Chem, Gcs. v. 399 ; Ann. Chtm. Pharm. clxxi, 1.

424 THE ETHYL GROUP.

and, in order to remove any ethyl iodide which may be present
it is digested with an inverted condenser with 10 gnuns of silver
nitrite, the whole being heated to boiling. The product is then
purified by fractional distillation, when about 340 grams of
nitroethane are obtained.

Nitroe thane is a colourless strongly-refracting liquid having
a pleasant peculiar ethereal smell. It boils at 113** — 114"* under
a pressure of 737 mm. and has a specific gravity at 13* of
1'0582, that of its vapour being 2-557. When ignited it bums
with a pale flame. Its vapour cannot be heated above the
boiling point without exploding.

In contact with nascent hydrogen it is converted into
ethylamine. This latter compound can be obtained in a
perfectly pure state by digesting nitroethane in a flask with
an excess of iron filings, and then adding acetic acid and a few
drops of water, the whole being warmed until a reaction takes
place, after which the flask is placed in cold water and the
reaction is so regulated that the liquid does not boil. The
liquid is then distilled with caustic potash, and a large yield of
the base is thus obtained. If nitroethane be employed which
contains a small quantity of ethyl nitrite, some ammonia is
formed at the same time, and this can readily be removed by
collecting the distillate in hydrochloric acid, evaporating over
sulphuric acid, crystallizing, and treating with alcohol, when the
insoluble sal-ammoniac remains behind. If nitroethane be
heated with hydrochloric acid of specific gravity 1*14 it is con-
verted into hydroxylaminc and acetic acid :

{cS>o, + H«o = ^^(«H)H^ + {cabH.

That nitroethane acts as a weak acid might bo expected from
the fact that it contains the nitro-group (see p. 188).

Sodium-nit roethanc, CoII^NaXOg, is obtained by acting on
sodium with nitroethane diluted with benzene, or on nitroethane
alone with alcoholic soda, when a white solid mass is obtained.
This may be washed with absolute alcohol and dried on a
water-bath. This compound is so slightly soluble in alcohol that
very small quantities of nitroethane produce a precipitate with
alcoholic solution of soda, whereby it may be readily detected.
Alcoholic potash or ammonia however do not give any precipitate.
Sodium nitroethane is a white light amorphous powder, which
on heating in the open air burns off like gun-cotton, but when
heated in a narrow test-tube detonates loudly. If kept

NITROETHANE. 425

for a length of time it becomes brown, and it deliquesces
quickly on exposure to air. The aqueous solution gives a
blood-red colour with ferric chloride, and a deep green colour
with sulphate of copper. Silver nitrate gives a white pre-
cipitate which soon becomes brown and afterwards black from
separation of metallic silver. Mercurous nitrate gives a dirty
green precipitate, whilst mercuric chloride added to the con-
centrated solution of the sodium compound yields, after standing
for a few moments, a crystalline mass consisting of a very stable
compound having the composition ClHgCgH^NOg, the constitution
of which is represented by one of the following formulae :

It is soluble in water with difficulty, and acids separate nitro-
e thane from its solution.

275 MondbroinnitroetJiane, CgH^BrNOg. When nitroe thane is
dissolved in an equivalent quantity of caustic soda or potash, and
bromine added drop by drop, the colour of this substance dis-
appears, and, on cooling with water, the addition of bromine may
be continued until the liquid appears yellow, when a heavy oil
separates out. This is a mixture of nitroethane, monobrom-
nitroethane and dibromnitroethane, and from this the pure
monobromnitroethane can be obtained only with difficulty.
It is, however, easily prepared by adding little by little to the
calculated quantity of bromine a solution of nitroethane in
caustic potash.^ The explanation of the fact that when
bromine is added in excess at the commencement of the opera-
tion only the monobrom compound is formed, but that when
it is added little by little the dibromnitroethane is produced,
may be readily explained. The constitution of nitroethane and its ^
bromine substitution-products is given by the following formulae :
CHjj CHg CH,

CH2NO2 CHBrNOg CBrgNOo.

and from these it is easy to understand why bromnitroethane
is a stronger acid than nitroethane, whilst dibromnitroethane
possesses no acid properties (p. 426). The following equation
represents the change which occurs when bromine is added to
potassium nitroethane :

C,H,KNO, + Br^ = CgH.BrNOg + KBr.

^ Tscherniak, Lifbig's Ann, clxxx. 126.

426 THE ETHYL GROUP.

The bromnitroethane, however, at once decomposes a corre-
sponding quantity of the potassium salt, and nitroethane is
liberated, upon which the bromine does not act, whilst the
potassium compound of the bronmitroethane produced is acted
upon by bromine.^ According to this explanation only nitro-
ethane and dibromnitroethane should be formed. The occur-
rence of the monobrom-compound is accounted for by the
fact that the potassium nitroethane is more slowly attacked by
the brom-compound than the potassium salt is by bromine
itself. The decomposition takes place more slowly, and a
certain excess of the monobrom-compound must be present,
so that the quantity of the dibrom-compound obtained depends
entirely upon the length of time during which the reaction
proceeds. If this time be reduced to a minimum, a pro-
duct is obtained which boils at 140** — 149°, from which the
pure compound boiling at 146° — 147° may be easily obtained
by fractional distillation. It is a very heavy oily liquid
having an extremely penetrating smell, is easily soluble in
alkalis, and yields a crystalline compound with caustic soda,
whilst with alcoholic ammonia it unites to form a mass of
glistening crystalline scales. These salts cannot, however, be
obtained in the pure state, as they decompose easily with
formation of a bromide.

Dibromnitroethane, CgHjBrgNOj. In order to obtain this
compound the requisite quantity of bromine is added to nitro-
ethane, and a small quantity of water poured on to the top of
the liquid, and to this mixture (which must be cooled down and
shaken) dilute caustic potash is added until decolorization
ensues. The dibromnitroethane which then separates out is
removed, and bromine again added to the aqueous solution until
it becomes yellow-coloured, when a further quantity of the
dibrom-compound is obtained. The raw product is decolorized
by shaking with caustic potash and adding it to that obtained,
mixed witb "water, dried over chloride of calcium and distilled.^

Tlfis substance is a colourless mobile liquid, having a very
penetrating odour, and boiling at 165°.

376 Dinitroethane, C2H^(N02)2. To prepare this com-
pound, bromnitroethane is dissolved in twice its volume of
alcohol, and the liquid shaken up with a solution of potassium
nitrite dissolved in its own weight of water. Alcoholic caustic

1 Meyer and Tschcrniak, Li^iga Ann. rlxxx. 114.

Meyer anc
V. Meyer,

Lifbig'n Ann, clxxv. 128.

DINITROETHANE. 427

potash is then added, the liquid being cooled, and a mixture of
potassium bromide and the potassium salt of dinitroethane
separates out, as is seen by the following equation :

CH3 + KOH + KNO2 = CH3 + KBr + H^O.
CHBrNOo C]

IKCNO^),

The crystalline mass is washed out with ether, and then the
dinitroethane separated by means of dilute sulphuric acid.

It is a colourless strongly-refracting liquid, having a faint
alcohol-like smell, and a peculiar sweetish taste, boiling at
185**— 186^ and having a specific gravity of 1-3503 at 2S''5.
It is somewhat soluble in water, and is a tolerably strong acid
which decomposes carbonates, although not very easily. It is
converted into hydroxylamine, ammonia and acetic acid, by
the addition of tin and hydrochloric acid, and the product also
contains some aldehyde. This decomposition is represented by
the following equations :

CH3 CH3

+ 4>B^= I + 2 N(OH)Hj + HjjO.
H(NOjj)j CHO

CH3 CH3

+ N(0H)H2= I +NH8.

HO CO.OH

Dinitroethane forms well crystallized salts. The potassium
compound, C2H3K(N02)2, is obtained by adding alcoholic potash
to a solution of dinitroethane in alcohol. It forms pure
yellow, brightly glistening crystals, which become opaque and
red on exposure to air, but regain their colourless appearance
when again placed in the dark. On quickly cooling the hot
aqueous solution, the compound separates out in the form of
tiibles or long needles, and by evaporation, or by slow cooUng,
it is obtained in fine monoclinic prisms. It explodes very
violently by a slight blow, or even at the touch of a warm
object, with formation of red vapours.

The yellow salts which dinitroethane forms with sodium,
ammonium, barium and calcium, are also soluble in water and
crystallize well. The silver salt, C5jH3Ag(N02)2, is a fine
yellow crystalline precipitate, which is deposited from warm

428 THE ETHYL GROUP.

solution in bright metallic-glistening scales, and is as explosive
as the potassium compound.^

Bromdinitroetliane, C2H3Br(X02)2, is formed when an
aqueous solution of potassium dinitroethane is shaken with
the calculated quantity of bromine water. It is a colourless
heavy oil having an extremely pungent smell. It is volatile
in presence of aqueous vapour, but when it is heated alone it
decomposes suddenly with formation of bromine vapours. It
is decomposed by caustic potash as follows (ter Meer) :

C2H3Br(N02)2 + 2 KOH = C2H3K(NO,)2 + KBr -h H^O + O.

277 Ethyl Nitrolic Acid, C2H3(N02)NOH. This compound,
discovered by Victor Meyer,^ is easily formed when an alkaline
solution of nitroethane is mixed with potassium nitrite and
then acidified with dilute sulphuric acid :

CH.3 CH3

CH2 4- ON.OH = CN.OH + H^O.

NO2 NO2

It also occurs when an aqueous solution of hydroxylamine is
well shaken with dibromnitroethane dissolved in alcohol for
the purpose of fine division :

I I

0Br2 + N(0H)H2 « CNOH + 2HBr.

In order to prepare it, nitroethane is dissolved in the requi-
site quantity of weak caustic soda, an excess of potassium
nitrite added, and the whole acidified, so that nitrous fumes
are evolved. Alkali is then added in excess, the reddish -
brown solution again acidified, and this process repeated three
or four times.* The liquid is then shaken up several times
with ether, which dissolves the nitrolic acid, and this separates
out in crystals on evaporating the ethereal solution. A single
crystallization from water suffices to yield it chemically pure.
It crystallizes in splendid pale-yellow transparent rhombic prisms

* ter Meer, Lubig'n Ann. rlxxxi. 1. * LUbig'n Ann. clxxr. 88.

• ter Meer, LUbig*i Ann, clxxxi. 1.

ETHYL NITROLIC ACID. 429

having a bright lustre and a slight bluish fluorescence and re-
sembling in general appearance crystals of saltpetre. This body
has an intensely sweet taste. It is so much more soluble in hot
than in cold water that if a solution be saturated by the warmth
of the hand, crystals at once form when the hand is removed.
Nitrolic acid dissolves in solutions of the alkalis and alkaline
earths with an intense red colour. The salts which are thus
formed are, however, extremely readily decomposed, and have
not been obtained in the pure state. Their solutions yield,
with various metallic salts, coloured precipitates, which are also
very unstable. Nitrolic acid gradually decomposes on keeping,
leaving acetic acid containing the oxides of nitrogen, and when
heated it begins to melt at 81° and decomposes quickly, often
with explosive violence, according to the equation :

2 C2H4N2O3 = 2 CoH.Og + NOo + N

If it be heated with water, or better with dilute sulphuric acid,
nitrogen monoxide is obtained, together with aoetic acid, and the
same reaction takes place with concentrated sulphuric acid in
the cold. In this way two successive reactions take place. At
first acetic acid, hydroxylamine, and nitrous acid are formed :

CHj CHq

=NOH + 2 H,0 = C=0 + N(OH)H. + NO.H,

I I

NOj OH

and the latter two compounds mutually decompose as follows :

NOH3 + NO,H - 2H2O + NjO.

Sodium amalgam and water also give rise to acetic acid and
nitrous acid, together with ammonia formed by the reduction
of the hydroxylamine. It is clear that hydroxylamine is pro-
duced in this decomposition, because if zinc and dilute hydro-
chloric acid be employed for the reduction, only acetic acid
and hydroxylamine are obtained : ^

CH3 CH3

I I

C=N.OH + H.,0 + 2 IL = 0=0 + 2 H»N.OH.

I •

NOj OH

* Meyer and Locher, Lichig a Ann. clxxx. 170.

432 THE ETHYL GROUP.

The separation and purification of the phosphlnes is accom-
plished without any difficulty, these bodies thus exhibiting a
marked difference from the amine bases, the separation of which
is difficult and tedious. In the first place it must be borne in
mind that under the above conditions a tertiary base is not formed.
In order to separate the ethyl phosphine, the contents of the tube
are brought into an apparatus filled with hydrogen (Fig. 62)»
into which a slow current of water, free from air, is allowed to
enter. This decomposes the salt of the primary base, correspond-
ing to the iodide of phosphonium, into ethyl phosphine and
hydriodic acid. The first of these is condensed by passing
through a spiral tube surrounded by ice and dried over caustic
pota.sh. As the current of hydrogen carries away a con-
siderable quantity of the very volatile ethyl phosphine, the
gas is passed through a concentrated solution of hydriodic
acid. At last the whole is warmed, and when no further
evolution of ethyl phosphine takes place, a strong solution
of caustic soda is allowed to run into the retort, when so
much heat is evolved that diethyl phosphine volatilizes; and
this is then condensed by an ordinary cooling apparatus in
an atmosphere of hydrogen, and also dried over caustic potash.

Ethyl phosphine is a very mobile colourless liquid, in-
soluble in water, and possessing a strong refractive power.
It boils at 25^, and does not act on vegetable colouring matters.
Its smell is most overpowering, closely resembling that of the
carbamincs, and its vapour, like that of the latter bodies,
produces an intense bitter taste on the tongue and in the
throat. The vapours bleach cork like chlorine, and caoutchouc
brought in conUict with them is rendered translucent and loses
its elasticity. Ethyl phosphine ignites in contact with
chlorine, bromine, and fuming nitric acid, and yields with
sulphur and carbon disulphide volatile compounds.

Ethyl phosphine is a weak base, which unites with concen-
trated \vdracids and the elements of tlie chlorine group to form
salts which are quickly docomi)osud by water. The hydrochloride
forms a i)latinichloride which crystallizes in fine crimson-red
needles. Ethyl phosphonium iodide is a splendid salt, crystal-
lizing in shining white four-sided tables slightly soluble in con-
centrated hydriodic acid. On the addition of ether it separates
out in large woll-forniod tables, which are so thin that they
exhibit iridescence. Heated in an atmosphere of hydrogen they
sublime at 100"*, forming a mass resembling sal-ammouiac.

TRIETHYL PHOSPHINE. 433

280 Ethyl Phosphmic Add, P(C2H5)03H2. This substance is
obtained by the action of fuming nitric acid on ethyl phos-
phine, and may be regarded as orthophosphoric acid in which
hydroxyl is replaced by ethyl. It is separated from the
phosphoric acid, which is* formed at the same time, by boiling
the solution with oxide of lead, and treating the mixture
of the lead salts with acetic acid, which leaves the lead phos-
phate insoluble. Sulphuretted hydrogen is then passed through
the solution, and the filtrate evaporated on a water-bath. The
residual oily liquid solidifies on cooling to a spermaceti-like
mass, which melts at 41° and can easily be distilled. Although
it is very soluble in water, it is only with difficulty moistened
by this substance. It is dibasic ; the silver salt, P(C2H5)03Ag2,
is an insoluble yellow powder.^

Diethyl Phosphine, P(C2H5)2H,

is a colourless liquid, lighter than wat^r and having a high
refiractive power. It boils at 85®, and possesses an extremely
penetrating smell, but one quite diff'erent from ethyl phos-
phine. It absorbs oxygen with great avidity, becoming thereby
so hot that inflammation may ensue. It dissolves very easily in
acids. Its salts, which are not decomposed by water, crystallize
only with difficulty, with the exception of the hydriodide and
the platinichloride, the latter forming fine large orange-yellow
prisms, "which however are very unstable.

Diethyl phosphine combines with sulphur and carbon di-
sulphide to form liquid compounds. Nitric acid oxidizes the
base to diethyl phosphinic acul, 'P{C^^fi^, a liquid which
does not solidify at — 25^ and yields a silver salt, P(C2H5)202Ag,
which is precipitated from its aqueous solution in fine silky
needles.

Triethvl Phosphine, P(C2H5)3.

281 This was first prepared by Cahoursand Hofmann,^ by the
action of zinc ethyl on phosphorus trichloride, in a similar w^ay
as the corresponding methyl compound (see p. 232). Hofmann
afterwards found that it is better to decompose the double
compound of triethyl phosphine and zinc chloride, formed by
the continued action of concentrated caustic potash, and to
distil the base from this mixture.^ This compound is also

' Hofmann, Brr. DciUsch. Chcm. Ges. v. 110 ; Chfm. Soc. Jmim. xxv. 422.
« Chan. Hoc, Joimi. xi. 01. ' Phil. Trans. 1860, 410,

VOL. III. F F

430 THE ETHYL GROUP.

278 Dinitroethylic Acid} (C2H5)N202H. Nitric oxide is very
slowly absorbed by zinc ethyl. The reaction may, however, be
accelerated by working underpressure. The first product of this

reaction is ethyl zinc dinitroethylate, NgOg-j y^p^xr which

may be obtained when an ethereal solution is employed, in
large colourless transparent rhombohedral crystals which oxidize
in the air, and are decomposed by water with evolution of gas,
as follows :

2N A { Z^C^H/ ^^^ " ^^*^ "^ NjO,(C,H02 Zrx + Zn(OH)^

Zinc hydroxide is, however, not precipitated, but a basic salt is
formed which yields an opalescent solution having a strong
alkaline reaction and a peculiar bitter taste. When car-
bon dioxide is passed into the liquid the normal zinc salt,
2N^O^(C2H5)2Zn.+ H2O, is formed, crystallizing in thick
rhombic prisms (Zuckschwerdt). If this be decomposed with
dilute sulphuric acid, and the liquid distilled under diminished
pressure, a solution of the free acid is obtained, possessing
an acid reaction and a pungent taste. It is an extremely
unstable compound, decomposing even at the ordinary tem-
perature with evolution of nitrogen, of the monoxide and
dioxide of nitrogen, and of ethylene.

The sodium salt is easily prepared by passing nitric oxide into
sodium zinc ethyl, Na Zn (02115)3.2

A series of other salts have been prepared from the zinc salt,
of which those of the alkalis and alkaline earths deflagrate like
guiipowder ^en heated below a red-heat, and the zinc salt
when quickly warmed to 300* bums with a fine bluish-green
flame. The copper salt, 2N^O^(C2H5)2Cu + HoO, crystallizes
from a fine purple-coloured solution in long needle-shaped four-
sidfid prisms of the same colour. Nascent hydrogen converts
dinitroethylic acid into ammonia and ethylamine : '

N202(C.,H,)H + 4 H2 = NH3 + C2H5.NH2 + 2 H2O.
From this it appears that the acid contains one atom of

1 Frankland, Phil. Trans. 1857, p. 68.

* Frankland and C. C. Graham. Joum. Chem. Sor. 1880, I. 578.

• Zuokschwerdt, ytnn. Chem. Pharm. clxxiv. 302.

ETHYL PHOSPniXE. 431

nitrogen in direct combination with ethyl, and that the foUow-
ing formula represents its constitution :

C,H,— N— X— OH.

Diazodhoxane, (C^^^Jd^, is produced by the action of ethyl
iodide on silver hyponitritc (Vol. I. par. 2:17) ; it is a light, colour-
less liquid, possessing a peculiar ethereal odour. Although it is
almost as explosive as nitrogen chloride, it was found jx^ssible
to determine its vapour density, which is 41. Hydrogen in the
nascent state converts it into alcohol and nitrogen gas. Hence
its constitution is most probably expressed by the formula :

CjHg -0-N = N-0- C0H5.1

PHOSPHORUS BASES OF ETHYL.

279 Ethyl Phofiphim, P(C2H0H2. This compound, discovered
by Hofmann,* is obtained by a method analogous to that employed
for the preparation of the corresponding methyl compounds
(p. 229). A mixture of five grams of zinc oxide, twenty grams
of phosphonium iodide, and twenty grams of ethyl iodide, is
heated in a closed glass tube of about 50 cbc. capacity for from
six to eight hours to 150^ It is best first to bring the phos-
phonium iodide into the tube, then the oxide of zinc, and lastly
the iodide of ethyl. Mixed in this way the bodies do not attack
one another in the cold ; and the tube may be easily sealed up.
On opening the tube, after tlie operation is o^er, a disengage-
ment of gas takes place, as various gaseous bodies are formed
in the reaction, amongst which ethane is probably contained,
and also frequently phosphuretted hydrogen. Tlie chief product
of this reaction is ethyl phosphonium hydriodide, which forms a
double salt with the zinc iodide also formed :

2C.^HJ + 2PH,I + ZnO = 2 PCCUyHjI + Znl, + HoO.

This reaction is accompanied by another one, in which diethyl
phosphine is produced, this body combining directly with zinc
iodide :

2 CoHJ + PH4I -f ZnO = P( C,H,),H J, Znl, -h H,0.

* Zom, Ber. Dcvtach. Chrm. (7at. xi. IfiSO.

■ lier. Deuisch, Chcm. Ors. iv. 430 ; Ch-m^ Sor. Joum, xxiv. 713.

TUIETUYLPHOSPHINE COMPOUNDS. 437

insoluble in ether. If an aqueous solution of the hydro^
chloride be mixed with a slight excess of platinic chloride, and
heated to boiling, the red precipil^ate which at first forms
disappears, and light yellow crystals separate out from the con-
centrated solution, having the composition Pt[P(C2H5)3]^PtCl4,
and therefore analogous to Magnuses green salt (Vol. II. part ii.
p. 411). This compound is readily soluble in ether, and crys-
tallizes from ethereal solution in large amber-yellow transparent
mouocliuic prisms, which melt at 150^ and may be heated to
250'' without decomposition. Together with this compound
an isomeric body is formed, crystallizing in small white prisms.
K the yellow compound be heated with triethylphosphine and
water, colourless crystals having the composition [PCCgHj) J^PtCIj
are formed, which are easily converted with separation of tri-
ethylphosphine into the white compound already mentioned, and
give with silver oxide and water a strongly alkaline solution,
from which other salts corresponding to the plato-diammonium
compounds can be prepared.^

283 TrUthylplwsphine Sulphide, P(C2H5)3S. If a piece of sul-
phur be thrown into a test-tube containing triethylphosphine it
melts with evolution of heat, running about on the top of the
liquid until at last it disappears. On cooUng, the liquid solidifies
to a splendidly crystalline mass. This experiment requires care,
inasmuch as the vapour of the base when brought in contact
with air forms an explosive mixture. In order to prepare the
sulphide in larger quantity, flowers of sulphur are heated in a
dilute ethereal solution of the base as long as they dissolve.
Thfe ether is then evaporated off and the residue crystallized
from boiling water. On cooling, it separates out in long glisten-
ing needles or hexagonal prisms, which melt at 94°, and are
volatile in a current of steam. When heated with sodium, tri-
ethylphosphine is produced, whilst nitric acid converts this
compound into the oxide.

Triethylphosphine Selenide, P(C2H5)3Se. Selenium combines
directly with this base, but with less energy than sulphur.
The compound crystallizes from aqueous solution with the same
ease with which the sulphide does, and is decomposed in contact
with the air.

Triethylpliosphine Carbonyl Sulphide, T^C^^^fiS^^ This mag-
nificent and characteristic compound is formed by the direct
union of the base with carbon disulphide, the combination

» Cahours and fJal. /?»/// *SV. rhim. [2], Niv. 3S6.

438 THE ETUYL GROUP.

taking place so energetically that an explosion may occur. It
is, therefore, better to prepare the compound in an alcoholic or
ethereal solution. It is insoluble in water, difficultly soluble in
ether, but easily dissolves in hot alcohol, from which, on cooling,
it is deix)sited in red needles resembling chromium trioxide^
whilst by the spontaneous evaporation of the ethereal solu-
tion large deep-red monoclinic crystals are obtained exhibiting
dichroism, melting at 95* and evaporating at 100^ The com-
pound is soluble in strong hydrochloric acid, and this solution
yields, with platinic chloride, a yellow amorphous compound,
[P(C2H^)3H]2PtClo, which is insoluble in alcohol, and very
easily decomposed. When an alcoholic solution is boiled with
silver oxide or silver nitrate the following reaction takes place :

PraH5)3CS, + 2 AgoO = AgjS + Ag, + C0« + P(C,HO,S.

Moist air gradually produces a similar change. If, however, it
is heated with water to 100** the following reaction occurs :

4 P(aH,)3CS, + 2 HP = 2 P(aH,)3S + P(aH,)30 +

P(aH,)3(CH3)OH + 3CSo.

The methyl triethyl phosphonium hydroxide thus formed yields
a platinichloride crystallizing in splendid octohedrons.

The formation of the red compound takes place so easily and
sa quickly that it may be used as a means of detecting the
smallest trace cither of carbon disulphide or of triethyl phos-
phine.* If it is desired to test for the latter body, the liquid is
poured on to a watch-glass, and the vapour of carbon disul-
phide allowed to How on to it from a bottle containing this
liquid, when the glass becomes covered with a network of red
crystals. By help of the triethylphosphine the presence of
exceedhigly small tmces of sulphide of carbon may be detected,
as, for example, in the most carefully purified coal-gas.*

The constitution of this peculiar compound is probably as
follows :

I p-c;h
s=c/ \aa

'2 "-5

^\^len heated with a saturated solution of sulphuretted hydro-
gen to 100" it decomposes into carbon disulphide, trietliyl-
phosphine sulphide, and yellow crystals having the formula

• Tho otliLT UTtiiiry )»1iob{)hiiirb form Himilur coiuimiuikLs.
' ^r»flnuul^ Phil. Trans, lS6o, |i. VH.

TETRAETHYLPHOSPHONTUM COMPOUNDS. 439

CgHjgPS^ insoluble in ether, and probably having the constitu-

tion CS -J GT>/ri^Tj N XT If these be heated with water, carbon

disulphide is separat id, and an alkaline solution is formed which
yields with acids well-defined salts. The difficultly soluble
iodide crystallizes in long needles, having the composition
P(SCH3)(C2H,)3U

Tetraethylphosphonium Compounds.

284 Wlien trietliylphospliine is mixed ^vith ethyl iodide a
violent reaction takes place in a few moments. The liquid froths
up, and solidifies on cooling to a white crystalline mass of
tetraethylphosphonium iodide. Tliis compound is also formed
together with triethylphosphine, when absolute alcohol acts on
phosphonium iodide (Vol. I. p. 477) :

4C2H5.OH + PH,I = P(C2H5),I + 4H2O.

It is exceedingly soluble in water, less so in alcohol, and
insoluble in ether. If ether bo added to an alcoholic solution
until the white crystalline powder which begins to separate
dissolves on boiling, finely formed crystals are deposited on
cooling. If silver oxide bo added to its solution, silver iodide
is quickly formed, and a strongly alkaline liquid which retains
some silver oxide in solution. If this be allowed to dry over
sulphuric acid, metallic silver separates out in the form of a black
powder or in that of a mirror, and a crystalline mass of the
hydroxide is obtained, which is odourless, and possesses a bitter
taste somewhat resembling that of phosphonis itself. Its solu-
tion exhibits most of the reactions of caustic potash, except
that it does not easily dissolve the oxides of zinc and alumi-
nium. On dry distillation it is decomposed into triethylphos-
phine oxide and ethane. The chloride, sulphate, and nitrate
prepared from this are crystalline, but extremely deliquescent
bodies. The platinichloride is an orange-yellow precipitate,
which is difficultly soluble in boiling water. The aurichloride
crystallizes from hot water in glistening golden needles.

Tricthylmcthylphosplionium Iodide, P(C2H5)3(CH3)I. If methyl
iodide bo brought together with triethylphosphine, it unites
with it vdi\i such force that an explosion may occur, and hence
it is necessary to dilute with other. The compound resembles

* Hofraanii, Vroc, Rcty. Soc. xi. 283.

440 IHE ETHYL GROUP.

that of tetraethylphosphonium, and, like this, yields a stroDgly
alkaline hydroxide and a platinichloride which has already been
mentioned.

ARSENIC COMPOUNDS OF ETHYL.

285 These bodies exhibit close analogy with the corresponding
methyl compounds. But, with the exception of the triethyl-
arsino, they have not been so carefully examined as the latter
series.

Triethylarsine, Aa(C2ii^^ occurs together with arsendi-
methyl, As2(G2H5)4, as the principal product of the action of
ethyl iodide on sodium arsenide :

AsNag + 3 CsjHgl = AslC^Hg), + 3 Nal.

The product is subjected to distillation, and the distillate
rectified in an atmosphere of carbon dioxide.^ Triethylarsine
is also formed by the action of zinc ethyl on arsenic trichloride.*
It is a highly refracting mobile liquid possessing a disagreeable
smell, boiling at 140** and having a specific gravity of 1*151
at 16°7, whilst that of its vapour is 5**-278 (Landolt). It
fumes in the air and takes fire when slightly warmed. When
the air is allowed to act slowly upon it, tabular crystals
having an acid reaction are formed. The composition of these
has however not been determined. Triethylarsine is decomposed
by concentrated nitric acid with evolution of light and heat,
but an acid of specific gravity 1*42 converts it into triethyl-
arsine nitrate, which forms deliquescent crystals.

Triethylarsine Qjtiiky A&((^^^fi, is formed, together with
other bodies, when an ethereal solution of triethylarsine is
allowed to evaporate in the air, as well as when the correspond-
ing iodide is heated with caustic potash. It is a liquid
insoluble in water, which may be distilled without decomposi-
tion, and possesses an irritathig smelL When warmed with
concentrated hydnx'bloric acid it evolves a most unbearable
odour, ])robably due to the formation of a chloride which
however has not yet been isolated.

Triethylarsine Dromide, ^iS^^^^v^y is produced when an
alcoholic solution of its constituents is allowed to evaporate.

' biuilolt, Ann, Chtm. Phann, Ixxxix. 801 ^ xcii. 361.
2 Cnhours an<l llormrinn, Compt, liend. xli. 831.

ARSENIC COMPOUNDS OF ETHYL. 441

It forms yellow crystals which have a bitter taste and excite
saeezing.

Triethylarsiru Iodide, As(C2H5)3lj, is obtained as a yellow
precipitate by adding iodine to an ethereal solution of triethyl-
arsine. By the action of platinic chloride on triethylarsine
the salt Pt[As(C2H5)3l^PtCl^ is produced which is isomor-
phous with the corresponding phosphine compound (p. 437).
An isomeride is also formed at the same time in long
light yellow prisms. Both bodies are converted into the salt
[As(C2H5)3]^PtCl2 by the further action of the arsenic base
(^Cahours and Gal.)

Tridhylarsiiie Suljyhide, As(C2H5)3S, is produced when an
ethereal solution of triethylarsine is warmed with flowers of
sulphur. It crystallizes in fine prisms soluble in hot water and
melting a little above 100°. It has a bitter taste. Hydro-
chloric acid decomposes it with evolution of sulphuretted
hydrogen, and its solution precipitates black sulphide of silver
from silver salts, but it has no action on those of copper
and lead.

Tbtraethylarsonium Compounds.

a86 The iodide, As(CoH,j)^I, is readily produced by gently heat-
ing ethyl iodide with triethyl arsine. It is easily soluble in
water and alcohol, and crystallizes in long colourless needles
which turn brown on exposure to air. When distilled
with caustic potash it decomposes into the bodies from which
it is formed. It unites with iodine to form the periodide,
As(C2H5)^l3, a body which in appearance resembks potassium
permanganate. A compound with arsenic tri-iodide, As(C2H5)^I
+ Aslj, may be obtained by heating arsenic with ethyl iodide
to 180° ; it forms red tables and crystallizes from alcohol
in needles, and is decomposed by caustic potash with forma-
tion of tetraethylarsonium iodide, and distilled with this body
ir. yields pure triethylarsine.

If an alloy of arsenic and zinc be heated with ethyl iodide
to 175°— 180^ the compound 2As(C2H5)J + ZnIg is ob-
tained crystallizing from alcohol in fine prisms. A correspond-
ing cadmium compound has also been prepared. Both bodies
are decomposed by caustic potash in a similar way to the
arsenic iodide compound. ^

' Caboure, Compt, Eend. xiix. 87 ; 1. 1022. Ann. Chem. Pharm, cxii. 228;
cxvi. 364.

442 THE ETHYL GROUP.

Tctraethylarsonium Hydroxide, As(C2H5)^OH, is obtained by
acting with silver oxide on an aqueous solution of the iodide.
A strongly alkaline caustic liquid is left behind, which on
evaporation in a vacuum yields the hydroxide as a deliquescent
crystalline mass, and this when saturated with hydrochloric
a(id gives the chloride, As(C2H5)^Cl + 4H2O, a crystalline
substance soluble in water and alcohol and uniting with
mercuric chloride and platinic chloride to form crystalline
compounds.

Various other tetraethylarsonium salts are known. More-
over diviethylethylarsine, diethylmcthylarsine, and their com-
pounds and derivatives have been prepared.^

Diethylarsinc or Ethyl Cdcadyt, As^{Cfi^^. In order to
prepare this body, a mixture of one part of sodium arsenide and
five parts of quartz sand is placed in a number of small flasks
and each moistened with ethyl iodide. As soon as the energetic
reaction is over, the mass is heated in connection with a
reversed condenser and ethyl iodide again added until all the
triethylarsine is converted into the arsonium iodide. Tho
product is then extracted with ether in an atmosphere of
carbon dioxide, the Eolution mixed with absolute alcohol and
the ether distilled off. On addition (f water free from air
to the residue, diethylarsine separates out, and this is dried and
rectified in a current of carbon dioxide. The same compound
is also formed when diethylarsine iodide, As((u^}i^J,, is distilled
with zinc amalgam.*

Diethylarsine is a heavy highly refracting liquid having an
unbearable alliaceous (dour and boiling at 185** — 190°, and
oxidizing quickly in the air without however taking fire. In
this cat:e diethyluisine oxide, a substance which has not yet
been fully examined, is produced. It unites a'so with the
elements of the chlorine group and with sulphur, forming
fconqx)untl3 which closely resemble the corresponding methyl
compounds but have not been further examined.

aUiyl Cacoilylic Acid, AfiO(C2H^20H, is formed by the
action of air on the foregoing compound in the presence of
water, or, more rapidly when diethylarsine is shaken up with
water and mercuric oxide, when a readily soluble and crystalline
mercuric salt is formed. This is decomposed by baryta-water,

* CttliourM, Amu Chtm, PKarm. c\\\\. 192, 329 ; Ann. Cliim. Phya. [3], Ixii.
291.
^ Cuhuurd and RicLc, Commit. R* nd. xxxvL 1001 ; xxxix. 541.

ANTIMONY COMPOUNDS OF ETHYL. 443

the liquid treated with carbon dioxide, and afterwards the
barium exactly precipitated with sulphuric acid. On evapora-
ting this solution, the free acid is obtained in glittering scales
or tables which have an acid reaction and a bitter taste. They
melt at lOO"" and are not attacked by concentrated nitric acid or
even by aqua-regia (Landolt). The same compound is also
formed when diethylarsine iodide is treated with silver oxide
and water :
2 AsCCgHj),! +3 AgaO+HgO = 2 AsO{CJI,)j011 + 2 Agl + 4 Ag.

Mondhylarsine Compounds are but little known. The iodide
is formed by the action of iodine on diethylarsine iodide :

As(C,H,),I + I, = As(C,H,)I, 4- C,H,I.

It may also be prepared in a similar way from diethylarsine.
Its properties have not been fully examined. When treated
with silver oxide and water it forms a crystallizable arsenvuyiw-
ethylic acid, AsO(C2Hg) (OH)^ (Cahours).

Some compounds are also known which contain both methyl
and ethyl, but they have not been more definitely examined
(Cahours).

ANTIMONY COMPOUNDS OF ETHYL.

287 Triefhylstihinc or Stiheihyl, Sb(C2Hj3. In order to pre-
pare this compound, ethyl iodide is allowed to act on potassium
antimonide,^ mixed with three times its weight of sand, in an
atmosphere of carbon dioxide. The violent reaction which
takes place must, to begin with, be moderated by cooling down
the flask, which is afterwards gently warmed and the products
of the reaction distilled off. In this case not only stibethyl
but also tetraethylstibonium iodide is formed, and hence
the crude product is rectified over potassium antimonide. It is
perhaps better to prepare triethylstibine iodide, which will be
hereafter described, from the crude product and to decompose
this with zinc. Triethylstibine is also easily formed by the
actiou of ziuc ethyl on antimony trichloride.*

Triethylstibine is a highly refracting thin liquid possessing

^ Potassium antimonide is obtained by igniting five parts of croani of tartar
with four parts of antimony, when a crystalline regulus is obtained, having a
bright metallic lustre, und containing twelve per cent, of potassium (C. Lowig
ami E. Schweizer, Ann. Chcm, Pharm. Ixxv. 315^.

« A. W. Hofmann, PhiL Mag. [4], xv. 147

444 THE EIHYL GROUP.

an unpleasant alliaceous odour, boiling at 158''*5 under a pressure
of 730 mm. and having a specific gravity at 16"* of 1'3244, that
of its vapour being 7*438. It fumes strongly on exposure, and
takes fire in the presence of excess of air as well as in oxygen,
burning with a luminous flame. By the action of alcoholic
solution of platinic chloride on triethylstibine a fine crystalline
compound, Pt[Sb(C2H5)3]^PtCl^, is obtained (Hofmann).

Triethylstibine Oxide, Sh(C^H.^fi, is formed by the slow oxi-
dation of triethylstibine in the air or under water, as well as by
evaporating its alcoholic solution. It is best obtained by acting
on silver oxide with an aqueous solution of the iodide or oxy-
iodide.^ It can also be prepared by decomposing the sulphate
with baryta water. The aqueous solution gives, on evaporation in
a vacuum, a syrup which gradually solidifies to an amorphous
mass. Its solution has a bitter taste and, like the alkalis,
precipitates many metallic salts. With acids it forms salts which
have a bitter taste, but do not act as emetics.

Triethyl$tibi7ie Chloride, Sb(C2H5)3Clj. Triethylstibine takes
fire in chlorine gas. In order to prepare the chloride, the oxide
or one of its salts is treated with concentrated hydrochloric acid,
when the above compound is precipitated as an oily liquid
which smells like turpentine and has a specific gravity of
1-540 at 17".

Triethylstibine Bromide, Sb(C2H5)3Br2, is obtained by adding
an alcoholic solution of bromine to a well-cooled alcoholic
solution of triethylstibine, and precipitating the product with
water. It is a colourless, highly refracting liquid, having a
specific gravity of 1*953 at IT*, and possessing an unpleasant,
turpentine-like smell, and on warming giving off a vajMur
which excites te'irs and sneezing. Like the chloride, it decom-
poses when strongly heated. Its alcoholic solution acts on
metallic salts like potassium bromide.

Triethylstihiiu Iodide, ^^{p^^^^^ In order to prepare this
compound, iodine is added to an alcoholic solution of triethyl-
stibine so long as the colour disappears. The solution is
allowed to evaporate, and crystals separate out, which may be
purified by recrystallization from alcohol and ether. Tliis body
forms colourless transparent needles, which melt at 70°'5, and
begin to volatilize at 100^ though they decompose at a tem-
perature slightly above this. Triethylstibine iodide dissolves in
water, and is easily soluble in alcohol and ether. It acts

> 31erk, //»». Chem. Pharm, xcvii. 822.

TRIETHYL8TIBINE COMPOUNDS. 446

towards chlorine, concentrated sulphuric acid, and metallic salts
like potassium iodide. By the action of zinc ethyl on the iodide
a pasty mass is obtained which, on distillation, yields a heavy
liquid, probably pentaethyl-stibine.

TrUthylstihine Oxyiodide, Sb2(C2H5)gOl2, is formed by allow-
ing an alcoholic solution of triethylstibine iodide, to which
ammonia has been added, to evaporate spontaneously. It is
also produced by the union of the iodide and oxide in alcoholic
solution, or by adding hydriodic acid to a solution of the oxide
in ether until a turbidity occurs.^ The oxyiodide deposits in
hard, colourless, glassy, odourless octohedrous or tetrahedrons.
When treated with an aqueous solution of mercuric chloride,
the corresponding chlorine compound is fi^rmed, consisting of
a striated crystalline, very deliquescent mass.*

Triethylstibine Stdphafe, Sh(Gfi^.^SO^ is best obtained by
acting with copper sulphate on triethylstibine sidphide. It is
very easily soluble in water, and separates out from the syrupy
solution in small white crystals. When decomposed by baryta
water, and the filtrate evaporated, a soluble compound of tri-
ethylstibine and baryta remains behind, which is soluble
in alcohol ; thLs solution is decomposed by carbon dioxide
with .formation of triethylstibine oxide.^ The basic salt,
[Sb(C2H5)3]2(OH)2SO^ is formed by decomposing the oxyiodido
with silver sulphate. On drying the solution in a vacuum over
sulphuric acid, a gummy mass remains.

Triethylstibine Nitrate, 8^02^^6)3(^03)2, is obtained by dis-
solving triethylstibine or its oxide in nitric acid. It is easily
soluble in water, and crystallizes in large rhombic prisms
melting at 62°'5, having an acid reaction, and deflagrating on
heating. The basic salt, Sb(02HJ3(OH)N03, is formed by the
decomposition of the oxyiodide with silver nitrate, and forms
a striated crystalline mass which is not deliquescent, though
readily soluble in water.

Triethylstibine Antimonite, Sb(C2H-)3(Sb0.^)j,, is obtained,
together with the oxide, when triethylstibine is slowly oxidized.
In order to prepare it, an ethereal solution of the latter com-
pound is allowed to evaporate by exposure to air. The residue
is then extracted with a mixture of alcohol and ether, and the

* Backton, Quart. Joum. Chem. Soc. xiii. 115.
' Strecker, Ann. Chan. Pharm. cv. 3(J8.
> Ibid,

446 THE ETHYL GROUP.

antimonite obtained aa an amorphous powder, easily soluble in
water and alcohol^

Triethylstibine Sulphide, ^h{0^^^, is formed by dissolving
flowers of sulphur in an ethereal solution of triethylstibine and
evaporating the filtrate. It is also produced by the action of
sulphuretted hydrogen on the oxide, and forms a light crystal-
line mass, having a silver-white colour, and smelling like mer-
captan. It has a bitter taste, is easily soluble in water, and is
decomposed by dilute acids with evolution of sulphurctteil
hydrogen. When boiled with a solution of potassium cyanide,
triethylstibine and potassium thiocyanate are produced, and its
aqueous solution behaves towards metallic salts like potassium
sulphide (Buckton).

Triethyhtihine Thioantimonite, Sb(C,H5)3(SbS2)2, is obtained
as a pale yellow amorphous precipitate when sulphuretted
hydrogen is passed into a solution of the antimonite, and it is
also formed when freshly precipitated sulphide of antimony
containing free sulphur is added to an alcoholic solution of
triethylstibine. Dilute sulphuric acid decomposes it with
separation of antimony trisulphide and evolution of sulphu-
retted hydrogen.

THethyhtihitu Selcniile^ Sb(C2H5)3Se, is formed in an analogous
way to the sulphide, which it closely resembles.

Tetraethylstibonium Compounds.

•

288 These were discovered by R. Lowig,- and termed by him
stibethylium compounds. The point of departure for these is
the iodide obtained by the combination of ethyl iodide with
triethylstibine.

Ti'traethyldihonium Hydroxide, ^h(fjfi^fy^, is obtained by
the action of silver oxide on an aqueous solution of the iodide.
The filtrate is first evaporated on a water-bath and then in a
vacuum, and it leaves the compound as an oily liquid which
does not solidify, is easily soluble in water, has a strong alkaline
reaction, and behaves like caustic potash towards the metallic
salts, &c.

Tetraethylstilxmium Cldoride, Sb(CoHJ^Cl, is obtained by
neutralizing the hydroxide with hydrochloric acid. It crj's-

* C I.<6wiji;, j4nH, Chem, Pharm, IxrxviiL 323.
' Ann. Chrm. Pharm. xcvii. 822.

BISMUTH COMPOUNDS OF ETHYL. 447

tallizes in deliquescent needles, and unites with platinic chloride
and other metallic chlorides.

The bromide is a similar substance, but is not deliquescent.

Tetraethylstibajiium Iodide, Sb(C2H5)J + 3H20, is obtained by
heating ethyl iodide, triethylstibine, and water together to 100".
On slowly evaporating the solution, the compound crystallizes
in hexagonal prisms, but separates out in needles, when a hot
solution is quickly cooled. This compound is always formed as
a by-product in the preparation of triethylstibine.

Other salts of this group have been prepared. They are
crystal lizable, but have not been accurately investigated.

Tctraethylstiboimcm HydrosiUphide, ^h{C'fi^^^y is obtained
by the action of sulphuretted hydrogen on the hydroxide. It
is an oily liquid, misciblc with water, which behaves towards the
metallic salts like potassium hydrosulphidc.

In addition to the above, certain Mcthyltviethylstihonmm com-
pounds have been prepared and examined by Friedlander.^

BISMUTH COMPOUNDS OF ETHYL.

289 Triethylbisviuthine, Bi(C2Hg)3, was obtained by Breed * by
the action of ethyl iodide on an alloy of bismuth and potassium,
and afterwards examined more particularly by Diinhaupt.* It
is a mobile liquid having a specific gravity of 1*82, possessing a
very unpleasant smell, and producing, when inhaled, a burning
taste on the tip of the tongue. Exposed to the air, it evolves
thick yellow fumes, which ignite with a slight explosion. It is
not volatile, but if it is heated by itself it begins to decompose
at 50** to G0°, with separation of bismuth and evolution of a
combustible gas, and when the temperature reaches ISO*' — 160**
a sharp explosion takes place.

Mhyl'Bisinvih Oxide, Bi(C2H5)0, is obtained from the corre-
sponding iodine compound by precipitation with caustic potash as
an amorphous yellow powder, which takes fire on exposure to air.

Ethyl'BismiUh Chloride, 'BiiG^^GU, is formed by the action
of a warm alcoholic solution of corrosive sublimate on a dilute
solution of triethyl bismuthine in alcohol :

Bi(C,H^8 + 2 HgCl, = Bi(C,H,)CIj + 2 Hg(C,H5)Cl.

^ Jaunt, PraJd, Chem. Ixx. 449. ' SilL Journ. [2], xiii. 404.

3 Journ. Prakt. Cliem, Ixi. 399.

448 THE ETHYL GROUP.

On cooling, ethylmercury chloride first separates out, and
then the mother-liquor yields on evaporation small white crystals
of ethylbismuth chloride.

Ethyl-Bismuth Iodide, 'R\{C^^l^ is formed by the double
decomposition of the chloride with potassium iodide. It is
scarcely soluble in water, and crystallizes from alcohol in yellow
six-sided scales.

Ethyl'BismiUh Nitrate, Bi CgHg (NOj^g, is obtained by the
action of an alcoholic solution of silver nitrate on the iodide.
When evaporated on the water-bath, the solution deposits basic
bismuth nitrate, but on evaporating the liquid in a vacuum, a
striated crystalline mass, having an unpleasant metallic taste, is
obtained. This has a smell of rancid butter, and decomposes
with deflagration when heated to 40^

BORON COMPOUNDS OF ETHYL.

290 These compounds, discovered and investigated by Frank-
land,^ have a special interest, inasmuch as they have not only
led to the recognition of the quantivalence of boron, but have
also pointed the way to a new method for determining this
element quantitatively.

TrU'thy/fwrine or Borethyl, 'B{G^^^, is formed by the action
of zinc ethyl on ethyl borate (see p. 367) :

3 Zn(C,H^, + 2 B(0C,H,)3 - 2 B(C,H^, + 3 Zn(OC,H,V

Triethylborine is also formed when the vapour of boron
trichloride is passed into zinc-ethyl.

It is a colourless, easily mobile liquid, having a penetrating
smell. Its vapour acts violently \x\yoii the mucous membrane,
and provokes a copious flow of tears. It boils at 95*, and at 2.T
has a specific gravity of 0*69G1, that of its vapour being 3*400.
Wlien the vapour comes in contact with air, it forms a slight
bluish -white smoke, which when in the dark is seen to be
caused by a lambent blue flame. The li(|uid is spontaneously
inflammable in air, burning with a beautiful green and some-
what fuliginous flame. In contact with oxygen it explodes.

Boron Didhylctharid*-, ^{O^^j^Q^l^, is formed when one
molecule of ethyl borate is acted upon by two molecules of zinc-
ethyl. It is a colourless, mobile liquid, possessing an ethereal

^ Phil. Tttnis. ISdil, jwirt i. p. 107; Proc. Iloy, Sue, xxy, lfi5 (1876).

BORON COMPOUNDS OF ETHYL. 449

smell, and a sharp taste. It boils at 102**, and takes fire on
exposure to the air, burning with a green, slightly luminous
flame. The specific gravity of its vapour is 3'914. In contact
with water it is converted into Boroii I>icthylhydr(xcide,
6(02115)20 H, a liquid which also takes fire spontaneously, and
decomposes on heating ; it has an ethereal smell, and a sharp,
pungent taste.

This latter body slowly absorbs oxygen on exposure to air, with
formation of Boron Ethyl-hydroxethoxide, 'B(pfi^{OC^^O'B.,
a colourless and mobile liquid, which crystallizes about 8**, and
smells like borethyl, and has a sharp taste. On treatment
with water, it decomposes with formation of alcohol and ethyl
boric acid, B(C2H0(OH)2, a crystalline and volatile body, pos-
sessing an intensely sweet taste and a pleasant ethereal smell.
When heated in a current of carbon dioxide to 100°, it sublimes
in splendid crystals closely resembling those of napthalene.
Although the compound has an acid reaction no salts have been
obtained from it.

Boron Etho-diethoxide B(C2H5)(OC2Hg)2,is formed by the slow
action of the air on borethyl. It is a colourless liquid, which
may be distilled under diminished pressure with only partial
decomposition. It is decomposed at once by water with forma-
tion of alcohol and ethylboric acid, which was first obtained in
this way.

jyihoron Eth<ype7Udlioodde, 'B^{0^^{OQ^^^, is formed by heat-
ing two molecules of ethyl borate with one of zinc ethyl. It
is a colourless mobile liquid, having a sweet taste, and a
faint ethereal odour. It boils at 112°, and distils without
decomposition, but its vapour-density, which was found to be
2*78, indicates that its vapour is a mixture of ethyl borate, and
boron ethodiethoxide :

B2(C,Hj)(OC,H,)5 = (CjH,)B(0C2H,), + BCOC^H,),.

Water decomposes it into boric acid, ethylboric acid, and

alcohol.

Ammonio^boric Ethide, B(C2H5)3NH3. Borethyl absorbs
ammonia with avidity with formation of the above compound,
which is an oily liquid, having an aromatic smell and an
alkaline reaction. Carbon dioxide does not act upon it even
in the presence of water, but it is decomposed by ax;ids. Its
vapour-density has not been determined, although that of
ammonio-boric methide has been ascertained, and in this case

VOL. 111. G Q

i50 THE ETHYL GROUP.

tike rafOUT-dtumtj oorresponds to that of a mixture of equal
molecules of its oompouents. From this, as well as from the
Tapoor-demitj of the pentaethylate, it would appear that tziad
boron mav, like the elements of the nitrogen group, occur in
the pentatomic condition. Hence the above compounds in the
liquid state have the following constitution :

Ammoiiio'boroii Methide. Boron«etiiopentethoridf.

H CH, OC.H5 OC^i

aj J J

H— N = B— CH, C,H,— B =- B— OC^

OCA OCA

k k

SILICON COMPOUNDS OF ETHYL.

291 Silicon Tetraethide, Si(C,H5)^ was discovered by Friedel
and Crafts/ and is obtained by heating zinc-ethyl with silicon
chloride to 160^:

2 Zn(C,H^, 4- SiCJ^ - 2 ZnCl, + SiCCjHg)^.

The reaction is complete in three hours, and on opening the
tube a considerable quantity of a gaseous hydrocarbon issues,
which bums with an almost non-luminous flame. The residue,
on distillation, yields silicon-ethyl, whilst zinc chloride and
metallic zinc remain behind. The distillate, which also con-
tains silicon tetrachloride and a hydrocarbon, is treated with
water, dried, and the liquid subjected to fractional distillation.

Silicon-ethyl is a colourless liquid, lighter than water, boiling
at 152"* — 154**, and possessing a specific gravity of 0*8341 (Laden-
burg), whilst the specific gravity of its vapour is 5 13. It is
easily inflammable, and bums with a luminous flame, emitting a
white cloud of silica. It is not attacked either by potash or
nitric acid, and with cldorine it forms substitution products.
In these properties it closely resembles the paraffins. It may,
indeed, be regarded as nonane, C^H^q, in which one atom of
carbon is replaced by silicon, and may therefore be termed
ailico-nonane, or tetraethyl-silicomcthane.

A Bull Soc. Chim. t. 174, 238 ; Ann. CMm. 7%ys. [4], jdz. 834.

SILICON COMPOUNDS OF ETHYL. 451

Silicon Hexethyl or HexethyUsilicoethane, (fifi^^i — Si(C2Hg)3,
IS formed by the action of zinc-ethyl on silicon tri-iodide (vol. i.
563). It is an oily liquid, in smell somewhat resembling silicon
tetraethyl, and boiling at 250"— 253^'

Silico-nonyl Compounds, — The chloride, SiCgHiQCl, is the first
product of the action of chlorine on silicon-ethyl. At the same
time other isomeric compounds are formed, from which the mono-
chloride boiling at 185*^ can only be separated with diflSculty. It
is, however, easy to prepare the corresponding alcohol, inasmuch
as if the portion of the crude product, boiling between 180** and
200^ be heated with potassium acetate and alcohol, the dichlor-
silico-nonane present is alone attacked. An oily liquid separates
out from the contents of the tube on addition of water, and this
is treated with strong sulphuric acid, which leaves silico-nonjl
chloride unattacked. The liquid, which then is still not pure,
and boils between 180** — 190°, is heated to 180** for some hours
with an alcoholic solution of potassium acetate, when the
acetate is formed. This compound boils at 208° — 214°, and has
a faint smell like acetic acid ; and when it is heated with a
solution of potash in dilute alcohol to 120° — 130°, silico-nonyl
alcohol, SiCgHjg-OH, is obtained. This is a liquid insoluble in
water, having a smell like camphor, and boiling at 190.* Sodium
dissolves in this alcohol with evolution of hydrogen, and the
formation of gelatinous sodium silico-nonylate, which is decom-
posed by water into the alcohol and caustic soda.*

SHicO'heptyl Compounds. — When zinc-ethyl is allowed to act

on ethyl silicate, a reaction takes place which, however, soon

ceases. If sodium be added, a violent action begins even at the

ordinary temperature, zinc separating out and a considerable

evolution of gas occurring. The following products are thus

obtained :

B.P.
Ethyl orthosilicopropionate, SiCaH^COCgHg), 166°-5

Diethyl silicon-diethyl-oxide, Si(C2H6)2(OC2H5)2 159*

Ethyl silocoheptyl-oxide, Si(C2H5)30C2H5 155°-5

Silicon ethyl, Si(C2H5), 153*

Silicoheptane, SiCCgH^aH lOr

Silicoheptane or TriethylsUico-methane, Si(Gfi^fi, is the last
product of the above reaction, and is formed, together with

* Friedcl and Ladenburg, Ann, Chim, Phys, [5] xix. 890.

- Friedel and Crafts, Compt, Rend, Ixi. 792 ; Ann, Chem, Pharm, cxzxviii. ID.

O G 2

452 THE ETHYL GROUP.

silicon ethyl, from the ethyl silicoheptyl-ozide, this giving off
oxygen and ethylene. It is a colourless liquid boiling at 107",
having a specific gravity of 07510 at 0**, and possessing a smell
resembling the petroleum hydrocarbons. It is insolahle in
water and in concentrated sulphuric acid, does not undeigo
alteration in the air, and is easily inflammable, burning with
a luminous flame. The specific gravity of its vapour is 4*1.

This compound contains one atom of hydrogen in direct com-
bination with silicon, and Lence this should possess the pn>-
j>erties of the hydrogen in silicon hydride ; and this is, indeed,
the case, for whilst silicon ethyl or silicononane is not attacked
by fuming nitric acid, silicoheptane is oxidized at once with
explosive violence by this acid.

292 Siiicohqyii/l Alcohol ox Tricthi/kUicol, SiiC^^^OH. Tliis
singular compound is of great theoretical interest, as it is the first
example of a silicon alcohol. It is a tertiary alcohol which not
only in its constitution, but also in most of its properties, may
bo considered to be triethyl-carbinol, in which one atom of
carbon has been replaced by silicon. It is obtained by the
action of the corresponding chloride on dilute ammonia ;

Si{(ljr,)3Cl + NH3 -h H^O = SiCC^HjjOH 4- JsH.Cl.

Triethylsilicol is a colourless thick liquid, insoluble in water,
having a strong smell resembling camphor, boiling at 154", and
having a si)ooific gravity of 0*8709 at 0^ and a vapour density
of 4 07. It is easily combustible, burning with a luminous
flame, and leaving a residue of silica. When treated with
fuming suli)liuric acid the following decomposition occurs :

(C^HJ^SiOH + SO3 = C.H^SiO.H + 2 C.H, -f H, + SO^

This oxidation is very similar to that which the tertiary
alcohols undergo. 1 ho silicopropionic acid, which is formed
at the same time, will be described hereafter.

Silicol forms with sodium the very deliquescent compound
(C2Hg)3Si.ONa. If carbon dioxide be passed into an ethereal
solution of silicol, another amorphous delitiuescent compound,
(OjHJjSi.O.CO.ONa, is deposited. Tliis sodium silicoheptyl
carbonate leaves, on ignition, a residue of pure sodium
carbonate :

2 (C JI,)3SiC0,Na = [c'h 'hsi } ^ + ^^^« + NasC03.

ETHYL SILICOHEPTYL OXIDE. 453

Ethyl SUicoheptyl Oxide ) (C2Hg)3Si \ q . , , . , ^^^^^,
or Tridhyldlican Ethylate, ] C^Hg J ^' ^^ ^^^ ^^"^"^ product

of reduction of ethyl silicate. It is a pleasantly smelling
liquid, boiling at 153°, insoluble in water, and undergoing
no change on exposure to air. WTien heated with acetyl oxide
(acetic anhydride) for some time in closed tubes to 250°, the
following reaction takes place :

^^h)^^ I () J. C2H3O I Q _ (€2115)381 ) Q , C2H5 \ ^

C2H5 1 ^ + aH30 J ^ - C2H3O / ^ + C2H3O / ^-

The silicoheptyl acetate thus formed is a liquid boiling at
168°, and having a pleasant ethereal smell, resembling at the
same time camphor and acetic acid. By heating it with a
solution of sodium carbonate it is converted into triethyl-
silicol.

Silicoheptyl Oxide y /n^i i^\^g- \ 0- This ether was discovered

by Friedel and Crafts, and obtained as a by-product in the
preparation of silicon-ethyl.^ It was afterwards obtained by
Friedel and Ladenburg, by acting with zinc-ethyl on silicon oxy-
chloride, SigClgO.^ It is also obtained from triethyl-silicol by
removing from this body the elements of water, either by means
of sulphuric acid or phosphorus pentoxide. It is likewise
formed by the action of caustic potash on silicoheptyl chloride,
and, lastly, by heating ethyl-silcoheptyl oxide with hydriodic
acid :

«> ^1(02X15)3 1 o 4- 2 HI = ^^(^2^5)3 lo4-2r!HT4-HO

It is a thick, colourless, almost odourless liquid, boiling at
231°, and having at 0° a specific gravity of 0*8590.

Silicohejytyl Chlaride, (00115)38101, is formed by heating ethyl
silicoheptyl oxide with acetyl chloride for some hours to 180° :

^^'^0 ^' } O + C2H3OCI = (C2H5)3SiCl + ^2^|p^ } O.

It is a colourless liquid, fuming on exposure to air, and
possessing a penetrating camphor-like smell, and burning with
a luminous green-mantled flame. It boils at 143°*5, has a
specific gravity at 0° of 0 9249, and is slowly decomposed by
water.

* Ann, Chcm. Pharm, cxzzTiii. 19. * Ibid. czlTii. 855.

454 THE ETHYL GROUP.

Silicoheptyl Bromide, (C^^^iBx, Bromine acts violently
on silicoheptane, and hence it must only be added drop by
drop, and the mixture well cooled. The bromide is a liquid
boiling at 161°, and possessing properties analogous to the
chloride.

SiHcon-duthyl Compounds. When equal molecules of ethyl
silicate and zinc-ethyl are heated in a closed tube with sodium
the chief product consists of silicon dicthyl-ether or diethylsiliconr

diethylate, Si(C2R^2i^^2^5)r "^^^^ ^^ ^ pleasantly smelling
liquid, boiling at 155°-8, and having at 0*" a specific gravity
of 0'87o2, and a vapour-density of 602.

When heated with an acid chloride under pressure, the oxy-
ethyl groups are replaced one after another by chlorine. The
compound which is first formed, (C2Hg)2Si(OC2H5)Cl, is a liquid
fuming strongly in the air, boiling between 146** and 148*, and
being slowly decomposed by water. DicthylsHicon diMaride,
(02115)281012, boils at 128** — 130°, possesses a smell resembling
silicon chloride, and, like this compound, fumes in the air, and
is decomposed by water with formation of diethylsiUco-ketone,
(02115)2810. This latter compound, previously obtained by
Friedel and Crafts by the oxidation of silicon-ethyl, is also
formed when silicon-diethyl ether is heated with hydriodic acid :

Si(C,H5),(0C,H,), + 2 HI = Si(C,H,),0 + 2 C,H,I + H,0.

It is a deliquescent syrup, insoluble in water, which can
be distilled at a high temperature without decomposition.
At —15° it does not solidify, and it is a substance possessing few
characteristic properties.

Silicon-monethyl Compounds. The first product of the action
of zinc-ethyl and sodium on ethyl silicate is monethyl silicic ether ^
or orthosilico propionic ether, 02X1581(002115)3. This body was
discovered by Friedel and Ladenburg,* and prepared in a similar
way by the action of zinc-ethyl and sodium upon triethylsilicO'
chloroformate, Si01(OC2H5)3. It is a pleasantly smelling liquid,
boiling at 159**, and having a vapour-density of 6'92. When
heated with acetyl chloride under pressure it forms ethylsUicon
trichloride, 021^581013, a strongly refracting liquid, boiling at
about 100**, which is decomposed by water with violence into
silicopropionic and hydrochloric acids.

C2H5SiCl3 + 2H2O = CjH^SiOjH 4 3HC1.

' Ann, Chem, Pharm. cxiiz. 259.

COMPOUNDS OF ETHYL WITH THE METALS. 466

Silicopropionic acid, which is thus formed, is also produced
by warming ethyl orthosilicopropioDate or diethyl silico-ketone
with concentrated potash. A better plan, however, is to warm
the ortho-ether with concentrated hydriodic acid :

C^jHgSiCOC^H^), + 3 HI = C^H^SiO.OH + 3 C^Hgl + H,0.

It is a white amorphous powder, which on heating becomes
incandescent, leaving behind silica containing finely divided
carbon. The acid is soluble in caustic potash, and is precipi-
tated from the solution either by hydrochloric acid or by sal-
ammoniac.

Ethyl silicate is not attacked at the ordinary atmospheric
pressure when heated with zinc-methyl and sodium. If, however,
ethyl silicate be heated with zinc-methyl gradually to 300** in
closed tubes, ethyl orthosilic(Hicetate, CH3Si(OC2Hg)j, is formed.
This is a liquid boiling between 145** and 151**, and which, when
heated with hydriodic acid, is converted into ortJiosilic(Hicetie
add, CHjSiO.OH, a body which closely resembles orthosilico-
propionic acid.*

COMPOUNDS OP ETHYL WITH THE METALS.

Beryluum Ethide, Be(C2Hg)2,

293 Is formed by heating crystallized beryllium with mercury-
ethyl to 130°. It is a colourless liquid, which fumes in the
air, and takes fire when slightly warmed. It boils at 185° —
188**, and is decomposed by water with violence, beryllium
hydroxide being produced.^

Magnesium Ethide, ^giC^B.^^

Is formed by heating ethyl iodide with magnesium filings to
120** — 130**. It is a colourless, very mobile liquid, possessing
a strong alliaceous odour. It takes fire when exposed to
air, and is violently decomposed by water with formation of
magnesium hydroxide.*

^ Ladenbnrg, Ann. Chem. JPharm, clxxiii. 143.

* Cahours, Compt, Rend. IxzvL

> Cahoara, Ann, Chim. Phya. [8], Iviii. 5.

456

THE ETHYL GROUP.

Zinc Etuide, or Zinc-Ethyl, Zn(C^^^

294 This important compound, which has ah-eady frequently
been mentioned, was discovered on the 1 2th June, 1849, by Frank-
land,' in Bunsen's laboratory in Marburg, at the same time as
zinc-methyl. He obtained it by heating ethyl iodide with an

excess of finely granulated zinc in a strong
tube drawn out to a capillary point, as in
Fig. 89. As soon as the zinc is introduced,
the tube is drawn out, as shown in the
figure, and then it is warmed, and the point
a dipped into ethyl iodide, which, when the
air cools, rises into the tube. This is then
boiled so as to drive out the air, and again
inserted into the iodide, the requisite quantity
of which can then be introduced. The tube
is melted off at the point b, and as soon as
the reaction is complete, the point is softened
in the flame of the blowpipe, and the gases
allowed to escape as gradually as possible.

This method is, however, not adapted for
preparing zinc-ethyl on a large scale, as the
employment of glass tubes of sufficient
dimensions under so high a pressure is
accompanied by considerable danger. Frank-
land, who was then Professor in Owens
College, obtained from James Nasmyth an apparatus of such
strength that the preparation of the substance could be con-
ducted on a large scale without fear of explosions occurring.

This apparatus although not now used in the manufacture
of zinc-ethyl merits description as having done good service,
and being of historical interest. It consists of a tube of wrought
copper (a, Figs. 90, 91) 45 cm. in length and 3 cm. internal
diameter, the sides being 1*25 cm. in thickness. This tube
is closed at bottom by a screw-plug, and is furnished at top
with a brass flange {b b), which can be closed by the brass cap
(dd), which screws on to a lead collar. A stopcock placed in
the position of the screw-plug (c) serves as an outlet for the
generated gases or fur distilling off the liquid formed. This
digester is heated by means of a cylindrical oil-bath (Figs. 92
and 93) heated by a suitable gas-lamp.

» Chem, Soc, Joum, iL 2»7 ; Phil. Trans, cIxt. 259.

Fio. 89.

ZINC ETHIDE.

457

An equal volume of auhydrous ether was added by Franldand
to the ethyl iodide, as this accelerates the reaction, prevents
the formation of large quantities of gaseous products, and largely
increases the yield of zinc-ethyl (Brodie).^

Pebal * afterwards found that zinc which had been once acted
upon by ethyl iodide, or which had been washed with sulphuric
acid, attacked the iodide under the ordinary atmospheric pres-
sure, Rieth and Beilstein ^ employed in place of zinc an alloy
of this metal with sodium, obtained by heating 4 parts of zinc
to the boiling-point and then adding 1 part of sodium, the

Fig. 90.

Fig. 91.

whole being well mixed, poured out, and when cold the outer
layer cut off, and the last traces of free sodium being got rid of
by washing with water. It is not necessary in this case to add
ether. Beilstein and Alexejeff* afterwards noticed that the
reaction takes place easily when a mixture of one part of this
alloy is heated with 8 parts of zinc turnings and 10 parts of

^ Joum, Chcm, Soc. iiL 409.

* Ann, Chcm, Pharm. cxviii. 22 ; cxx. 194 ; cxxi. 105.

* Ann, Chcm, Pharm, cxxiii. 245 ; cxxiv. 248.

* Zeitsch. Chem, 1864, 101 ; BuU, Soc Chim, [2], ii. 51.

THE ETHYL GROUP.

ethyl iodide. Wichelhau3 ' found that the addittoa of the alloy
is not necessary, and recotnmeDds zinc to be used in the form
of coarse tilings. Chapman ^ has shown that the reaction takes

place more quickly if to the mixture a small quantity of dno-
eth;l be added.

In order to prepare zinc-ethyl according to one of the latter-
mentioned metliods the apparatus Fig. 94 is used, aJready de-
scribed under Zinc-methyl (see p. 248). This is filled with carbon
dioxide, and aliut o£F at C with a small quantity of mercury.
It is heated in a water-bath so long as the iodide of ethyl ia
condensed in the receiver, and continues to run back into the
flask, this process generally lasting from two to three hours.
The gases which are continually evolved escape through the

short column of mercury. They consist, according to Beilstein
and Rieth, of a mixture of ethane, ethylene, and butane,
formed by the action of iodide of ethyl on the zinc-ethyl, and
their quantity is considerably increased if the zinc is not
present in excess. In order to carry out the operation success-
fully it is absolutely necessary that no trace of moisture shall
be present either in the materials employed or in the apparatus,
as othei-wise the reaction is much retarded. Extraordinary
care, therefore, in freeing the materials perfectly from mobture

460 THE ETHYL GROUP.

is amply repaid in the increased quantity of the product
(Frankland). When the reaction is complete, the flask con-
tains a solid mass consisting of excess of zinc together with a
compound of zinc-ethyl and zinc iodide, having the composition
Zn(C2H5)I. The flask is then connected with the upper part
of the condenser, and placed in a paraffin- or oil-bath, a current
of carbon dioxide being led in through the stopcock A, and the
zinc-ethyl which distils over being collected in a vessel provided
with a mercury valve. The whole must be at last heated to
180** in order to decompose the above-mentioned compound :

The method proposed by Gladstone and Tribe ^ for the
preparation of zinc-methyl (p. 246) is also recommended for that
of zinc-ethyl, as the following experiment shows. Ninety grams of
zinc fllings and 10 grams of reduced copper are placed in a flask
of 300 cc. capacity, and heated over the flame of a ]^unsen s
burner for about five minutes until the whole consists of dark-
grey small granular masses, care being taken not to heat the
metals so as to form an alloy. The mass is then allowed to cool,
and 87 grams of ethyl iodide added, and the whole warmed in
connection with a reversed condenser to 90^ when in a few
seconds the reaction begins, and is completed in fifteen minutes.
On heating in the oil-bath, in an atmosphere of hydrogen, the
distillation of zinc-ethyl began at 160®, and after an hour the
whole had passed over. In this way 31 grams was obtained
instead of the calculated quantity, 34*3, or 90 4 per cent, whilst
in the older operations not more than 80 per cent, of the quantity
is obtained.

An improved method of preparation now employed in
Professor Frankland's laboratory is first to heat the zinc filings,
after they have been washed with acid, stroDgly in a glass
flask, so as to decompose all the hydroxide. Next, to add an
equal weight of ethyl iodide and a single crystal of iodine, and
heat gradually to about 90** with a reversed condenser. As
soon as no ethyl iodide is seen to run back, the whole is allowed
to cool, and a bent tube is attached to the flask, the zinc-ethyl
being distilled from an oil-bath. In this way zinc-ethyl can
be easily prepared in any quantity.

Properties, Zinc-ethyl is a colourless, mobile, highly re-

* Joum, Ch4m. Soe, 1879, L 671.

ZINC-ETHYL COMPOUNDS 461

fracting liquid, possessing a peculiar but not unpleasant smell,
boiling at 118**, and having a specific gravity of 1*182 at 18".
It takes fire at once on exposure to air, burning with a luminoiis
green-mantled flame and evolving dense white fumes of zinc
oxide. If a porcelain capsule be held in the flame, a black
spot of metallic zinc is formed, surrounded by a deposit of the
white oxide. Zinc-ethyl takes fire instantly in chlorine, burning
with a pale smoky flame. When brought in contact with bromine,
a violent explosion occurs ; but when the action is moderated,
ethyl bromide and zinc bromide are formed. Iodine acts in a
similar way, and if ether be not employed as a diluent a violent
decomposition takes place with evolution of light and heat.

Zixc-Ethvl COMrOUNDS.

295 ZinC'EthyUEthoxride, C^^ZnifiGfi^. When dry oxygen
is passed into an ethereal solution of zinc-ethyl it is absorbed,
and the vessel becomes filled with thick white vapours, which
disappear as soon as one atom of oxygen has been employed for
every molecule of zinc-ethyl. The compound, which is in-
soluble in ether, has not been accurately studied. It appears
also to be formed by the action of zinc-ethyl on absolute alcohol*
Water decomposes it according to the following equation ;

^° { O'^k + 2 H,0 = Zn I gg + HO.C,H, + C,H,.

By the further action of oxygen on the ethereal solution of
zinc-ethyl, zinc-cthoxide or zhic didhylate, Zn(OC2H5)2.^ a com-
pound already mentioned, is formed as a white powder, which
is decomposed by water with evolution of gas.

Zinc-amine. If dry ammonia be passed into an ethereal solu-
tion of zinc-ethyl, ethane is evolved, and zinc-amine, Zn(NH2)2,
is produced in the form of a white amorphous precipitate :

Zn{g;g; + 2NH3=Zn{^H^ + 2C,H,.

Water and alcohol decompose this compound instantly, with
formation of ammonia. When heated with ethyl iodide to 150*
diethylammoniumiodide is produced. At a red-heat zincamide
decomposes into ammonia and zinc-nitride, NgZuj, a grey non-
volatile infusible powder, which decomposes water with forma-
tion of ammonia with such energy that it becomes red-hot on
being moistened.

* Lissciikc, Zcitsch. Chcm 1864, 678. ' Frankland, Phil. Trans, 1855, 267.

462 THE ETHYL GROUP.

If zinc-ethyl and diethylamine be heated together, zinc-
di ylamine^ Zn j ^(C^H*)*' ^ produced, and is a body re-
sembling zincamine in properties.

Sodium Ethide.

296 If one part of sodium and 10 parts of zinc-ethyl be brought
together at the ordinary temperature, the sodium dissolves after
some days completely, and an equivalent quantity of zinc is
precipitated. On distiUing off the excess of zinc-ethyl from the
clear thick liquid in a current of hydrogen, the compound,
NaCjHg 4- Zu(Cfi^^ is obtained in crystals melting at 27*. All
attempts to prepare pure sodium-ethyl from this have as yet
proved unsuccessful. When gently warmed, decomposition takes
place, zinc and sodium remaining behind and hydrocarbons
being evolved. If the compound be heated with sodium in the
water-bath it also decomposes easily. On exposure to air it at
once takes fire, burning with almost explosive violence.' If
ethyl iodide be added to its solution in zinc-ethyl, the following
reaction takes place :

NaCjHg + C,H,I =1 Nal + C^H, + C^He-

This explains why sodium-ethyl is not produced when
sodium is heated with ethyl iodide, as this substance, when
formed, is at once decomposed by the excess of ethyl iodide
according to the above equatioD.*

Sodium ethide absorbs dry carbon-dioxide with formation of
sodium propionate (Wanklyn). Potassium acts on zinc-ethyl
even more powerfully than sodium does, a double compound
analogous to the preceding being obtained.

Cadmium Ethide, CdCC^Hg)^

Is formed by heating cadmium with ethyl-iodide, when the
compound of the metallic iodide with cadmium-ethyl is obtained,
and this is decomposed at a temperature between ISO"" and 220^
at which temperature, however, the cadmium-ethyl undergoes
partial decomposition. It is a colourless liquid, resembling zinc-
ethyl, is spontaneously inflammable, and bums with the evolution
of brown fumes.^

^ Frankland, I^roc Roy. Soc yiii. 602.

« M'anklyn, Phil. Mag, [4], XTii. 226.

• Frankland, Prce. Roy Soe. ix. 845.

« Wanklyn, QuaH. Joum, Cktm. Soe, iz. 193.

MERCURY ETHIDE. 463

Mercury Ethide, B.giCJi^)^

297 Was first prepared by Buckton,^ by the action of mercuric
chloride on zinc-ethyl. It is now obtained by a much more
simple reaction, according to the method of Frankland and
Duppa.^ For this purpose a mixture of one part of ethyl acetate
and ten parts of ethyl iodide is shaken up with sodium amalgam
containing 0*2 per cent, of the former metal :

Hg + Na, + 2 aH,I = Hg(C,H,)2 + 2 Nal.

In this case the flask must be dipped frequently into cold
water, in order that the temperature may not rise too high.
When a sufficient quantity of sodium iodide has been formed
to render the mass thick, the acetic ether is distilled off from a
Avater-bath, together with the excess of ethyl iodide, and this
mixture used for a second operation. Water is then added to
the residue. The mercury ethide which separates out is
separated from the liquid and treated with alcoholic potash,
washed with water, dried over chloride of calcium and rectified.
The part which the acetic ether plays in this reaction is not
understood. No reaction takes place, however, unless it be
present, even when ethyl-ether is used. On the other hand, the
othyl acetate may be replaced by ethyl formate or methyl acetate.
None of these ethers appear to suffer any alteration, and it is,
moreover, remarkable that this reaction takes place the more
readily the smaller the quantity of sodium present in the
amalgam. Mercury ethide is a colourless liquid, having a
peculiar but not unpleasant smell, boiling at 159**, and having
a specific gravity of 2*444, that of its vapour being 9*97. It
is easily inflammable, burning with a luminous flame, and giving
off vapours of mercury. It is poisonous, but acts much less
•violently than mercury methide, inasmuch as it is less volatile.

At the ordinary temperature sodium acts slowly on mercury
ethide, giving rise to a grey spongy mass which takes fire on
exposure to air, and explodes under the most trifling change
of condition. When gently warmed, it yields a mixture of
ethane and ethylene, from which it would appear that this body
contains sodium-ethyl (Buckton ; see p. 462).

When mercury ethide is heated in a closed vessel with granu-
lated zinc to 100**, it is completely converted into zinc-ethyl.
Cadmium acts only slowly and incompletely on it. Bismuth,
on the other hand, acts on it somewhat easily with formation

of triethyl-bismuthine.

' Joum, Chcm. Soc, xvL 17. ' Joum, Chem. Soe, xvi. 415.

ALUMINIUM-ETHYL. 4G5

it yields butane, or its products of decomposition, and mercury
iodide.

Merciiry-Ethyl SidplMte, (C2H5Hg)2SO^, is formed, together
with pure ethane, by the action of concentrated sulphuric acid
on mercury-ethyl. It crystallizes from alcohol in silvery-white
scales (Buck ton).

Mercury-Ethyl Nitrate, CgHjHgNOg, is obtained by acting
upon the base wdth nitric acid, as also by the decomposition
of the iodide with silver nitrate. It is easily soluble in water,
less so in alcohol, and crystallizes in transparent prisms, which
on heating decompose with slight deflagration.

Mercury-Ethyl Cyanide, CgHjHgCN, is obtained by saturating
the hydroxide with alcoholic hydrocyanic acid. It deposits
in large crystals which are very volatile and when heated emit
an intolerable odour. The vapour violently attacks the
mucous membrane, and the compound appears to be very
poisonous.

Mercury-Ethyl Sulphide, {O^^g)^, is precipitated in the
form of a yellowish-white powder by the action of ammonium
sulphide on an alcoholic solution of the chloride. It is soluble
in an excess of the precipitant as well as in ether, and, when
the ether is allowed to evaporate, separates out in the crystalline
form.

In addition to the above, many other mercury-ethyl compounds
have been prepared.

Aluminium-Ethyl, A1(C2H5),.

299 The first observations on this compound were made almost
simultaneously by Cahours ^ and by Hallwachs and Schafarik.2
It is, however, to the investigations of Buckton and Odiiug'
that we owe our more exact knowledge of this body. It is
obtained by heating mercury-ethyl with aluminium foil to 100°.
A colourless liquid is thus obtained, which fumes in the air, and
even takes fire w^hen exposed to the air in thin layers, burning
with a bluish-red-mantled flame. The compound boils at 194°,
and the specific gravity of its vapour at 234° is 4 5, whereas
that corresponding to the above formula is 39. Hence it would
appear this body does not possess a constitution similar to
that of aluminium chloride. Water decomposes it with great

* Ann. Chim. Phys. [3], Iviii. 6. • Ann. Chcm, Pharm. cix. 206.

' Proc. Bfiy Sor. xiv. 19.

VOL. III. H H

460 THE ETHYL GROUP.

violence ; iodine converts it into ahiminium-cthyl iodide^
AlgCCgHg^glg. This compound can also be obtained by heating
aluminium with ethyl iodide. It is a colourless, unpleasantly-
smelling liquid, fuming in the air, and boiling at 340"* — 350°,
and being likewise decomposed by water.

When dropped into a vessel filled with oxygen or chlorine it
takes fire, burning with a violet light.

Compounds of Lead with Ethyl.
300 Of these two are known :

Lead Tetraethyl. Lead Triethyl.

The formula of the first of these compounds points out that
lead acts as a tetrad element towards the positive elements or
radicals. In its compounds with the negative elements, how-
ever, it acts as a diad, as is shown by the fact ascertained by
Roscoe,* that the vapour-density of lead chloride corresponds to
the formula PbClg. In lead-triethyl, on the other hand, two
atoms of metal are connected together by one combining unit.

Lead-Tdraethyl, Vh(f^^^^, is formed, together with lead tri-
ethyl, by the action of ethyl iodide on an alloy of lead and
sodium. It may be more readily obtained in the pure state
by treating zinc-ethyl with lead chloride.* Frankland and
Lawrance* recommend the following plan. Dry lead chloride
is added to zinc-ethyl, contained in a thick glass vessel, until no
further action takes place, the whole being stirred with a glass
rod. Metallic letitl then separates out in a s{)ongy form :

2PbCl, + 2Zn(C2Hj2 = PKf'2H5)4 + Pb + 2ZnCl^

The product is carefully mixed with water, and subjected to
distillation.

Lead-tetraethyl is a colourless, slightly smelling liquid, having
a specific gravity of 1*62^ and boiling at about 200** with partial
decom|x>sition and separation of lead. Lender a pressure of
11)0 mm. it may be distilled without decom{)osition at 152^
and it may also be volatilized in a current of ste^im without

^ Proc. Roy. Soc. xxvii. 426.

' Hurkton, Chui. Uaz, 1858, 415 ; Pmc. Rmf, !\oc, ix. C85 ; Cahours, Ann.
Chim. Vhys. [«]. Ixii. 257.
• Joum. rhtm Stw. isri). i •JH.

LEAD-ETIIYL COMPOUND& 4G7

the slightest decomposition occurring. It is easily inflammable,
burning with an orange-coloured, blue-mantled flame, emitting
clouds of lead oxide. It is not attacked by ammonia, carbon
dioxide, carbon monoxide, cyanogen, oxygen, nitric acid, or
sulphuretted hydrogen ; but it absorbs sulphur dioxide quickly,
with formation of diethyl-sulphone and lead-diethyl sulphonate
(Frankland and Lawrance) :

PKCjHs), + 3S0, = (C,H^,SO, + (C,H,.SO^,Pb.

Weak acids do not act upon it. Concentrated acids, on
the other hand, decompose it with formation of lead-triethyl
compounds and ethane.

Lead'Triethyl, V\{C^^q^ is easily formed by the action of
ethyl iodide on an alloy of lead and sodium.^ For its prepara-
tion the best mode is that suggested by Klippel.^ Three parts
of lead are fused in a crucible, which is then withdrawn from
the fire, and one part of sodium added, the whole being stirred.
The crucible is then filled with sand, and allowed to cool slowly.
In this way a fine crystalline alloy is obtained, and this, having
been finely powdered, is placed in a flask connected with an
inverted condenser, the mass having been previously moistened
with ethyl iodide. A violent reaction takes place, and lead-
triethyl is formed, which is then extracted with ether.

Lead-triethyl is a mobile liquid insoluble in water, only
slightly soluble in alcohol, but readily so in ether, having a
specific gravity at 10" of 1*471. Heated alone it undergoes
decomposition, but it volatilizes slightly in an atmosphere of
ether. The vapours of this body attack the mucous mem-
branes with great violence, exciting a flow of tears (Klippel).
On exposure to light, as well as on heating with .water, it
decomposes with separation of lead.

Lecul'Ethyl Coinpmtiids. If iodine be slowly added to a solu-
tion of lead-triethyl in alcohol and ether, the unstable iodide,
(C2H5)3PbI, is formed, and this, when treated with freshly
precipitated oxide of silver, yields Icad-cthyl hydroxide^
{C^^^hOU, This hydroxide is also obtained, according to
Cahours, by the distillation of the chloride with solid caustic
potivsh. The oily distillate solidifies after some time to a crystal-
line mass, possessing a slight but peculiar odour provocative
of sneezing. It is slightly soluble in water, and easily so in

^ I-owig, Joum, Prdkt, Chcm. Ix. 304.
- Jonrn. Prakt. Chcm. Ixxxi. 287.

H n 2

468 THE ETHYL GKODP.

alcohol and ether. Its solution has a strono: alkaline reaction
and a sharp caustic taste, giving rise to an unpleasant sensation
in the throat. Like caustic potash, it saponifies fats, and, even
at the ordinary temperature, it is slightly volatile, and for this
reason it produces white fiimes when brought into contact with
hydrochloric acid. It decomposes ammouiacal salts, and pre-
cipitates the salts of many metals.

Lead'Eihyl Chloride, (C2Hj3PbCl, is obtained by heating lead*
tetraethyl with hydrochloric acid :

(C^HJ.Pb + HCl = (C^HJjPbCl + C^H,.

If the action be continued too long a further decomposition
occurs, and lead chloride is formed (Cahours). Lead-ethyl
chloride is easily soluble in alcohol and ether, crystallizing in
long bright needles, which when warmed emit a mustard-liko
smell, and when more strongly heated decompose with detonation.

Lead-Ethyl Sulphate, [(C^HJjPbJ^SO^, is obtaineil by the
action of dilute sulphuric acid on the solution of the base.
It is a white precipitate, which is only slightly soluble in water,
but dissolves in alcohol if free sulphuric acid be present, and
crystallizes from this solution in hard glistening octohedrons.

Lead-Ethyl Nitrate is formed when an ethereal solution of
lead-triethyl is brought in contact with an alcoholic solution of
silver nitrate :

(aHJ.Pb, + 2 AgN03 = 2 (C,H^3PbN03 + 2 Ag.

The nitrate remains on evaporation as a thick liquid, having
a butter-like smell. This on standing solidifies to a saponaceous
mass, which detonates on heating.

Lead-Ethyl Carbonate, [(02H^)3Pb]2C03, is obtained in small
hard glistening crystals by allowing the alcoholic solution of the
base to evaporate spontaneously. It is scarcely soluble in water,
has a strong burning taste, and can be recrystallized from ether.

Lead- Ethyl Cyanide, {C^^^hC^, is formed by heating the
chloride with alcohol and potassium cyanide in closed tubes to
100^ It forms a blood-red liquid, which on the addition of
water yields a white precipitate, and this can be obtained crys-
tallized in fine prisms from an ethereal solution.

Lead-Ethyl Thiocyamte, (C^jHJjPbSCN, is prepared by heat-
ing the chloride with silver thiocyanate. It is soluble in water,
alcohol, and ether, and crystallizes from the last solvent in prisms
resembling those of potassium thiocyanate.

COMPOUNDS OF TIN WITH ETHYL. 469

In addition to the salts of lead-ethyl above described, other
compounds with both inorganic and organic acids liave been
prepared.

Compounds of Tin with Ethyl.

301 The following compounds of tin and ethyl are known:
(1) (2) (3)

Tm-Tetraethyl or Tin-Triethyl or Tiu-Diethyl or

Stannic Ethide, Stiinnoso-Stannic Ethide. StHnnoos Ethidc.

SnCC^H^, Sn/O^H,)^ Sn,(C,H^,

Of these the first corresponds to tin tetrachloride, and the last
to tin dichloride. As the molecular formula of the last-named
substance has been shown by Victor Meyer ^ to be SuoCl^ from
its vapour-density determination, we must assume that in the
stannous compounds the two atoms of tin are connected by
double linkage, whilst in the triethyl compounds a single link-
ing only exists.

Tin-Tdraethyl or Stannic Ethide, Sn(CoHg)^, is obtained
by the action of zinc ethyl on tin tetrachloride,- tin-triethyl
iodide, or tin-diethyl di-iodide.^ It is, however, best obtained
by gradually adding fused anhydrous stannous chloride to zinc-
ethyl, until the latter has been almost completely decomposed.
The mass is then distilled in an oil-bath, the liquid distillate
treated with water and dilute sulphuric acid, washed with
water, dried, and rectified over chloride of calcium.* In this
process tin-diethyl is first formed, but this easily decomposes,
as Cahours has shown, into tin and tin-tetraethyl.^

Stannic ethide is a colourless liquid, having a slightly ethereal
odour, boiling at 181°, possessing a specific gravity of 1*187,
while that of its vapour is 8021 (Frankland). It is very in-
flammable, burning with a luminous blue-mantled flame, and
emitting clouds of stannic oxide. In oxygen it burns with
a very bright white flame. Neither sodium, magnesium, nor
aluminium acts upon it at its boiling point ; nor is it attacked
in the cold either by ammonia, carbon dioxide, carbon monoxide,
cyanogen, nitric oxide, oxygen, or sulphuretted hydrogen.

Tin- Triethyl or Stannoso-Stannic Ethidc, Sug^CgHg)^ is

' Bfr. Deutsch. Chem. Ges. xil. 1195.

2 Buckton, Phil. Trans. 1859, 426. > Buckton. ift. 424.

* Fmnkland and Lawrance, Joum. Chevx, Soc. 1879, i 130.

* Ann. Chrin. Phann. cxiv. 227 and 354.

TIN-TRIETHYL COMPOUNDS. 471

small quantity of alcohol. The reuidue Is then purified by
distillation.

Tin-triethyl iodide ia a colourless liquid Itavingaveryptuigeat
smell. It boils at 235° — 238°, and at 22° has a specific gravity of
1833. It forms a crystalline mass vrhen cooled in a mixture
of ether and carbon dioxide. It combines with ammonia to
form tin-friethi/l-aiitinoniuni-iodide, (CjHj)jSnNHgI, a compound
soluble iu water and alcohol, and crystallizing in long prisms.
On heating this melts, and may be sublimed in fine crystals.
It has a strong pungent and ammoniacal smell, and ia
(lecomi>osed by boiling water. The iodide also forms similar
compounds with the monajnines.

Tin-trieOiyl SuliiluUe, (G^HJoSnaSO^, is obtained by neutral-
izing the oxide with sulphuric acid or decomposing the iodide
with silver sulphate. It ia slightly soluble in water, and crys-
tallizes from alcohol in glistening colourless prisms. This
compound is also formed by the action of sulphur dioxido on
tin-t«t methyl in presence of air. At the same time Tin-trietkyl
ethyl sielphonate, (GjHJjSnSOjCjHj, is produced, and forms an
oily liquid (Frank land and Lawranco).

The nitrate ia obtained as a syrup by evaporating ita aqueous
solution. Indistinct crystals may also be obtained.

Tin-triethyl Cyanide, (CjH5)jSnCN, is obtained by warming
the iodide with silver cyanide. It aublimea as a snow-white
ninss,or crystallizes in thin uee<nes. It crystallizes &om alcohol
in silky elastic prisms.

Tin-triethyl Cyanate, (CjH5)jSnOCN, is obtained by warming
the iotlide with silver cyanate in presence of alcohol. It
crystallizes in thin prisma, and produces compound-ureas, with
ammonia an<l the amines. That obtained by the action of
ammonia, which yields a well crystallizable oxalate, has the
composition, CO | gH,^^^^^^^^

Tin-triethyl Tkiocyanate, \C^^)^a^G:^, is formed by the
decomposition of the iodide with silver thiocyanate, and crystal-
lizes in colourk'sa prisms from alcohol.

Tin-triethyl Hydrosulphidc, (CjHJjSnSH, ia produced by the
action of sulphuretted hydrc^en on an alcoholic solution of
the oxide, and it crystaUizes on evajjoration. If an equivalent
quantity of the hydrate bo added to its solution, the
formed, which is k'ft behind as an oily liquid on evapj
tlie alcohol.

le si^^ll^s

ACETYL C0M1»0UNDS. 473

^n addition to these, various other salts have been prepared.

Hcthyl Sulphide, (C2H5)2SnS, is a whit« powder precipi-

^y sulphuretted hydrogen from a solution of one of its

'". is insoluble in dilute acids and ammonia, but dissolves

»iig hydrochloric acid, caustic potash, and the sulphides

iho alkali metals. In the dry state this body has a most

disagreeable smell, resembling that of decomposing horse-radish.

A peculiar compound having the composition (OjHJ^Snglj

is formed amongst the products of the action of tin on ethyl

iodide, and is obtained, according to Frankland, by treating tin-

diethyl-dimethyl with iodine. It is a heavy oily liquid, having a

strong smell resembling mustard- oil, and acting very injuriously

on the lungs. Tliis compound requires further investigation.

TlIALLIUM-DIETHYL COMPOUNDS.

304 ^Vhen an ethereal solution of thallium trichloride acts on
zinc-ethyl, thallium-diethyl chloride, (C2H5)2T1C1, is produced,
and this crystallizes from hot water in glistening scales. A
series of crystalline thallium-diethyl salts are obtained from
this by double decomposition with silver salts. If the easily
soluble sulphate be decomposed by caustic baryta, thallium-
diethyl hydroride is obtained, crystallizing from hot water in
fine silky glistening needles, having an alkaline reaction, and
decomposing at 211** with explosive violence.^

ACETYL COMPOUNDS.

305 Aldehyde or AcHaldehyde, C2H^G. In his memoir on oxide
of manganese, published in 1774, Scheele mentions that if this
oxide be placed in a closed flask, together with strong rectified
spirit of wine and vitriolic or muriatic acid, and the mixture
distilled at a moderate temperature, the alcohol which passes
over possesses the smell of nitric ether. On the other hand,
in his treatise on ether, published in 1782, Scheele states that
if alcohol be distilled with sulphuric acid and black oxide of
manganese, ether is first obtained, whilst ^Hn^tbe end of the

' Hansen, Bcr. D^utsch. Ch^m, Gcs. iii. 0 ; ^^^^^^^^fhem, Ph<irm,
clxxvi. 257.

474 THE ETHYL GROUP.

operation acetic acid passes over. Other chemists made observa-
tions of a similar character. Thus, Dabit, in the year 1800,
recommended, for the preparation of ether, the addition of black
oxide of manganese to a mixture of sulphuric acid and alcohoL
He explained the formation of ether from alcohol by the
removal of a part of the hydrogen and its oxidation to water, and
not, as Fourcroy and Vauquelin had shortly before suggested,
by the removal of the elements of water. In the same
year the last-named chemists repeated Dabit's experiments,^ and
found that the ethereal liquid thus produced is distinctly
diflferent from common ether, possessing a smell resembling
that of ordinary nitric ether. Their views with regard to tho
relation of this body to alcohol are remarkable. "In this opera-
tion," they say, " the alcohol does not lose any carbon but only
a portion of its hydrogen, which combines with the oxygen of
the black oxide of manganese." Hence they conclude that the
liquid obtained in this way contains more carbon and oxygen
and less hydrogen than alcohol. From their statements it is
clear that the body which they examined was a mixture of
several compounds. This product was, at the time, not further
investigated, and it was not until 1828 that Dobereiner, studying
the action of oxidizing agents upon alcohol, observed the occur-
rence of a peculiar liquid to which he gave the name of oxygen-
ether. This he prepared by the action of a mixture of alcohol
and sulphuric acid upon either potassium chromate, potassium
nianganate, or manganese dioxide. At tho same time Gay-
Lussac stated that the body possessing the peculiar suffocating
odour which had before been noticed was a mixture of alcohol,
ether, and oil of wine. In the following year Dobereiner ex-
pressed the opinion that in tho oxidation of alcohol two
substances are formed, a heavy and a light oxygen-ether, the
latter differing from common ether, as he had found in 182J^,
not only by its peculiar smell, but also inasmuch as it is converted
into a resin when heated with potash. He also showed that a
liquid possessing similar properties may be obtained by tho
action of platinum bhick on alcohol. Various chemists now
investigated this subject without coming to a satisfactory con-
clusion. They, however, proved that the heavy oxygen-ether,
obtained by the action of sulphuric acid and manganese
dioxide, mainly consists of oil of wine. The boily obtjiined by
tho action of ])latinum black was found to contain a compound to

* S'.ir IVtluT |nv|>jiiv k la inaniert' ilu ritoym l)al»it, Jmi. dc Chi/niCf xxziv. 818«

ACKTALDKTIYDE. 476

which Liebig gave the name of acetal (to be hereafter described).
In addition, however, to acetal, the product contains a still more
volatile liquid possessing a pungent smell, and this is the cause
of the production of the brown resinous mass formed by the
action of caustic potash. Liebig then pointed out the peculiar
power of reducing silver salts which this substance possesses, and
Dobereiner observed that this same body is produced by the
action of nitric acid upon alcohol, thus accounting for the
fact that it always occurs in crude so-called nitric ether (ethyl
nitrite). He next showed that the body thus obtained possesses
the power of forming a crystalline compound with ammonia,
and three grains of this compound were sent by its discoverer
to Liebig, and it was the examination of this preparation
which led to the true explanation of this somewhat compli-
cated subject. Liebig proved that in the first act of oxidation
alcohol loses two atoms of hydrogen, as Dobereiner had sup-
posed, giving rise to the above-mentioned volatile liquid, for
which he proposed the name of alcolwl - dehydroyenatum or
aldehyde}

Aldehyde is not only formed by the action of various
oxidizing agents, such as chlorine, upon alcohol, ether, and
other ethyl compounds, but is also produced when the vapours
of these bodies are passed through a red-hot tube, a variety
of other compounds being formed at the same time.

306 Preparation, — Liebig gives the following directions for the
preparation of aldehyde : A mixture of 4 parts of 80 per cent,
spirit, 6 of manganese dioxide, 6 of sulphuric acid, and 4 of
water is distilled. When gently warmed the mixture begins
to froth slightly, and the aldehyde, together with alcohol and a
few other products, passes over. The process is interrupted as
soon as the distillate begins to redden litmus, which is usually
the case when 6 parts of liquid are contained in the receiver.
The distillate, consisting of aldehyde, alcohol, &c., is mixed with
an equal weight of calcium chloride and again distilled, the
receiver being kept very cold. After 3 parts have passed over
the distillate is again rectified with an equal weight of calcium
chloride until \\ parts have passed over. This last portion
is anhydrous, but the aldehyde contains alcohol and certain
compound ethers. For the purpose of purification one volume
of this liquid is mixed with two volumes of ether, the mixture
surrounded by cold water, and dry ammonia gas passed in to

* Ann, Pharm. xiv. 133 ; xxii. 273.

476 THE ETHYL GROUP.

saturation. The gas is rapidly absorbed with great evolution of
heat, and crystals of aldehyde-ammonia separate out. These
crystals are washed three times with absolute ether and dried.

The preparation of the aldehyde from this compound is very
easy. The aldehyde-ammonia is dissolved in its own weight of
water, the solution brought into a retort, and 3 parts of sulphuric
acid previously mixed with 4 parts of water added. On
gently warming this in the water-bath the aldehyde is evolved
with frothing. The distillation is stopped as soon as the water
in the water-bath begins to boil. The hydrated aldehyde which
passes over is then dried by rectification over an equal bulk of
calcium cliloride in coarse lumps. Heat enough is evolved by
the combination of the calcium chloride with the water to raise
the liquid to the boiling-point, so that good condensation is
required from the very beginning. The distillate thus obtained
is mixed with pounded chloride of calcium and again distilled
from a lukewarm water-bath at a heat not exceeding 30**.

Stadeler ' recommends the use of potassium dichromate in
place of manganese for the oxidation. Fifteen parts of this salt
are brought into a large retort standing in a freezing mixture
and connected with a spiral condensing-tube surrounded with
water having a temperature of 50^ A cold mixture of 10 parts
of alcohol and 20 parts of sulphuric acid, previously diluted with
three times its volume of water, is then poured on to the broken
pieces of dichromate, the freezing mixture removed, and the
vapours of aldehyde which come off condensed in the cylinders
(', c, Fig. 95, partly filled with ether and surrounded by a freez-
ing mixture. At the end of the operation the retort requires
to be slightly warmed. The ethereal solution is then treated
with ammonia in the way already described, and the aldehyde
regained from the aldehyde-ammonia, which has the empirical
formula Cgll^O.NIIj, by the above-mentioned method.*

Aldehyde is obtained on the large scale as a by-product in the
manufacture of spirit, where it comes over with the first runnings
(see p. 294), and may be obtained perfectly pure by the use
of a rectifying column.*

It may also be cheaply obtained and in quantity by the action
of ozonizeil air upon alcohol, and is likewise formed by the dry
distillation of a mixture of the calcium salts of acetic and formic
acids :

* Joitrn. Pral'i. Chnn. Ixxvi. r»4.
^ lltnniDW, /Ciifir. Chfm. Intl. ii. 27r».

PBOPEBTIES OF ALDEHYDE.

I
CO

I
OH

CH„
I
C^O

[

307 Properties. — Acetaldehyde ia a colourless, easily mobilo
liquid, boiling at 20°8, and having at 0° a specific gravity of 0*8009
(Kopp). Its vapour density was found hy Liebig to be 1'532.
It baa a peculiar ethereal suffocating odour, and its vapour,
when inhnled in large quantity, produces a cramp, wbich for

Fio. 95.

a few seconds takes away the power of respiration (Liebig). It
is miscible with water in all proportions, heat being evolved,
and it ia likewise soluble in botli alcohol and ether. The
addition of water raises the boiling-point of aldehyde. Thus,
a mixture of one part of aldehyde and three parts of water
boils at 37°. It is, however, separated from its aqueous solution
by the addition of calcium chloride. Aldehyde likewise dissolves
sulphur, phosphorus, and iodine, the liiat with a brown colour,
and it is easily infiaminable, burning with a luminous flame.

47JJ THE miYL GROCP.

Like all aldehydes (see page 172), acetallehyde readily under-
goes change. It absorbs atmospheric oxygen, and is slowly
converted into acetic acid Oxidizing substances bring about
this change more quickly. When warmed with an ammoniacal
srjlution of silver nitrate, silver separates out as a minor-like
deposit which adheres firmly to the glass :

C^,0 + Ag,0 = 2 Ag + C^,0^

This serves for the detection of the smallest trace either of
aldehyde or of silver. When the solution contains one part
of silver nitrate to 1,000 of water a brilliant mirror is formed,
with 2,000 of water, the mirror-like deposit is only partial, and
the solution becomes violet coloured, owing to the presence of
finely-divided silver. When the solution is still more dilute, no
depcisit of silver is obtained, the violet tint alone being observed.
This can be noticed when one part of nitrate solution is diluted
with 4,000 of water, such a liquid producing only the slightest
opalescence ^ on admixture with a chloride.

It was formerly supposed that when aldehyde acts upon silver
oxide, or when alcohol is oxidized by platinum black, a com-
pound was formed intermediate between aldehyde and acetic
acid. To this the name of acetous, aldehydic, or lampic acid
was given. Hcintz and Wislicenus proved that this body is
a mixture of acetic acid and aldehyde.^

Under certain circumstances aldehyde combines with nascent
hydrogen to form ethyl alcohol This reduction is not brought
about by zinc and hydrochloric acid, whereas sodium amalgam,
in presence of water, as well as in presence of dilute acids,
does eflfect this change.' Alcohol is also produced when aldehyde
is heated with zinc and ammonia at 30'' to 40'' under a slight
increase of pressure.*

When chlorine acts upon aldehyde, acetyl chloritle, as well as
various other products which will be afterwards tlesc*ribed, are
firmed, acconling to the duration and other conditions of the
experiment.*

According to the theory of types, aldehyde is coiisiiKrod as

OHO)
etyl hydride, * \t !' • T^^^^^ view is in accordance with

» W. and H. Ilo««'rH, Journ. Prakt, Chrm. xl. 240.
' ^'"U'J- "^W' cviii. 101.

• Wurtz, i'lu/iftt, HfH'i, liv. 915; Ann, Chem. Pharm, cxxiii. 140.

• Ij«»riii, Com}*t. Ji' iuL Ivi. 845 ; Ann. Chcm, Phann. cxxviii. 3o5, 884.

• Wurtz. Ann. Chim, Phin. [3], xiix. 58; />«//. So,'. Chim [2], x\y. 08;
£rr, Dfufsih. rhfm, (h^, iii. 790.

ace

POLYMERIZATION OF ALDEHYDE. 479

its formation from acetic acid, as well as with the action of
chlorine upon it. In many other reactions, however, it behaves
as the oxide of the dyad radical ethidene. Thus, phosphorus
pentachloride converts it into ethidene dichloride or dichlor-
ethane, CH3.CHCI2. These compoimds, as well as others which
it forms with ammonia and with the acid sulphites of the alkali
metals and other bodies, will be described under the ethidene
compounds.

Aldehyde is used in the arts for the manufacture of aldehyde
green, one of the so-called aniline colours.

308 Polymerization of Aldehyde. — Small quantities of weak
reagents convert aldehyde into polymeric modifications. Of
these a large number were formerly supposed to exist. A more
accurate examination has reduced this number to two.

Paraldehyde, CgHjgOg, was first obtained by Fehling, and
described as elaldehyde.^ It is easily formed by the action of
small quantities of mineral acids, zinc chloride, or carbonyl
chloride on aldehyde. It is best obtained by adding a few drops
of concentrated sulphuric acid to aldehyde, evolution of heat
and contraction taking place. On cooling the liquid to 0*",
paraldehyde crystallizes in large prisms which melt at l(f'b.
The liquid boils at 124°, and at 15° has a specific gravity of
0 998. A determination of its vapour density gives the number
4*583,^ which agrees with the above molecular formula; the
constitution of paraldehyde is, therefore, probably represented
by the following formula :

CH3

\
O

CHq CH CH CHq.

It is slightly soluble in water, dissolving more readily in
cold than in hot water. Phosphorus trichloride converts it
into dichlorethane, being first split up into three molecules of
acetaldehyde. This decomposition also takes place when its
vapour is heated, or when it is distilled in contact with a body

* Ann. Chem. Pharm. xxvit 319.

2 Weidenbusch, Ann. Chem. Phnnn. Ixvi. 152.

480 THE ETHYL GROUP.

in presence of which it has been formed, as, for instance, with
sulphuric acid.

The behaviour of paraldehyde towards carbonyl chloride is
remarkable. A mixture of these two bodies is extremely diffi-
cult to separate, boiling pretty constantly about 45'. Hamitz-
Hamitzky, who first examined the substance, believed it to be a
definite compound and termed it chloracctene, giving to it the
formula CgHjCl, and remarking that it decomposes into aldehyde
and hydrochloric acid. This fact was afterwards confirmed by
Friedel, who showed that on standing it decomposes gradually.

The existence of a compound isomeric with chlorethylene,
possessing such singular properties, could not be theoretically
accounted for, and this gave rise to many hypotheses, until
Kekul6 and Zincke proved that " the most remarkable pro-
perty of this body is its non-existence." ^ They, noticed that
carbonyl chloride acts as a kind of ferment on aldehyde,
small traces being able to convert a large quantity into par-
aldehyde, heat being evolved. If, however, this latter sub-
stance remain for any length of time in contact with carbonyl
chloride it is partly re-converted into aldehyde without evolution
of heat. The substance obtained by the action of aldehyde
or paraldehyde on carbonyl chloride is, therefore, a mixture of
the two modifications of aldehyde, the proportion between
these being dependent on the temperature and the quantity of
the ferment. If this mixture be gontly warmed, aldehyde and
carbonyl chloride pass over first; the distillate becomes warm
by the renewed formation of paraldehyde, but on quickly
shaking the compound with lead oxide, pure aldehyde is first
obtained, and afterwards pure paraldehyde. Hydrochloric acid
acts similarly to carbonyl chloride, but, as it appears, still more
energetically.*

309 Metaldeliydc. The formation of this substance was first
obser\'ed by Liebig, who found that needle-shaped crj'stals are
occasionally deposited from aldehy<le, and that these possess a
composition identical with the original substance.* This com-
pound was then further investigated by Fehling,* Weidenbusch,*
and Kekuli5 and Zincke.^ It is formed together with paralde-
hyde by the action of acids, carbonyl chloride, .&c., on aldehyde,

* Bfr. J>uisch. Chem, OcJi, iii. 136 ; Chrm. Soc, Jnurn. xxv. 401.

' Ann, Chem. Pharm. clxii. 125. • w//ri. Phnrm. xiv. 141 ; xxv. 17.

♦ fb. xxvii. 310. » lb. Ixvi. i:.2.
^ lb, clxii. 145.

METALDEHYDE. 481

cooled in a freezing mixture. It is likewise produced when
aldehyde is allowed to remain in contact with calcium chloride
or zinc chloride at ordinary temperatures. Moreover, it is some-
times formed, under unknown conditions, when aldehyde is
allowed to stand by itself.

Metaldehyde separates out in needles, or in clear colourless
quadratic prisms, which sublime at 100**, without previous
fusion. When heated to 112'' to 115°, in a closed tube, metalde-
hyde passes into ordinary aldehyde, and for this reason it has not
been possible to determine its vapour-density, or its molecular
weight. On heating with carbonyl chloride, sulphuric acid, &c.,
it yields aldehyde, and it behaves like the mono-molecular
compound towards phosphorus pentachloride.

Aldehyde-Besin is formed by the action of aqueous or alcoholic
potash on aldehyde, when the liquid first becomes yellow, next
brown, and then solidifies to a reddish-brown resinous mass, the
composition of which has not been ascertained. At the same
time formic acid and acetic acid are formed, together with a
very volatile, strongly-smelling compound, which, when well-
cooled, condenses to an oily liquid. This quickly absorbs
oxygen, and is converted into a golden-yellow, thick liquid,
smelling of cinnamon, which quickly becomes resinous (Weiden-
busch). This same resin is also formed when alcoholic solution
of potash is allowed to remain in contact with the air. The
colour as well as th^ smell which alkalis produce with aldehyde
are so characteristic that the latter compound may be easily
detected by this means when mixed with other bodies.

When the vapour of aldehyde is passed over heated caustic
potash or soda-lime the following reaction takes place : ^

CgH.O + KOH = C2H3KO2 -h Hg.

310 Farathialdehyde, CgHigSg. By passing sulphuretted
hydrogen into an aqueous solution of aldehyde, Weidenbusch
obtained a colourless oily liquid, which, when treated with small
quantities of sulphuric or hydrochloric acid, is converted into
a white crystalline mass, to which he gave the name of acetyl
mercaptan.2 This liquid was afterwards termed sulphaldehyde.
Hofmann then showed that it possesses the above molecular
formula, as its vapour density is 6°'29,* and Klinger proved that

* Damns and Stas, Anii. Chim. Phya. [2], Ixxiii. 115; Ann. Chem, Pharm,
xxxw. 161.

* Atm» Cktm. Phann. Ixvi. 158. » Bcr, DeuUcIi. Chan, Ges. iii. 588.

] I

482 THE ETHYL GROUP.

tlic coinpouiid obtained in the above manner is a mixture of two
i«oineric modifications.*

a'Parathialilchyde is obtained by repeated crystallization uf
tluj above compound from alcohol, or by passing sulphuretted
hydro^'en into a dilute acidified solution of aldehyde ia alcohol,
wlieu other bodies are formed at the same time. These can be
Boparated by repeated crystallization. To the above-mentioned
licpiid thiiddehyde, Klinger gave the probable fonnula, C^HgS^.
This, when suspended in water and treated for some time with
sulphuretted hydrogen, passes into another oily body, which
apparently has the composition 4C^H„S2 + HoS, and does not
andergo change in i)rcsence of hydrochloric acid. If, however,
some aldehyde be added to this, it quickly solidifies, and the
solid mass consists mainly of a-parathialdehyde. This crys-
tallizes from alcoliol in long white prisms, or from concentrated
solution in thin tables. These melt at 101°, and the liquid
boils at 24G' — 247°. It foniis with silver nitrate two com-
pounds ; one, C^jH^^Sj 4- AgNOg, forms white opaque needles
concentrically grouped, the other, CgH,.^S3 -f SAgNOj, crystal-
lizes in microscopic prisms. A warm solution of common salt
separates the thialdehyde from both of these.

^-Parathialdchi/de is formed from the foregoing compound
by warming it with acetyl chloride, and also by dissolving it
in cold sulphuric acid and adding water. It crystallizes from
solution in glacial acetic acid in long glistening needles which
melt at 124° — 125"*, the liquid boiling with slight decomposition
at 245° — 248°. The determination of its vapour density gave
the number GO, which is rather lower than that required by
theory. With silver nitrate this btxly also yields two compounds,
viz., C^jHj2S3 4- AgNOg, crystallizing in compact colourless
needles, and C'^jUj.^S3 + SAgNO^, in tine scales possessing a
j>early lustre.

The cause of the isomerism of the above thialdehvdes has
not vet been established. It is ]>osj?ible that thev have a
different chemical constitution, but it is more probable that
their difference is due to physical isomerism.

* JJ',: Deutsche Ch/n/i. Gcs. x. liJU3 ; xi. I«r2;j.

HISTORY OF ACETIC ACID. 483

ACETIC ACID, CjH^Og.

311 It has already been mentioned that the only acid with
which the ancients were acquainted was vinegar, and that the idea
of acidity was expressed by a closely related word. The eflferves-
cence produced by vinegar when poured on certain substances
was also noticed in very early times, and is mentioned in the
Proverbs of Solomon,* whilst the solvent action of vinegar on
many bodies had also attracted attention. Thus Pliny says,
concerning the properties of vinegar, " Aceto summa vis est in
refiigerando, non tamen minor in discutiendo ; ita fit ut infusum
terrae spumet.'*

The ancients held exaggerated views respecting the solvent
power possessed by vinegar. This is shown by the well-known
story, related by both Livy and Plutarch, of Hannibal dissolving
the Alps by means of vinegar, whilst Vitruvius states that
silicious rocks, which can be neither attacked by the chisel nor
by fire, are dissolved when heated and then moistened with
vinegar.

The vinegar of the ancients was of course an impure wine-
vinegar, and it is to the alchemists that we owe the first pro-
duction of pure acetic acid by distillation. Geber, in his treatise
De Investijatione Magisterii, writes : "Aceti acerrimi, cujuscunque
genera, subtiliantur et depurantur, et illorum virtus sive effectus
per destillationem melioratur." Basil Valentine apjiears to have
been acquainted w-ith the preparation of strong but impure
acetic acid, obtained by the distillation of verdigris (which he
termed a vitriol), for he says : " Take the proper oleum vitrioli
made out of the vitriol of verdigris." But on the other hand,
the alchemists often used the name of philosophical vinegar
for oil of vitriol.

Acetic acid obtained from verdigris was afterwards termed
spiritus veneris or acctum radicale. Stahl in 1697 described
better methods for obtaining strong acetic acid. Thus, he
allowed weak vinegar to freeze, and poured off the acid, which
remained liquid, from the solid mass which separated out. In
his Specimen Bechcrianum, published in 1702, Stahl describes
the neutralization of the vinegar with alkali, the evaporation

* Sec vol. ii. part. i. p. 32.

I I 2

484 THE ETHYL GKOUP.

of the solution, and the distillation of the solid salt with
sulphuric acid. He states in another work, published in 1723,
that acetic acid may be obtained in a similar way from sugar
of lead by the action of oil of vitriol. He also mentions that
the strong acid is inflammable, a fact which had not been
recognised up to that time, as it had been supposed that acetic
acid differed from alcohol, especially in not being inflammable
Yon Lauraguais made the same observation in 1759, and he
also noticed that concentrated aculum radicale could be
obtained in the crystalline state, a fact soon afterwards con-
firmed by other observers. So that Durande, in editing
Morveau's Handbook of Chemistry in 1777, terms the solid acid
vinaigre glacial, a name still used. In 1772 Westendorf sug-
gested the use of acetate of soda instead of the potash salt for
the preparation of the acid, and Lowitz in 1789 discovered that
aqueous acetic acid may be so far concentrated by frequent
rectification over powdered charcoal as to crystallize when
cooled, and to this substance he gave the name of ice-like
acetic acid.

31a The production of acetic acid by the dry distillation of
wood or other vegetable fibre must have been known in early
times ; thus Glauber speaks of it in his Fumi Novi PhUosophvci^
published in 1648, in a way which shows that wood-vinegar
was a well-known substance at that time. He says that its
properties do not differ greatly from those of common vinegar,
for which reason he teimed it a^^etum lignorum, and states that
by rectification it may be made as good as acctxtm vini} Boyle
is even more precise in his identification of pyroligneous with
ordinary acetic acid, for he says, "Also guiacum and divers
other woods, that do not at all taste sour, will, being distilled
in retorts, afford spirits, that are furnished with store of
acid particles, which as I have tried will hiss upon alkalies, and
will dissolve coral, and even lead itself calcined to minium
and make sacchancm satumi of it."

In his Elementa Chemiae, published in 1732. Boerhaave states
that acida acetosa is formed by the action of heat on vegetable
substances. This expression points to the conclusion that in
former days the existence of a variety of different kinds of
acetic acid was assumed. Indeed every organic acid was looked
upon as a mollification of acetic acid. Thus, the plants now
known to contain oxalic acid are still termed acdosffy acetosellf,

> Glaul>er, Op. {vd, ltf59) p. 31.

HISTORY OF ACETIC ACID. 486

&c. Even when formic acid was discovered, it also was believed
to be a modification of acetic acid. It therefore appears not
unnatural that a distinction should have been drawn between
acetic acid and pyroligneous acid, and it was not until the
year 1800 that Fourcroy and Vauquelin proved that the acid
obtained by the dry distillation of wood, as well as of sugar,
gum, &c., is simply acetic acid mixed with a small quantity of
an empyreumatio oil.

When animal substances undergo dry distillation acetic acid
is also formed. The substance thus obtained was, however,
considered by Berthollet in 1708 to be a peculiar substance
to which he gave the name of acide zoonique. But Th^nard
showed in 1802 that this substance is identical with ordinary
acetic acid, as well as with the acid obtained by the destructive
distillation of wood.

313 The early views concerning the formation of acetic acid
from alcohol are but vague. They agree in considering that no
addition is made to the alcoholic liquid in its conversion into
acetic acid, the change consisting essentially of a decomposition
of the constituents of the alcohol, but not of a combination of
them with another body. Thus, Basil Valentine says that the
materials placed in the fermenting vat have assumed another
property, being no longer wine, having been transmuted into
vinegar by putrefaction.^ It was later assumed that vinegar
was formed by the combination of alcohol with saline particles,
such, for instance, as those of cream of tartar. For example,
Lemery says : " The spirit of vinegar consists in an acid ; essen-
tial or tartareous salt is very different from spirit of wine ;'* ^ and
Macquer in 1778, in his Dictionary/ of Chemistry, says that
it is not possible to form any definite idea of the changes which
take place in the acetic fermentation, though it appears as
if an intimate combination of the acid constituents with the
combustible constituents of the wine takes place.

Priestley having proved that common muriatic acid is an
aqueous solution of " a marine acid air," and hydrofluoric acid
a solution of " fluor acid air," he, for a short time, looked upon
acetic acid as containing '* a vegetable acid air," but soon found
that no such thing could be obtained from it.^

We owe to Lavoisier the first proof that acetic acid is a
product of the oxidation of alcohol. He observed that when

* Ed. PetraeuSf p. 61 . ^ Keiirs transl. p. 577.

' Obaervatioiifi on different kinds of Air, iii. 403.

48C THE ETHYL GROUP.

wine exposed to the action of the air is converted into vinegar
its volume becomes smaller. He showed, moreover, that wine
is converted into vinegar by other oxidizing agents.

The composition of acetic acid was accurately determined by
Berzelius in 1814, and Saussure having at the same time ascer-
tained the composition of alcohol, it now became possible to
explain the mode in which the latter was converted into the
former substance. It was, however, at this time supposed
that a large quantity of carbonic acid escapes during the
process, and it was not until 1822 that Dobereiner showed that
in the oxidation of alcohol only acetic acid and water are
formed. And it is to him that we owe the true explanation, for he
determined the quantity of oxygen which is needed to produce
the change.^

314 Acetic acid occurs widely distributed in nature, portly in
the free state and partly in the form of salts and ethers. According
to Yauqueliuy Hermstadt, and others, it is contained in the
juices of many plants, and especially of trees, either free or
combined as potassium or calcium acetate. It also occurs,
together with other volatile acids, in water which has been
distilled from odoriferous flowers or from aromatic acids and other
vegetable substances. As triacetin, 0311^(0211302)3, it is found
as an oil in the fruit of the spindle-tree, Ero7iymus europaeus,
and in the oil of the seeds of Crotan tiylium, whilst the liquid
oil from the seeds of Hcradcum gignnteum and H, sjH)ndyleum
contain octyl acetate, OgHj-.02H302, whilst sycoceryl acetate,
OigHgg. O2H3O2, is found in the resin of the Ficus rvhiginosa.
Various animal liquids also contain small quantities of acetic
acid, and it is likewise found in other products of fermentation
and putrefaction of organic bodies, as well as formed by their
dry distillation. It is, moreover, a product of a large number of
oxidizing processes, and, as it does not undergo change, even in
the presence of powerful oxidizing agents, it is often the final
product of the complete oxidation of compounds which contain
one or more methyl groups. Many carbon compounds which
do not contain the methyl group, also yield this acid when
heated with alkalis, for the alkali not only acts as an oxidizing
but also as a hydrogenating agent.

315 SyntheMA of Acetic Acid. — It has already been stated that
acetic ncid can In? built up from its elements (see p:ige 179).
Of the diffiTent synthetic* methoils, that bv ini'iins of trichlur-

» Schireig. Journ, liv. 410.

SYNTHESIS OF ACETIC ACID. 487

acetic acid claims our attentioD, as having been discovered the
fu^st.

Trichloracetic acid was first prepared by Dumas in 1830, b;
actiug on acetic acid with chlorine. In 1S43 Kolbe found that
when carbon disulphide is treated with chlorine at a red-heat,
carbon tetrachloride, CCI4, is formed. And two years later he dis-
covered that the vapour of this compound, when passed through
a red-hot tube, is converted into chlorine and tetrachlorethjlene,
CCl^. Chlorine in the sunlight acts upon this latter body in
presence of water, giving rise to trichloracetic acid, inasmuch
as hexchlorethane is formed, and this in the nascent condition is
decomposed as follows :

CCI3.CCI3 + 2 HjO = CCij.CO.OH + 3 HCI.

Now shortly before this, Melsens had observed that trichlor-
acetic acid in aqueous solution is converted into acetic acid in
presence of potassium amalgam, and thus the problem! of the
synthetic production of acetic acid was satisfactorily solved.

316 Manufacture of Vinegar. — All oxidizing agents convert
alcohol iirst into aldehyde and then into acetic acid. Ozone
readily effects this change, as does pure oxygen or air in presence
of platinum black. In absence of this latter substance neither
strong nor dilute alcohol can be thus oxidized. On the other
hand, fermented liquors, when exposed to air, soon become
sour. This depends upon the fact that they contaiu nitrogenous
compounds which are able to act as carriers of atmospheric
oxygen. This, however, they can only do when the percentile
of alcohol present does not rise above a certain limit. It is
for this reason that strong wine, such as port or sherry, does
not become sour on exposure to air.

Various processes are adopted for the manufacture of vinegar,
and the product, according to its mode of preparation, goes by
various names.

Wine Vhiegar is prepared in large quantities in wine-growing
countries, and especially near Orleans, from the poorer quali-
ties of wine. The manufacture is carried on in the open
air, or in buildings termed vijiaigrerUs, which always have a
southern a.spect. The vinegar casks, called mothtra, hold from
50 to 100 gallons, and a number of these casks are j"
rows. The process is often carried on in the open air^^
from 8 to 20 such rows form what is termed a
Two holes are bored on the top of the front end of ■

488 THE ETUYL GROUP.

for the purpose of charging, ami also for allowing firee access
of air.

In commencing the operation, these casks are one-third filled
with the strongest vinegar, boiling hot, and to this, the charges
of wine, 2^ gallons to each cask, are added at intervals of eight
days. When the casks are more than half filled, one-third of
the contents of each " mother " is syphoned off, and this opera-
tion repeated as long as desired. The temperature of the whole
sljould be kept from 24"* to 2T C. Wine vinegar always con-
tains acetic ether, as well as the other ethereal salts contained in
wine, and these give to it the fragrant smell and taste for which
it is valued. The wine prepared from other fruit as well as
grapes is sometimes also used for the manufacture of vinegar.
For the explanation of the changes which here take place the
chapter on fermentation must be consulted.

Malt Vinegar is largely manufactured in England. In this
j)rocess the wort is allowed to ferment and the fermented liquor
brought into ciisks placed on their sides with the bung-holes
open, an additional circulation of air being kept up by means
of an orifice bored at each end of the cask near its upper

edge.

317 Qnivk Viiufjar Process. — After it had leen proved that
acetic acid is an oxidation product of alcohol, the manufacture of
vinegar by a (^uick process was introduced in 1823 bySchutzen-
bach. The vinegar generator, technically called a graduator, is
a large tun of oak (Fig. 06), frequently 13 feet high, 15 feet
wide at the bottom and 14 feet wide at the top. A horizontal
I>erforated shelf is fjistened in the tub, 18 inches from the
bottom, and two inches above this eight or ten holes are
bored in the side of the tub and inclining downward from
the outside. A similar disc is placed one foot from the top of the
tub; with the holes 1 inch apart and \ inch in diameter. These
holes are loosely filled with cotton-wick or ]>ack-thread, a knot
being made at the top to prevent them falling through. Be-
tween these shelves the interior of the tun is filled with deal
shavings, which have been well washed and afterwanls stove-
dried. Charcoal is sometimes used. The whole being arrange<i,
strong vinegar hoateil to 20° — 25° is poured into the graduator
and allowed to stand for one or two days, and after this weak
spirit containing 5 — 7 per cent, of alcohol is introduced, .<»ome
fermented malt- liquor being also added. This then runs
through tlu» shavings and comes in contact with a large quantity

MANUFACTURE OF VINEGAR. 480

uf air, when oxidation occurs, and consequently evolution of heat
takes place and the circulation of air becoraeB rapid. The fresh
air cornea in through the lower holes, and having lost some of
its oxygen passes out through the upper ones. The graduator, to
begin with, acta but slowly, and it ia only after some time that a
quick action commences. Tbia depends upon the fact that tbe
acetification is due to tbe shavings becoming gradually covered
with a microscopic organism (Hfi/codeniia ajxti), or, as it is some-
times called, "mother-of-vinegar." It has been shown by Pasteur

Fio, PB.

that the formation of vinegar is due to the growth of this oi^an-
ism, which plays the part of a carrier of atmospheric oxygen, and
according to the observations of this distinguished chemist the
rapidity of the process may be greatly increased by the addition
of a small quantity of the mycoderm at the beginning of the
operation. The constant presence of alcohol is, however, neces-
sary, as in its absence the acetic arid is burnt by the ferment
into carbon dioxide a:ul water. Weak alcohol is oxidized more

490 THE ETHYL GROUP.

quickly than strong. When very strong acetic acid is needed,
the mixture has to be passed througli three tubs and a fresh
quantity of alcohol added, and sometimes submitted to a fourth
tub in order to obtain an acid of the requisite strength.

As the successful working of the graduator is greatly depen-
dent on the temperature, which must range between 36"* and 40',
a thermometer is always employed, and it is moreover necessary
to ascertain that the flow of the liquor is regular, and that it is
properly diffused over the chips. The amount of air wliich is
allowed to have access must also be regidated. If this is insuffi-
cient a loss takes place, inasmuch as a considerable quantity of
volatile aldehyde is formed, the smell of this compound being
almost always recognisable in the vinegar-house. If, on the other
hand, too much air be allowed to pass through the graduator a
loss takes place through the volatilization of alcohol vajwurs.
To regulate the supply of air it is not uncommon to join the
top of the graduator with a flue and damper connected with
a chimney.

According to theory, each percentage- volume of alcohol should
yield a vinegar containing one per cent, by weight of acetic acid,
but, owing to unavoidable loss, these proportions are not attained
in practice. In addition to this, a portion of the alcohol does
not undergo oxidation, and this is larger as tlie strength of the
vinegar increases ; and thus the strongest vinegar which can be
prepared in this way, rising up to 10 to 15 per cent, of acetic
acid, usually contains several tt-nths per cent, of alcohol. In
good working, 100 liters of any given percentage of alcohol by
volume will yield 84 kilos, of vinegar containing the given per-
centage of acetic acid by weight ; but the process is often
attended with a loss of 20 per cent., as it is difficult to keep
the summer temperature exactly at the requisite point, and
when the ferment becomes hot the oxidation takes place at an
extremely rapid r.ate. ^ In many vinegar-works the vinegar fly
(^DrofiophUa cr/laris) occurs in enormous numbers. The larvoe of
this tly live in fermenting liquors, especially in those undergoing
the acetous fermentation, and are also found in decaying fungi
and rotten fruit The vinegar eel {Anquillula acefi) is also
frcciucntly found in the vats, and is often from 1 to 2 mm. in
length. It was forme riy supposed to bo an infusoria, but is now
reco;?nised as belonging to the Xrmnfotfra.

Spirit vinegar is colourless. TIm* vinegar for table use is

* Kr:inior» Hfr. Ent^r. ('hf,ti. Imi. ii. 3P9.

PREPAHATION OF PURE ACETIC ACID. 491

oftou coloured yellow by bumt-sugar, and not uiifrequcDtly
cream of tartar and acetic etlier are added to give it the flavour
of wine-vinegar. Tlie adulteration of vinegar with sulphuric
acid is not infrequent, the law permitting an addition of O'l per
cent, of this latter acid, as it was believed that by this means the
vinegar was rendered more stable, although this is an error.
In order to detect the presence of free sulphuric acid in vinegar,
a piece of filter-paper is wetted with the vinegar under exami-
nation and dried, or the acid is evaporated with a small quantity
of sugar. In either case carbonization occurs if free sulphuric
acid be present. Free mineral acids may also be detected by
boiling 100 grams of the vinegar with about 50 milligrams of
starch for about thirty minutes. If mineral acids are present
tlie starch is converted into dextrin and starch-sugar, neither of
which are turned blue by iodine.

318 Preparation of Concentrated Acetic Acid. — la addition to
its uses for the table, vinegar is employed for the preparation
of various acetates, and these again for the preparation of
strong acetic acid. This is, however, obtained in larger
quantity from pyroligneous acid, which is neutralized with
lime and thus separated from wood-spirit and acetone, and the
residue evaporated to dryness. In tijis way a crude calcium
acetate is obtained which has a brown or black colour and yields,
on distillation with hydrochloric acid, noetic acid, possessing a
strong empyreumatic odour, largely used for many purposes in
the arts. In order to obtain a pure acid from this source the crude
brown or black calcium salt is heated in a drying furnace to a
temperature of about 232" to carbonize the resins and other
impurities. The mass thus obtained is termed white or grey
acetate. Another process, proposed by Voickel,^ accomplishes this
end more completely. Tlie solution of the crude salt when about
half evaporated is treated with hydrochloric acid until a weak
acid reaction is observed, when a large quantity of tar as well as
of carbolic acid, creosote, and other bodies, separates out The
clear solution yields, on evaporation, a brownish coloured residue,
which can then be ignited for further purification. By distilla-
tion with the requisite quantity of hydrochloric arid, acrtlc acid
containing from 40 to 50 per cent, of the pure acid 1 "*^~
obtained. When this has a tarry smell or contiias aat^
hydrochloric acid, it may be purified by distillation over a
■{uaiitity of potns.^ium dichromate or potassium pot
> Ann. Chem. J^rm. IxixiL 19.

492 THE ETHYL GROUP.

When chloride of calcium is added to a solution of calcium
acetate and the whole concentrated, crystals of calcium chlor-
acetate, Ca(C2U302)Cl, are obtained. This salt can easily be
prepared from the pure pyrolignite of lime, and it has been
suggested by Condy to employ this salt as a means of preparing
pure acetic acid.^ Acetic acid is now manufactured in Newcastle-
on-Tyne according to this process, although it does not appear
to have been generally adopted. There seems to be a prejudice,
although quite an unfounded one, against the use of the acid
thus prepared.

The sodium salt is now always employed for the preparation
of concentrated acetic acid, as this salt can be easily obtained.
The water of crystallization which it contains must be first
removed by heating, and at last the temperature is raised up
to the fusing point of the anhydrous salt. This operation
was formerly conducted in iron boilers, in which very serious
explosions took place, owing to the top layers of hydratcd salt
falling into the fused mass at the bottom. Sheet-iron pans
are now employed, 6 feet long, 4 feet wide, and 2 feet deep.
Care has to be taken that no sparks fall into the fused mass, as
if this is the case the whole takes fire and bums aw^ay like tinder.
After cooling, the solidified crystalline mass is broken up into
small pieces and distilled with the requisite quantity of strong
sulphuric acid. The distillate is not anhydrous acetic acid, but
contains a few per cents, of water, owing to the fact that the
sulphuric acid used for the decomposition is never anhydrous,
and that in the operation of fusing a certain quantity of sodium
carbonate is formed. It is, however, easy to obtain pure acetic
acid from this product, for, on distillation, an aqueous acid
passes over first, and afterwards the anhydrous acid. This
latter separates out in crystals when it is cooled, and the liquid
portion being poured off, the crystals are melted again, so that
by a repetition of this operation pure glacial acetic acid is
obtained.

319 Properties. — Pure acetic acid is a colourless liquid having
a strongly acid and pungent smell and taste. It crystallizes on
cooling in large transparent glistening tables which melt at
16°*7.^ If melted in a closed vessel and allowed to cool down,
acetic acid retains its liquidity, even at a temperature below
0**, but on opening or shaking the vessel, or on dropping in a

* Spon's Ennjel. Jnduntr, Arts, 25.

* KiKlorif, Bcr, l^utuch, Ckem, Oft. iii. 390.

PROPERTIES OF ACETIC ACID.

493

small piece of solid acid, the whole solidifies, and the tempera-
ture rises to 16°'7. A small addition of water lowers the melt-
ing point considerably, so that an acid containing 13 per cent,
of water melts below 0°, and one containing 38 per cent, of
water and corresponding to the formula CgH^Og -|- 2H2O has a
melting-point of — 24°. If more water be added the melting-
point rises again. ^ The specific gravity of acetic acid at 0° is
1*0800 (Kopp), whilst at 15"* it possesses the specific gravity of
1*0553 (Oudemanns).^ If water be added, the specific gravity
rises at first until an acid containing 70 per cent, is obtained. On
a further addition of water the specific gravity remains unaltered,
so that aqueous acetic acid containing 76*5 to 80 per cent,
possesses the same specific gravity, namely, according to van
Toom * and Roscoe,* 10754 at 15°*5. The specific gravity then
diminishes, so that an acid containing 43 per cent, has at 15°
the same specific gravity as the anhydrous acid (Oudemanns).
Hence it follows that the concentration of the aqueous acid
caunot be determined, as that of alcohol can be, by the specific
gravity, but trituration with an alkali must be employed.
Riidorff has shown that the melting-point of the pure acid is
considerably lowered by the presence of a slight trace of water,
and upon this fact he has founded a method for determining
the strength of high percentage acetic acid.^ This was
formerly ascertained by shaking up the acid, together with oil
of lemon, and observing how much of this dissolved. The
German Pharmacopoeia still states that 10 parts of pure con-
centrated acetic acid dissolve 1 part of this oil A dilute acid
takes up less, and in proportion to the quantity of water which
it contains.

Basil Valentine was aware that vinegar when distilled yielded,
to begin with, a weaker, and later on a stronger acid ; and in his
treatise, ** Vom grosscn Stein der uralten Weisen," he distin-
guishes in this respect between the behaviour of acetic acid and
that of alcohol, and he says that *'in the distillation of spirit of
wine the spirit comes over first and the phlegma last ; when,
however, this by a long-continued warmth has been converted
into vinegar, its spirit is not so volatile as before, and on dis-
tilling the vinegar the aquosity passes over first and the spirit
last." ^ It has already been stated that Lowitz found that a low

* Grimanx, Compt. Bend. Ixxvi. 486.

* Joum, Praht, Chem. vi. 171.

* Loc cit.

' Jaum, Prakt. Chem. \\ 452.
* Jonrn. Chem, Soc. xv. 270.
'» /W. Pdracusy p. 51.

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7 -.

POTASSIUM ACETATE. 495

evolution of heat. If bromine be added to the solution contain-
ing hydrobromic acid, red needle-shaped crystals separate out,
and these on drying over caustic lime possess the composition
4(CVH^Oa.Br2) + HBr. The hydrochloric acid solution yields
a similar compound with bromine.^

As acetic acid is very hygroscopic, it absorbs water from various
saline solutions and precipitates the salts, this being especially
the case with many sulphates. It withdraws the water of
crystallization from Glauber-salt, whilst on the other hand
Glauber-salt crystallizes from a warm solution of anhydrous
sodium sulphate in dilute acetic acid.

Acetic acid is employed for a variety of purposes. In the
concentrated state it acts as a valuable solvent for many carbon
compounds, as the hydrocarbons, &c., and it is, therefore, employed
in the laboratory in organic researches, and it is largely used in
those industries which are dependent on organic chemistry.
AVhen warm it dissolves phosphonis and considerable quan-
tities of sulphur. It acts as a strong caustic on tender parts of
the skin, producing blisters and wounds which heal only with
difficulty.

Aromatic vinegar is also used largely in cases of fainting,
whilst acetic acid serves as the best antidote for poisoning with
alkalis or their carbonates. A more or less dilute acetic acid is
largely employed in calico-printing in the preparation of the
acetates of iron and alumina, respectively termed iron- and red-
liquors. It is also used in the manufacture of colouring matters,
and in other branches of industry. In pharmacy, photography,
and chemical analysis it is also extensively employed.

Acetic acid, which is used for analytical, pharmaceutical, and
certain other purposes, must be free from mineral acids and
metals, nor should it contain any empyTeumatic admixtures. It
ought not to decolourize a solution of potassium permanganate.
Pure dilute acetic acid does not do this, although the strong acid
does so if it be allowed to remain for any length of time in
contact with the air, inasmuch as it acts as a solvent for the small
organic particles which occur in the atmosphere. In order to
purify such an acid it requires to be distilled over potassium
dichromate or potassium permanganate ; on the large scale this
is eflected in copper retorts having a silver condenser, and in
order to prevent the metul being attacked the distillation is
generally carried on in an atmosphere of carbon dioxide.

^ Hell and Mulilliausvr, 2>Vr. DcutscJi. ^"^J^^^- -1<^- '> ^'»- -^1 J ^^i- '-7-

4% THE ETUYL GKOCP.

THE ACETATES, OR THE SALTS AND ETHERS

OF ACETIC ACID.

321 It has already been stated that the first' organic compounds
obtained were those prepared by the action of acetic acid on the
alkalis. The property possessed by acetic acid of attacking
metals was also early observed, and a test employed to detect
the presence of gold depended upon the fact that it is un-
attacked by this solvent, whilst copper is converted into verdigris.
In the following pages only such of the acetates will be described
as have either a special practical value or a theoretical interest.

Potassium Acetate, CjHgKOj. In the impure state this salt
was known to the ancients. It is stated by Pliny that a solution
of wood-ashes in vinegar was used as a medicine. By evapo-
rating such a solution, Raymond Lully obtained this salt in the
solid state, without however noticing its peculiar properties ; for,
on heating the residue, he obtained carbonate of potash, which he
considered to be a body differing from that obtained by lixiviating
the ashes with water. The first description of the true salt was
given by Philip Miiller, a surgeon in Freiberg, who described it
under the name of trrra foliata in his Miracula et Mystcria
Chymiro-Mcdka, published in 1610. At that time, and for
many years later, acetic acid and tartaric acid were not dis-
tinguished as different bodies; and, as acetate of potash was
chiefly prepared with ignited cream of tartar, it received the
name of tartarus viniy tartnrus rfgeticraius, arcanum tartaric &c.

In order to prepare this salt, acetic acid is neutralized with
purified potashes, and the solution evaporated. A white finely-
divided powder is then obtained, or a foliated white crystalline
mass, from which appearance its name of terra foliata was
derived. It is extremely deliquescent, dissolving at 2° in 0*531,
and at the boiling-point in 01 25 pai-t of water, the saturated
solution boiling at 1G9°. Tlie sjilt crystallizes from this solution,
on cooling, in transparent prisms, but only with difficulty. It is
also easily soluble in dilute, as well as in absolute alcohol, and is
precipitated in the cryst'iUine form from this solvent by the
addition of ether. It possesses a strong siiline taste. On
heatiii;:; it melts, forming an oily liquid, which solidifies at 292"
to an op.i(|uc cryst 111 line mas.^. In this act of solidification.

THE ACETATES. 41*:

especially if the salt be not completely fused, large crystals are
thrown up out of the mass. It decomposes at a red-heat with
evolution of acetone and other products. A current of carbon
dioxide passed through the alcoholic solution precipitates
potassium carbonate.

Acid Potassium Acetate or Potassium Diacetate CaH3K02+
CjH^Oj, is formed by dissolving the normal acetate in acetic
acid. If the solution be allowed to evaporate over sulphuric acid,
crystals containing six molecules of water are obtained, but on
evaporation at a high temperature the anhydrous salt is formed
in long colourless needles, which are less deliquescent than the
normal salt. It melts at 112'', and decomposes at 200^ with
evolution of pure anhydrous acetic acid, which however is not
completely driven off till 300**. Hence Melsens^ suggested the
preparation, by this means, of pure glacial acetic acid from dilute
acid by distilling the latter with potassium acetate, the receiver
being changed as. soon as the temperature reaches 300^ This
method has not, however, come into use.

Potassium Tmacetate, C2H3K02+2C2H^02, is obtained by
dissolving five parts of anhydrous potassium acetate in eight
parts of glacial acetic acid, when it is deposited in fine
deliquescent tablets, melting at II 2^ and decomposing with
evolution of acetic acid at 170^

322 Sodium Acetate, CgHgNaOo. was first described in 1736
by Uuhamel, who showed that it is a different compound from
the potassium salt. J. F. Meyer mentions this compound in his
Alchemical Letters as terra foliata tartari crystallisabUis, In
order to prepare it, dilute acetic acid is saturated with sodium
carbonate and the solution concentrated by evaporation. It
is also prepared by neutralizing distilled pyroligneous acid
with soda, evaporating and fusing the residue to destroy
empyreumatic tarry matters. It is likewise obtained by
decomposing calcium acetate with Glauber-salt, the compound
obtained in this latter manner being purified by recrystallization.
It crystallizes with three molecules of water in monoclinic
prisms. It dissolves at the ordinary temperature in about 2*8,
and at 124^ the boiling-point of the saturated solution, in 0 5
parts of water. In spirit of wine it is less soluble, and in
absolute alcohol almost insoluble. The crystals possess a mild
bitter saline taste. At dS"" the salt begins to fuse, and is
perfectly liquid at 75°, again solidifying to a mass of prismatic

* Ann. CJt^m, Pharm, liL 274.
VOL. III. K K

498 THE ETHYL GROUP.

needles on cooling, the mass remaining for some length of time
at 58°. If the hot liquid be poured into a closed flask, or one
the neck of which is stopped with cotton wool and allowed to
cool, it remains liquid for a length of time even at 0'', but
solidifies with evolution of heat when a small crystal of the salt
is dropped in. It loses its water of crystallization when placed
over sulphuric acid, as well as when heated to 100^ The
anhydrous salt fuses without decomposition at SlO^'and solidifies,
frequently forming large pearly crystals which take up seven
molecules of water on exposure to air, and deliquesce to a super-
saturated solution. The salt dried over sulphuric acid, on the
other hand, only re-absorbs its water of crystallization, and does
not deliquesce. According to Berthelot, this depends upon the
fact that the anhydrous salt obtained by the latter process still
contains traces of the aqueous solution, which prevent the fonna-
tion of a supersaturated solution. It has already been stated
that sodium acetate is employed for the manufacture of pure
acetic acid, and it is also largely used in the preparation of other
acetyl compounds and likewise in medicine.

Sodium Diacetate, C^HgNaOj + C^Kfi^ + HJO, is prepared
by quickly evaporating a solution of the normal salt in concen-
trated acetic acid (Fehling).

Sodium Triacetate, CgHjNaOg + 2C2H^02, is formed by dis-
solving one part of fused sodium acetate in six parts of boiling
glacial acetic acid (Lescoeur).

Other molecular compounds of sodium acetate and acetic
acid have been prepared by Villiers.^

323 Ammonium Acetate, C^Rj^M^O^. — At the beginning of
the seventeenth century this substance was recommended as a
medicine by Raymund Minderer, an Augsburg physician. Hence
it was termed liquor ophthalmicus Minderii. Tachenius, in
hilt Hipjxycrates Chymicus, published in 1666, states that this
medicine is prepared from acetic acid and the volatile alkali.
As it was for a long time known only in solution, it was fre-
quently termed sal-ammoniacum liquid um. In order to prepare
it in the solid state, either its solution is evaporated in a current
of ummonia, or glacial acetic acid is saturated with ammonia
gas. The siilt i.s then obtained as an odourless, saline mass.
When hot glacial acetic acid is saturated with carbonate of
anmionia, ammonium acetate separates out on cooling in large
neeillos easily .soluble in water, and which readily lose ammonia.

' Omipf. Ji^nd. Ixxxiv. 774 ; Ixxxv. 7W, 1284.

TIIK ACKTATKS. 499

^t is used in medicine in cases of alcoholic poisoning. The liqtcar
umoniw ncdatis or spirit us Mindcrii of the Pharmacopoeia
mtains 15 per cent, of ammonium acetate, and is obtained
by neutralizing dilute acetic acid with ammonia. According
to Berthelot, the ammonium acetate of the shops is an imper-
fectly crystalline mass, having the composition 2 02H3(NHJO2 +
C,H,02 + 3 H,0.

Ammonium Diacefate, Coii.^(i!ill^)0.j^ + CjH^Og, is formed by
evaporating a solution of the normal salt, and also by distilling
the dry salt. It is obtained as an oily liquid, which gradually
solidifies, but often still remains fluid, and this when touched
with a crystal of the solid salt solidifies. It fuses when warmed,
and distils without decomposition at 120^ and hence it may also
be obtained ])y distilling a mixture of sal-ammoniac and potas-
sium acetate. It crystallizes on cooling from aqueous solution
in long needles, which deliquesce on exposure to moist air.

Ammonium Scsquia relate, 2 C2H3(NHJ02 + SO^H^gH" HgO,
is obtained by dissolving the commercial salt in its own weight
of gla<;ial acetic acid. It crystallises in flat needles.

324 Calcium Acetate, (C^H^02)2 Ca + 2H2O, crystallizes in
needles or prisms, which effloresce partially on exposure at the
ordinary temperature and completely at 100°, forming a white
powder. It possesses a saline taste, is easily soluble in water, less
so in spirit of wine, and dissolves lead sulphate easily. It has
already been stated that this salt is used in the preparation of
acetic acid and pyroligneous acid, and is employed in calico-
printing. With calcium chloride it forms the compound
CaCl(C2H302) + 5H2O, crystallizing in large monoclinic crys-
tals, which do not undergo change on exposure to air, but at 100°
lose their water of crystallization without alteration of form.

Zinc Acetate, (C.2H30.,)2Zn, is formed by dissolving zinc, its
oxide, or carbonate, in acetic acid. It seems to have been
known to Geber, who says: "Tutia calcinatur, et resolvitur
in aceto distillato, et sic est pnx^parata." On evaporating its
solution at a high temperature, it separates out as a white
crystalline crust, and this contains one molecule of water. This
salt is employed as an astringent in medicine, both for inward
and outward use.

325 Lead Acetate, (CoH302)2Pb. — This salt is first men-
tioned by Basil Valentine, who says : * ** Mark that pure dis-
tilled acetic acid poured on powdered saturnum (lead oxide)

* Oj)era, Ed, Petr. 98.

K K 2

6D0 THE ETHYL GROUP.

and warmed in the water-bath entirely loses its acid and
becomes sweet like sugar. If then two or three parts of
the vinegar be distilled off, and the rest placed in a cellar,
thou wilt find a white transparent stone like a crystal." In
another place ^ he describes the preparation from white lead,
and says the crystals " look like well-refined sugar or salt-
petre." This salt was soon afterwards known under the name
of sugar of lead, and Libavius, in his Alchymia, calls it sacchai'um
plurnbi quintessentiaie, ^

Sugar of lead is prepared on the large scale by dissolving the
calculated quantity of litharge in acetic acid. For this purpose
it is best to employ a 45 per cent, acid, and to every 100 parts
of such an acid to add 86*5 parts of finely ground litharge, the
mixture being heated to the boiling-point. The liquid is first
allowed to clarify, and then brought into a crystallizing vat,
where it remains for from one to two days. It is usual, however,
to employ a more dilute acid, this being heated in a copper pan,
at the bottom of which a piece of metallic lead is soldered to
prevent the copper being acted on ; to this the requisite quantity
of litharge is added. The clarified liquid is then boiled down
in a second pan to a specific gravity of 1*5, and the crystals
allowed to deposit in wooden vessels lined with lead or copper.
In this way sugar of lead is obtained as a coarsely crystalline
mass, which is broken up into lumps, dried, and in this form
sent into the market An excellent quality of sugar of lead
is obtained by exposing sheet lead in a closed chamber to the
united action of air and the vapour of acetic acid. A mixture
of normal and basic acetates is obtained, which is then dissolved
in acetic acid and allowed to crystallize. The mother-liquors
from the various portions are again worked up till they become
too impure to yield a fine commercial article. They are then
evaporated, and thus the so-called grey sugar of lead is obtained.

For certain commercial purposes a brown sugar of lead is
manufactured, cheap pyroligneous acid being substituted for
the more expensive colourless acid.

Lead acetate dissolves at the ordinary temperature in 1*5, at
40* in 1*0, and above 100** in 0*5 parts of water. From the
hot solution it separates out on cooling, in monoclinic prisms or
tables, which contain 3 molecules of water of crystallization,
And it is less soluble in alcohol. Exposed to warm air it efflor-
slightly, and loses the whole of its water when dried over

» Opera, 808. « Ub. II. Tract. II. Cap. IV.

LEAD ACETATES. 501

sulphuric acid. At lOO"" it also loses water, and at the same
time a small quantity of acetic acid. The anhydrous salt
crystallizes from hot alcohol in six-sided tables. It melts at
280**, the liquid solidifying again at 200** to a crystalline mass.
When heated more strongly, the fused salt loses acetic acid, and
the liquid suddenly solidifies, with formation of a basic salt.
Lead acetate has a weak acid reaction and a sweetish and an
astringent metallic after-taste. If paper be dipped in a solution
of lead acetate and then dried, it bums like tinder when ignited.
Lead acetate is largely used in the arts, as, for example, in the
preparation of the alum mordants, chrome-yellow, and other
lead pigments, as well as in the laboratory for the preparation
of the various acetyl compounds. In medicine it is used as a
sedative and astringent, and in cases of diarrhoea, &c. Taken
in large quantities it acts as a powerful poison.

Basic Lead Acetates are formed from the normal salt by
removal of acetic acid, or by the assumption of lead oxide.
Only two such salts are with certainty known. Others have
been described, but they are probably mixtures.*

Libadc Lead Acetate, c^H^o!Pb \ ^ ^ ^«^ ^ obtained by

dissolving the calculated quantity of litharge in a solution con-
taining the calculated quantity of the normal acetate. It is
also formed when the latter salt is incompletely decomposed by
ammonia. It is very soluble in water, but dissolves less readily
in alcohol and separates out in crystals on addition of the latter
solvent to its aqueous solution. At 100"" it loses its water and
is converted into a white mass.

CgHgOjPb^O

Tribasic Lead Acetate, ^^r • — This salt is formed

CgHjOjPb j O
when a solution of sugar of lead is treated for a length of time
with an excess of lead oxide. It is obtained in pearly crystal-
line needles when 100 volumes of a solution of the normal
acetate saturated at SO** are mixed with 100 volumes of boiling
water, and 20 volumes of pure strong ammonia added to the
mixture and the whole allowed to cool. Ammonia precipitates
from this solution either other basic salts or lead hydroxide
according to the amount added.

Solutions of basic lead acetates rapidly absorb carbon
dioxide from the air, and then become turbid. This also occurs

^ I.riwp, Joii/rn. Prakt. Chrm. xoviii. 385.

502 THE ETHYL GROUP.

when spriDg-water is added. Such solutions were known in
very early times, as the fact is mentioned by Geber; they
become milky on exposure to air, and hence were afterwards
called lac virghutle. The French chemist, Goulard, employed
this solution in 1760 as a medicine, which, mixed with
alcohol, was known as GotUard's lotion, Imd-vinegar, or acetum
saturni. According to the Pharmacopoeia, Liquor plumbi sub-
acctatis is prepared by boiling 5 oz. lead acetate, 3? oza. of lead
oxide, with a pint of water, and then adding as much water to
the filtered solution as will bring the whole up to 20 fluid ounces.

Lead Acetochloride, CoHjO^PbCl, is obtained by heating lead
chloride with lead acetate and acetic acid, or by using the
chloride of an alcohol-radical instead of the first of these
substances. It crystallizes in needles, which are decomposed
by water with separation of lead chloride.

Corresponding compounds with bromine and iodine arc also
known.

326 Copj)er Acetate, (fj^fi^j^w, — Theophrastus, who wrote
300 B.C., describes in his treatise ** irepl XiOwv,'* a basic acetate
of copper, to which we give the name of verdigris {vei-t dc gris).
He terms it 409 and describes the method of preparation which
is still adopted, namely, that of exposing plates of copper to the
air in contact with the marc or refuse of grapes, that is, the
grapes after the juice has been expressed. Dioscorides also
mentions that verdigris is formed when copper plates are hung
above a strong vinegar, or when the residues from working up
the copper are moistened w4th vinegar. Pliny describes the
manufacture of the same body, termed by him aerugo, in much
the same way. Geber appears, however, to have been the first
to observe that verdigris can be obtained from vinegar in the
form of crystals. This prepiration, which is the normal salt, was
called distilled verdigris; but in 1789, when the anti-phlogistic
nomenclature came into use, it was tenned ucHitc de cnivjr
crystallise, as distinguished from adtitc de cuicre avec vrc^s
d'iKvide de cuicre,

Nornud Copper Acetate, (C2H302)2Cu + HgO, is obtained by
dissolving verdigris, copper hydroxide or the carbonate in acetic
acid. It dissolves in 13 parts of cold and «5 parts of boiling
water, and crystallizes in dark blue transparent prisms which
eflSoresce on the surface when exposed to the air, and at 1 00** or
over sulphuric acid lose their water and become white. If a
solution saturato<l at 60'' be acidified with acetic acid and

COPPEK ACETATES. 503

allowed to stand in the cold, large blue rhombic prisms are
obtained^ and these on warming to 30** become green and moist,
being converted into the ordinary salt and water.

Basic Copper Acetate, commonly termed verdigris, is formed
by the action of acetic acid on copper in the presence of air.
Verdigris was formerly entirely manufactured in France and
Belgium, and especially at Montpellier ;- and hence the French
name for this is vert de Montpellier,

Large quantities of verdigris are now made in England and
Germany by steeping cloths in pyroligneous acid, or the refuse
grapes from the wine factories, and bringing these in contact
with sheets of copper.

After some weeks these plates are taken out and exposed to
the air for some time, and then dipped into water, or, pre-
ferably, into damaged wine, again set up to dry and the ver-
digris scraped off; and this process of dipping, drying, and
removing the verdigris occupies about eight days, and is
repeated until the whole of the copper is converted into
verdigris. The blue verdigris thus obtained chiefly consists

of the dibasic copper acetate, n^xj^Q^n fO + 6H2O. The

12 «5 ^

same salt is prepared, according to Berzelius, in blue needle-
shaped crystals by covering a copper plate with a mixture of
the normal salt and water, and allowing this to remain in con-
tact with the air for several months. When blue verdigris is
brought in contact with water it decomposes, a light-bluish
crystalline powder of tribasic copper autnte remaining behind.
This substance also occurs when a solution of the noimal salt
is treated with copper hydroxide. In this case a green pf>wder
is obtained which, however, possesses the same composition as

C,H,0,Cn j 0
the blue, namely, ^^ ^ r\ + 2H.2O. By decomposing

C2H3O0CU I ^

the blue verdigris by means of water the normal salt is fonned,
and the sesquibasic copper acetate, (C2H302)20Cu2 + (C2H302)2Cu
+ 6H,0 ; and this latter salt is also produced when ammonia is
added to a hot solution of the normal salt until the precipitate
which is formed dissolves ; on cooling, this salt separates out, and
more is formed on the addition of alcohol to the mother liquor.
The so-called green verdigris is, according to Berzelius, a mixture
of this salt with two other basic acetates. It is prepared by
throwing vinegar frequently on to copper-scale.

60i . THE ETHYL GROUP.

The various acetates of copper are used as pignieut colours,
and also in dyeing and calico-printing as resists, preventing the
indigo imparting a permanent blue colour to the cloth. They
are also used in medicine, and are extremely poisonous.

Copper Acetoarsenite, SCuAsjO^ + Cu(C2H,02)2. — This sub-
stance, according, to Ehrmann,^ is the chief constituent of
emerald-green and imperial- or mitis-green. It is obtained
by boiling together verdigris, arsenic tiioxide, and water; also
by dissolving arsenic trioxide in a boiling solution of potash,
and adding copper sulphate, when a dirty-green precipitate is
formed which, on addition of sufficient acetic acid to impart to
the liquid a distinct smell, and on continued boiling and on slow
cooling, separates out as a fine bright-green powder. Accord-
ing to the proportions between the copper salt and the arsenic
trioxide, a lighter or darker green precipitate is obtained.'
These differences are probably due to variations in the
composition of the precipitates.

327 Silver Acetate, C^HjAgOg, is a very characteristic salt of
acetic acid. It is obtained as a white precipitate by adding
silver nitrate to a moderately concentrated solution of an
acetate ; or by dissolving silver carbonate in hot acetic acid.
In each case it crystallizes out on cooling in glistening flat
elastic needles, which dissolve in about 100 parts of cold water
and blacken on exposure to daylight. When the acetic acid
which is used for its preparation contains small traces of
homologous acids, instead of forming fine bright broad needles
the salt is deposited in small indistinct crystals or is thrown
down in the form of a crystalline powder (Schorlemmer).

Mereurous Acetate, (C2H,02)2Hg2, is obtained by precipit&ting
the nitrate with a soluble acetate in the form of delicate
micaceous laminae, which at the ordinary temperature dissolve
in 133 parts of water, and readily blacken on exposure to air.

Mercuric Acetate, (C2H,02)2Hg, crystallizes in transparent
four-sided tables which dissolve in 4 parts of water at 10** and
in one part of water at 100.°

328 Aluminium Acetates, — We owe to Walter Crum * the com-
plete investigation of these salts. The normal salt is not known.
When a solution of aluminium sulphate is mixed with one of
sugar of lead or calcium acetate, the liquid obtained, which

^ Ann,, Pkarm. xii. 92.

' Braconnot, j4nn. Ckim. Pkys. [2], xyi. 53.

^ Liebig, Itrperi. PKarm. xiii 44(5.

♦ f'hnn. .C/w. ynwrn. vi. 21 •I

ALUMINIUM ACETATEa LOo

smells of acetic acid, acts as a mixture of the normal with a
basic salt. This, known under the name of red-liquor,' is
used in calico-printing, and is obtained for certain purposes by
dissolving freshly precipitated aluminium hydroxide in strong
acetic acid. If the solution obtained by decomposing sulphate
of alumina with sugar of lead is afterwards freed from lead by
sulphuretted hydrogen, and from sulphuric acid by baryta water,
and allowed to evaporate in a flat dish at a temperature below
38^ a residue having the composition (O^Hfi^^ AlgO + 48^0
is obtained, which is a gummy mass perfectly soluble in water.
If the above solution be diluted until it contains from 4 to
6 per cent, of alumina, an insoluble sesquibasic salt contain-
ing five molecules of water separates out in white crusts after
standing for some days. If, however, the solution be heated
to boiling the basic salt separates out as a granular powder
insoluble in acetic acid.

329 Ferrous Acetate, (C^^fi^^ ^® + 4H2O, is obtained ty dis-
solving iron in acetic acid and evaporating the solution in
absence of air, when it is deposited in greenish-white mono-
clinic crystals, very soluble in water, and absorbing oxygen
rapidly, especially in solution. This salt is also used largely
in calico-printing, and known under the name of black-liquor
or iron-liquor. Iron mordants appear to have been used in
early times in the East. They were first obtained by placing fer-
mentable organic bodies, such as malt, in contact with iron and
water. In 1782 Boothman patented the steeping of iron-filings,
&c., in water mixed with some such fermentable vegetable
matter; whilst in 1780 the first English patent on the subject
was taken out by Flight, who proposed to " steep iron in water
drawn from tar or tarry oil, and to mix the liquor with starch
or gum.'* In order to prepare iron-liquor, iron-filings or any
refuse scrap-iron is digested with crude pyroligneous acid of
specific gravity 1'035, usually at a temperature of 66°, but oc-
casionally in the cold. It is also obtained by decomposing
green vitriol with calcium acetate, or by the action of a solution
of sugar of lead on ferrous carbonate.

Ferric Acetate, (C2H302\Fe2. — Geber mentions the solubility
of ferric oxide in acetic acid, — " Crocus ferri dissolvendus est in
aceto distillate, et est clarificandus et hajc aqua rubicunda, crocea
congelata, dat tibi crocum aptum, et est factum." It is obtained
by dissolving the calculated quantity of ferric hydroxide in

^ So rolled because it yieldf; Tnadd*»r r^ds nnrl pinks.

506 THE ETUYL GROUP.

acetic acid, or by the decomposition of lead acetate with feiric
sulphate. According to E. Meyer, this solution deposits
transparent dark red glistening crystals which contain four
molecules of water. When this reddish-brown solution in
boiled it becomes of a darker colour, the basic salt being formed
which, on slight dilution, separates out, but, on cooling, either
partially or wholly re-dissolves. Ferric acetate is used in
medicine as Tinctura fti'^'i acetatis. According to the Pharma-
copceia, it is formed by mixing solutions of persidphate of iron
and acetate of potash, shaking well, filtering to separate the
precipitated sulphate of potash, and then adding to the filtrate
as much rectified spirit as will make the tiltered product measure
one pint. This is sometimes called KlaprotKs iron tificture.

Ferric acetate is also used in dyeing as a mordant, and is
usually prepared by decomposing calcium acetate with ferric
sulphate or iron alum.

With ferric chloride and ferric nitrate, acetic acid forms a
series of double salts studied by Scheurer-Kester.^ These are
all soluble in water and possess the following composition and
appearance :

Fe.Clj,(C2H302)4+ SHgO, yellowish -red prisms.
Fe*Cl/CJl3t>2)30H -h SHgO, hard black crj'stals.
Fe Cl2(Nb3)^(C2H302)2 4 H.O, yellowish-red crystals.
Fe2(N03)2(C2H302)4 + 6H2O, blood-red deliquescent needles.
Fe2(N03)4(C2H302)2 + 8H2O, sm«ill inonoclinic prisms.
Fe2(N03)(C2H302)40H 4 2H2O, hanl red-brown rhombic prisms.
Fe2(N03)2(C2H302)30H-f 21^0, dark red crystals, resembling

potassium ferrocyanide.

Ferric hydroxide dissolves easily in ferric acetate, with forma-
tion of easily decomposable basic salts.

330 Reactiotijs of Acetic Acid and its salts, — The acetates, with
the exception of a few bjisic salts, are all soluble in water, the
most difficultly soluble being mercurous acetate and silver
acetate ; for this reason the nitrates of these met-als produce a
white precipitate in a not too dilute solution of an acetate.
This dissolves in hot water, separating out on cooling in char-
acteristic crystals. When an acetiite is heated with concentrated
sulphuric acid, a strong smell of acetic acid is evolved, and on
the addition of alcohol the pleasant and characteristic odour of
acetic ether is noticed. A still more characteristic test is the

1 Ann, Chim. Phys. [3], Iv. 330; Ixiii. 422; Ixviii. 472.

THE ETIIEKS OF ACETIC ACID. 507

conversion of acetic acid into cacodyl oxide (see p. 238). For
this purpose the acid is saturated with caustic potash, evaporated
with a small quantity of powdered arsenic trioxide and the
mixture heated in a test-tube, when the characteristic smell is
perceived (Bunsen). The acetates, like the formates, give with
ferric chloride a dark red coloration, which disappears on the
addition of a mineral acid. They are distinguished from the
formates inasmuch as they do not reduce silver and mercury salts,
and likewise by their reaction with concentrated sulphuric acid.

Ethers of Acetic Acid.

331 Methyl Acetate, C^fijSK^. — This was first prepared in
1835 by Dumas and Peligot ^ by distilling a mixture of wood-
epirit, glacial acetic acid and oil of vitriol. It is contained in crude
wood-tar and in crude wood-spirit. In order to prepare this
ether, the method adopted is similai to that used for the pre-
paration of ethyl acetate. Methyl oxalate may also be heated
with its own weight of glacial acetic acid and some fuming
hydrochloric acid added. -

It is a mobile liquid, possessing a pleasant refreshing smell,
boiling at 59*'5, and having a specific gravity at U** of 086684
(PieiTe) and a vapour-density of 2*595 (Cahours).

Ethyl Accfaic or Acetic Etiur, C^HgO^-CgHg. — This substance
was discovered by Lauraguais. who published a mode of prepara-
tion in the Memmrs of the Paris Academy in 1759. It consisted
in heating strong acetic acid, obtained by distilling verdigris,
with alcohol. The fact that the ether could be thus produced
was contradicted by some, but corroborated by other chemists.
Thus, for instance, Scheele in 1782 denied that acetic acid when
distilled alono with alcohol produced the ether, but he added
that it was easily formed when a mineral acid was present in
the mixture of alcohol and acetic acid, or when an acetate was
treated with a mixture of alcohol and a mineral acid. Pelletier
in 1786 proved that by frequent cohobation acetic acid and
alcohol alone are able to form acetic ether.

For the preparation of acetic ether an excellent plan, proposed
by Frankland and Duppa, is usually adopted. 9 kg. of con-
centrated sulphuric acid is brought into a deep earthenware
vessel and 3G kg. of alcohol of 93 per cent, is mixed with
this, being brought to the bottom of the vessel by means of a

' --/w?i. Chim, Fhijs, Iviii. 46. - Dittuiiir, Jouni. Chcm. 6V. xxi. 480,

608 THE ETHYL (JROUP.

narrow glass tube connected by a caoutchouc tube with a con-
venient reservoir standing at a considerable elevation. The glass
tube is used as an agitator during the continuance of the flow of
the alcohol. In this way the liquid attains a high temperature
without loss of alcohol, and this greatly favours the formation of
sulphovinic acid. This mixture is allowed to stand protected from
moisture for twenty-four hours before use. It is then poured
gradually, so as to prevent heating, on to 6 kg. of previously
dried and fused sodium acetate broken into small pieces and
placed in a copper still immersed in cold water. The mixture
is then allowed to stand for twelve hours before distillation is
commenced. This can then be carried on over a naked fire
or gas-flame, and continued until water alone passes over. In
this way about 6 kg. of acetic ether absolutely free from alcohol
can be obtained, and this requires only one rectification over
fused and powdered calcium chloride.^

Ethyl acetate is also formed easily when a mixture of alcohol
and acetic acid, in the proportion of equal molecules, is allowed
to run into sulphuric acid heated to 130^ In this way ethyl-
sulphuric acid is first formed, and this decomposes with the
acetic acid, forming acetic ether, which distils over whilst the
sulphuric acid is again acted upon. By means of 10 grms. of
sulphuric acid 232 grms. of crude ethyl acetate are obtained.*

Acetic ether is a mobile liquid possessing a penetrating,
refreshing smell and a pleasant burning taste. It boils at 74°*3
under the normal pressure, and has a specific gravity at 0** of
0*91046 (H. Kopp). Its vapour-density was found by Boullay
and Dumas to be 3016. It easily dissolves in about 12 parts of
water, of which, on shaking, it takes up about 3*3 per cent. It
mixes with alcohol, ether, acetic acid, &c , in all proportions, and
dissolves a large number of resins, oils, and other organic bodies.
When in the pure state it does not undergo alteration on ex-
posure to the air, but if it contains water it gradually becomes
acid. Its purity cannot be tested by a determination of specific
gravity, inasmuch as mixtures of water and alcohol or ether in
certain proportions do not affect this. In order to detect these
impurities it is heated in a closed vessel with an excess of
titrated solution of caustic soda and the amount of alkali used
for the decomposition determined volumetrically. If acetic

» Phil. Trans. (1865). clri. 87.

' Kghis Ber. Drutsch. f'hrm. Grs. vi. 1177. A similar method hoA aim he»n
df'wriri^.l hy Pphal ifiuH. .SV. Chm. xxxiii. 850).

ACETYL OXIDE. 509

ether be brought in contact with iodine and aluminium foil,
a violent reaction takes place represented by the following
equation : ^

2 Al + 6 C,H,.C,H80, + 3 1, = 6 C,HjI + Alj(C^,OjV

Acetic ether is used in medicine. Its action in many cases
resembles that of common ether, but it possesses a more agree-
able taste and smell. It is also used for addition to the poorer
classes of wine, liqueurs, &c. It is also sometimes employed as
a solvent, and is used in the laboratory for the synthetic prepar-
ation of fatty acids, ketones and other compounds, as will be
hereafter described.

Chlorine and bromine form substitution-products with ethyl
acetate. By the action of chlorine perchloracetic ether,
CCI3.CO2.C2CI5, is obtained as the last product. This is an oily
liquid, smelling like chloral, possessing a burning taste, and
boiling under partial decomposition at 245^^ It is polymeric
with trichloracetyl chloride, and easily splits up into two mole-
cules of this substance, which it resembles in its reactions with
water and alkalis.

Mhyl Orthoacetate, CH3C(OC2H5)3, is obtained by heating
sodium ethylate free from alcohol with trichlorethane, CClj.CHj,
to from 100** to 120''. It is a colourless, peculiarly unpleasant-
smelling liquid which has not yet been obtained in the pure
state. When heated with water to 100° — 120** it is converted
into alcohol and common acetic ether.'

OXIDES OP ACETYL.

332 Acetyl Oxids, or Acetic Anhydride, (CgHgO)^©, was dis-
covered by GcrharJt/ and formerly termed anhydrous acetic
acid. He obtained it by the action of acetyl chloride on
anhydrous sodium acetate :

^I3i|+c,H3o|o = c;h;o}o-^ci}

In order to prepare it by this process, one part of acetyl

^ Gladstone and Tribe, Joum, Chem, Soc. 1876 (2), 357.

^ Leblanc, Atul Chim. Phy», [3J. x. 197.

» Oeuther, Zeitsch. Chem. 1871, 128.

* CompUs Bendvs, xxxiv. 755 ; Ann. Cliim. Phys. [3], xxxvii. 311.

r>io

THE ETHYL GRuUP.

chloride is allowed slowly to flow on to one part of finely
powdered s^xlium acetate or 125 parts of potassium acetate,
the whole being distilled as soon as the reaction is complete.
As, however, acetyl chloride is formed by the action of the
chlorides of phosphorus on acetates, it is not necessary to em-
ploy acetyl chloride already prepared, and the reaction may bo
modified in a variety of ways. Thus, for example, one part of
phosphorus oxychloride may be allowed to act on two parts
of potassium acetate, when sufticient heat is evolved to
cause the mixture of acetyl chloride and acetyl oxide to
distil over, and this can be rectified over potassium acetate
until a drop of the distillate shaken up with water does not
give any reaction for hydrochloric acid. For this method of

Fkj. j>7.

preparation the apparatus used in Fig. 97 is use<l. The ar-
rangements are simple. The double-necked bottle contains
quicklime or caustic sotln, in onler to retain the vapours of the
chloride, which would otherwise escajKi into the air, and are
very irritating.

Another nictluKl of preparation consists in adding, by degrees,
7 piirts of ] phosphorus pentachloride to 2 parts of gla<*ial acetic
acid. The mixture of a<*t'tyl chloride and phosphorus oxy-
chloride thus obtained is then distilled with 20 parts of sodium
acetate or an tMiuivalent quantity of pota>!sium acetate. A«*etic

ACETIC ANHYDRIDE. 511

anhydride is also easily prepared by acting on acetyl chloride
with an equal number of molecules of glacial acetic acid, in
connection with an inverted condenser, until no further fumes
of hydrochloric acid escape.^

The anhydride prepared by one or other of these processes is
then purified by fractional distillation.

The following methods of preparation are of special theoretical
interest :

(1) By heating lead acetate with carbon disulphide : ^

2 (C2H302)2Pb + CSg = 2 (C^HaO)^ + CO, -f 2 PbS.

(2) By heating acetyl chloride with caustic baryta ; ^ and

(3) By distilling glacial acetic acid withphosphonis pentoxide,
when acetic anhydride is produced in small quantity.*

Properties. — Acetyl oxide is a colourless, mobile, highly re-
fracting liquid, having a smell resembling acetic acid, but
being less acid and much more irritating. It has a specific
gravity at 0** of 10969, and at 15° of 1-0799, and boils at
137°-8 (Kopp). Its vapour- density at 152° is 3*67:3, whilst
at 255*^ it is 3*489, theory requiring 3*533. It is insoluble
in water, but when allowed to remain for some time in con-
tact with the liquid it is converted into acetic acid, and hence
it becomes acid on exposure to moist air. It is also quickly
decomposed in presence of alkalis. When heated with caustic
lime, anhydrous baryta, oxide of lead, or mercuric oxide, the
corresponding acetates are formed.^ When warmed with an-
hydrous potassium acetate, it forms a solution which on cooling
deposits colourless needles, having the composition 2C2H3KO2
-f (021130)20. These deliquesce slowly in the air, and when
heated decompose into their constituents. This occurs, however,
at a temperature above the boiling-point of acetyl oxide ; and for
this reason, in the preparation of the anhydride, the temperature
at the end of the operation must be considerably raised.

When acetyl oxide is heated with the alcohols, it forms the
corresponding acetates, and lit nee it may be used for the pre-
paration of such bodies, and is especially useful in enabling
us to determine the number of alcoholic hydroxy Is contained

* KanoDikoir and Saytzeff, Ann. Chem. Phamn. clxxxv. 192,
- Broughton, Chcm. Soc. Journ. xviii. 21.
' (lal, Ann. Chem. Pharm, cxxviii. 126.
•* Gal and Etai*d, Conipf. Rend, Ixxxii. 457.
' Bccharnp, Ann. Vhim. PIij/s, [5], xii. 5(i.

512 THE ETHYL (iROUP.

iu the compounds of the polyvalent radicals.^ It is decomposed
by chlorine into acetyl chloride and monochloracetic acid : '

C2H3O 1 n ^ CI I C2H3O \ ^ CjHjClO \ ^

Bromine acts in a similar way upon it. Aluminium chloride
acts in the cold on the anhydride with formation of acetyl
chloride and aluminium acetate.^ According to Schiitzenberger
it also combines with chlorine monoxide to form a colourless
liquid, which decomposes very easily, and is explosive. This
he terms chlorine acetate, and he gives to it the formula
C^HjO^Cl.* Aronheim,^ in investigating this subject, came to
the conclusion that this body is only a mixture, which, however,
Schiitzenberger does not admit.® By acting with iodine upon
it, colourless, shining, short prisms are obtained, having the
composition (0211302)31, which explode when heated above 100*.
Aronheim did not succeed in preparing this substance.

SUico-acetic Anhydride, or Silicon Acetate, SiO^(C2H30)^, was
obtained by Friedel and Ladenburg^ by acting with silicon
chloride upon glacial acetic aad or the anhydride. It forms
white, apparently quadratic, crystals, which rapidly absorb
moisture from the air, and are violently decomposed by water
with formation of acetic and silicic acida The compound
decomposes when heated under ordinary pressure, but under a
pressure of 5 to 6 mm. it melts at 110"* and distils at 148^ It
can be recrystallized from anhydrous ether.

When ethyl silicate is heated with acetic anhydride to 180*
the compound SiO^CC2Hg)3C2H30 is formed as an oily liquid,
boiling between 192' and 197'.»

Acetyl Dioxide, or Acetyl Peroxide, (C2H302)02, was discovered
by Brodie,* and obtained by gradually adding barium dioxide to
an ethereal solution of acetyl oxide :

„ CH3.CO \ .. ^ j.^^ _ CH3.CO.O ) ^ CH3.CO.O ( ^^
^ CH,.CO ) ^^ ^ ^^^2 " CHjCO.O j "^ CH3.CO.O ] '^

It is a tliick and very strongly smelling liquid, which may be

' Sohiitzeiiltei^r, Compl. Rend, Ixi. 4S5.
2 Gal. -4 nil. Chitfu Phya, [3], Ixvi. 187.

• Amlrianowsky, Bull S'tc. Chim. [2], xxxL IM.

• Ann, Chem, Pharm, cxx. 113.

■ Ber. DcuUch, Chem, Oe$. xii. 26.

• Bull. Sor, Chint, xxxi. 194.

' Ann, Chf.m, Pharm. rxW. 174.

• Friotlel und Crafts Ann. Chim. Phifn. f4). ix. 5.

• Pt-oe, Ri^. Soc, ix. 3C1 ; Phit. Tran*. 18»J3. 407.

HALOID COMPOUNDS OF ACETYL. 613

kept for some time in the dark without decomposition, but, on
heating, explodes as violently as chloride of nitrogen does. It
resembles hydrogen dioxide, inasmuch as it bleaches indigo-
solution, and oxidizes potassium iodide, potassium ferrocyan-
ide, &c., but it does not reduce solutions of either chromic or
permanganic acid.

Baryta-water decomposes it, with formation of barium acetate
and hydrated dioxide of barium.

HALOID COMPOUNDS OF ACETYL.

333 Acetyl Chloride, C.2H3OCI, was discovered by Gerhardt,
and obtained by acting with phosphorus oxychloride on fused
potassium acetate : *

POCI3 + 2 CgHsO^Na = 2 C2H3OCI + NaCl + NaPOj.

To prepare it in this way it is advisable to add the phos-
phorus oxychloride, which must be well cooled, to the calculated
quantity of potassium or sodium acetate in order to avoid
the formation of acetyl oxide. The apparatus. Fig. 98, may
be used for this purpose. The powdered acetate is contained
in the glass flask connected with the tubulus of the retort by
means of a piece of caoutchouc tubing. By raising the flask
the substance falls into the retort, whilst by lowering it an
air-tight caoutchouc joint is formed.

It may also be obtained by adding phosphorus pentachloride
to acetic anhydride,^ when the same apparatus may be used.
A better yield is obtained by using phosphorus oxychloride.*
The apparatus described under acetic anhydride may be em-
ployed. Another very convenient method of preparation is by
the action of phosphorus trichloride on glacial acetic acid :

PCI3 + 3 ^2^«2 } O = 3 ^2^30 I ^ p(0H)3.

The trichloride is mixed in the cold with an excess of glacial
acetic acid, and the mixture heated on the ^ater-bath. At

^ Ann. Chini, Phys. [3], xxxvii. 285.

2 Kitter, Ann, Chev\. Pharin. xcv. 208. •

* Kanonnikow, ih. clxxv. 378.

VOL. IIL L L

6U THE ETHYL GROUP-

ftbout 40° the reaction begins, and as the temperature rises it is
quickly completed.* The product is purified by fractional dis-
tillation ; and if the distillate contains any chlorine compounds
of phosphorus, it may be conveniently distilled over some
anhydrous sodium acetate.

Acetyl chloride la a highly refracting mobile liquid, which
at 0" has a specific gravity of 11305 and boils at 55°. Its
vgpour-density is 2'87- On exposure to moist air it fumes
strongly, and it possesses a suffocating smell, resembling both
hydrocblaric and acetic acids. Its vapour rapidly attacks the
eyes and the mucous membrane, and when inhaled produces

coughing and even spitting of blood. If a few drops are brought
into water, they soon dissolve, acquiring a rotatory motion,
and forming acetic acid and hydrochloric acid. If a small
quantity of Water is poured into the chloride, a violent reaction
takes place, which may even become explosive. When a
mixture of acetyl chloride and acetyl oxide is treated with
sodium- amalgam, and the product distilled with water, acetic
ether is obtained.*

When acetyl^ hloride is treated with sodium-amalgam until the
reaction is complete, and then snow added, and afterwards some

THIACETIC ACID. 616

more amalgam, a liquid is obtained containing ethyl alcohol,
which can be readily isolated.^

Acetyl Broinide, CgHjOBr, was obtained by Bitter in 1855 by
acting with phosphorus pentabromide on acetic acid.* In
order to prepare it, 240 grams of bromine are gradually added
to a mixture of 90 grams of glacial acetic acid and 33 grams of
amorphous phosphorus, and the whole distilled, when the re-
action is complete.' It is a colourless liquid, which fumes in
the air, becomes yellow on exposure, and boils at 81**. In its
general properties it closely resembles the chloride.

Acetyl Iodide, CgHjOI, is formed by acting with iodide of
phosphorus on acetyl oxide :

3 (C,H30),0 + 3 1^ + P^ = 6 C2H3OI + P2O3.

The mixture is heated until no further reaction takes place ;
then the whole is distilled, and the distillate shaken up with
some mercury and rectified.

Acetyl iodide is a brown transparent liquid, which, when
freshly prepared, does not contain any free iodine, and does
not become decolorized on shaking with mercury. It boils,
with decomposition, at about 108°. It has a very suffocating
smell, and is at once decomposed in contact with water.*

SULPHUR COMPOUNDS OF ACETYL.

334 Thiacetic Acid, CgHjOSH. — Kekul6 first prepared this
compound by acting on glacial acetic acid with phosphorus pen-
tasulphide.^ It is also obtained by treating potassium mercaptide
with acetyl chloride.® For the purpose of preparing thiacetic
acid 300 parts of phosphorus pentasulphide are warmed with
108 parts of acetic acid, the retort being half filled with the
mixture and heated until the reaction begins : the flame is
then withdrawn, when the thiacetic acid comes over without

^ Linnemann, Ann. Chem, Pharm, czlviii. 249.

' Loc, cU. ' Gal, Ann. Chem. Pharm. cxxix. 53.

^ Guthrie, Ann. Chem. Pharm. ciiL 335.

* Proc. Roy. Soc. vii. 38.

• Jaquemin and Vosselniann, Compt. Rend. xlix. 371.

L L 2

618 THE ETHYL GROUP.

Acetamide forms colourless needles, whicli have a strong smell
resembling that of the excrement of mice. They melt at 78**,
forming a liquid which solidifies to a crystalline mass. This
boils at 222^ is easily soluble in water and alcohol, but insol-
uble in pure ether. When heated with water it decomposes into
acetic acid and ammonia. In the presence of alkalis or acids
this decomposition takes place more quickly. It may be heated
alnlbst to 360** without suflfering decomposition. Distilled with
phosphorus pentoxide or zinc chloride it is converted into aceto-
nitril with loss of water, and at the same time some quantity of
acetic and hydrocyanic acids are formed. When brought into
the animal body it passes out in the urine unaltered (Bodecker).

Acetamide acts as a weak base and combines with a few
of the strong acids.^ The hydrochloride, (C2HjO.NHj)2HCl, is
obtained by passing gaseous hydrochloric acid into an alcohol-
ether solution of the amide. It forms long sharp needles with
a strong acid taste, and is soluble in water and alcohol, but not
in ether. The alcoholic solution, on standing for some time,
deposits crystals of sal-ammoniac. In the preparation the
compound, C2H30NH2,HC1, is first formed, and this readily
passes into the foregoing body by loss of hydrochloric acid.*

If acetamide be dissolved in cold strong nitric acid, and the
solution allowed to evaporate, colourless crystals of the com-
position CjHjO.NHjtHNOs, are formed, and these, on heating,
first fuse and then deflagrate.

Like the other acid-amides the hydrogen in acetamide can
be replaced by certain metals (Strecker). Of the products thus
formed, silver a^tamide, CjHjO.NHAg. and mtrcury acetamide^
(C2H30.NH)jHg, are the most important

Ethyl Acetamide, Cfifi.^'B.{Cfi^, was obtained by Wurtz,*
by evaporating a solution of ethylaminc and ethyl acetate, as
well as by acting on ethyl isocyanate with glacial acetic acid :

N { ^^^ + 0,H,O.OH = N j cJhJo + CO

It is also formed by heating othylamine acetate.^

It is a thick colourless liquid, soluble in water, boiling at
20.5^ Dry chlorine gas converts it into chlortthyl cuxtamidr,

^ Strecker, ^nii. Chun. Pharm. ciii. 821.

* Pinner ADd KlHn, Ber. Dtularh. Chtim. G^n. x. 1889.

* Ann, Ch^m. Pharm. Ixxvii. 834.

* Linnemann, Wien, Akad, Ber, Ix. 44.

ACETAMIDE. 519

C2H30.NC1(C2H5), a neutral mobile liquid, which has a faint
camphor-like smell, and easily undergoes decomposition.^ .

336 Diacetamide, (CjHgO)^!!, was first obtained by Strecker
by heating acetamide hydrochloride in closed tubes to 200^ as
well as by acting on beated acetamide with hydrochloric acid.
It is then formed hf the following equation :

2 U-? H + HCl = N J aHoO + NH.Cl.

The distillate, which contains some acetyl chloride, acetonitril,
and much free acetic acid, as will be explained hereafter,
solidifies to a mixture of acetamide and diacetamide. This
is dissolved in ether and hydrochloric acid passed in, when
acetamide hydrochloride separates out, whilst diacetamide
remains in solution.^ It is also formed in small quantity by
the action of acetyl chloride on acetamide (Kekul^), as well as
when acetonitril is heated with glacial acetic acid to 200"* — 250^^
Its formation is perfectly analogous to that of acetamide from
acetonitril and water.

Diacetamide is easily soluble in water, alcohci, and ether, and
^ccystallizes in long needles which melt at 74° — To"* (Wichelhaus),
the liquid boiling at 215° (Linnemann). It is distinguished
from acetamide by not possessing basic properties, but acting
as a weak acid, turning litmus red, and forming a silver salt
which has not been specially examined.

JEthyl Diacetamide, N(C2H30)2C2H5, is a colourless liquid
boiling at 185° — 192°, obtained by Wurtz by acting on glacial
acetic acid with ethyl isocyanate at a temperature of 180° — 200°.

337 Triacetamide, N(C2H30)3, is formed with difficulty by heat-
ing acetonitril with acetic anhydride to 200°. It crystallizes from
anhydrous ether in small elastic needles, which melt at 78° — 79°,
are odourless, possess a perfectly neutral reaction, and do not
exhibit any basicity. This is easily explained, inasmuch as the
basic character of the ammonia is altogether destroyed by the
replacement of the three hydrogen atoms by three acid radicals.
It however does not possess the character of an acid, because it
does not contain any hydrogen replaceable by a metal, whilst
diacetamide is a stronger acid than acetamide.

^ Tscherniak and Norton, Compt. Rend. Ixxxvi. 1409.
' Ann, Chem, Pharvi. ciii. 321.

' Kekule, Lehrb. i. 574 ; Gautier, CoDipt. Rend. Ixvii. 1255 ; Linnemann,
jrien, Akad, Brr. Ix. 44.

520 THE ETUYL GROUP.

Acetdianiine,CfiQif2' — ^^^ hydrochloride of this base remains,
mix^d with sal-ammoniac, in the residue obtained in the prepa-
ration of diacetamide from acetamide and hydrochloric acid. It
may be separated from sal-ammoniac by dissolving it in a mix-
ture of ether and alcohol. It crystallizes in colourless prisms, and
with platinum chloride forms the compound (C2H^Nj,HCl)2PtCI^.
It is easily soluble in water, and on evaporation is deposited in
reddish-yellow crystals. If the hydrochloride be treated with
silver sulphate, the sulphate of acetdiamine, (C2HgN2)2SO^Hj, is
obtained, and this separates from alcoholic solution in pearly
scales. Tlie free base cannot be prepared, inasmuch as in
presence of water it decomposes into ammonia and acetic acid.
Its formation and constitution are seen from the following
equation :

CHg CJMj CH3.

-7

C(^B)y

CO.NH2 CO.OH C(NH)NH2.

Tawildarow, who repeated Streckcrs experiments on heating
acetamide and hydrochloric acid, obtained only a mixture of
sal-ammoniac and acetamide.^

338 Acetyl Carhmiide or Acetyl Urea,CO{^B.^{^Yi,Gfifi>),
is produced by heating urea with acetyl chloride to 120". It
crystallizes from water, in which it is easily soluble, in stellar
prisms. It is difficultly soluble in alcohol, and separates from
alcoholic solution in four-sided silky needles. It melts at 200**,
and solidifies to a crystalline mass, which, when dissolved in
alcohol, deposits thick rhombic prisms.^

Diaccft/l Carbamide, CO(NH.C2H30).„ is produced by heating
urea with carbonyl chloride to 50°, whilst at the same time
acetyl chloride, sal-ammoniac, carbon dioxide, and acetonitril
are formed. Diacetyl urea crystallizes from hot alcohol in
rhombic needles, which on heating first melt and then
sublime.'

Acetyl Cyanide, C^HgO.CN, is obtained by heating silver
cyanide with acetyl chloride to 100\ It is a colourless liquid,
boiling at 03°, and its vapour poi-sesses a density of 2*4. It
has a smell analogous to that of hydrocyanic and acetic acids,

* 7?T. lkH*3th. Chnn. Hex. v. 477.

- /inin, Ann, Chem. Phirm xcii. 40.3.

• K. Sell III Mt, Jouni. Pritli. Chrm, ['Jj, v. O;'*.

ACETONITIIIL OR METHYL CYANIDE. 521

and is insoluble in water, swimming on the surface of this
liquid like oil, and being gradually converted into these two
compounds.* Owing to its easy decomposability, it must be
assumed that this compound is related to the carbamines,
and that the cyanogen in this is connected with the acetyl
group by means of nitrogen. If, however, it be heated
with hydrochloric acid it is transformed into pyro-racemic
acid, CH3.CO.CO.OH, and hence it behaves as the nitril.
of this acid.^ It is, therefore, probable, that this latter is
formed only under the action of heat, or in the presence of
hydrochloric acid.

Acetyl cyanide is easily converted into the polymeric com-
pound (021130)2(0 N)2; this forms large tabular crystals, melting
at 69°, and remaining liquid for some time. This boils at 208°-
209°, and yields a vapour which has a density of 4*9 to 5 0.
It decomposes with water into hydrocyanic and acetic acids.
(Hiibner).

Acetyl TJiiocyanate, OgHgO.SON, is formed by the action of
acetyl chloride on lead thiocyanate. It is a colourless liquid,
which becomes red on exposure to air, attacks the eyes
violently, and boils at 131° — 132°.3 This compound may perhaps

be acetyl mustard-oil, N -! p^ ^

ACETONITRIL AND ITS DERIVATIVES.

339 Acetonitril or Methyl Cyanide, OH3CN, was discovered by
Dumas* in 1847, who obtained it by distilling ammonium
acetate with phosphorus pentoxide. In conjunction with
Leblanc and Malaguti, Dumas afterwards prepared it by dis-
tilling potassium cyanide with potassium ethyl sulphate. The
authors state that the c(»mpound thus prepared is mixed with
hydrocyanic acid and ammonium formate, which impart to it
a most unpleasant smell and taste, and render it poisonous.
These impurities may, however, be got rid of by heating it

' Hiibner, Ann. Chcm. Pharm. cxx. 334.

- Claiseii and Shadwell, Ber, Deutsch. Chcm, Gts, xi, 1563.

^ Mi<iuol, Compf. Rend. Ixxxi 1209.

^ Compt, llend. xxv. 383.

622 THE ETHYL GROUP.

with mercuric oxide, and then distilling with phosphorus pent-
oxide. The poisonous properties then, to a great extent, dis-
appear. ^ We now know that the unbearable odour arises from
an admixture of the isomeric methyl carbamine (see p. 224),
and this may easily be got rid of by treatment with dilute
sulphuric acid.^

Pure acetonitril is likewise obtained, according to Hofmann
and Buckton, by mixing equal volumes of acetamide and phos-
phorus pentoxide, when a rapid evolution of heat takes place and
the compound distils over :

CH3.CO.NHj = CH3.CN + H,0.

The product is then washed with dilute caustic potash in order
to remove hydrocyanic and acetic acids, and dried over phos-
phorus pentoxide.*

It may likewise be prepared by boiling acetamide with some
glacial acetic acid, and passing the vapour through a distillation-
tube, suggested by Bel-HenniiiQ^, which is so long that the
undecompoaed amide flows back again, whilst water and the
nitril distil over. This decomposition, however, only takes
place very slowly.*

Acetonitril is also found in the products of distillation of the
beet-root vinasse,^ and likewise occurs in coal-tar naphtha. It is
a colourless liquid, which at O*" has a specific gravity of 0*8052,
possesses on ethereal and aromatic smell, and boils at 82"
(Oautier). It is singular that on addition of alcohol the boiling
point of this substance is considerably reduced. The mixture
which boils at the lowest point is one containing 44 per cent,
of the nitril, and the boiling point is lowered to 72'''6, whilst on
further addition of alcohol it again rises. In order to separate
the acetonitril from admixture with alcohol, the whole is
frequently distilled over calcium chloride from a water-bath, and
tho last traces of alcohol removed by distillation over phos-
phorus pentoxide. Methyl alcohol acts similarly to the ethyl
alcohol/

The vapour-density of acetonitril is 1*45 (Dumas). When

^ Compi, Bend, xxv. 442 and 474. - Gautior, Hull. Av. Chim. 12], ix. 2.

' Ann. (*hem, PKarm, c. 130. * I>«in*i\M', BulL Soc. Chim, xzxiii. 456.

• Vincent, Buil. Sik-. Chim, xxxi. 15«.

• Vincent and DelAohanal. Bull, Soc, Chim, xxxiii. 405.

ACETONITRIL. 5i3

ignited, tne nitril burns with a bright red-mantled flame. It
is miscible with water, and when heated with caustic potash
acetic acid is formed (Dumas). When its solution in absolute
alcohol is treated with hydrochloric acid or sulphuric acid it
forms ethyl nitrate.^ When mixed with an equal number of
molecules of dry hydrobromic or hydriodic acids, it forms crys-
talline compounds which have not been fully investigated.^
Heated with bromine to 100^ it forms the compound
CjHjNBr^ a slightly yellow crystalline mass, which Aimes on
exposure to air, melts when gently heated at 65^ and sub-
limes in apparently rhombic prisms. When silver nitrate
is added to its alcoholic solution, only half of the bromine is
precipitated, and hence it is probably bromacetonitril hydro-
bromide, CH^rCN.HBr.*

Phosphorus pentoxide dissolves readily in acetonitril ; and if
this liquid be distilled at first, a portion of the acetonitril
passes over, and afterwards a gelatinous residue remains behind,
resembling silicic acid. This is a compound of phosphorus
pentoxide with acetonitril, and decomposes into its constituents
when more strongly heated (Vincent and Delachanal).

When acetamide is distilled with phosphorus pentachloride,
and the distillate rectified, that portion being collected by it-
self which boils at 72"*, a colourless thin liquid is obtained,
having the composition CgHgNPClj. This has a strong smell,
and attacks the eyes and mucous membrane. It sinks, when
poured into water, and decomposes after a short time into
phosphorous acid, hydrochloric acid, and acetamide.

When heated with an equal number of molecules of titanium
tetrachloride, tin tetrachloride, or antimony pentachloride,
acetonitril combines directly to form white crystalline com-
pounds capable of being sublimed, and of being decomposed
bv water.*

Ci/anmethine, C^H^Ng, is formed by the action of sodium on
acetonitril, when at first a violent action takes place, but the
action must be stimulated afterwards by warming on a water-
bath. In this reaction marsh gas is evolved, together with
other products (see Cyanethine).

The cyanmethine or trimethyl cyanuride thus obtained is

^ Backantz and Otto, Ber. Deutach. Cfwm. Ges. ix. 1590.
' Gautier, Ann. Chem. Pharm, cxliL 289.

• Eogler, Ann. Chem. Pharm, cxxix. 124 ; cxxxiii. 137 : cxlii. 65.

* Henke, Ann. Chfm, Pharm. cvi. 272.

624 THE ETHYL GROUP.

soluble in water, aifficultly soluble in alcohol, and crystallizes
in monoclinic prisms which melt at 180° — ISl**, and sublime in
white needles. It has a bitter taste, like quinine, and its vapour
has an irritating smell. Cyanmethine is a monacid base. Its
salts, as a rule, crystallize well, and, like many organic bases,
it combines with iodine in alcoholic solution, when crystals are
formed of the composition CgH^NjIg. These appear red by
reflected and yellow by transmitted light. When exposed to
the air, or on heating with water, they give up iodine. The
hydriodide also unites with iodine to form the compound
CgH^NyHI.Ig, forming crystals which are violet by reflected
and orange-yellow by transmitted light. This compound can
take up another molecule of iodine, when dark-blue prisms are
formed ; but this body owing to its extreme unstability has not
yet been obtained in the pure state.^

340 Fulminic Acid or NUro-acetonitril, G^^Q^O^Cl^. — In the
Philosophical Transactions for the year 1800,* Howard states
that he had found that when mercury is heated with nitric acid
and alcohol an explosive compound is formed. This compound
was afterwards known as Howard's fulminating mercury. The
same chemist then proved that a similar compound was formed
in the case of silver, as indeed Brugnaletti ^ had also shown.
Howard* believed that fulminating mercury was a compound
of nitrous ether (or, as he termed it, " nitrous etherized gas ")
and oxalate of mercury, with an excess of oxygen. Brugnaletti,
on the other hand, considered the explosive body to be oxalate
of silver. Again, at a later date, it was believed to be a double
salt of oxalate of ammonia and the oxalate of mercury or silver.
This view of the composition of these explosive bodies was held
until 1822, when Liebig, in his first research, showed that they are
the salts of a peculiar acid to which he gave the name oi fulminic
acid, and the composition of which he sought to determine.*
This was definitely ascertained in a research which he made in
1824 in association with Gay-Lussac,® in which it was shown
that fulminic acid possesses the same composition as cyanic
arid. As, however, at this period, the existence of isomeric
b<j<lics had not been proved, it was nut deemed possible that
bodies possessing properties so totally different could have an

» Bayer, Bcr. IkuUch. Chtm, Oea. ii. 319; iv. 176 -• Part i p *>04

3 Ann. dr Chim. xxvii. (179S), p. 331. * Phil. Trans. l80o! p! 222!

» Ann. dr. Chim. xxiv. 294 (1823). ' *

« lb. XXV. 28 ) (li>J4). C'oiin»«rc also Lkl»i;(, Ann. rhnn, Pharm. 1. 429.

Fl'LMlNIC ACID. 525

identical composition. Liebig, therefore, in 1825 suggested that'
perhaps cyanic acid contains somewhat less oxygen than fulminic;
but this was disproved by Wohier in the same year. Shortly
afterwards Liebig ascertained beyond doubt that fulminate and
cyanate of silver have the same composition.

Respecting the constitution of the first of these acids, a
variety of views were put forward. That it contained cyano-
gen was shown by the fact that, in a variety of decompositions,
its salts yield hydrocyanic acid. Laurent and Gerhard t were
the first to propose the view that it is a nitro-compound, and
they considered it as a secondary nucleus derived from the
primary nucleus, C2H^, namely, C2N(N02)H2. The investi-
gations of Schischkoflf^ and Kekuld^ then proved that fulminic
acid, which is not known in the pure state; must be regarded
as nitro-acetonitril. Being a nitro-compound, it possesses
acid properties, and forms salts, all of which are highly
explosive. Of these fulminate of mercury is prepared on the
large scale.

Silver Fulminate, C2(N02)NAg2. — In order to prepare fulmi-
nating silver the following process is recommended by Liebig and
Gay-Lussac. One part of silver is dissolved in 20 parts of nitric
acid of specific gravity 1*36, and 27 parts of 86 per cent, spirit
of wine added, and the whole gently heated until it froths up.
The liquid is then removed, and 27 parts or more of spirit of
the same strength added, in order to reduce the violence of the
reaction. Fulminating silver separates out on cooling, the
weight of which is equal to that of the metal employed. The
reaction is represented by the following equation :

CH5.CH,.0H + 2 AgNOa + ^J^z = CN.CAgj(N02) + 2 HNO3 + 2 HjO.

The nitrogen trioxide required for this reaction is obtained
by the action of the nitric acid on the alcohol. That the above
correctly represents the reaction was proved by Liebig, inasmuch
as he showed that it is also obtained when nitrogen trioxide is
passed into an alcoholic solution of silver nitrate.^ Silver
fulminate crystallizes in white opa^^ue glistening needles, having
a bitter metallic taste, and being scarcely soluble in water.
It has been shown that, given in certain doses, it produces
violent convulsions (Pagot-la-Foret), while in doses of 0 3 gram
it acts as a narcotic (Ittner).

* Ann, Cficm, Pfumn. ci. 213 ; Suppl. i. 101. '^ lb, ci. 200; cv. 279.

•* Ann, Pharni. v. 287.

526 THE ETHYL GROUP.

Fulminating silver is an extremely dangerous body, as it ex-
plodes most violently on percussion or on heating, emitting a blue-
reddish-white flame (Liebig). It is therefore necessary that the
greatest care be taken in its preparation. Large vessels must be
employed, in order that none of the liquid may froth over and
afterwards dry up and the dry mass explode. The vapours which
are evolved must not come in contact with any flame ; and when
the liquid is stirred, a wooden stirrer, aad not a glass one, must
be made use of. It even explodes in the moist state, but not
so readily as when dry. Hence it must be taken up only with
paper, and kept in vessels of paper or cardboard, and not placed
in a glass bottle, where the friction of the stopper might cause
explosion. If fulminate of silver be thrown into a bottle con-
taining chlorine, it deflagrates before it touches the bottom*, and
does not crack the vessel (E. Davy). When ignited under a
diminished pressure amounting to 2 to 3 mm. by means of a
platinum wire heated by an electric current, it burns slowly with
a visible flame. It dissolves in hot aqueous ammonia, and
on cooling white crystalline grains separate out of ammonium
silver fulminate, C2(N02)NAg(NH^). This explodes more vio-
lently than silver fulminate, and deflagrates even under a
liquid when it is touched with a glass rod. If fulminate of
silver be heated with water to the boiling point, and potassium
chloride added as long as an opalescence is produced, potasgium
silver fidminatc, Q^(^0^^ kjgK., is formed, and this, on evapor-
ating the solution, is deposited in long, white, glistening tab-
lets, which are also very explosive. Similar double salts are
also formed with the chlorides of the other metals of the alkalis
and alkaline earths. When nitric acid, not in excess, is added
to a solution of the potassium salt, hydrogen silver fulminate,
C2(N02)NAgH, is thrown down as a white powder, which can
be obtained in crystals from hot aqueous solution and has an acid
reaction. If this be boiled with mercuric oxide and water, a
double salt of the fulminates of mercury and silver is obtained
(Liebig).

341 Mercury Fulminate, Cj(NO,)NHg. — Various methods have
been published for the preparation of this compound. Accord-
ing to Liebig it is best prepared on the small scale as follows.
Three parts of mercury are dissolve<l in 36 parts of nitric ftcid
of specific gravity 1*34, without warming. After complete
solution the liquid is poured into a glass flask which is capable
of containing 18 times the quantity, and containing 17 parts

FULMINATING MERCUKY. 527

of alcohol of from 90 to 92 volumes per cent. The liquids axe
then well mixed and again poured into the first vessel, which is
of the same size, shaken in order that the nitrous fumes shall
be absorbed, and the whole then allowed to stand. After a
few minutes, bubbles are seen to be evolved, and a highly
refracting liquid is seen to separate out on the bottom of the
flask, and the whole is then well shaken up so as to mix this
with the rest. The liquid then becomes black, with separa-
tion of metallic mercury, and a very violent reaction takes place,
which is moderated by the gradual addition of 17 parts of
alcohol. Thin crystals of mercuric fulminate separate out oa
cooling.

On the large scale it is best prepared by dissolving 1 part of
mercury in 10 parts of nitric acid of specific gravity 1'33, and
to every kilogram of the acid 1 liter of alcohol of specific gravity
0833 is added. The reaction generally begins spontaneously,
but sometimes it has to be induced by slight warming. The
operation is carried on either in a tubulated retort, in which
case the gases evolved, consisting of nitrous fumes, hydrocyanic
acid, &c., are led into a flue, or large glass balloons are em-
ployed, and the decomposition carried on in these in an open
wooden shed. The reaction is left to itself as soon as the
alcohol has been added, and the operator does not again
approach the shed until the operation is complete.

Fulminating mercuiy forms white or often grey-coloured
prisms, which are anhydrous and have a specific gravity of
4*42. It is insoluble in cold water, and crystallizes from hot
water in silky needles which have the composition 2C2(N02)NHg
+ HgO (Schischkoflf) and have a sweet metallic taste. Warm
aqueous ammonia at 30° — 35*^ dissolves about four times its
weight of mercuric fulminate, and on cooling large finely
developed prisms separate out (Steiner).

Mercuric fulminate explodes violently on percussion, but
when ignited with a flame it only bums quickly like gun-
powder, and with a reddish flame, the following decomposition
taking place :

CHg(NO^CN = 2 CO + Ng + Hg.

In the moist state it can be handled without danger, and when
heated to 100** it does not explode if the crystals do not con-
tain any inclosed mother-liquor. If this be the case, how-
ever, they decrepitate on heating, and the flame thus produced

528 THE ETHYL GROUP.

may cause violent explosions to take place below 100^ Hennell,
whose name has formerly been mentioned, and who was chemical
operator to the Apothecaries' Company in London, was killed in
1842 when conducting experiments on filling hand-grenades
with fulminating mercury to be used in the first Afghan war.
The effects of the explosion of this compound are, however, only
felt at a short distance from the point of explosion. Thus, the sub-
stance may be detonated by heat in a glass tube from 2 to 3 cm.
in width without the tube being broken, the metallic mercury
which is formed condensing on the cold parts of the tube.^
The pressure exerted by the gases which are evolved by the
decomposition of fulminating mercury is less than that caused
by the explosion of an equal weight of gun-cotton, the much
greater action of the former detonating agent being accounted
for by the density of the compound, and by the fact that the
decomposition occurs in an infinitely short space of time. For
this reason, the gases evolved, at the first moment are actually
compressed into the volume of the solid compound, and a pres-
sure of no less than 48,000 atmospheres is exerted on a solid
surface exposed to the detonating agent. Berthelot and Vieille
have recently exploded fulminating mercury in a steel bomb-
shell of such dimensions that the final pressure did not rise
above fifty atmospheres, and yet a distinct impression of the
solid salt was made in the steel where the detonator was placed.
Fulminating mercury was formerly solely used for the prepa-
ration of percussion caps, and it is still used for this purpose ;
but it is now employed on a much more extensive scale for the
manufacture of the detonators used for exploding gun-cotton,
dynamite and other nitro-glycerin preparations.

Mercuric fulminate readily forms soluble double salts with
potassium cyanide, potassium thiocyanate, and ammonium
thiocyanate (Steiner).

Other metallic fulminates can easily be obtained from mer-
curic fulminate.

Zinc Fulminate, C2(N02)NZn. — A solution of this salt is ob-
tained by leaving zinc and water in contact with mercuric fulmi-
nate. On allowing the solution to evaporate spontaneously clear
rhombic tables of the above salt are obtained, and these are very
explosive. If baryta water be added to the freshly-prepared so-
lution until no further precipitation takes place, and the barjta
contained in solution be precipitated by means of carbon dioxide

' Silliman, Amrr. Jouni. (1819), i. 169.

DECOMPOSITION OF THE FULMINATEa 529

and the solution evaporated, bright four-sided prisms separate
out from the syrupy residue, consisting of a double salt of ba-
rium fulminate and zinc fulminate. If this be decomposed uith
the exactly necessary quantity of sulphuric acid, a liquid is ob-
tained which has a smell resembling hydrocyanic acid, and a taste
which is at first sweet and afterwards pungent and astringent.
This dissolves various bases, giving rise to double salts contain-
ing zinc, which were investigated by E. Davy,^ and looked upon
by him as pure fulminates. This, however, was shown by Fehl-
ing ^ to be erroneous. These are chiefly soluble in w^ater, possess
a sweetish taste, precipitate a silver solution, and are explosive.

Coffcr Fulminate, C2(N02)NCu, is obtained by boiling copper
with water and mercuric fulminate. It forms green crystals,
diflScultly soluble in w^ater, which when heated explode violently.

342 Decompositions of the Fulminates. If a fulminate be dis-
tilled with bleaching powder and water, chloropicrin is formed,
and this is also produced, together with cyanogen chloride,
by the action of chlorine :

CHg2(N02)CN + 3 CI2 = CClgNOg -h CNCl + HggClg.
Bromine acts in a similar way, but at the same time dihrom,-
nitro-acetoniti-il, C^Q^iO^li^Br^, is formed. This is insoluble
in water, and separates out from ether and alcohol in large well-
formed crystals, which smell like chloropicrin, melt at 50°, and
begin to decompose above ISO"*, but may be distilled in a cur-
rent of steam. If iodine be added to mercuric fulminate in
the presence of ether, di-iodo-nitro-acetonitril, C2(N02)Nl2, is
formed. This separates out in large monoclinic prisms on
evaporating the solution, which melt at 86° with decomposition.*
By the action of sulphuretted hydrogen on the fulminates,
ammonium thiocyanate and carbon dioxide are produced, to-
gether with a metallic sulphide. According to Steiner,* a very
unstable intermediate product is obtained, having the composi-
tion C2H^N202S, produced by the combination of sulphuretted
hydrogen with nitro-acetonitril, and possessing the following
constitution : C(N02)H2

NH2.

^ Trans. Dubl. Soc. 1829 ; Berzelius, Jdhrcsh, xix. 95 and 120.

' Ann. Pharm. xxvii. 130.

' Sell and Biedemianii, Ber. Deufsck. Chein, Gcs. r. 89.

* Bcr. Dentaeh. Chem. Gcs, viii. 1177 ; ix. 779.

VOL. 111. M M

630 THE ETHYL GROUP.

In order to obtain this in the pure state, ether is poured on to
mercuric fulminate, and sulphuretted hydrogen led into the mix-
ture, which is kept well cooled. On allowing the ether slowly to
evaporate spontaneously, the above compound separates out in
microscopic crjstals. If it is gently warmed with water it is de-
composed into the above products, and when quickly warmed sul-
phur separates out. The body undergoes the same decomposition
at the temperature of summer' in a few hours. By the further
action of sulphuretted hydrogen on the ethereal solution, am-
monium thiocyanate, oxalic acid, and free sulphur are obtained.
If mercuric fulminate be heated with aqueous ammonia, urea
and guanidine are formed, together with other substances (Steiner).
Gladstone also obtained urea, together with ammonium thio-
cyanate, by acting with sulphuretted hydrogen on a solution of
copper fulminate in an excess of ammonia.^

FuLMiNURic Acid, or Isocyanuric Acid, C3H3N3O3.

343 This compound was obtained almost simultaneously by
Liebig ^ and by SchischkoflF.^ It is formed by boiling a soluble
metallic chloride or iodide with water and mercuric fulminate :
2 C,(NO JNHg + HgO = G^(i!i0^n^^fi + COg + NH3.

It is also produced, together with ammonium thiocyanate, by
acting on an aqueous solution of barium sulphide with mercuric
fulminate (Kekule), as well as when the same is warmed with
alcoholic solution of ammonia, when the basic mercuric salt is
formed (Steiner). In order to prepare the acid, from 60 to 75
grams of well-washed mercuric fulminate are boiled with 700 to
800 cc. of water and GO cc. of a saturated solution of sal-
ammoniac until the yellow crystalline precipitate of oxy-di-
mercuric ammonium chloride, NHjHggOCl, separates out The
flame is then removed, and ammonia added to the solution ia
order to precipitate the mercury as mercury ammonium chloride.
On evaporating the filtrate impure ammonium fulminurate is
obtained, which can be purified by recrystallization.

On precipitating with acetate of lead the insoluble basic
lead fulminurate is obtained, and this is then decomposed by
sulphuretted hydrogen. Instead of the lead salt, the difficultly
soluble silver fulminurate may also be employed, and this may
be obtained from the potassium salt, whose preparation is
described below.

> Juurn. rhrui, So^ i. 22S (1849). ' Ann. Chan, Pharm, «cv. 282.

' Ann. Chan. Pharm. xcvii. AS; ci. 213 ; Suppl. i. 101.

FULMINURIC ACID. 631

On evaporating the aqueous solution of fulminuric acid, a
syrupy liquid is obtained, which, when placed in a warm situa-
tion, solidifies to an indistinctly crystalline mass, crystallizing
from alcohol in small colourless prisms. It has an acid taste and
reaction, and decomposes on heating with slight deflagration.

Potassium Fulminicrate, CgHgBLNgOy In order to prepare
this salt two parts of mercuric fulminate are gradually added
to a saturated solution of one part of potassium chloride, and
the mixture boiled gently until the whole is dissolved. It is
then filtered through a warmed filter, and on cooling deposits
a curdy precipitate consisting of a compound of the potassium
salt with mercuric oxide, and this may be decomposed by
sulphuretted hydrogen. Potassium fulminurate crystallizes
from solution in hot water in colourless, long, glistening, highly
refracting prisms, which decompose with incandescence when
heated to 225^

Ammonium Fulminurate, C3H2(NHJN303, forms fine, shining,
white, highly refracting needles, melting and blackening at
150**, and evolving hydrocyanic acid, cyanic acid, and ammonia,
which latter partially unite to form urea.

Ouprammonium Fulminurate, CQH^Cu(NH3)^NgOe. When an
ammoniacal solution of copper sulphate is heated with fulminuric
acid to the boiling-point, and the solution allowed to cool, the
above salt separates out in splendid, glistening, dark-blue,
very characteristic prisms. It is scarcely soluble in water, and
slightly soluble in ammonia, permanent in the air, and de-
composes at 150** with detonation.

Silver Fulminurate, CgHgAgNgOg, separates out in long, thin,
silky needles when hot solutions of the ammonium salt and
silver nitrate are mixed and allowed to cool.

The constitution of fulminuric acid is not known with cer-
tainty. From the reactions which follow it appears probably to be

CO.NH.,

C(N02)H

An.

Trinitroacetonitril, CQSO^fil^, is formed when a fulminurate
is gradually added m small quantities to a well-cooled mixture
of concentrated sulphuric acid and nitric acid ;

CN.C(N0.^)II.C0.NH2 + 2 NO3H = CN.C(N02)3 + QO^ + NII3 + H^O.

M M 2

i32 THE ETHYL GROUP.

It is a white crystaUine substance, closely Tesembling campbor,
melting at 41^*5, and decomposing with explosion when heated
to 220^ but may be volatilized in a current of air at GO^ It
is decomposed by water, especially quickly on warming, icto
carbon dioxide, ammonia^ and nitrofonn (see p. 263).

IHniiroacetoniiTil, C(X02)2H.CX. The ammonium corapoun 1
of this body is formed when sulphuretted hydrogen is passed
into an ethereal solution of the foregoing compouud :

CN.CCNOJ3 + 4 H^s = c^^C(^'OJ),^'H^ + 2H5O + 285.

It crystallizes from water in colourless glistening neeilles,
whicli, when gently heated, have a strong smell, and on quick
heating decompose. If sulphuric acid be added to the aqueous
solution and the whole shaken up with ether, a syrupy licjuid
is left on evaporation, from which dinitroacetonitril separates
out in transparent tables. This forms several crystalline salts,,
of which the silver compound, C^S.C^SO^^kg, is as explosive
as -fulminating silver.

Concentrated sulphuric acid acts upon ammonium fulminurate
violently ; carbon dioxide is evolved, and with it a powerfully
smelling body which attacks the eyes and mucous membrane,
and may be condensed to an oily liquid and solidified to crystals.
This compound is easily inflammable, and burns with a light
almost equal to that of magnesium wire. Steiner* considers
that this is nitro-acetonitril, but he could not fix its compo-
sition in consequence of not obtaining a sufficient amount cf
substance.

If the action of sulphuric acid be moderated by cooling
and mixing, a compound isomeric or polymeric with fulminic
acid is obtained according to the equation :

C3H3N3O, + H,0 =. QHoN.O, + NH3 + CO^

This is insoluble in cold water, and separates out from boiling
water in crystals. It has an acid reaction, deflagrates on heat-
ing, and is not altered even by concentrated nitric acid. From
its aqueous solution, mercuric nitrate throws down a white
amorphous precipitate of (C2HNj02)2Hg, which also decomposes
with deflagration when heated.

^ Ber. Dfutseh. Ckem. Ot$, Iz. 782.

SUBSTITUTION PRODUCTS OF ACETIC ACID. 633

SUBSTITUTION PRODUCTS OF ACETIC ACID.

344 The three atoms of hydrogen of the methyl in acetic acid
can be replaced one by one by diflferent elements or radicals.
The mono- substitution products contain the dyad radical ^Zyco/yi,
— CHg— CO— , and these compounds will therefore be described
at a later period, only those being now mentioned which contain
the halogens, as these latter are closely connected with the di-
and tri-substitution products, and these cannot so readily be
genetically connected with any other groups.

Chlorine Substitution Products.

Monochloracetaldehyde, C2H3CIO, is obtained by the action
of sulphuric acid on cblor-acetal, CjHgCl (003115)2, and also by
treating chloi'-ethylene, CgHjCl, with hypochlorous acid in the
presence of mercuric oxide.^ The same compound is contained
in the products of the reaction of phosphorus trichloride on
dichlor-ether.^ It is a powerfully smelling liquid, which has
not yet been obtained in the pure state, and easily oxidizes on
exposure to air with formation of chloracetic acid.

MONOCH LOR ACETIC AciD, CgHgClOg,

Was first prepared in 1844 by Leblanc,^ by acting with
chlorine on acetic acid, but not in the pure state, whereas,
by passing chlorine on to the surface of heated glacial acetic
acid which was exposed to the action of sunlight, R. Hoflfmann *
succeeded in preparing it in the pure condition. For the pre-
paration of this substance on the large scale, the process suggested
by Hugo Muller ^ is the best. For this purpose 500 cc. of acetic
acid of 95 per cent, are mixed with about 50 grams of iodine
in a large flask having a long wide tube attached to its neck,
and then the whole heated to the boiling point, whilst a steady
current of dry chlorine is passed into the liquid. The hydro-
chloric acid which is evolved, passes away through a side-tube

» Saytzeff and Glinsky, ZeitsrJi, Chrm. 1867, 675 ; 1868, 617.

• Aleljanz, Ber. Deutsch. Chem. Ges, • Ann, Ckim, Phys. [3], x. 212.

* Ann, Chcm. Pharm, cii 1. • Journ, Chem, i>oc xvii. 398.

534 THE ETHYL GROUP.

whilst the vapours condense and flow back through the long
neck of the retort. A violent reaction begins as soon as iodine
trichloride is formed. The mixture is well heated for some time
to the boiling-point, even after the chlorine has been passed
in for some days, until vapours of free iodine make their appear-
ance, due to the decomposition of some iodacetic acid which is
formed. Then the product is submitted to fractional distillation,
and the portion which passes over below ISO"* is again treated
with chlorine, whilst the portion between 180** and 188** solidifies
on cooling, and can be purified by recrystallization and
rectification.

Pure monochloracetic acid is also easily obtained by acting
upon acetic anhydride, placed in a water-bath, with chlorine :

c^hJo } o + CI, = c,H,cio, + c,h;cio.

Acetyl chloride then distils off, and the residue consists of
chloracetic acid, which may be purified in the way already
described.^

Monochloracetic acid solidifies, on slow cooling, in long needles,
and crystallizes from glacial acetic acid in large transparent
rhombic tables. When carefully heated it sublimes in pointed
needles, which melt at 62**, and boil between 185** and 187%
yielding a vapour which at 203° has a specific gravity of 3*81, and
this density diminishes as the temperature rises ; at 270** it is
3*283, whilst according to theory the number is 3*263 (Cahours).
The specific gravity of the fused acid is 1*3947 at 73° compared
with water at the same temperature. It deliquesces in the air,
has a slight smell when cold, which on heating becomes stronger
and more pungent. When brought on to the skin it produces
blisters and destroys the epidermis. Hence it is frequently used
for the cure of warts and corns. When a tolerably concentrated
aqueous solution is boiled, hydrochloric acid and oxyacetic acid
or glycoUic acid, C2H3(OH)Oj, are formed. Its salts decompose
in a similar way on heating with water. Most of them are
easily soluble and crystallizable.

Potassium Monochlor acetate, 2C^^\0j&. -f 3H2O, crystallizes
on evaporation in a vacuum over sulphuric acid in non-deli-
(luescent tablets, which decompose easily on heating. It combines
with chloracetic acid to form a difficultly soluble salt, having

' Uiil, A,i.K iVtitn. Phyn. [IK], Ixvi. 18".

MONOCHLORACETIC ACID. 535

the composition CgHgClOgK -f CgHjClOg, which crystallizes in
pearly scales.

Barium Monochloracctate, (C2H2C102)2Ba + SHgO, crystallizes
from hot saturated solution in small rhombic prisms.

Silver MonocMoracctatey CgH^ClOgAg, is difficultly soluble in
cold water, and forms pearly glistening scales which easily
blacken on exposure to light, and deflagrate when heated from
110° to 120.^

Ethyl Monochlor acetate, C^HgClOgCgHg, was first prepared by
Willm^ by the action of chloracetyl chloride on alcohol. It is
also formed by passing hydrochloric acid into a mixture of chlor-
acetic acid and alcohol.^ In order to prepare this ether, the
solution thus saturated is distilled until the residue divides
into two layers. The upper one is poured ofif, washed "^^dth
water, and then dried over calcium chloride, and the pure ether
is separated by fractional distillation.* It is also obtained easily
by distilling a mixture of sulphuric acid, chloracetic acid, and
alcohol.

Ethyl monochloracetate is a colourless liquid, heavier than
water, possessing a burning taste and an ethereal smell. It
boils at 143°*5, and its vapour, which has a density of 4*46
(WiUm), attacks the eyes.

ifonocJdoracetyl Chloride, ^ ^ c\\^ ^^ ^^^ prepared by

Wurtz * by the action of chlorine on acetyl chloride. It is easily
formed when iodine is also added ,^ and is likewise produced by
the action of phosphorus trichloride on aramoniacal acetic acid.*
It is a liquid which boils at 110*', possesses a strong smell, fumes
in the air, and acts in a similar way upon water and alcohol
as acetyl chloride does.

Manochloracetyl Bromide, ^ ^ I jg formed by the action

of bromine on a mixture of chloracetic acid and amorphous
phosphorus. It is a liquid boiling at 127°, the vapour of
which acts powerfully upon the eyes (Gal, De Wilde).

Monochloracetamide, C2H2CIONH2, is obtained by the action
of ammonia on the corresponding chloride or on the ethyl

^ Ann. Chim. Phys. [3], xlix. 97. ^ lleintz, Pogrf, Ann, cxiv. 440.

•* Menschutkin and Jemiokajew, Zcitsch. Chcm. 1871, 5.

• Ann, Chim, Phys, [8], xlix. SS.

• JazukoTi'itsch, Zeitsch, Chcvi. 1868, 234.

• De Wilde, Ann. CJinn. Plvniii. cxxx. 372; (lal, ih. cxxxii. 177 ; Ball. St*r..
Chtm, [2], i. 428.

63G THE ETHYL GROUP.

compound ether (Willm). It crystallizes from aqueous solution
in prisms, and from alcohol in glistening tablets. It melts at
119°*5, and sublimes at a higher temperature. When distilled
with phosphorus pentoxide, chloracetonitrU, CoHgClN, is formed,
a liquid which boils at 115°— 120^*

Monoddoracetijl Plwsphamide, CgHgClOPHo, is formed by the
action of phosphuretted hydrogen on the chloride as a yellowish
powder, which on exposure to moist air decomposes into
chloracetic acid and phosphuretted hydrogen.^

DiCHLORACETIC ACID, CoHgClgO^,

345 Was obtained by Miiller as a by-product in the prepara-
tion of monochloracetic acid, and by Maumen(5^ by exposing the
latter substance in a large balloon to the action of dry chlorine
in the light. The formation of this compound from chloral
or trichloracetic acid, first observed by Maumen^, is of much
interest. He obtained it from this body by the action of
silver oxide."* Wallach* then showed that the compound
ethyl-ether is obtained by the action of chloral upon an
alcoholic solution of potassium cyanide whilst the aqueous
solution of the latter salt, as also of potassium ferrocyanide,
gives rise to the free acid or to potassium dichloracetate.*^
This peculiar reaction is represented by the following equation :

CCI3.COH + KCN + H2O = CHCI2.CO.OH + HCN + KCL

It is thus seen that an atom of chlorine is removed by the
potassium, the cyanogen combining with one atom of tho
hydrogen of the water, whilst the second replaces the atom of
chlorine, and the oxygen converts the aldehyde into the acid.

In order to prepare dichloracetic acid it is best to start from
dichloracetic ether,^ for the preparation of which pure
potassium cyanide must be employed if a good yield be desired,®
and care must be taken to work in a good draught owing to tho
rapid evolution of torrents of hydrocyanic acid. The ether is
diluted with its equal volume of alcohol, and to this the
calculated quantity of alcoholic potash is added, when the

' Engler, Ann. Chcm. Phnnn. cxlix. 297.

- StciiuT, />cr Jkuhrh. C/tem. Get. viii. 11 73.

' Compt, lUnd. lix. 84. * Compt, Rend, Ixi. 953.

» Dcr. Dt'uLsch, <'hnn. Grs. vi. 114 ; Ann, Chcm. P/iarm. clxxiii. 293.

• Jj^T. Ikutsch, Chi'hi. Grs. X. 1525.

7 n^r, n-uffch, r/,r,iK Gru. i.<. 1212. • Ih. x. 477.

CHLORAL. 637

liquid is converted, with evolution of beat, into a thick pasty
mass, consisting of glistening scales of potassium dichloracetate.
These are then washed with alcohol and dried. The salt is
next brought into a tube lying in a slanting position in a com-
bustion furnace, and dry hydrochloric acid led over it until tho
gas escapes at the other end, when the dichloracctic acid is
distilkd off in a current of hydrochloric acid. It is a liquid
which boils at 189** — 191^ crystallizes at 0^ and at 15** has
a specific gravity of 1'5216. It is very caustic, and on heating
evolves suffocating vapours. The salts are chiefly easily
soluble.

Ethyl DicMoracetate, C2HCl202C2Hg, is a liquid boiling at
loQ!" — 157^ and having a specific gravity at 22** of 1*29. By
tho action of ammonia it yields dichIora<:etamide, C^HC1/)2NH,
crystallizing in large rhombic prisms melting at 94*^ 5, and
beginning to sublime at 100°, and being volatile in a current of
steam.

Trichloracetaldehyde, or Chloral, C2HCI3O,

346 Was discovered in 1832 by Liebig, who obtained it by
the action of chlorine upon alcohol,^ its true composition being
first recognized by Dumas in 1834.^ It is formed when nascent
chlorine is brought in contact with sugar or starch.^ Although
it is a trichlorinated aldehyde, it is not formed when chlorine is
passed into aldehyde, as condensation-products are then formed,
as, for instance, trichlorbutyl aldehyde. If, however, water and
calcium carbonate be added, the hydrochloric acid is neutralized,
and the trichlorinated product is tliea formed.'* The view enter-
tained by Liebig and by Regnault,^ that aldehyde is first formed
by the action of chlorine upon 'alcohol, and this afterwards
converted into chloral by substitution, would thus appear to be
untenable, and a more satisfactory explanation of its formation
had to be found. This w^as at last given by Lieben,® as follows :

Aldehyde is first formed :

CH3.CH2OH + CI2 = CH3.C0H*+ 2HCL

The nascent aldehyde acts upon the alcohol with formation of
ethidene diethyl ether or acetal :

CH3COH + 2 HO.C2H5 - CH3,CH(OC2H5)2 + H2O.

1 j4nn. Pharm. i. 189. 2 ^^^^ chim. Phys, Ivi. 123.

' Stadler, Ann, Pharm. Ixi. 101. * Pinner, -5cr. Dcutsck, Chcm. GV.*. iv. 256.

* Ann. Chiin. Phtjs, [2], Ixxi. 420. « Per. DcxUscK Chem, Gcjf, iii. 76, 390.

538 THE ETHYL GROUP.

The acetal is converted into trichloracetal, and this is con-
verted by the hydrochloric acid into ethyl chloride and the
so-called chloral alcoholate :

CCI3.CH { ggA + HCl = CCI3.CH I gg^jj^ + C^H^Cl.

From the solid mass thus obtained the chloral is liberated by
the action of sulphuric acid :

CCls.CH I Q^^ -h H.SO, = CC1,.CH0 + C^gHSO, + H^O.

The chloral is then purified by distillation over quicklime.
It is a colouriess mobile liquid, which boils at OO^G, and
has, at 0°, a specific gravity of 1*5183 (Kopp), and a vapour
density of 513 (Dumas). When cooled in a mixture of solid
carbonic acid and ether, it solidifies to a mass which melts at
— 75°.^ It has a peculiar sweet and pungent smell, and a bitter,
biting taste, and acts, especially in the form of vapour, destruc-
tively on the skin. Nascent hydrogen reduces it to aldehyde.
Like this latter compound, it combines with the acid sulphites
of the alkali-metals to form crystalline compounds, and it
also unites with ammonia to form a body which reduces silver
from its solution in the form of a mirror. When heated with
alkalis it decomposes into chloroform and formic acid :

CCI3.CHO + H,0 = CCI3H + CH^O^.

Chemically pure chloral may be kept for any length of time
without undergoing change ; but if it contains impurities, it un-
dergoes polymerization, and this takes place especially quickly in
presence of sulphuric acid. It is thus converted into metachloral
or insoluble cJdoml, a white amorphous body, insoluble in water,
alcohol, or ether. If heated to 180° — 250^ or with sulphuric
acid, this yields ordinary chloral. Small quantities of anhy-
drous trimethylamine convert chloral violently into a perfectly
white mass, from which, however, the base can again be driven
oflF in a current of air. This body appears to be a mixture
partly of soluble and partly of insoluble polychlorals. If treated
with alcoholic ether, chloral alcoholate is obtained.^ Concen-
trated sulphuric acid converts chloral into chloraUUd, C^HCl^O,,
a substance which will be hereafter described (see Trichlorlactic
Acid).

' Rerthclot, Bull. Soc, Chim. xxix. 3.

' M< yer and Dalk, Jnn. Chrm. Phnrm. rlxxi. 77.

CHLORAL HYDBATE. 539

Chloral Hydrate, C^CIsHO.+HOg or CCl3.CH(0H)

347 This is the most important compound of the group. It is
formed by the direct union of water with chloral, and is pre-
pared on the large scale as it is a most valuable medicine. For
this purpose 25 kg. of absolute alcohol are placed in each of
several large glass balloons, and treated with chlorine conti-
nuously for six to eight weeks. The vessels are surrounded by
cold water, and this is gently heated with steam, so soon as
the chlorine ceases to be absorbed, and then the temperature
gradually allowed to rise to 60°. When the action is complete
the alcoholate is allowed to remain in contact with sulphuric
acid for several hours, at a temperature of 60°, and the chloral
which separates out is rectified over calcium carbonate. It is
then brought in contact with the requisite quantity of water,
and the product purified by recrystallization. As a solvent,
either chloroform or a mixture of ethylene chloride and ethidene
chloride, obtained as a product in the manufacture of the
chloral, is made use of.^

Chloral hydrate crystallizes in monoclinic prisms, which
easily dissolve in water, alcohol, carbon disulphide, and liquid
hydrocarbons, &c. It has a peculiar and, on warming, a
somewhat pungent smell, a sharp taste, and a specific gravity
of 1-8. It melts at 50°— 51°, and boils at 9r-5. The specific
gravity of its vapour is 2*83 (Naumann), from which it appears
to be a mixture of the vapours of water and chloral, and these,
on cooling, again unite together. This is also proved by the
fact that it is possible, by help of a fractionating apparatus,
partially to separate these constituents.^ Concentrated sulphuric
acid decomposes it into chloral and water, and the alkalis act
upon it as upon chloral.

In the year 1869 Liebreich' discovered that, when taken
internally, chloral hydrate produces sleep, and acts as an
anaesthetic agent ; and he introduced it with great success into
medicine, so much so, that one manufactory in Berlin, which
in 1869 prepared about 150 kg., in 1873 manufactured
13,000 kg., and a like increase is noticed in several other
manufactories. The sleep produced by chloral is quiet, and

^ Ktu. ffandwCrtcrh. ii. 597.
' Naumann, Ber. DciUsch. Cftcm. Ges. xii. 738.

* lb. ii. 26D ; Das Chloral Hydrate^ cin ncues Hiqmoticum und Andslhelicum,
Berlin, 1871.

610 THE ETHYL GROUP.

is without any unpleasant symptoms. Liebreich was led
from his experiments to conclude, from the ready conversion of
chloral into chloroform by alkalis, that its physiological action
depended on the formation of chloroform produced by the weak
alkaline reaction of the blood. Other physiologists are of
opinion that, in the passage of chloral hydrate through the
body, chloroform is not produced, and that its action is to be
ascribed to its own specific properties. The doses prescribed
for sleeplessness amount to from 1'5 to 5 0 grams.

According to Liebreich, chloral hydrate is an antidote for
strychnine, whilst the latter substance serves as an antidote for
the former.^

Chloral hydrate, which is to be used in medicine, should
give a clear solution in water, and, on addition of sulphuric
acid, the chloral should separate without any brown colour.
The aqueous solution should have a neutral reaction, and, on
the addition of nitric acid and nitrate of silver, no opalescence
should occur. For the purpose of determining the quantity
present in the commercial product, according to the method
of V. Meyer and Hatfter,^ a weighed quantity is brought into
contact with an excess of a normal soda-solution, and the
amount of formic acid produced is determined by titration
with normal acid. If, to begin with, the chloral hydrate had
an acid reaction, the aqueous solution must be shaken up with
calcium carbonate before addition of standard soda.

Chloral not only combines with water, but also with
sulphuretted hydrogen, alcohols, and various other bodies.
The compounds thus formed must be regarded as containing
the dyad radical trichlorethidene, and a description of these
will be given hereafter.

Trichloracetic Actd, CHClgO,,

348 Was discovered by Dumas in 1838, who obtained it by
the action of chlorine on acetic acid in presence of sunlight*
Malaguti then found that the substance believed by him
to be chloraldehydo, C.^CI^O, when decomposed by water
yields this same acid, from which reaction it is scon that
the substance supposed to bo the aldehyde is indeed the

* Ber. Ikutsch. Clie^n, Gea. ii. 673. ' Ber, DexUsch, Clum, Ot9. vL (KK).

• CompUs Hfndiia, viiL 609 ; Ann. Chftn. Pharm. xxxii. 101.

TRICHLORACETIC ACID. 641

chloride of this acid.^ Cloez^ obtained it by the action of
water upon perchlorforraic ethyl ether :

CICO.O.CCI2.CCI3 + 2H2O = HO.CO.COg + 3HC1 +CO2.

It has already been stated that Kolbe obtained it by synthesis.
He also found that it mi^jjht be obtained by treating solid chloral
with nitric acid or otlier oxidizing agents.^ Judson* showed
that it may also be obtained from liquid chloral; but as chloral
hydrate is a commercial article it is now always prepared
from this substance, and many oxidizing agents are used for
this purpose.^ The simplest plan of preparation is to treat
chloral hydrate with three times its volume of fuming nitric
acid, and to place the whole mixture in the sunlight until
the red fumes have disappeared ; the liquid is distilled until
tlie temperature reaches 190*", and the residue is then heated for
some time to the boiling point.

If chloral be saturated with nitrogen trioxide and heated in
a closed tube in the water-bath, trichloracetic acid is also formed,
and is obtained in the pure state on opening the tube and
allowing the gases which are formed to escape.^

Trichloracetic acid crystallizes in rhombohedral scales 6r
needles, melts at 52°'3 (Clermont), boils at 195'' (Judson,
Clarmont), and its vapour has a specific gravity of 5*3 (Dumas).
It deliquesces in moist air, and on heating has a very pungent
and suflFocating odour. It destroys the epidermis, and produces
blisters oa the skin. It is not attacked by concentrated
sulphuric acid even when warmed, but alkalis decompose it easily
with formation of chloroform :

CCI3.CO.OK + HOK + CCI3H f CO I qI

An alcoholic solution of sodium alcoholate, containing caustic
soda, decomposes it as follows : ^

CCl3.CO.ONa+5HONa=3NaCl+CO(ONa)H+CO(ONa)2+2H20

It is a very strong acid, forming a series of salts which are
very similar to the acetates, and have been especially examined
by Clermont.

^ Ann. Chim. Phys. [3], xvi. 4 ; xxx. * Tb, rrii. 297.

5 Ann, Chcm, Pharm. liv. 182. * Chem. Soc. Joum, xxiv. 232.

* Clermont, Campt, Itend. Ixxiii. 112 ; Ixxiv. 1492; Ixxvi. 774.

• Wallach, Ber. Deuttch. Chem. Gta. ▼. 266.
' Klien, Jahreah. 1876, 621.

642 THE ETHYL GROUP.

Ammonium Trichloracetate, CgClgOaCNH^, is deposited in
fine prisms on the spontaneous evaporation of its neutral
solution. These melt at 80°, and begin to give off ammonia
and chloroform at 110°— 150^ until at 160° the liquid
solidifies to nacreous scales consisting of the anhydrous salt.
At a higher temperature it decomposes into ammonium chloride,
carbon monoxide, and carbonyl chloride (Malaguti). When dis-
tilled with phosphorus pentoxide it yields trichloracetonitril,
C2CI3N, a liquid boiling at 81°. The normal salt combines
with one molecule of trichloracetic acid to form the so-called
acid salt, which crystallizes in octohedrons unalterable in
the air.

Potassium TrichlaracetcUe, CjjClgOgK, is obtained by the
action of potassium permanganate on chloral hydrate. It
forms thin silky needles which deliquesce in moist air, and
it also unites with one molecule of the acid to form an acid
salt, which is likewise formed by the action of the permanganate
on an excess of chloral hydrate. It crystallizes in transparent
octohedrons which are not altered on exposure.

£thi/l TricJUoracetate, 0201302(02115), is obtained by distilling
the acid with alcohol and sulphuric acid, as well as by the
action of trichloracetyl chloride on alcohol. Perchlorformic ether
and perchloracetic ether and similar perchlorinated compounds
react in an analogous way. Ethyl trichloracetate is an oily
liquid, possessing a peppermint-like smell and a specific gravity
of 1'367. It boils at 164°, yielding a vapour whose density is
6 64 (Leblanc).

Trichloracetic Anhydride, (020130)30, is obtained by the action
of an excess of phosphorus trichloride on trichloracetic acid. It
is a liquid possessing a faint not unpleasant smell, boiling at
222° — 224°, and rapidly absorbing moisture from the air and thus
passing into trichloracetic acid.^

Trichloracetyl Chloride, O2OI3OOI, was prepared by Malaguti
in 1844 by heating perchlorethyl ether :

S;:ca:}o = cci,coci + c,ci,

It also occurs in the preparation of the perchlorinated ethers,
and, as has been stated, was first termed chloraldehyde. It is
evident that this compound may also be obtained by the action
of phosphorus trichloride on trichloracetic acid. It is a caustic,

' Bncknry mid Thomson, Ber. Ikiitsch, Chnn. Gen. x. 698.

MONOBROMACETIC ACID. 543

strongly smelling liquid, which fumes in the air, has a specific
gravity at IS** of 1*608, boils at 118°, and has a vapour density
of 6-32.

TtichloTdcetaviide, CClg.CO.NHg, was first prepared by Cloez
in 1845 by the action of ammonia on perchlorethyl formate. It
is formed in a similar way from the other perchlorinated ethers.
It forms white scales, and crystallizes from ether in fiat prisms
or six-sided prisms. It possesses a sweetish taste and aromatic
smell, melts at 138°, and boils at 238°— 240°. When heated with
phosphorus pentoxide, trichloracetonitril is formed.

TricJdoracetapJiosphamide, CgCljO. PHg, is obtained by acting on
phosphuretted hydrogen with the chloride, and forms colourless
scales which have a sb'ght garlic-like smell and a bitter taste.
It is insoluble in water.^

Bromine Substftction Products.

349 Mondbroniacetic Acid, C^HgErOo, was first prejmred by
Duppaand Perkin ^ by heating acetic acid with bromine to 120°
— 125°, and is also formed, together with acetyl bromide, when
acetyl oxide is treated with bromine.^ In order to prepare it,
three parts of acetic acid are heated with four parts of bromine in
a sealed tube for several hours to 120°, and at last from 150° to
1G0°, this being done to avoid a rapid evolution of hydrobromic
acid, which would burst the tube. Air is then led through the
tube in order to remove the greater quantity of the hydrobromic
acid, and the residue is slowly distilled. The portion passing
over between 200° and 210° is almost pure bromacetic acid,
which can then be purified by rectification and crystallization.
It forms glistening tablets which melt at 100°. The liquid
boils at 208° with slight evolution of bromine vapour, and the
crystals deli({uesce rapidly in the air. When brought upon the
skin it produces deep wounds, and on heating with water it
decomposes like trichloracetic acid. The salts are usually
crystalline, and mostly deliquescent.

Ethyl Mcnobromacetate, €2113610^(02115), is obtained by dis-
tillation of equal parts of acid, alcohol, and sulphuric acid. It
is a liquid wliich possesses a powerful smell, and boils at 150°.
Ammonia decomposes it easily, with formation of ammonium

' Cloez, Ann, Chim. Phy^. [3], xvii. 309.
* Chan. Soc. Journ. xi. 22 ; xii. 1.
3 Gal. Ann. Chim. Phijs. [3], kvi. 187.

544 THE ETHYL GROUP.

bromide ; but at 0^ it forms monobromacetamide, which may be
purified by recrystallization from alcohol. It melts at 1G5^ ^

Monohromacctyl Chloride, CHgBr.COCl, is a colourless,
sli^'htly fuming, strongly smelling liquid, boiling at 127**, or at
the same temperature as its isomeride chloracetvlbromide.

Monohromacctyl Bromide, CHjBr.COBr, is obtained by the
action of bromine on acetyl bromide. It is a very strongly
smelling liquid, boiling at 150^

Dihromacctyl Aldehyde, CgHgBrgO, is produced by the regulated
action of bromine upon aldehyde. It is an oily liquid, pos-
sessing a penetrating smell, boiling at 140** — 142°, and forming
with water the hydrate, C^ HgBrgO + HgO, crystallizing in long
needles.^

Bibromacetic Acid, C^H^BrgOg, was prepared by Duppa and
Perkin at the same time as bromacetic acid. According to
Carius,^ it is best obtained by heating acetic ether with bromine
to 120°— 130°:

C^Mf>^{G,a-^^ 2 Brg = C^H^Br^Oj + C.H^Br + HBr.

It is a white crystalline mass, melting at 45°, and boiling with
slight decomposition at 232° — 234°.

Ethijl Dihroviacctate, C2HBr202(Cj,H5), is formed by the action
of sulphuric acid on a mixture of alcohol and dibromacetic acid,
as well as by boiling an alcoholic solution of tribromacetalde-
hyde with potassium cyanide.* It is an oily liquid, smelling
lihe peppermint, which boils at 192°, and is converted by am-
monia into dibromacetamide, CgHBrjO.NHj, which crystallizes
in long needles, melting at 15G^

Dihromacetyl Bromide, CHI>ro.COBr, is formed by heating
acetyl bromide with the requisite quantity of bromine to 150^
It is a colourless liquid, fuming in the air, and boiling at 194°.

Tribromac^taldchyde, or Bromcd, CBr.,.COH, was discovered
in 1832 by Lowig,^ and is contained amongst other products of
the action of bromine upon alcohol and ether. In order to
prepare it, it is best, according to Schaffer,* to pass bromine
vapours slowly into alcohol, and to subject the product to dis-
tillation. The product passing over between 165* and 180** is
treated with water, when bromal hydrate is formed ; and this

» Kesnel, Brr, Ikutaeh, Chem, Ges. xi. 2115.

• Pinner, Bcr. Veuiseh. Chem, Gca. vii. 1499. 3 76. iii. 33C.
< Kenii. Bcr, DcuL^h. Chem. Oes. viii. 695.

• Antu Pharm. iii. 288. • Ber. Ikularh. Chem. Oe». ir. 866.

BROMAL HYDRATE. 645

can be purified by re-crystallization, and bromal obtained from
this by the action of sulphuric acid. It is an oily liquid,
possessing a peculiar pungent smell and a sharp burning taste.
It boils at 172° — 173^ and has a specific gravity of 3 '34.
It decomposes in contact with acids into formic acid and
bromoform.

Bromal Hydrate, C2Br3HO + 2H20, or CoBr3H(OH)2+H20,
crystallizes, according to Lowig, in large transparent prisms
having the form of sulphate of copper.

Tribromacetic Acid, CgHBr^O^, was prepared by Gal^ by
decomposing its bromide with water. It is also easily formed
by exposing bromal ^ or bromal hydrate ^ to the action of fuming
nitric acid. It crystallizes in transparent, glistening, permanent,
monoclinic prisms, melting at 135°, and boiling with partial
decomposition at 250°.

Its salts, which have been investigated by Schaflfer, are, with
the exception of the mercurous and silver salts, easily soluble
in water, and, on warming the solution, are easily converted
into bromoform and a carbonate.

Ilthj/l Tribromacetate, C2Br302(C2H5), is produced by the action
of the bromide upon alcohol, and is an oily, pleasantly smelling
liquid, boiling at 225°.

Tribromacetyl Bromide, CBrg.COBr, is formed by heating the
dibrom- compound with an excess of bromine to 200°. It Ls a
fuming liquid, boiling at 220° — 225°, and being slowly decom-
posed by water.

Tribromacetamide, CBr3.CO.NH2, has as yet only been ob-
tained by the action of bromine on asparagine * and by that of
anmionia on hexbromacetone : ^

CBr3.CO.CBr3 + NH3 = CBr3.CO.NH2 + CBrgH.

It is slightly soluble in cold, and rather more so in hot water ;
but may be readily crystallized from benzene in large prisms,
melting at 119° — 121°, and possessing a sweet and burning
taste. Sulphuric acid converts it into ammonia and tribromacetic
acid.

Bromchloracetic Acid, CgHgBrClOg, is formed by heating equal
molecules of chloracetic acid and bromine to 1G0°. It is a
caustic, strongly smelling liquid, boiling at 201°. It forms an

* Compt. Bend, Ivi. 1257. * Schaffer, loc, eU,
' Gal, Compt. Rend. Ixxvii. 786.

* Gnaresctii, Ber. Dcutsch. Hhtin. Gcs. ix. 1436.
» Wcidol and Gruber, ih. x. 1148.

Vr)L. III. N X

546 THE ETHYL GROUP.

ether boiling at 160° — 163"*, smelling like peppermint, and by
ammonia is converted into an amide which crystallizes in long
needles melting at 126^^

Iodine Substitution-Pboducts.

' 350 Moniodacetic Acid, CgHjIOg, was obtained by Perkin
and Duppa 2 from its ethyl ether by decomposition with baryta
water, barium being precipitated from solution by dilute
sulphuric acid, and the liquid evaporated in a vacuum. It is
also formed by heating acetic anhydride with iodine and iodic
acid:

3 (C2H30)20 + 3 Ij + IO3H = 6 C^HjIOa + HI.

The iodic acid must be present in excess in order to prevent
the formation of free hydriodic acid. On cooling, the product
solidifies, and this is treated with boiling benzol.* The com-
pound crystallizes out from this in pearly scales, and from
aqueous solution it can be obtained in rhombic tables which
melt at 82°, and decompose when more strongly heated.
Hydriodic acid reduces it in the cold with separation of iodine
to acetic acid, and this reaction explains why iodine alone does
not form substitution-products with acetic acid. Its salts are
easily soluble, and readily decompose.

£thyl Moniodacetate, C2H2l02(C2H5), is formed by heating
the chlor- or brom-acetic ether with alcohol and potassium
iodide, as well as when ethyl thiocyanacetate, a body to be here-
after described under the glycolyl compounds, is heated with
ethyl iodide to 120°:

CHjSCN CH2I

C2HJ = I + C2H2SCN.

O.OC2H, CO.OC2H5

If the resulting mixture of ethers be treated with baryta-water
the iodine compound is decomposed, and the iodoacetic acid can
then be easily obtained by the method above described.* Ethyl
iodoacetate is a heavy oily liquid, which becomes brown and
boils at 178°— 180°.

Moniodacetamidc, C2H2lO^NH2, is formed by the action of
potassium iodide on an alcoholic solution of the corresponding

' Cech and Steiner, Bcr, Dcutsch, Chrm. Oa. viii. 1174.

• Phil. Mag, [4], xviii. 54. » SchiitrenberRer, Compt. Rend. Ixvi. 1840.

^ Joum, Chem, Soc, xiii. 1.

THE lODACETIC ACID& 547

chloro-compound. It crystallizes in transparent prisms, which,
when heated, melt, become yellow, and decompose, with evolu-
tion of iodine vapours.

Di'iodacetic Acid, CgHgl^Og, was obtained by Perkin and
Duppa ^ by the action of milk of lime on the ethyl ether, and
decomposing the calcium salt with hydrochloric acid. The
heavy oily liquid which then separates out gradually solidifies,
forming large sulphur-yellow opaque rhombohedrons, which
have a slightly acid reaction and a metallic taste, and
smell somewhat like iodine. It does not act on the skin, and
is only slightly soluble in water. It volatilizes slowly in the
air, and melts on heating, decomposing at a higher temperature
with partial sublimation. It forms slightly yellow-coloured
crystalline salts which are readily decomposed.

Ethyl Di'iodacetate, C2Hl202(C2H5), is formed by heating the
corresponding brom-ether with potassium iodide and alcohol.
It is a yellowish liquid which has a sharp burning taste, and
attacks the eyes and nose strongly. Treated with aqueous
ammonia, di-ioddcetamide, CjIHOj-NH^, separates out as a
light-yellow crystalline mass.

Cyanaeetic Add, CN.CHyCOjH, is easily formed from the
mono-substituted acetic acids by replacing the halogen by
cyanogen. It acts as a nitril of the dibasic malonic acid,
03^(00^2^ under which it will be afterwards described.

^ Loc, cU,

N N 2

COMPOUNDS CONTAINING THREE ATOMS OF
CARBON, OR THE PROPYL GROUP.

351 Propane, CjHg. This gas, formerly called propyl hydride,
was obtained by Berthelot by heating propylene dibromide,
CjHgBrg, or other compounds containing three atoms of carbon,
with potassium iodide and water.^ Another method adopted by
the same chemist was to heat allyl iodide, C3H5I, acetone, C^H^G,
glycerin, CallgOa, &c., with hydriodic acid of specific gravity 1'9
to 275°.^ Ronalds ^ then showed that crude American petroleum
contains propane in solution, and Schorlemmer * prepared it by
the action of zinc and sulphuric acid on propyl iodide.

Propane is a colourless gas, slightly soluble in water, and
somewhat more soluble in alcohol. When exposed to a tempera-
ture of from — 25° to — 30** it condenses to a colourless liquid.*
Propane is easily attacked by chlorine in diffused daylight with
formation of primary and secondary propyl chloride, as well as
higher substitution-products (Schorlemmer). •

PRIMARY PROPYL ALCOHOL, C3H7OH.

352 Chancel^ in 1 8.53 showed that this compound was contained
in fusel oil obtained in the manufacture of wine-brandy, but lie
did not investigate it fully. Mendelejeff,® who in 18G7 examined
a sample of this same fusel oil, did not succeed in separating

* Ann. Chim. Fhys. [3]. li. 56 and 70. » RuU. Soc. Chim. [2], rii. 56,

' Joum, Chfin, Site, xviil ^ti. * Proc. Jtoy, Soc, xvi. 34 ; xviL 872.

* I>«'febre, Cowpi. Krmf. Ivii. 1352. • Proc. Roy. Soc, xviii. 29.
' Compt. Rrnii. xxxviii. 410 ; Ann. Chnn. Phnr,n. Ixxxvii. 127.

* Zrifsrh. r/zz-wi. [-21. iv. 2>.

THE PROPYL SERlEa 549

propyl alcohol from it, and Tromsdorflf ^ was also unable to find
it in fusel oil From the above observations it might naturally
be inferred that the existence of the primary alcohol is doubtful,
the more so as all attempts to prepare it synthetically proved
abortive. Thus Butlerow ^ endeavoured to obtain it by acting
with zinc-methyl on ethylene iodhydrin, IH2C.CH2.OH, but
only obtained the secondary aJcoholj and Linnemann and Siersch^
arrived at the same result in attempting its synthesis by acting
on propylamine prepared from ethyl alcohol, with nitrous acid.
Shortly afterwards, however, Fittig* succeeded in recognizing
the presence of the primary alcohol in fusel oil. The explanation
of the failure of other chemists to obtain this compound is the
impossibility of separating it by fractional distillation when present
in only small quantities. If, however, the mixed alcohols be
converted into the bromides, a separation of these latter com-
pounds may then easily be effected. At the same time
Schorlemmer '^ prepared the alcohol from propane, and
Linnemann ^ obtained it by the reduction of propionic anhydride,
which he had prepared synthetically from ethyl alcohol. The
existence of considerable quantities of propyl alcohol in a variety
of diflferent kinds of fusel oils was then recognized, and the
properties of this alcohol were more exactly examined.^ Kramer
and Pinner® found that the '* faints," or the latter portions of the
distillate obtained on rectifying crude spirit of wine (p. 295), is
rich in propyl alcohol Indeed it is now prepared in quantity
by fractionating this liquid, and sold by Kahlbaum of Berlin.^
These " faints," as well as the still less volatile or ordinary fusel
oil, are mixtures of several alcohols and of fatty acid ethers, and
their relative quantities depend on the nature of the material
from which the alcohol was obtained. The following gives tlie
composition of the " faints " from potato-spirit according to
Rabuteau : ^®

• Tagblatt, Frank f. Naturf, 1867, 52.
« ZHtack. Chtin. [*2], iii. 680.

• Ann, Chem. Phai'm, cxliv. 137.

• Zeitxh. Chem, [2], iv. 44.
» Proc Jioy. Soe. loc, cU.

• Ann, Ckcm. Pharm. cxlviii. 251.

' Pierre and Pucliot, Compt, Bend, Ixvi. 302 ; Ixx. 354 ; Bull, Soc. Chim, [2],
xiv. 53 ; Chancel, Ann. Chem, Pharm, cli. 298 ; Compt. Rend, Ixviii. 669 ;
Chapman and Smith, Joum, Chem. Soc, xxii. 193.

• Ber. Deutach. Chem. Ges. iii. 75.

» Ber, Entw, Chem. Ind. ii. 274-276.
" Conipl. Rend. Ixxxvii. 600.

660 THE PROPYL GROUP.

Cbc. per liter. B. P.

Secondary propyl alcohol . . . 150 85**

Primary propyl alcohol .

Isobutyl alcohol . .

Normal butyl alcohol . .

Methylpropyl carbinol

Isomeric arayl alcohols .

Mixture of higher homologues of

the alcohols and ethers . . . 170

Water 125

Mixture of aldehyde, acetic acid,

and alcohol 75

30 97"

50 109"

65 116'9

GO 120"

275 128"-132

1.000

Trimethyl carbinol, or tertiary butyl alcohol, also appears to
be contained in this liquid.

Primary propyl alcohol is also found, together with ethyl
alcohol and butyl alcohol, in the acid liquors of the starch
manufacture, and also in the products of the lactic and butyric
fermentations.^ It is also formed in the peculiar fermentation
of glycerin,* about which information will be hereafter given.

It has been already stated that Linnemann was the first to
obtain propyl alcohol synthetically. Saytzeflf * also prepared it
by synthesis by acting with sodium amalgam on a mixture of
propionic acid and propionyl chloride ; whilst Rossi * obtained it,
by a method already described, from ethyl alcohol.

Propyl alcohol resembles spirit of wine in its odour. It has
a specific gravity at 0° of 0'8198, and boils, according to various
observers, from 96° to 98°. The latter number is probably
the correct one, as the boiling-points of the normal alcohols
increase 19"*6 for every increment in composition of CHj.* It is
miscible in every proportion with water, but, on the addition of
calcium chloride and other easily soluble salts, it separates out
from aqueous solution. The specific gravity of the vapour is,
according to Chancel, 202. If the alcohol be treated with
aluminium and iodine, hydrogen is evolved and ahiminium
propylate, Al2(OC3H7)^, formed. On distillation under diminished

^ Bouchanlat, Compt. Kind, IxxviiL 1145.

' Fitz, Ber. VeuUch. Chnn, Qc9, xiii. 36.

* Zrit9ck. Chnn. 1S70, 105. * rVmrV. KauK Ixx. 129.

^ Grimshaw and Schorlemtncr, Journ, Ckon. Soc, xxvi. 10^2.

PRIMARY PROPYL ALCOHOL. 551

pressure, this compound comes over as a heavy liquid, solidify-
ing to an amorphous mass.^

Primary propyl alcohol is not used in the arts or manufac-
tures, but frequently employed in scientific research. Its deriva-
tives closely resemble those of ethyl alcohol, and are prepared
in a like manner. A short description of these may therefore
suffice.

Propyl Oxide or Dipropyl Ether ^ (OsH7)20, is a colourless liquid
smelling like common ether and boiling at 85° — 86**, obtained by
Chancel by heating a solution of caustic potash in the alcohol
with propyl iodide. Methylpropyl Etlier may be obtained in a
similar way, as a liquid boiling at 49'' to 52'' and possessing
analogous properties to common ether. Ethylp^opyl Ether, boil-
ing at about 63° — 64°, can likewise be prepared (Brlihl).

Propyl Chloride, C3H7CI, is obtained by acting with hydro-
chloric acid or phosphorus trichloride on the alcoliol (Pierre and
Puchot). It is also formed when the iodide is heated to ISO""
with mercuric chloride (Linnemann). It is an easily mobile
liquid boiling at 46°*5 and having a specific gravity at 0° of
0-9156.

Propyl Bromide, C3H7Br. In order to prepare this compound
it is not necessary to employ the pure alcohol, but fusel oil or
the residual spirit rich in propyl alcohol may be at once treated
with bromine and phosphorus. The products can be easily
separated by fractional distillation, and the propyl bromide thus
obtained boils at 71°, and has a specific gravity of 1*3497.
The remarkable fact must here be noticed that primary propyl
bromide when heated with aluminium bromide is transformed
by intramolecular change into the secondary compound.^

Propyl Iodide, C3H7I, boils at 102°, and has a specific
gravity at 0° of 1'7842. Heated with six times its volume of
water for twenty-four hours at 100°, it is converted into the
alcohol.

Propyl Nitrite, C3H7O.NO, was prepared by Cahours, by acting
with nitrous acid upon the alcohol. It is a pleasantly smelling
liquid, boiling at 46'— 56°.

Propyl Borate, (03117)3603, is obtained by acting upon propyl
alcohol with boron trichloride. It is a mobile, slightly ethereal
smelling liquid, possessing a burning and bitter taste; it boils at
172^ to 175°, and has a specific gravity at 16° of 0*867 (Cahours^.

* Gladstone and Tribe, CJicm. Soc. Jauni. 1880, i. 4.

' Kekule and Schrotter, Ber, D^utsch. Chem. Ocs. xii. 2279.

552 THK PROPYL GROUP.

Propyl Silicate, (03117)48104, is formed in a similar way to the
foregoing compound, and is a liquid boiling at 225° to 227° and
having a specific gravity at 18° of 0 915. It is easily de-
composed by water with separation of silica (Oahours).

Propyl Carbonate, (03117)2008, is obtained, according to
Oahours, by treating the oxalate with sodium. It is a liquid
boiling at 156° — 169° and possessing a pleasant smell.^

Propyl Chlorocarbonate, CsH^O-OOCl, is obtained by acting
with carbonyl chloride on the alcohol. It is a very pungent
liquid which attacks the eyes, and boils at 115°'2. If this
ether be allowed to act on sodium propionate, the carbonate is
formed, boiling at 168°* 2.^ Ammonia converts the chlorocar-
bonate into propyl carbamate, O3H7O.CO.NH2, which is also
obtained by heating the alcohol with urea (Oahours). It
forms large colourless prisms diflScultly soluble in water, which
melt at 50°, the liquid boiling at 194° — 196°. If an excess of
urea be employed, prop^/l allophanatc, H2N.OO.NH.CO.O.C3H7,
is formed. This crystallizes from alcohol in pearly crystals which
melt at 150° to 160°.

Propyl Formate, (03Hy)0H02, is a pleasantly smelling liquid
boiling at 83°.

Propyl Orthoformate, (03H70)30H, boils at 196°— 198^

Propyl Acetate, (03117)0211302, resembles acetic ether, but
smells like pears. It boils at 102°, and has a specific gravity at
0° of 0-913.

Propyl ffydrosidphide, O3H7.SH, was obtained by Homer by
treating the bromide with potassium hydrosulphide. It is a
disagreeably smelling liquid boiling at 67° — 68°.^

Propyl Sulphide, (03117)28, is obtained by the action of the
iodide on an alcoholic solution of potassium sulphide. It is
a disagreeably smelling liquid, boiling at 130° — 135°, which
forms trisulphine compounds with the iodides of the alcohol
radicals.*

Propylamine, C3H7NH2, was first prepared by Mendius,* by
acting with hydrochloric acid and zinc on an alcoholic solution of
propionitril. Silva^ then obtained it by acting on silver cyanate
with propyl iodide, and treating the mixture of propyl isocyanate

^ Cotnpt. Rend, Ixxvii. 749. ' Roese, Ann, Chem. Phann. ccv. 227.

' Her, DeiUsch. Chem, Ots. vi. 784. * Cahoura, Compt, Rend. Ixxvi. 133.

* Ann, Chrin. Phann. rxxi. 129.

• lb. Ixix. 473 ; Bu\ IkutM^h. i'hnn. (ns. ii. f.aO.

PROPYL COMPOUNDS. 563

and isocyanurate thus obtained, with potash and distilling.
Linnemann also prepared it in the same way.^

It is a liquid possessing a strongly amnioniacal smell and boil-
at 49''*7. It is miscible with water with evolution of heat, and
the aqueous solution precipitates the salts of iron, copper, lead,
aluminium, nickel, cobalt, silver, and mercury, and, of these, the
aluminium and silver precipitates dissolve in an excess of the
base. Propylamine forms crystallizable salts and easily combines
with the iodides of the alcohol radicals.

Tetrapropylammanium Iodide, N (03117)41, was obtained by
Bomer by heating propyl iodide with alcoholic ammonia,
separating the bases which are formed by treatment with soda,
and mixing with propyl iodide, when the above compound is
formed with considerable evolution of heat. It crystallizes
from water in fine white prisms, and yields an alkaline very
deliquescent hydroxide on treatment with silver oxide, and this,
on heating with water, is converted into propylene and tripro-
pylaimne, N (03117)3, the platinicliloride of which crystallizes in
splendid red tablets.^

Propyl Carbami7i€, ON.O3H7, is obtained by the action of the
bromide on cyanide of silver. It is a strongly smelling liquid,
boiling at 95^—100°. ^

Propyl ThiocyanatCy NOS.O3H7, is obtained by acting on silver
thiocyanate with the bromide. It boils at 1G3°, and has a dis-
agreeable smell (Schmitt).

NiTEO-COMPOUNDS OF PROPYL.

353 Priraary Nitropi'opaiie, OgH^NOg, is formed together with
propyl nitrite when silver nitrite acts upon propyl iodide. It is
a liquid very similar to nitroethane, and boils at 125'' — 127**.*
By the action of bromide on its solution in potash, substitution-
products occur similar to those of nitroethane.

Monohromnitropropanc, OgHgBrNOo, is a heavy, oily, strongly
smelling liquid, boiling at 160° — 165°, and easily soluble in
alkalis.

Dibromnitropropane, C^^lfiv^Oot is an oil closely resembling
the foregoing compound, boiling at 184"* — 186^ but is not
soluble in alkalis.^

* Ann, Chem. Pharm. clxi. 45. * Ber, Deutsch, Chan, Ota, vi. 784.

* Schmitt, ZcUsch. Chan. [2], vi. 676.

* V. Meyer, Ann, Chan, Pharm. clxzi. 36.

* Meyer and Tschemiak, Anii. Chan. Pharm, dxxx. 118.

654 THE PROPYL GROUP.

Dinitropropane, C^^f^O^^. When a solution of monobrom-
nitropropane and potassium nitrite in dilute spirit of wine is
mixed with alcoholic potash, the potassium salt, C3H5K(X02)«,
separates out, mixed with potassium bromide. This latter is
removed by washing with cold water. If the potassium com-
pound be added to dilute sulphuric acid, dinitropropane separates
out as an oily, colourless liquid, which possesses a faint alcoholic
smell and a sweet taste. . It boils at 189^ and has a specific
gravity of 1*258 at 22''*5, and reddens litmus-paper. Its salts
have a yellow colour, and are explosive. The potassium salt
is difficultly soluble in cold water, and crystallizes from the hot
solution in needles or striated prisms.^

Dinitropropane is also formed by the action of hot con-
centrated nitric acid on dipropylketone, (C3H7)2CO. The body
thus obtained was formerly considered to be nitropropionic acid,
as no determination of the nitrogen had been made, and the
analyses of the few salts which were examined pointed to
this conclusion.*

Propyl Nitrolic Add, C3H5(N02)NOH, is prepared in a
similar way to ethyl nitrolic acid. It crystallizes from ether in
large light yellow prisms, having a bluish fluorescence, possesses
a sweet taste, and in its other properties closely resembles the
ethyl compound.'

Compounds of Propyl and the Metals.

354 Arsenic Compounds of Propyl. When propyl iodide is
heated with arsenic for about thirty hours to 180°, the compound
Aslj + As(C3H7)^I is formed, and this, on cooling, solidifies to
reddish-brown crystals. If zinc arsenide be employed in
place of the latter element, prismatic crystals having the com-
position Znlj + 2As(CH3)^I are produced. Both these com-
pounds yield, on distillation with potash, the very unpleasantly
smelling tripropyUirsine, As(C3H7)3, which readily unites with
the alcoholic iodides.*

Beryllium Propyl, Be(C3H-)2, is obtiined by heating beryllium
with mercury propyl, and is a liquid boiling at 244** — 24(>\
fuming in the air, and not being spoDtaneously inflammable.^

^ ter Mcer, Lichig's Ahh, clxxxi. 19.

' Chanoel, Ann, Chim. Phtji, [8], xii. 146; Kiirz, Ann. Chnn, P/mrm. clxi. 201).
' Meyer, Ih. clxxv. 114. * Cahuura, Conijtt, Rend, Ixxvi. 752.

^ Cu,itj)(. JUntl. Ixxvi. 1383.

COMPOUNDS OF PROPYL WITH THE METALS. 566

Zinc Propyl, 211(03117)2, was prepared by Cahours by heating
zinc, together with propyl iodide, to 120'' — 130°. It boils at
158"* — 160°, fumes in the air, and is easily inflammable.^

Mercury Propyl, Hg(Cj,H7)2. This compound is obtained by
acting upon the iodide with sodium amalgam in presence of
acetic ether. It is a mobile liquid, having a faint smell when
cold, and, on heating, this becomes stronger. It has a specific
gravity at 16° of 2124, and boils at 189°— 191°. It is easily
attacked by acids, with formation of propyl mercury salts. The
iodide, CjH^Hgl, is converted by moist silver oxide into the
crystalline, strongly alkaline, hydroxide (Cahours).

Aluminium Propyl, A1(C3H7)3, is prepared similarly to the
zinc compound, and is a spontaneously inflammable liquid, which
boils at 248—252°.

Tin Propyl Compounds, By heating propyl iodide with tin-
foil, dipropyl tin di-iodide, {C^B^)^ti1^, is formed. This is a
liquid boiling at 270° — 273°, and is converted by alkalis into
the corresponding amorphous oxide. Hydrochloric acid converts
it into the dichloride, which forms fine crystals, melting at 80° —
81°. If propyl iodide be brought in contact with an alloy of tin
and sodium containing 10 per cent, of the latter metal, tripropyl
tin iodide, {C^^)^xii, is formed as a liquid possessing a pungent
smell, and boiling at 260° — 262°. This, when heated with
caustic potash, yields the hydroxide, (C3H7)3SnOH, which distils
over as an oily liquid, and this on cooling solidifies to a crystal-
line mass. It has a powerful smell, an alkaline reaction, and on
distillation with caustic baryta yields the oily oxide [GJS^)^iijd,
which again easily combines with water. Hydrochloric acid
converts the oxide into the volatile chloride, which has a smell
stronger than that of the iodide.

Tin Tetrapropyl, Sn(C3H7)^ is obtained by heating tripropyl
tin iodide with zinc propyL It is a liquid possessing a strongly
ethereal smell, boiling at 222^ — 225°, and having a specific
gravity at 14° of 1*179.^

* Campi. Bend, Ixxvi. 751.

- Cahours, Conipt, Rend. Ixxvi. 136 ; Ixxxviii. 725 ; Cahours and Demarcay,
16 Ixxxviii. 1112.

556 THE PROPYL GROUP.

PROPIONIC ALDEHYDE AND PROPIONIC

ACID.

355 Propionic Aldehyde, CgHgO, is formed when propyl alcohol
is acted upon by moderate oxidizing agents, and also when a
mixture of calcium formate and calcium propionate is subjected
to dry distillation. It is a thin liquid, possessing a suffocating
smell, boiling at 49°'5, and having a specific gravity at 0** of
0 804 (Rossi). ^ It is not miscible in all proportions with water,
requiring five times its volume for complete solution, and it is
easily transformed into propionic acid by further oxidation.

Propionic Acid, CjHgOg.

356 This acid was obtained by Gottlieb,^ in 1844, by oxidizing
metacctone, C^^Hj^O, and also by heating sugar, starch, gum, &c.,
with concentrated caustic potash ; and to it he gave the name of
mctacetonic acid.^ Redtcnbacher then obtained it by ferment-
ing an aqueous solution of glycerin by means of yeast.*

The synthetic production of propionic acid from ethyl cyanide
(propionitril) was discovered by Dumas, Malaguti, and Leblanc,^
as well as by Fninkland and Kolbe.* Wanklyn^ afterwards
showed that it is formed by the direct combination of carbon
dioxide and scMlium ethylate. Lastly, Ulrich® obtained it by
indirect reduction from lactic or oxypropionic acid.

Propionic acid is also formed in a variety of other ways, thus,
Strecker^ obtained it by the fermentation of calcium lactate.
Ncillncr,^^ in 1841, proved that a peculiar acid is found amongst
the fermentation-products of calcium tartrate, and to this he
gave the name of i^seudo-acetic acid. Berzelius ^^ considered this
to bo a mixture of butyric and acetic acid, whilst Nickl6s"
believed it to be a peculiar com|X)unil of these two acids, and
thereftjre termed it butyro-acetic acid. On the other hand,
Dumas and his friends came to the conclu.sion that it is

* Lif.hiijs Ann. rlix. 79. - Ann. Chem. Phann, Hi. 121.
» Ann. Chnn. Phann, Hi. 11. « Jb. Ivii. 174.

» Ciwifft. AVm/. XXV. 070 ami 781 ; Ann. Chrm. Phann. Ixiv. 829, 334.
« Chem. SW. Jnurn. I 60. ? Th. x. 103. « lb, oix. 271.

• Ann, Cfum. Phann . xcii. 80. »« /h. xxxviii. 299

" BcrzfUnA .lahrtsh, xxii. 233. »-' Ann. Ckcm. Phann, Ixi. 343.

PROPIONIC ACID. 667

identical with propionic acid, because, like this last-named acid,
it possesses a constant boiling-point.^ Again, Limpricht and
Uslar * found that though butyro-acetic acid forms salts which
have the same composition as the corresponding propionates, the
free acid may be converted by simple distillation into acetic and
butyric acids.

These contradictory statements have recently been fiiUy ex-
plained by the investigations of Fitz.^ He finds that the fer-
mentation of calcium lactate, calcium tartrate, calcium malate,
and glycerin may give rise to any one of these free acids, or a
mixture of them, the exact nature of the product depending
upon the special ferment causing the change. This chemist
has shown that various species of schizomycetes {Bacillus)
exist, and that the particular fermentation which takes place
depends upon the presence of a certain definite species of
the ferment. This he has proved by preparing these several
ferments in the pure state, and thus bringing about any special
kind of fermentation desired. For further information on this
point, the article on ** Fermentation " must be referred to.

In order to prepare propionic acid, propionitril is heated in a
flask connected with an inverted condenser with either aqueous
or alcoholic potash until no further evolution of ammonia
occurs, and until the smell of the nitril has disappeared. Tlie
liquid is then evaporated down, and the residue distilled with
slightly diluted sulphuric acid. In this case it is not necessary
to employ pure propiomtnl ; it suffices to heat ethyl iodide with
alcohol and powdered potassium cyanide until it is decomposed,
and then to treat the distillate as described.*

Propionic acid, as Frankland and Kolbe have shown, is also
formed when the nitril is heated with tolerably dilute sulphuric
acid. In order to prepare it in this way, Linnemann ^ recom-
mends treating the nitril with its own weight of strong sulphuric
acid previously mixed with water in the proportion of seven to
three. The mixture of nitril and diluted acid is then heated in
connection with a reversed condenser, and the acid distilled off.

The atjueous acid obtained by one or other of these methods
is then converted into the sodium salt, which may again be
decomposed by concentrated sulphuric acid or heated in a
stream of dry hydrochloric acid gas (Linnemann).

^ Ann. Chem. Fhami. Ixiv. 329. "^ lb, xciv. 321.

' Ber. Deiitsch, Chem, Qes, xii. 476.

* Williamson, Phil. Mag. [4], vi. 204.

* Ann, Chem, Pharm, cxlviiu 251.

658 THE PROPYL GROUP.

According to Beckurts and Otto,^ the acid is most readily
prepared by heating to 100° one part by weight of the nitril with
three parts by weight of a mixture of three volumes of water
and two of sulphuric acid until the oily layer which is separated
out does not increase in volume. This latter is then almost
pure propionic acid, which may be easily freed from water by
rectification.

Fitz^ states that the fermentation of calcium lactate and
calcium malate is much to be recommended as a source of
propionic acid. Propionic acid is also formed, together with
other acids of the fatty series, in the putrefaction of various
organic bodies, and it is likewise found in the products of dis-
tillation of wood.*

Propionic acid is a colourless liquid, possessing a smell re-
sembling acetic acid, but also like that of butyric acid. It
boils at 140®, and has a specific gravity of 1016 at 0". It is
miscible in all proportions with water, but on the addition of
calcium chloride, or other easily soluble salts, it separates out
and swims on the surface as an oily liquid. For this reason, as
well as because its salts Iiave a fatty feel, the name which it
now bears was given to this acid by Dumas (wporo^, the first,
wtov, fat).

The Propionates.

357 The propionates are all soluble in water, and almost all
crystallize readily. Those of the alkali-metals yield, when
heated with arsenic trioxide, a smell resembling that of cacodyl.

The following are the most characteristic salts :

Silver Propionate, CgH^OjAg, is thrown down as a crystalline
precipitate when silver nitrate is added to a solution of a pro-
pionate. It dissolves in 119 parts of water at IS"", and much
more easily in boiling water. It crystallizes on cooling in
glistening tablets, and sometimes in large broad needles.

Lead Propioruxte, (CgH^Oj) jPb, crystalhzes with great difficulty,
and on evaporating its solution, it usually remains in the form
of a gummy mass. When its solution is evaporated with finely
divided oxide of lead, a basic salt of the composition 3(C3HjOj)jPb
+ 4rbO is formed. This may be dissolved from the residue by
cold water. On boiling this solution it separates out in needles

* Ber. D*'ut9ch. Chem, Gts. x. 262. • Ih. xi. 1899.

' Hams Compt, Jhnd, Ixviii. 1222 ; Anderson, Chem, News^ xiv. 257 ; Kr&mer,
•ml GrodHki, Ber, DtutMh^ Chem. Qrn. xi. 135d.

THE PROPIONATES. 669

or as a crystalline powder. It dissolves at the ordinary tem-
perature in from 8 to 10 parts of water.

This characteristic salt is well adapted for the separation of
propionic from formic and acetic acids. The mixture of acids
is evaporated to dryness with oxide of lead, the residue treated
with cold water, and the precipitate of the basic lead propionate
thrown down on boiling the solution. The basic salts of the
other two acids remain in solution, and may be separated by
filtration of the boiling liquid.^

Methyl Propionate, C3H5O2.CH3, possesses a pleasant smell,
boils at TO'^'S, and haa at 0° a specific gravity of 0*9578.

Ethyl Propionate, CsH^Og-CgHg, boils at 100°, and has at 0° a
specific gravity of 0 9138.

Propyl Propionate, CgH^O^-CgH^, is a liquid boiling at 124^
and having a specific gravity of 0*9022 at 0".

Propionyl COMrOUNDS.

358 Propionic Anhydride or Propionyl Oxide, (CgHjO)^©, is
obtained by the action of propionyl chloride on sodium pro-
pionate. It has a smell resembling acetyl oxide, and is a liquid
boiling at 168**— 169°, and having a specific gravity at 15° of
10169.

Propionyl Chloride, C3H5OCI, is formed by heating propionic
acid with phosphorus trichloride, but has as yet not been
obtained pure.

Propionyl Bromide, CgHgOBr, is prepared in a similar way,
and is a pungent smellmg liquid, fuming on exposure to the
air, boiling at 96°— 98°, and having at 14° a specific gravity of
1*465.«

Propionyl Iodide, C3H5OI, is obtained by the action of phos-
phonis and iodine upon the acid. It is a colourless heavy liquid,
boiling at 127°— 128° (Sestini).

Propionamide, C3HgONH2, is formed by acting with aqueous
ammonia on ethyl propionate,^ or by passing ammonia into heated
propionic acid until the boiling-point rises to 200°. It forms
readily soluble crystals which melt at 75° — 76°.*

* Lmnemann, ylnn, Chem. Phnnn. olx. 195.
a Sestini, Dull. Soc. Chim. [2J, xi. 468.

« Bull Soc, Chim. [2], xv. 228.

* Kngler, Ann. Chrm. Pharm. cxxxiii. 143.

560 THE PROPYL GROUP.

Substituted Propionic Acids. The mono-substitution products
exist in two isomeric forms :

o-Brompropionic Acid. iS-Brompropionic Acid.

CHj CHgBr

CHBr Ca

CO2H. CO2H.

The first of these is formed by heating propionic acid with
bromine; if the bromine be employed in excess Dibrom-
propionic acid, CHgCBrgCOgH, is formed. Hence it is seen
that the substitution here takes place in the carbon atom at-
tached to the carboxyl group ; this is also found to be the case
with the other fatty acids. The yS-compounds, as well as the
remaining a-compounds, are not formed by the direct action of
bromine on the acid ; they will, therefore, be described further
on (see Lactic and Glyceric Acids).

Propionitril and its Derivatives.

359 Propionitril, CoHgCN, was first prepared by Pelouze,^ by
distilling a mixture of barium ethylsulphate and potassium
cyanide. He termed it cyanure d'ithyle, and described it as a
very poisonous liquid possessing a strong alliaceous odour. Its
chief rcacticms were then examined, as has been stated, by
Dumas, Malaguti, and Leblanc, as well as by Frankland and
Kolbe.

Pelouze's method does not give a good yield, and the product
contains the isomeric etliylcarbamine, which imparts to it an un-
pleasant smell and poisonous properties. According to Gautier,-
it may be purified by treating it with dilute sulphuric acid and
then warming it for some time with mercuric oxide.

Linnemann ^ obtained it by distilling equal weights of potas-
sium cyanide and jwtassium ethylsulphate. The portion boiling
at 110** is heated \\dth dilute hydrochloric acid until it has an
acid reaction, and then distilled ; the distillate is shaken first
with caustic potash, and afterwards with a concentrated solution
of calcium chloride. It is then dried over anhydrous }>()tcassium
carbonate, and, lastly, washed for several times with small

* Joum, Pharm. xx. 39P ; Ann. Phnrm. x. 240.

« Ann. Chim, /%y». [4]. xvii. 180. > Ann. Chrm, Phnrm. cxlviii. 252.

PROPIONITRIL. 5C1

quantities of water. By this process he obtained 2 G5 kilos,
from 20 kilos, of potassium cyanide.

Hofmann and Buckton ^ prepared it by heating propionamide
with phosphorus pentoxide. According to Gautier,^ it is best
obtained by Williamson's method.^ For this purpose ethyl iodide
is heated with potassium cyanide in closed tubes to 180** and thu
product distilled. The distillate is then washed with a weak
solution of calcium chloride, when any undecomposed ethyl
iodide sinks to the bottom, whilst the nitril swimming on the
top may be washed several times.

Propionitril is also obtained by the action of cyanogen
chloride on zinc-ethyl,* and also when the last-named substance
is treated with cyanogen gas,** when the following reaction
occurs:

CN C2H5 CN CN

2 I + Zn<' - 2 I + Zn<'

CN XSfi C2H5 ^CN

The substance obtained by one or other of these processes is
dried over chloride of calcium and rectified.

Pure propionitril is a mobile, peculiar, ethereal smelling liquid,
boiling at 97^ and solidifying at 68^ and possessing at 0° a
specific gravity of 0*8010 (Thorpe), that of its vapour being
1*928. It is tolerably soluble in water, but may be separated
by the addition of calcium chloride.

Propionitril combines with the hydracida® Tlie hydrochloride,
C3H5NHCI, is gradually formed when propionitril saturated
with hydrochloric acid is allowed to stand in a closed vessel.
It forms apparently monoclinic prisms which are slightly
soluble in water. It is decomposed into its constituents by dry
ammonia. On exposure to air, propionitril absorbs water and
is converted into sal-ammoniac and propionic acid. It melts
at 121**, and on standing at this temperature for some time is
converted into a yellow oil which does not again solidify. It
also forms compounds with the metallic chlorides, with carbonyl
chloride, and with cyanogen chloride.^

By distilling one part of potassium cyanide w^ith three* parts
of potassium ethylsulphate, Gautier obtained a compound of
the nitril with alcohol, CgHgNs^CoHgO, which boils at 79°, and is

> Proc. noy, Soe. viii. 168 (1856). « Loc. cit.

' Phil Mag. [4], ii. 206. * Gal, Aiin. Chem. Fharm. cxlvii. 126.

■ FranlcUnd and Graham, Chrm. Soc. Joum. 1880, i. 740.

* Oautier, loc cit. ^ Honke, Ann. Chrm. Pharm. cvi. 280.

VOU III. O O

562 THE PROPYL GROUP.

miscible in all proportions with water. It forms a crystalline
mass with cyanide of potassium, from which it may^be again
obtained in the pure state by distillation. The specific gravity
of the vapour is 1*618, from which it is seen that the above
compound cannot exist in the form of vapour.

Cyanethine, {C^H^^^^, was first prepared by Frankland and
Kolbe^ by the action of potassium on moist propionitril.
E. von Meyer ^ found that a better yield is obtained by employ-
ing dry propionitril and sodium. In this preparation ethane
is evolved, and a yellow solid mass remains, which is decomposed
by water, yielding caustic soda, sodium cyanide, propionitril,
ammonia, and sodium propionate. Cyanethine is very slightly
soluble in cold water, and crystallizes from hot water in pearly
scales melting at 189'', and boils with partial decomposition at
280''. It is a monad base, possessing a weak alkaline reaction.
The hydrochloride, CgHi^N^HCl + HgO, is very soluble, crystal-
lizes in large transparent striated prisms, and forms with
platinic chloride a double salt crystallizing in ruby red octohe-
drons. The nitrate, CgHjgN^NOjH, crystallizes in large prisms.

Cyanethine is a tertiary base, capable of uniting with one mole-
cule of ethyl iodide. If the resulting compound be treated
with oxide of silver and water, a strongly alkaline solution is
obtained of ethylcyaruthonium hydroxide, CJ3.^(Cfi^'NfiH^

When cyanethine is heated with strong hydrochloric acid,
sal-ammoniac is obtained, together with a monad tertiary base,
C^Hj^ONg. This crystallizes from hot aqueous solution in
splendid groups of needles which melt at 156° — 15T*. By the
action of phosphorus pentachloride the compound C^H^jClN,
is obtained. This is an oily liquid, possessing an unpleasant
persistent smell; it can be distilled in a vacuum without de-
composition, and when heated with ammonia is reconverted
into cyanethine, whilst nascent hydrogen converts it into the
base, CgHj^Nj, a colourless oily liquid boiling at 204® — 205*.
It dissolves readily in water with alkaline reaction, but, on heat-
ing, the solution becomes turbid, owing to the separation of the
compound. This compound possesses an unpleasant stupifying
smell, and acts as a powerful poison. When the vapour is in-
haled even in small quantities it produces stupor, and its
physiological action appears to be similar to that of conine,
CgHijN, the poisonous principle of the hemlock ; but its action

» Jaum, Chim. Soc, i. 60. « Joum, Pmii, Chem, [2], xxiL 261.

SECONDARY PROPYL ALCOHOL. 663

is even more powerful than that of this alkaloid, from which
it differs in composition by the replacement of one atom of
hydrogen by the elements of cyanogen. Hence it is perhaps
eonine cyanidCy C8Hi^(CN)N (v. Meyer).

SECONDARY PROPYL ALCOHOL, (CH3),CH0H.

360 This compound, also termed isopropyl alcohol, was obtained
first by Berthelot,^ in 1855, by combining propylene, CjH^, with
sulphuric acid and distilling the propyl sulphuric acid thus
obtained with water. At that time no isomeric alcohols were
known, and it was therefore assumed that Berthelot's alcohol
was identical with that first obtained from fusel oil.

Friedel ' then obtained a substance having the composition
of propyl alcohol by the action of sodium amalgam and water
on acetone or dimethyl ketone (CH8)2CO ; and Kolbe ^ gave it
as his opinion that this must be the first member of the series
of secondary alcohols, the possible existence of which he had
already predicted (see p. 182), and stated that this body on
oxidation would be found again to yield acetone, and this
on being put to the test of experiment by Friedel ^ was actually
the case.

A year before this, Erlenmeyer had obtained a compound
having the composition of propyl iodide by heating glycerine
with hydriodic acid. Further examination showed that this
belongs to the series of secondary compounds,^ and Berthelot
proved that this is the case with the alcohol obtained from
propylene.*

In order to prepare isopropyl alcohol, glycerine is distilled
with an excess of fuming hydriodic acid with addition of
amorphous phosphorus, when allyl iodide is first obtained^
according to the following equation :

C,H,(0H)3 + 3 IH = CgH.I + 3 H,0 + I,.

' Anf^ Chim. Phy$, [3], xliii. 399 ; Ann, CJiem, Pharm, xciv. 78.
" lUp. Chim, Pure, iv. 361 ; Ann. Chem. Pharm. cxxiv. 324.
» ZeOseh, Chem, 1862, 627. * Rip. Chim. Pure, ▼. 2^7.

■ Zeitaeh, Chem, 1861, 862 ; ib. 1862, 43 ; Ann, Chem, Pharm, cxxvi. 805 ;
ZeitMch, 1863, 380 ; ib, 1864, 642.
• dnnpt. Rend, Ivii 797 ; Ann. Chem, Pharm, cxxix. 126.

0 0 2

564 THE PROPYL GROUP.

This is then converted into secondary propyl iodide* by the
excess of hydriodic acid.

CH2 CH3

CH 4- 2HI = CHI + Ij.
CH^I CH3

The addition of the phosphorus serves for the purpose of at
once converting the iodine which is set free into hydriodic
lacid.

The iso-alcohol can be prepared from the iodide in a variety
of ways. In the first place, propyl acetate can be obtained
by heating the iodide with acetic acid and potassium or lead
acetate, and this is easily converted by caustic potash into the
alcohol. Secondly, the iodide may be heated with lead
hydroxide and water in connection with a reversed condenser;*
or, again, it may be simply heated with twenty times its weight
of water for forty hours to 100^' On distilling the product
obtained by one or other of these processes, aqueous isopropyl
alcohol is obtained, and this can be rendered anhy4rous in the
usual manner.

Isopropyl alcohol is a mobile liquid possessing a slightly
spirituous smell, boiling at 83* — 84", and having a specific
gravity at 15"* of 0*791. It forms with water the hydrate
2C3H8O + HjO, boiling constantly at 80°, and having the same
percentage composition as ethyl alcohol (Erlenmeyer). Accord-
ing to Linnemann, other hydrates exist, namely, SCjHgO +
2H2O, boUing at 78"— 80", and 3C^llfi + HgO, boiling at
81"— 82".*

Isopropyl Oxule or Di-isopropyl Ether, {C^S^fi, is formed by
the action of silver oxide on the iodide. It is a liquid boiling
between 60" and 62", and possessing a smell of peppermint
(Erlenmeyer).

Isopropyl Chloride, C3H7CI, is easily formed by heating the
alcohol with hydrochloric acid, or the iodide with corrosive sub-
limate. It boils at 34" — 36", and has a specific gravity at 0**
of 0 874 (Linneman).

Isopropyl Bromide, ( J^H-Br, is best obtained by acting upon

* Maxwoll SinipRon, Proe. Roy, Soc. xii. 533

* Pliiwitrky, Lifhig's Ann. clxw. 880.

' XiedoriHt, i6. clxxxvii. 891. * Ann. Chem. Pharm, cxzxvi. 40.

ISOPROPYL COMPOUNDS. 666

the iodide with bromine. It boils between 61'' and 63^ and at
13** has a specific gravity of 1'320 (Linnemann).

The remarkable conversion of the primary into the secondary
bromide by contact with aluminium bromide has already been
mentioned.^

Isopropyl Iodide, CjHyl. The preparation of this compound
has already been described. It boils at 89°, and has a specific
gravity at 0° of 1'735 (Erlenmeyer). It has already been stated
that this iodide can be readily converted into propane, which
may in its turn be transformed, at any rate partially, into the
primary chloride. It is thus seen that it is possible to pass
from the secondary compounds to the primary series, and vice versd.

Isopropyl Nitrite, C^HyNOg, is formed, together with secondary
nitro-propane, by the action of silver nitrite on the iodide. It
is an easily inflammable liquid which boils at 45°.^

Isopropyl Nitrate, CgH^NOj, was obtained by Silva by acting
with isopropyl iodide upon silver nitrate. It is a liquid boiling
at 101"* — 102°, and having at 0** a specific gravity of 1*054. It is
easily inflammable, burning with a white luminous flame, and
its superheated vapour explodes violently when ignited.

Isopropyl Borate, 8(003117)3, is obtained by heating the alcohol
with boron trioxide to 110° — 120°. It is a mobile liquid, resem-
bling ethyl borate, and boiling at 140°.^

Isopropyl Acetate, O3H7.OO2H3O, is a liquid possessing a
smell resembling acetic ether, and boiling at ^{f — 93^

Compounds of Isopropyl with Sulphur.

361 These are obtained by processes simikr to those described
under the corresponding ethyl compounds. The mercaptan,
C3H7SH, boils at 45°, and tlie sulphide, (C^M^\^, at 105°.
This latter forms with mercuric chloride the compound
(C3Hy)2S,HgOl2, crystallizing in white needles.*

OoMPOUNDS OF Isopropyl with Nitrogen.

362 Isopropylamine, OgH^NHg, is formed by the action of am-
monia upon the iodide^ or nitrate,^ or by the action of hydrochloric

• Kekul^ and Schrotter, Ber, Deutsch. Chem, Ges. xiL 2279.

5 Silva, Bull. Soc, Chim. xii. 227 ; V. Meyer, Jnn, Chcm. Pharm, clxxL 89.
» Councler, Ber, Deutsch. Chem, Ges. xi. 1107. * Henry, ib. ii. 496.

• Siersch, Ann. Chem, PJiann. cxlviii. 261.

• Silva, Bull, Soc. Chim. xii. 228.

566 THE PROPYL GROUP.

acid on isopropyl carbamine. It is a mobile liquid, which has a
sharp characteristic smell resembling herring-brine. It boils
at SV'5—S2'''5, and at 18"* has a specific gravity of 0-690.

Di'isopropylamiTie, (0^13^)^11^ boils at 83** '5 — 84^ and has
a specific gravity of 0722 at 22**.

Tri-isopropylamine has not yet been obtained in the pure
state.

Isopropyl Carbamine, CN.CjHy, is formed by heating the iodide
with silver cyanide. It is a liquid boiling at ST, and possessing
an ethereal smell which afterwards be<;omes offensive and
bitter.^

Isopropyl CyancUe, CjH^OCN, is a liquid boiling at 74***5, and
possessiog at 0^ a specific gravity of 0*8897, whilst that of the
vapour is 2*944.*

Isopropyl ThiocyanatCf CjH^SCN, is formed by heating the
iodide with potassium thiocyanate, and is a liquid possessing an
alliaceous smell and boiling at 149® — 151** (Henry).

NiTRO-COMPOUNDS OF ISOPltOPYL.

363 Secondary Nitropropane, or Psevdonitropropane,
(CH3)2CHN02, is formed, together with isopropyl nitrite, by act-
ing with the iodide on silver nitrite. It is a liquid resembling
primary nitropropane, but boiling at 115' — 118®, and being a little
heavier than water. Heated with alcoholic soda, the crystalline
compound (CH3)2CNaN02 separates out, and this deflagrates on
heating. It deliquesces on exposure to moist air, and its
solution gives precipitates with the various metallic salts.'

If psoudonitropropane be dissolved in an equivalent quantity
of strong caustic potash, and the requisite amount of bromine
added, Irompscudonitropropane, (CH3)2CBrN02, separates out.
This is a heavy powerfully refracting oily liquid, which possesses
a very strong smell and boils at 148® — 150°, and does not possess
acid properties.

Propylpsevdonitrol, (CH3)2C(NO)N02. In order to prepare
this compound, psoudonitropropane is dissolved in caustic potash,
rather more than one molecule of potassium nitrite in aqueous
solution added, and a slow stream of dilute sulphuric acid allowed
slowly to flow into this mixture, the whole being cooled. The

' Compt. Rfnd. Ixvii. 723 ; Ann, C/um. Pharm, cxlix. 155.

• Silva. Did. Chim, iiL 158 {loc. citX

• V. Meyer, Ann. Chem, Phann. clxxi. 39.

ISOPROPYL COMPOUNDS. 567

liquid soon becomes of a fine blue colour, and the nitrol separates
out as a solid mass insoluble in water, alkalis, and acids. It is
slightly soluble in cold alcohol and chloroform, but readily so
when warmed, giving rise to a pure blue-coloured solution, from
which the compound separates out on evaporation in transparent
crystals resembling those of calc-spar, but belonging to the
monoclinic system.^

Propylpseudonitrol melts at 76^ forming a blue liquid which
on rapid cooling again solidifies, but decomposes when heated
for some time with evolution of red fumes, another product,
fi-dinitrcpropane, (Cil^2^(J^^2)2* ^^^S formed. This is also
produced when the pseudonitrol is treated with a solution of
chromium trioxide in glacial acetic acid. This body is slightly
soluble in water and dissolves readily in alcohol, forming bright
white translucent crystals which closely resemble camphor. They
melt at 53^ and volatilize easily even at the ordinary tempera-
tore, as well as in presence of aqueous vapour, although the
body does not boil until 185°*5. It does not possess acid pro-
perties, and when treated with tin and hydrochloric acid yields
acetone and hydroxylamine :

CII3 CHjj

^\N0* + 4H2 = CO + 2N(OH)H2 + H20.

OH3 CH3

Compounds of Isopropyl with Phosphorus.*

364 Isopropyl Pliosphine, (C3H7)PH2, is a strongly refracting
liquid, possessing a penetrating smell, boiling at 41^ and taking
fire at the summer temperature on exposure to air. Its vapour
has a specific gravity of 2*673. When oxidized with nitric acid
isopropyl pho^hinic add, C3H7PO(OH)2, is formed. This is a
solid paraffin-like mass, which melts at 60° — 70°.

Di'isopropylphosphiiie, (C3F7)2PH, boils at 118°, possesses an
intense phosphine smell, and is much more readily ignited than
the foregoing compound. If a drop be brought on to filter-paper
it inflames at once, and bums with evolution of a dense white
luminous vapour without igniting the paper.

* V. Meyer, Liebig's Ana. clxxv. 120; clxxx. 144.
' Hofmanii, Ber, Ik\Usi:h, Chem. G^^. vi. 292 and 304.

568 THE PROPYL GROUP.

Tri'isopropylphosphirie, (03117)8?, closely resembles the corre-
sponding ethyl compound, and forms a crystalline hydriodide.
It likewise yields with carbon disulphide fine red crystals, and
also unites with sulphur, but the compound thus formed is not
crystalline.

Tctra-isopropylphosphonium Iodide, P(C8H7)^I, crystallizes from
water in cubes or octohedrons.

ACETONE, OR DIMETHYL KETONE,

(CH3),ca

365 In early times it was noticed that when sugar of lead is
subjected to dry distillation, a peculiar liquid is formed which
Libavius termed the quintessence of this salt. Boyle supposed
that it is formed from the vinegar, this giving up some of its
constituents to the lead. He also noticed that when potassium
acetate is distilled, a spirituous liquid possessing a strong smell
and taste is formed. Becher, who first observed the inflam-
mability of the substance obtained from sugar of lead, thought
that the sjnrUus ardens was in fact spirit of wine which had
been regenerated ; and Lemery, as well as Stahl, believe<l that
vinegar is a compound of spirit of wine and acid, the former
being carried away with the acids into the pores of lead,^ and
the latter being held back by the metal during the process of
distillation. The difference between this combustible spirit and
alcohol was first pointed out by Boerhaave in 1732. After his time
the body was but little investigated until 1805, when Tromms-
dorflf stated that on distilling acetate of potash or soda a liquid
was obtained which stands between alcohol and ether. Two
years later the brothers Derosne, in Paris, examined the liquid
which was obtained, mixed with acetic acid, in the distillation of
acetate of copj)er, and as the liquid appeared to them closely
to resemble the various compound ethers, they termed it (^fhcr
j)yroac(^fiqiff.'^ Lastly Chenevix found, in 1809, that the same
rompoimd is obtained when any one of the acetates is distilled,
and he gave to it the name of pvroacetir spirit, an<l believed

* LoiiuTV, A f'nui'fff It/ fhemiitfrif, tniiiM]Ht('<l liy Kfili, lOy.**, ]». 14«».
■-' .//**'. Lhim. Ixiii. 2^7.

ACETONE. 569

that it contained less oxygen than acetic acid.^ Various other
chemists also worked upon this subject.^

The correct composition of the compound we now term
acetone was first given by Liebig* and Dumas.* Kane ^ investi-
gated it carefully, and came to the conclusion that it was an
alcohol, giving to it the name of mosityl alcohol. Chancel,*
on the other hand, believed it to be a copulated compound, and
having the formula Cj,H^0,CH2.

After Williamson had ascertained the constitution of the
ketones, acetone was looked upon as being methyl acetyl, or
aldehyde (acetyl hydride) in which one atom of hydrogen had
beei. replaced by methyl. This view was corroborated by the
synthesis of acetone, accomplished by the action of zinc-methyl
on acetyl chloride, a reaction suggested by Chiozza,^ but carried
out by Freund.® As, however, the radical acetyl itself may be
considered to be composed of the groups carbonyl and methyl^
the present view respecting the composition of acetone, as also
of all ketones, is that these are compounds of two alcohol-
radicals with carbonyl. A further corroboration of this view
was given by Wanklyn,^ who observed that propionc, or dietliyl
ketone, is formed by the action of carbon monoxide on
sodium-ethyl.

It has already been stated that acetone is formed by the dry
distillation of the acetates. According to Liebig,^^ the barium
salt is best suited for this purpose, as it decomposes at a com-
paratively low temperature, and hence the formation of tarry
products which occurs when the calcium or the lead salt is used
is avoided.

Acetone is also formed, together with other products, when the
vapour of acetic acid is passed through a red-hot tube :

2CH3.CO.OH = CH3. CO.CH3 + CO2 + HgO.

It is likewise formed by acting on aldehyde with heated caustic
potash,^^ as well as by the dry distillation of the following sub-
stances together with lime, viz. citric, tartaric, and lactic acids,
sugar, gum, starch, &c.

' NicholAon*8 Joum. xxvi. 225, 340.

' Macairo and Marcet, Bib, Univ, xxiv. 126 ; Qiuirt. Journ. ScieiuXy xvii. 171 ;
Matteucd, Ann, Chim, Fhys. [2], xlyi. 429.
» Ann. Pharm. i. 223. * Ann. Chim. Phys. [2], xlvii. 203.

» Pogg, Ann. xliv. 473 ; Trans. Irvsh Acad, x\'iii. 134 (1838).
• V&mpt, Rend. xx. 1590. ^ Ann, Clveni, Pharm, Ixxxv. 232,

" lb. cxviii. 1. » Phil Mag. [4], xxxi. 605.

'" Zo-. cU, " Schlouiilcli, Zeitsch. Chcm. 1869, 335.

670 THE PROPYL GBOUP.

It is contained in large quantity in the products of the dry
distillation of wood, and is obtained from this on the large scale
(see p. 196;. It was also formerly obtained as a by-product in
the preparation of aniline,^ by the action of acetic acid and iron
on nitrobenzol and the distillation of the product with lime.
At present, however, hydrochloric acid is used in place of
acetic acid, and the crude aniline contains no acetone.

Acetone is found in the urine in cases of diabetes meUUus^
Qeuther believes that in these cases it is derived from the
decomposition of aceto-acetic acid,' but this has not been
proved.

Properties, — Acetone is a colourless mobile liqmd, possessing
a penetrating, refreshing, ethereal smell and a burning taste.
It boils at 56^*3 (Regnault), and has a specific gravity at 0** of
0*8144 (Kopp), that of its vapour being 2*002 (Dumas). It is
soluble in water, and acts as a solvent for many other carbon
compounds, such as fats, resins, camphors, &c.

When shaken with a concentrated solution of hydrogen sodium
sulphite, acetone deposits the compound CgBL^jO+NaHSOj, in
pearly scales, easily soluble in water, and less so in alcohol. The
sulphites of potassium and ammonium form similar compounds.
This process may be employed for purifying acetone, the crystals
being distilled with potash.

366 Monocfdoracetone, CH3.CO.CH2CI, was first prepared by
Riche,* by the electrolysis of a mixture of acetone and hydrochloric
acid, and then more fully investigated by Linnemann,^ who
obtained it by acting with hypochlorous acid in presence of
mercuric oxide on monobrompropylene, CHj,. — CBrzzCHj. It
is also formed when pure acetone is treated with chlorine, but
not to saturation,* as well as by the action of sulphuric acid
on dichlorglycide, CHClj - CCIIZCHJ (see Glycerin). It^ is a
strongly smelling, pungent, caustic liquid. It boils at 119* — 120**,
and at 16* has a specific gravity of 1*16, that of its vapour being
3*13. When brought in contact with potassium iodide, wiono-
iodoacetom, CHj.CO.CHjI, is fonned, a heavy oily liquid which
cannot be distilled without decomposition.

» G. Williams, Chenu News, ii. 231.

' PettiTS, Knulich, and Bctz, SchmUU, Jahrb. Gts. Med. cxii. 145; Mmrkowni*
koff, Liebig'8 Ann, clxxxii. 362.

» Zrifsch. Chem. 1868, 5. « Couq^t. Rend, xlix. 176.

* Ann, Chem. Pkarnu cxxxiv. 170; cxxxviii. 122.

• Ohitz and Fischer, Jovm. Prakt. Chrm. [2]. iv. 52 ; Bischoff. Ber. DetUsek.
Chem. Chs. v. 863, 963 ; Mulder, ih. 1007. ' ifcnrv. ih. 965.

CH LORACETONES. 671

Dichloracetonef CjH^ClgO, exists in two isomeric conditions;
the one obtained by Liebig and Kane, and termed by the latter
chemist mesilchloral, was afterwards investigated by Fittig.^ It is
formed when acetone is saturated with chlorine or when potas-
sium chlorate is added to a solution of acetone in hydrochloric
acid.^ The crude dichloracetone is a very caustic body, possess-
ing a pungent smell, due, however, to an impurity. When
purified by repeated fractional distillation it is obtained in
the form of a pleasantly ethereal smelling liquid,' boiling at
120", this is, singularly enough, at the same temperature
at which monochloracetone boils. It has a specific gravity of
1*236 at 21°, and its vapour density is 4*32.

The constitution of dichloracetone is represented by the for-
mula CH3.CO.CHCI2, for an isomeric compound is obtained by
oxidizing dichlorhydrin (dichlorisopropyl alcohol), CHgCl.CH
(0H).CH2C1, and accordingly has the following constitution,
CHjCl.CO.CH^Cl. It is a solid body, crystallizing in long
needles, fusing at 43°. The liquid boils at 170° — 171°, but eva-
porates at the ordinary temperature. It possesses an excessively
pungent odour, the vapour attacking the eyes violently.*

Trichlor acetone, C3H3CI3O, was first prepared by Bouis,^ by
the action of chlorine on a mixture of acetone and wood-spirit.
Kramer® afterwards obtained it by treating a mixture of acetone
and isobutyl aldehyde with chlorine. It is also formed, accord-
ing to Bischoff, when moist chforine is led into warmed acetone
in presence of sunlight. It boils at 170° — 172°, possesses a sharp
smell, and yields, with water, the hydrate, C3H3CLJO -I- 2H2O,
crystallizing in fine tables wliich melt at 43°. When mixed with
aniline and caustic potash an intense smell of phenyl carbamine
is produced, and hence the constitution of the substance is
CH8.CO.CCI3 or methyl-chloral.

Tetrachloracetane, CgHgCl^O, is produced by the action of
chlorine on a mixture of acetone and ethyl alcohol. It is a
liquid possessing a very strong and imtating smell, and, when
brought in contact with water, it yields the crystalline hydrate
C^Hfilfi + 4H2O, melting at 38°— 39°. As this also gives the
carbamine reaction it possesses the formula CHgCl.CO.CClj.

* Ann. Chem. Pharm, ex. 23. ' Stadeler, ib. cxi. 277.

* Borsche and Fittig, Ann, Chem. Phann. cxxxiii. 111.

* Markownikoff, Bcr. Dcuisch. Chem, Ges. iv. 662 ; vi. 1210 ; Glutz and Fischer,
JifUm, PrakL Cheui, [2], iv. 25 ; Von Hoermann, Ber, Deutsch, Chem. Ges. xiii.
1306.

* Ann. Chiin, Phya, [3], xxi. 111. • Bcr. lUutsrh. Chem. Gea, vii. 257.

572 THE PROPYL GROUP.

Pentachloracetone, CHCI2.CO.CCI3, has not been obtained as
yet from acetone, but it can be prepared by the action of chlorine
on quinic acid and other aromatic compounds, as well as on
albuminoid bodies and other substances. It is a mobile liquid
boiling at 190^ and possessing a sharp taste, and a smell resem-
bling that of chlorine. It forms a hydrate, C3HCI5O + iKfi,
which melts at 15** — 17**.^

HexddortKetom, CClg-CO-CClj, is formed by the action of
chlorine on an aqueous solution of citric acid exposed to the sun-
light. It is an oily, pungent smelling liquid, boiling at 200° — 20 1**,
and forming with water, at 6^ the hydrate CsCl^O + H^O,
which decomposes at 15°.^

Various bromine and iodine substitution-products of acetone
are also known.

Nitroso-cLcetonc is produced by the action of potassium nitrite
on an alkaline solution of aceto-acetic ether which is acidified
with sulphuric acid and then saturated with potash. After some
days dilute sulphuric acid is added, and the compound, is ex-
tracted with ether. It is a product of decomposition of the com-
pound nitro-aceto-acetic acid which will be described further on :

CH3.CO.CH(NO).CO.OC2H5 + H20 = CH8.CO.CH3(NO) +

CO2 -h HO.CjH^.

Nitroso-acetone is easily soluble in water, and crystallizes in
glistening tablets or prisms, which melt at 65"*, and decompose
easily at a higher temperature, but may be volatilized in a
current of steam. It is an acid which dissolves in alkalis with
formation of a deep yellow colour.'

Condensation-Products of Acetone.

367 Acetone forms a series of condensation-products. Some
of these have been known for a long time and have been investi-
giitctl by various chemists. We shall here describe only the
better known of these bodies. Hygroscopic agents give rise to
the following compounds :

Mesityl oxide . . . C^Hj^O.

Phoronc ('^^Hj^O.

Mesitylene .... C^H^^

* Sttidelcr, Anii. C/wtn. Phorm. cxi. 277. » IMaiitamour, i&. xxxi. 326.

» Moy»T iiiui Ziiblin, B r. Ikut^h. t'hcm, Iks. xi. 602.

CONDENSATION-PRODUCTS OF ACETONE. 573

Of these, the least is a triinethyl-benzol, aiid will be described
later on.

Mesityl Oxide, C^yf). This body was discovered in 1838
by Kane.' He obtained it by acting on acetone Avith sulphuric
acid or hydrochloric acid. The latter mode of preparation is
recommended by Baeyer * as the best. Acetone is saturated in
the cold with this gas, and then allowed to stand, for some weeks,
and the product afterwards washed with water and caustic soda.
It is distilled in a current of steam, and the distillate, which still
contains chlorine, treated with a small quantity of alcoholic
potash and mesityl oxide and phorone obtained from the washed
and dried product.^

Mesityl oxide is a mobile liquid smelling of peppermint,
boiling at 132°, and acting like acetone. On oxidati<jn it yields
acetic acid, and when treated with phosphorus pentachloride
yields a heavy liquid dichloride, CgHj^Clg, which decomposes on
heating. It combines with bromine to form the compound
CgH^QBrgO, resembUng the foregoing compound. When heated
with dilute sulphuric acid it decomposes with assumption of water
into two molecules of acetone.

From these facts it would appear that mesityl oxide possesses
the following constitution :

CH3

/C = CH - CO - CH3.
CH3

Phorone, CgHj^O, crystallizes in large yellow prisms, which
melt at 28"* and boil at 190° — 191°. It possesses a smell some-
what like that of geranium and not unpleasant, producing in
many persons headache and sickness. In its chemical properties
it resembles mesityl oxide. It is converter! by oxidation into
acetic acid, and bromine converts it into the tetrabromide,
CgHj^Br^O, which crystallizes from alcoholic solution in colour-
less transparent flat monoclinic prisms which melt at 88° — 89°.

Wlien boiled with dilute sulphuric acid it decomposes first
into acetone and mesityl oxide ; its constitution may, therefore,
be represented by the following formula, and this is corroborated
by its formation from triacetonamine (see p. 574) :

g]^3\c = CH - CO - CH = C<(gg3-

* Traiia. Roy. Irish Acad. 1838 ; Porig. Ann. xliv. 473.

- Ann. Chein. Pharni. cxl. *Jl>7. * C'luiscn, ib. cl::xx. 1.

674 THE PROPYL GROUP.

Acetone Bases.

368 According to Stadeler,^ the base acetonine, CgHjgNj, is
formed when a mixture of ether and acetone is saturated with
ammonia at 100*'. Heintz states that this base does not exist.
He obtained a series of different bases ^ which have also been
investigated by Sokoloff and Latschinoff.' These bases may be
separated by means of their platinum double chlorides.

IHacetonamine, C^HigNO, is a colourless liquid, difficult to
obtain in a pure state, as it partially decomposes on distillation
into ammonia and*mesityl oxide. With acids, it forms, however,
a series of stable salts which crystallize well. When it is
treated with potassium nitrite, mesityl oxide is formed, whilst
sodium amalgam yields diacetone alkamine, C^H^^NO, a liquid
possessing a slightly ammoniacal smell, and boiling at 174*'-^175^

Diacetonamine probably possesses the following constitutional
formula :

CH3
H^_t— CH, - CO - CH3.

CH3

This is rendered more likely by the fact that on oxidation
it yields amidodimethyl acetic acid and amidodimethyl propionic
acid.

Triacetonamine, CpHi^NO, separates out as a hydrate, C^HjyNO
+ HjO, on addition of caustic soda to the oxalate, and this crys-
tallizes from ether in large rhombic tables which melt at oS"*.
The anhydrous base is obtained ftom the mother-liquors in the
form of long needles which melt at 34***6.

Triacetonamine volatilizes easily at the ordinary temperature,
and can be distilled without decomposition. Its salts are also
very stable. By the action of potassium nitrite on the neutral solu-
tion of the hydrochloride, nitrosotriacetonamine, C^Hjg(NO)NO,
is obtained, and tliis substance is easily soluble in alcohol and
hot water, crystallizing in needles which melt at 72** — 73^ When
warmed with caustic potash, phorone is produced.

* Ann. Chem, Pliann, czi. 277.

• Ann. Chem. Pharm. clzziT. 133 ; clxxviii. 305, 326 ; dxzxi. 70 ; clzxziii.
276, 290 ; clxxxix. 214 ; cxd. 122 ; cxcii. 339 ; cxciv. 53 ; czcriii. 42.

» Ber. DetiUch. Chem. Gf4. vii. 1384.

THE ACETONE BASES. 575

When triacetonamine is treated with sodium amalgam and
water, triacetonalkamine, CgHjgNO, is produced; this crystal-
lizes firom hot water in pyramids which easily volatilize, melt at
128^*5, and have a sweet burning taste.

Triacetonamine on oxidation yields the dibasic imi^ioe^iTTie^^/-
ac«todim«^y^2>ropi(mic acid, C7Hi^(NH)(C02H)2. From this fact,
and from the other reactions of the base, the following constitu-
tion may be deduced :

Other compounds belonging to this class have been prepared
by Heintz. For their description the memoirs already cited
must be referred to.

COMPOUNDS OF FOUR ATOMS OF CARBON,

OR THE BUTYL GROUP.

369 These compounds are derived from the follo^ving paraffins :

Butane. Isobutane.

CH.3 — CHj — CHg — CHg. OHg — CHv piT^

Four alcohols are derived from these ; from butane, in the
first place, one primary and one secondary ; and secondly, from
isobutane, one primary and one tertiary alcohol. One of these
was discovered by Wurtz, in 1852, in fusel oil from potato spirit,
and from beetroot molasses. This exhibits a striking analogy in
its reactions with common alcohol, and, on oxidation, yields an
acid which has the composition of butyric acid. Hence this
alcohol was supposed to possess a constitution analogous to
that of ethyl alcohol, especially as at that time even the
existence of isomeric alcohols was not dreamt of. Still its low
boiling-point was an anomaly, for Hermann Kopp had found
that in the homologous series of alcohols, for every increment
of CHg, the boiling-point rises 19**. and lience butyl alcohol
ought to boil at 116°, whereas various observers agreed that it
boiled constantly at 1 08°— 109^ In 1867 Erienmeyer found that
the butyric acid got by this oxidation is not common butyric,
but isobutyric acid, (CH3)jjCH.C02H, a body which had been
obtained synthetically from secondary propyl-iodide by con-
version into the nitril, and thus it appeared that fermentation
butvl alcohol is derived from isobutane.

A second butyl alcohol was discovered in 1863, by Do Luynes,
and to it he gave the name of butyleno hydrate, because it is so
easily converted into butyleneand water, and can also be readily
obtained from butylene. This was soon recognised as being the
secondary alcohol.

NORMAL BUTANE. 577

About the same time Butlerow prepared the tertiary alcohol
by synthesis, whilst the normal primary alcohol was first pre-
pared by Lieben and Rossi, in 1869, by the reduction of butyric
acid.

NORMAL BUTANE AND ITS DERIVATIVES.

370 Butaiu or Tctrane, C^H^^, was first prepared by
Frankland in 1849, by acting with zinc^ or mercury^ on
ethyl iodide. He termed it ethyl, a name which was after-
wards changed to diethi/l in order to distinguish it from butyl
hydride, which Wurtz had obtained from alcohol, and which, as
we now know, is isobutane.

In order to prepare pure butane, ethyl iodide, dried over
phosphorus pentoxide, is heated in sealed tubes, with the
requisite quantity of clean zinc, to 150°. An excess of this
metal must be avoided, as otherwise zinc-butyl would be
formed. According to Schoyen,^ the zinc is best employed in
the form of thin strips, and the ethyl iodide mixed with its
equal volume of pure ether. After the mixture has been heated
to 100°, the point of the tube is opened in the flame in order
to allow the ethane to escape ; this gas being formed in large
or small quantity, according to the care which is taken in drying
the materials. The tube is then again sealed, and heated for
several hours to 130° — 140°. It is then cooled with ice-water,
and the point opened, when a mixture of ethane and ethylene
is evolved. The cold water is now removed, and the regular
stream of gas wjiich is evolved collected over mercury. The
butane thus obtained may still contain small quantities of the
two other hydrocarbons, as well as of ethyl iodide. This latter,
as well as the ethylene, can ba removed by drying the gas
with a coke pellet, saturated with fuming sulphuric acid. Pure
butane is obtained after washing with caustic potasli, and drying.
It may, however, still contain a trace of ethane.

Butane occurs in American petroleum (see p. 140), and it is
also produced when butyric acid and succinic acid are heated
with from twenty to thirty times their weight of hydriodic acid

' Joum, Ckcin, Soc. ii. 263 ; Ann. Ohem. Phnrm. Ixxi. 171.

* Joum. CJiem. Soc. iii. 322 ; Ann. Chon. Phann. Ixxvii. 221.

• Ann. Chem. PJiarm, cxxx. 233.

VOL. III. P P

678 THE BUTYL GROUP.

for some hours to 280°.^ Butane is a colourless gas, which can
easily be condensed by cold to a liquid, which boils at + 1**, and
has a specific gravity of 0*6. Under a pressure of 2*25 atmo-
spheres the gas liquefies at 18** (Butlerow). The specific
gravity of butane gas is 2046. It is almost insoluble in
water, whilst absolute alcohol dissolves at 14°' 2, and under a
pressure of 744*8 mm., 18*13 volumes.

In diflfused daylight chlorine acts upon butane with formation
of substitution-products, amongst which butyl chloride occurs.
This compound is, however, not obtained pure in this way, but
its presence is ascertained by transforming it into butyric acid
(Schoyen). Carius obtained dibrombutane, a liquid boiling
between 155° and 162**, by the action of bromine on butane.*

PRIMARY BUTYL COMPOUNDS.

371 Primary Butyl Alcohol, C^H^OH. In order to prepare this
compound an aqueous solution of butyraldehyde obtained by
distilling a mixture of calcium formate and calcium butyrate, is
treated with 1 per cent, sodium amalgam, of which about 70
times the volume is needed. This is gradually added, the
liquid being kept slightly acid by the addition of dilute sul-
phuric acid. The whole is then distilled, and the alcohol dried,
first over ignited carbonate of potash, and then over caustic
baryta.^

In the above method of preparing the aldehyde a not in-
considerable quantity of the alcohol is formed, a part of the
formate being decomposed with evolution of hydrogen.*

Butyl alcohol is also formed by the action of sodium amalgam
on butyric anhydride diluted with butyric acid.^

(C.HyOgO 4- 4 H2 = 2 C,H,OH + H^O.

In place of the anhydride, a mixture of butyryl chloride and
butyric acid may be employed ; ® but, as in the former reaction,
this does not give a good yield. On the other hand it is formed,
together with other products, in tolerable quantity, by a peculiar

' Berthclot, Bull. Soc. Chim. vii. 62.
' Ann. Chem. Phann. cxxvi. 214.

* Lieben and Rossi, Ann, Chrm. Phann. clviii. 137.

* Pogliani, Bcr. IkuUch. Chrni. Ges. x. 2055.
** Linueinonn, Ann. Chvm. Pfuirm. clxi. 180.
° Saytzeff, Joiim. Prnkt. CJicm. [2], iii. 82.

PRIMARY BUTYL COMPOUNDS. 679

fermentation of glycerin/ brought about in the presence of a
schizomycetes. It has also been found in the fusel oil from
potato spirit.*

Butyl alcohol is a highly refracting, somewhat oily liquid,
possessing a peculiar smell, which excites coughing. It boils
at 117^ and burns with a luminous flame. At 0*" it has a
specific gravity of 0 8242, and dissolves in 12 parts of water,
but is separated on addition of calcium chloride. Its derivatives
are obtained in an analogous manner to the corresponding ethyl
compounds, from which they are chiefly distinguished by their
higher boiling-points.

ButyUethyl Oxide, O -< p^xj® is formed by the action of butyl

iodide on sodium ethylate, and is a mobile liquid boiling at
91***7, and having a specific gravity at 6° of 0-7694. In the
formation of this ether, a-butylene and ethyl alcohol are also
formed :

C.Hj^I + C^H^ONa = Nal + C^HsOH + C.Hg.

In order to remove the alcohol it must be rectified over powdered
calcium chloride.

Dibutyl Oxide, {G^^.fi, is obtained in a similar way to the
foregoing compound. Butylene is always evolved in its pre-
paration, and secondary butyl alcohol is produced, which may
be separated by distillation over sodium. Dibutyl ether boils
at 140°'5, and has a specific gravity of 0*784.

BtUyl Chloride, C^H^Cl, is obtained by heating the alcohol
with hydrochloric acid, or the iodide with corrosive sublimate.
It boils at 77°*6, and has at 0° a specific gravity of 0*9074.

BtUyl Iodide, C^H^I, boils at 129°*6, and has at 0° the specific
gravity 1 '643. This body serves for the preparation of other
butyl compounds, because it can be prepared from impure butyl
alcohol, and the impurities can be easily got rid of by fractional
distillation, whereas they are only removed from the alcohol
with considerable difficulty.

The other ethers of primary normal butyl have been but
slightly investigated. The alcohol dissolves in sulphuric acid,
with formation of a very stable acid sulphate, which yields an
easily soluble barium salt, (C4HgSO^)2Ba + HgO, crystallizing
in tablets.

^ Fitz, Ber. Dcutsck. Chcm. Ges. x. 278.
- Habuleau, Compt. liend. Ixxxvii. 500.

P P 2

680 THE BUTYL GROUP.

B.P.

Sp. Gr. at 0*.

9r-98°

0-856

182°

0-8523

B^ityl Carbonate, (C^H^)2C03, is formed, together with butylene
and butyl oxide, by heating the iodide with silver carbonate.
It is a pleasantly smelling liquid boiling at 207^.

Sulphur Compounds of Butyl. These are obtained from the
corresponding potassium salts by treating them with an
alcoholic solution of butyl iodide. They are mobile liquids
possessing an unpleasant smell : ^

Butyl hydrosulphide, C^H^SH
Butyl sulphide, (C^H^)2S

Nitrogen Bases, These are obtained from the chloride by
heating it with potassium cyanate and alcohol, when a solution
of the carbimide is first obtained, and this is then boiled with
caustic potash. The liquid obtained by distilling the product
is saturated with hydrochloric acid and evaporated, and the
residue distilled with lime. The distillate boils between 76**
and 208® and is a mixture of three bases, of which the primary
one is easily obtained pure by fractional distillation. Butyl-
amine, C4HyNH2, boils at 75° '5, has at 0** a specific gravity of
0 7553, fumes in the air, and is very hygroscopic, and its vapour
easily attacks caoutchouc and cork (Lieben and Rossi).

Cyanogen Compounds. Of these the only one which is known
is the mustard-oil, CS.NC^Hg, a liquid boiling at 167**, and
yielding a thio-urea which melts at 79^*

JNitro-compounds of Primary Butyl, Normal primary nitro-
butane, C^H^NOg, is obtained by the action of silver nitrite on
well-cooled butyl iodide. At the same time butyl nitrite,
which has not been specially investigated, is produced. Primary
nitrobutane boils at 151° — 152°, and possesses the characteristic
properties of the primary nitro-paraffins, but it is only a weak
acid. It yields substitution products with bromine. The
monobrom-compound yields, like bromnitroethane, dinitrobutane,
C4H8(N02)2, by the action of nitrous acid. This is a rather
sweetly smelling liquid which decomposes on heating. It is
a monobasic acid ; the potassium salt forms golden-yellow
tablets, and the silver salt crystallizes from hot water, in large
deep-yellow scales, which exhibit a bluish-violet colour by
reflected light. Neither of these salts is explosive.*

* Grabowsky and SaytzefT, Ann. Chem. Pharm. clxzi. 2.^1.
' Hofmann, Bcr. Dcutsch. Chcm. Gcs. vii. 511.
» Ziiblin, Bn. TkuLsch. Chem, Oes, x. 2083.

SECONDARY BUTYL COMPOUNDS. 681

SECONDARY BUTYL COMPOUNDS.

372 Methyl-ethyl Carbinol, CH3(C2H5)CH.OH, was first pre-
pared by De Luynes.^ He obtained the iodide by heating
crythrite with hydriodic acid, and converted this into the acetic
ether by the action of silver acetate, and then decomposed
this by caustic potash.

Butlerow and Ossokin prepared it from ethylene-iodhydrin,
C2H^I(0H), and zinc ethyl, when the crystalline compound,
C2H^(C2H5)0(ZnC2Hg), is produced. This is converted by the
action of water into the secondary alcohol, zinc hydroxide
and ethane. As the iodhydrin possesses the constitution
ICH2— CH2OH, it would be expected that the primary alcohol
would be obtained, but this is not the case, as it undergoes
molecular interchange during the reaction.

Another synthetic mode of formation was discovered by
KanownikoflF and Saytzefif.^ They found that, when a mixture
of equal molecules of ethyl formate, ethyl iodide, and methyl
iodide is heated with zinc and some zinc-sodium alloy, an im-
perfectly crystalline mass is obtained, which is decomposed by
water, and thus the products, which have been already descnbed,
are obtained. From this it is clear that the product of the
reaction contains the same compound as is obtained by the
action of zinc-ethyl on ethylene iodhydrin. The formation
probably takes place in two phases :

COH .CjH, CH(CX)0(ZdC,H,)

I + z< =1

OC,H, \CH3 6H3 +^"\0CX

The same compound may be still more readily obtained by
bringing together anhydrous aldehyde and zinc-ethyl.* Its
decomposition by water is represented by the following equation :

CH.CH/g^f^»^ H + "2 ^ =CH3.CH<gf « + C,H, + Zn(OH),.

This reaction gives a satisfactory yield.

* Ann. Ckim, Phys. [41, ii. 385 ; Ann, Chem, Pharm, cxxxii. 274. See also
Lieben, Ann. Chem. I harm. cl. 106. - Ann. Chem. Pharm, cxlr. 257.

• lb. clxxv. 374. ^ G. Wftgncr, Ann, Chem. Pharm, clzxxi] 261.

582 THE BUTYL GROUP.

Properties, Methyl-ethyl carbiiiol is a pleasantly smelling
liquid possessing a burning taste, boiling at 99", and having at
0° a specific gravity of 0*827. Oxidizing agents convert it
first into methykthyllcetone, CHyCO-CgHg, a body which is ob-
tained by various other reactions already mentioned ^ (see p.
182). This is a mobile liquid smelling like common acetone,
boiUng at 78°, and being converted by further oxidation into
two molecules of acetic acid. Like dimethylketone, it yields a
nitro-compound, CH3.CO.CH(NO)CH3, which crystallizes from
alcoholic solution in prisms, melts at 74**, and boils at about 186°
(Meyer and Zublin).

Secondary Butyl Oxide, [CH3(C2H5)CH]20. This has not as yet
been prepared from the alcohol, but it may be obtained by acting
upon aldehyde with hydrochloric acid, when ethidene oxy chloride,
(CH3.CHC1)20, isomeric with dichlorethcr is obtained, and this,
when treated with zinc-ethyl, easily exchanges its chlorine for
ethyl, and thus yields the ether, which is a mobile liquid boiling
at 120° — 121°, and being converted into the secondary iodide
on heating with hydriodic acid.

Secondary Butyl Iodide, CH3(C2H5)CHI. Erythrite, a body
closely allied to the sugars, and occurring in a variety of plants,
is the alcohol of a tetrad radical, and it yields the secondary
iodide in considerable quantity when heated with an excess of
concentrated hydriodic acid, amorphous phosphorus being added
to prevent the formation of free iodine :

C,H,(OH), + 7 HI = C,H,I 4- 4 H2O + 3 1,.

The same body occurs when ethyl-chlorether is heated with
hydriodic acid (see p. 339). It may also be obtained from the
primary iodide, as this, when .heated with alcoholic caustic
potash, yields ethyl-butyl ether and a-butylene, CH3 — CHj —
CH = CHo, which latter readily unites with hydriodic acid to
form the secondary iodide.^ It is a colourless liquid, boiling at
118°, which soon becomes brown on exposure to light.

Sulphur Compounds of Secondary Butyl are obtained firom the
iodide by reactions which have frequently been described. The
mercaptan, CH3(C2H5)C1LSH, boils at 84°— 85°, and smells like
asiifoetida, atul the suljJiido [CH3(C2H5)CH]2S, is an unpleasant
alliaceous Finelliug body, boihng at 165°.^

^ Fittig. Ann. Chan. Pharm. ex. 18; Fremiti, ib, cxviii. 3 ; Fnnkland aiid
Dup^ui, Chcm, Soc. Journ. xix. 395 ; Ann, Chan, Phami, cxxxviii. 836 ; Poiiofr,
\b, cxlv. 283 ; Ciinini, ib. clvii. 258.

' Saytzt'ff, Ihi\ Diutsch. Ch(m, Oca, iii. 870. » Keyinann, ib. vii. 12b7.

ISOBUTANE AND ITS DERIVATIVES. 683

Secondary Butyl Tliiocarhimide, CS.NCH(C2H5)CH3. Hof-
mann has shown that this substance is the chief constituent of
the oil of scurvy-grass (from Cochlcaria officinalis). He obtained
it artificially by heating secondary butyl iodide with ammonia,
monobutylamine being the chief product, and this, which boils
under 120^ can be converted into the mustard-oil by treatment
with carbon disulphide and mercuric chloride. It is a sharply
smelling liquid, boiling at 159°'5, and yielding, with ammonia,
a thio-urea, fusing at 133°.^ When the mustard-oil is heated
with sulphuric acid, a sulphate of a secondary butylamine is
obtained, and from this the base can bo separated out by potash.
It is a liquid, boiling at 63° (Hofmann, Reymann).

Secondary Nitrohutane, CYi^iQ^^ClS. (NOg), is formed
together with the nitrite and butylene by the action of silver
nitrite on the iodide. It is a liquid boiling at 140°, which yields
a pseudo-nitrol closely resembling the propyl compound, and
fusing with decomposition at 58°.

ISOBUTANE AND ITS DERIVATIVES.

373 Isohutane or Trimethyl Methane, (CH3)3CH, was obtained
by Butlerow, together with isobutylene, by acting with zinc on
tertiary butyl alcohol in presence of water. The isobutylene
can be easily removed from the gaseous mixture by means of
bromine. Isohutane is a colourless gas which liquefies at — 17°.

PRIMARY ISOBUTYL COMPOUNDS.

• hdbvtTjl Alcohol, (CH3)2CH.CHjjOH, occurs in varying quan-
tities in several fusel-oils, and is especially found in the spirit
from beet-root, potatoes, and grain.'- It is obtained from this by
fractional distillation, which, when small quantities are employed,
is rather a tedious operation and is not now carried on. The
faints are now distilled in a rectifying apparatus, and the isobutyl
alcohol separated from the propyl alcohol and other homologues

' Ber, JkutHch. Chan, Gc.h. vii. 508.

2 Wurtz, Ann. Chim. Phys. [3], xlii. 129; Pierre and Pucbot, Bull. Soc.
Chivi. xi. 43 ; Chiipmjiii uud Smith, Joum, Chan. Soc. xxii. 158.

684 THE BUTYL GROUP.

which these faints contain.^ In order to obtain it perfectly
pure it is test to prepare the iodide from the commercial product.
This can be readily purified by fractional distillation from the
other iodides, and then reconverted into the alcohol.

Isobutyl alcohol is a somewhat mobile liquid possessing a
spirituous smell, but at the same time a fusel-oil odour, some-
what resembling that of the flowers of the syringa (Fhiladelphvs
coronarii(s). It boils at 108° — 109°, and at 0° has a specific
gravity of 0*817. At the ordinary temperature it dissolves in 10
parts of water, the greater portion being separated from solution
on the addition of calcium chloride, common salt, potash, &c.

Isobutyl alcohol serves as the starting point for the preparation
of the various isobutyl compounds, which were first examined
by Wurtz, and afterwards by a number of other chemists.
They are obtained in a similar way to the ethyl compounds, and,
for this reason, it is sufficient to give their chief properties in
tabular form.

Ethers.^

B. p. Sp. Gr.

Ethyl isobutyl ether,C2H5.0.C^H9, 70°-80° 07509 at —
Uisobutyl ether, (C,H^)20, 100°-104° — —

The latter compound has not been obtained quite pure.

Ethers of Inorganic Acids.

» Isobutyl chloride, C^H^Cl, 68°-5 0-8953 at 0°

* Isobutyl bromide. C^H^Br, 92°-3 12490 „ 0°

^ Isobutyl iodide, C,HJ, 120°-6 16345 „ 0°

« Isobutyl nitrate, C^H^NO, 130° — —

^ Isobutyl borate, (C^HjjBOg, 212° — —

8 Isobutyl silicate, (C^H J.SiO^, 256°-260° 0-953 „ 15°
» Isobutyl carbonate, (C^H^)oCOs, 190

Ethers of the Fatty Acids.^^

Isobutyl formate, C^HgO(CHO), 98°-5 08845 at 0°

Isobutyl acetate, G^H^O(C2ll30), 116°-5 08596 „ 0°
Isobutyl propionate, C^HoO(C3H50), 135°7 08926 „ 0°

I Brr, Entw, Chcm, Ind. ii. 276.
' Wurtz, lor. cit.

•* Wurtz ; Linnemanii, Ann, Chan. Pharm. clxii. 17 ; Pierre and Puchot, ib.
clxiii. 276. <* Wurtz ; Linnemann, ib, clx. 240.

« Wurtz. 7 CouiK'ler, Journ. Prakt, Chem, [2], xviii. 882.

« Cahonrs, Cowpt. Knuf. Ixxvii. 1403. » WurU.

. »" Wurtz ; Pierre und Pudiot, Ann. Chi,n. Pinjs. f4], xxii. 234.

PRIMARY ISO-BUTYL COMPODNUa 585

Sulphur Compounds.

B.P. Sp. Gr. at

1 Isobutyl hydrosulphide, C^H^SH, 88" 0*8480 ll"-5

2 Isobutyl sulphide,(C,Hg)2S, 170°-5 0-8363 10°
Isobutyl trithiocarbonate, (Cfig\CS^, 285°-290''

In addition to this thiocarbonate other oxy-thiocarbonates are
known.^

Nitrogen Compounds.

* Isobutylamine, (C^Ho)NH2, 67°-5 07357 15"

^Di-isobutylamine, (C,H^)2NH, 135"-137°

« Tri-isobutylamine, (C^HjgN, 184"-186°

7 Isobutyl carbamine, C^H^. NC, 1 1 4°-l 1 7" 0 7873 4"

» Isobutyl thiocyanate, C^Hj^S.CN, 174"-176" — —

« Isobutyl mustard oil, C^H^-NCS, 161^-163° — —

1® Nitro'isobutane, C^HgN02 137"-140° — —

Isobutyl mustard oil forms a thio-carbamide melting at

00"— or.

Isonitrobutane exhibits the same reactions as its lower
homologues, but its nitrolic acid does not crystallize.

Phosphorus Compounds.^^

Isobutylphosphine, C5HQ.H2P, 62

Di-isobutylphosphine, (C^Hg)2HP, 153
Tri-isobutylphosphine, (C4Hg)3P, 215

Hofmann has also prepared several mixed butylphosphines.

METAI.LIC Compounds. ^2

Zinc -isobutyl, {CJig)^u, 185"-188

Mercury-isobutyl, {CJIg)Mg, 205"-207" 1835 15

Aluminium-isobutyl, {G^Ilg\Al, — — —

* Humann, jiitn, Chini, Phys, [3], xliv. 337.

^ Grabowsky and SaytzefF, Ann, Chcm. Pharm, clxxi. 253.
3 Mylius, Bcr, v. 974 ; vi. 3] 2.

* Wurtz ; LinnemaDn, Ann. Cfievi. Phami, clxxii. 22 ; Gautier, ih, clii. 223 ;
Reimer, Bcr. Dcufsch. Chew. Ges. iii. 756.

' Ladenburg, ib. xii 948. • lb. ; Sachtlebcn, ib, xi. 733.

^ Gautier, Ann. Chcm. Pluinn, dii. 222.

* Keinicr, loc. cU. • Koimer, loc. cit.

*" Demole, Ann, Ch*:ni. Pharm, clxxv. 142; Ziiblen, Ber, Deatsch, Chon, Oes,
X. 2087.

" Hofmann, Bn\ Dr.ufsch. Chem. Ccs, vi. 292.

'- Cahours, Cowpt. Bend. Ixxvii. 1403 ; Cahours ami Deniai-vav, ib. Ixxxix. 68.

TERTIARY BUTYL COMPOUNDS. 587

with formation of the acid ether, and this latter is decomposed
by distillation with water into the alcohol and sulphuric acid.^

In order to prepare larger quantities of trimethyl carbinol an
upright condenser is used, the inner cylinder of which is filled
with broken lumps of glass and is closed at the top and bottom
with doubly bored caoutchouc stoppers. To the lower stopper
is connected a gas-delivery tube which passes into the cylinder
to one-third of its height, and through which the isobutylene
enters ; the second opening of this stopper carries a tube which
serves to run off the acid which is produced, and this is provided
with a double bend so that the acid forms a liquid joint and
prevents the escape of the gas. The holes of the upper stopper
caiTy an outlet tube, and a tap funnel by means of which
sulphuric acid of 75 per cent, is allowed to run in. If it is
stronger than this, more or less of the isobutylene is converted
into polymeric modifications. This also takes place when the
temperature rises, and the ' whole, therefore, must be well
cooled, and the acid produced is allowed to run slowly off into
a large quantity of cold waier. This is then distilled, and a
small quantity of oily matter removed from the distillate by
filtration, and the liquid shaken up with carbonate of potash
and dried a second time over the ignited salt.

The tertiary alcohol is also formed when liquefied isobutylene
is shaken up for some time with 50 per cent, sulphuric acid.
Even water acidulated with sulphuric acid dissolves the hydro-
carbon slowly, but the action then requires months for its
completion.^

Another mode of formation of the carbinol appears at first
sight remarkable. If a mixture of isobutyl iodide and glacial
iicetic acid be added to moist freshly precipitated oxide of
silver, a mixture of trimethyl carbinol, its acetic ether, isobutyl
alcohol, and isobutyl acet^ite is formed, whilst isobutylene is
evolved.3 In this case a part of the isobutyl iodide is converted
into hydriodic acid and isobutylene, and this latter combines,
apparently in the nascent condition, with water or acetic acid to
fonn the tertiary compounds.

Trimethyl carbinol is also foUnd in small quantities in
commercial isobutyl alcohol.*

^ ZeilAch. Chr.hi, 1870, 236.
^ Butlerow, Ann. Chcm, Pharm, clxxx. 245.

3 Linnemanu, A7in. CJuyin. Phann. cliv. 130 ; clxii. 12 ; Butlerow, *6. clxviii.
113.

^ Butlerow, Ann. Chcm. Pharm. cxliv. 31.

TERTIARY BUTYL COMPOUNDS. 689

product of the reaction is isobutylene, and this reaction serves
for the purpose of converting the tertiary alcohol into isobutyl
alcohol. For this purpose the hydrocarbon is led into a solution
of hypochlorous acid, when isobutylene chlorhydrate or mono-
chlorisobutyl alcohol is formed. This, when treated with
sodium amalgam and water, yields up its chlorine for hydrogen.^
The following equations explain this reaction :

CH3 CHo CH3 CH3

\ / \ /

C + CI = COl

II I I

CHg OH C OH.

CH« CH« CHq CHo

\V \!/

CCl + Hj = CH + HCL

CH2OH CH2OH

Trimethylcarhyl Nitrite, (CH3)3C.O.NO. Silver nitrite acts
very violently on tertiary butyl iodide, and the nitrite, together
with a small quantity of tertiary nitrobutane, is formed together
with water and the oxides of nitrogen. The ether is a yellow oily
liquid, boiling at 76°— 78^ Tertiiiry NitrdbiUaiie, (CH3)3C.N02.
which is formed at the same time, has not as yet been
obtained pure. It is a liquid smelling of peppermint, and
boiling between 110° and 130°, and possessing no acid pro-
perties. It is not attacked by bromine and potash, nor does it
give any reactions with nitrous acid.

The isomeric nitrites are always formed in the preparation of
the nitro-paraffins, except in the case of nitromethano. Thus, by
the action of silver nitrite on ethyl iodide, almost equal quanti-
ties of the two isomers are obtained. This may be explained
by the fact that the ether is formed by a secondary reaction
in which a part of the iodide is converted into ethylene and
hydriodic acid, and this latter decomposed by the silver nitrite,
whilst the liberated nitrous acid combines with the ethylene to
form ethyl nitrite. The more easily an iodide decomposes into
an olefine and hydriodic acid, the smaller is the yield of nitro-
paraffin, and this is the reason why, in the case of the primary
compounds, a satisfactory yield is obtained, whilst in that of
the secondary it is smaller, and, in the case of the tertiary
compounds, very small.^

^ ^71/1. Ch^m, Pharm. cxliv. 24.

- Tschemitik, Ann. Chm. Pharm. clxxx. 155,

THE BUTYRIC ACIDa 691

Normal Butyric Acid, C3H7.CO2H.

In the year 1811, Chevreiil commenced his classical Recherckes
mr les Corps Gras} which have thrown so much light on the
constitution of the fats, and on the nature of saponification. A
more complete account of these researches will be hereafter
given under the subject of glycerin. We here only mention that
in 1818 he discovered the various volatile acids contained in
butter, and four years later discriminated between them, giving
to them the names of butyric, caproic, and capric acids. The
name for the first is derived from its origin, and from this the
expressions butyryl and the butyl compounds.

This acid occurs, however, not only in butter, but likewise in a
variety of other animal fats, as, for instance, in cod-liver oil. It is
also found in the muscle-plasma, in the secretions of various
insects, in perspiration, and in other animal liquids. It is also
widely distributed in the vegetable kingdom. Thus it has been
detected in croton oil and other fatty vegetable oils, in tamarinds,
the fruits of the soap-nut tree, and that of the Givgko bileba.
Ethers of butyric acid also occur in the oils of various species
of umbelliferae.

Pelouze and Gelis showed that butyric acid also is formed in
a peculiar kind of saccharine fermentation ; and the acid thus
obtained was afterwards investigated by them'* and by Lerclv
It also occurs in the products of many other fermentation pro-
cesses, and in the putrefaction of various substances. Thus it
has been detected in putrid cheese, in the sour licjuors from the
tan-yard, in decomposed cider, and in putrefying yeast. Together
with other fatty acids, it is a frequent constituent of the pro-
ducts of dry distillation of various organic substances, such as
amber oil, cnide pyroligneous acid, &c.

In order to prepare butyric acid, the process by fermentation
of sugar is usually employed, the method given by Bensch*
yielding the best product. For this purpose about 6 kg. of
sugar and 30 g. of tartaric acid are dissolved in 26 liters of
boiling water, and, after some days, 250 grams of putrid cheese
mixed with 8 kg. of sour skimmed-milk, are added together, as
well as 3 kg. of finely divided chalk. The mixture is then so
placed that the temperature of the mass shall be from 30° to 35^
The mixture is stirred up every day, and the liquid, after about

1 Paris, 1823; Ann. Chim. Phys, [2], xxiii. 23.

' Ann, Chim. Phys. x. 434. ' Ann. Chem. Pharm. Ixi. 177.

592 THE BUTYL GROUP.

a week, becomes a thick magma of calcium lactate. It is then
allowed to stand longer at 35°, the whole again becoming liquid,
and an evolution of hydrogen and carbon dioxide being observed,
and lasting for some weeks. As soon as the evolution of gas
ceases, the but3n:ic fermentation is complete. During the whole
operation the water, as it evaporates, must from time to time be
renewed. The whole is then diluted with more water, and 8 kg.
of crystallized carbonate of soda added to the solution, which
is filtered from calcium carbonate, evaporated to 10 kg., and to
this 11 kg. of dilute sulphuric acid added. The oily layer which
rises to the surface is separated from the aqueous liquid, which
still contains some butyric acid. For the separation of this latter
the liquid is distilled, and the distillate saturated with soda, the
butyric &cid being separated from this by sulphuric acid, and
the product added to the first portion. The crude acid contains
water and sodium sulphate. This latter is removed by distil-
lation, a small quantity of sulphuric acid being added, and care
taken to prevent the separation of the normal salt, as this woukl
produce percussive ebullition. The distillate is again dried over
calcium chloride, and again distilled. The product thus obtained
still contains some water as well as acetic acid and caproic acid,
from which it can be separated by fractional distillation. In order
to obtain the pure acid, the chief fraction boiling from 155** to
165° is dissolved in water, when the caproic acid remains behind,
and the pure calcium salt is prepared from this solution. ^ This
is again decomposed, as described, and from the product the pure
butyric acid is obtained by means of concentrated hydrochloric
acid.

The formation of butyric acid from cane sugar, C^jH^gOj,,
takes place in several stages. In the first place, the sugar is
converted by absorption of water into glucose, C^HjgO^, and
this decomposes into two molecules of lac^tic acid, CjH^Oj,
which, again, is converted, as is shown in the following equa-
tion, into butyric acid :

2 CgHgOa = C.HgOo + 2 CO.^ + 2 H^

This subject will be more fully treated under the article
' Fermentation." We may here simply remark that this fer-
mentation is produced by a species of schizomycetes, the germs
of which are either added in the putrid cheese, or may be
derived from the air. This, however, is not the only OTganism

* Lit'ben and Rossi, Ann, C%'ni, Pharm. clviii. 145 ; Qrillone, ib, clxT.

BUTYRIC ACID. 693

contained in the fermented liquid, and these bring about other
decompositions of the sugar. Hence, for this reason, it is more
rational to add individuals of the special ferment, instead of the
sour milk and putrid cheese.

According to Fitz, potato-starch is preferable to sugar. Ho
takes 100 grams of this to two liters of water at 40°, and to this
he adds a minute quantity of the schizomycetes Bacillus siibtilis,
and for its nourishment a mixture of 0*19 potassium phosphate,
0 02 magnesium sulphate, and 1 gram of sal-ammoniac. As
the fermentation proceeds only in neutral solution, 50 grams of
calcium carbonate are also added, and the process is completed
in about ten days. The products of this reaction are 1 gram of
alcohol, 0*33 of succinic acid, about 4 of acetic acid, and 34*7
grams of pure butyric acid ; whilst by the other process, Bensch
obtained only 29*2 grams of crude butyric acid from 100 grams
of sugar.

As acetic acid is a stronger acid than butyric acid, the latter
may be obtained in the pure state from a mixture of the calcium
salts by adding such a quantity of hydrochloric acid that only
the butyric acid is liberated.^

Butyric acid has been synthetically prepared by Frank land
and Duppa^ according to the reaction described on p. 180, and
Linnemann and Zotta ^ have also prepared it synthetically from
butyronitril.

Butyric acid is a mobile liquid having a strongly acid and
rancid smell. This is especially unpleasant in dilute solution.
Its taste is strongly acid. The concentrated acid produces a
white spot on the tongue, and attacks the skin like glacial acetic
acid. It boils at 163°, solidifies in a freezing mixture forming
a pearly glistening mass which melts at —2° to -|- 2°, and at 0*
has a specific gravity of 0*9817, and, at 14°, 0*9601. Like acetic,
butyric acid also possesses an abnormal vapour-density even at
temperatures tolerably far removal from its boiling-point, a
constant limit of 307 not being reached until a temperature of
250° is attained (Cahours).

Butyric acid is miscible with water in all proportions, and it
is thus distinguished from isobutyric acid. It forms easily
soluble salts, and strong acids separate it again from these as
an oily layer.

^ Jkr, JktUsch Chtni. Ocs, xi. 61.

' Froc, Hoy, Soe. xiv. 198 ; Ann, Chem, Phann, cxxxv. 217.
' Ann, Chart. Phann, clxL 175.
VOL. III. Q Q

504 THE BUTYL GROUP.

The Butyrates.

376 The salts of butyric acid are more or less soluble in ¥rater,
and mauy also are soluble in alcohol ; and they are chiefly crys-
talline. In the dry state they possess no smell, but ^hen moist
they generally emit a smell of the acid. Several of them are
wetted by water with difficulty, and exhibit a remarkable
rotatory motion like that of camphor when they are thrown on
to the surface of water. The most characteristic salts are the
following.

Calcium BiUyrate, (CfljO^)2C2L'\'^0, forms transparent scales,
which are more soluble in cold than in hot water. One part
dissolves at 14'' in 3*5, and at 22° in 5*1 parts of water. If the
solution be warmed beyond this point, the salt separates out
as a crystalline precipitate, this quantity being greatest at 70^
At higher temperatures it again dissolves, but even if the solu-
tion be heated in closed tubes to 110°, it does not wholly
disappear. On cooling, the salt dissolves s^ain readily if the
solution has not taken place in open vessels, in which latter case
some of the acid escapes and basic salts are formed.^

Prof Erlenmeyer, after having shown this experiment some
forty times in his lectures, observed that much less salt separated
out each time than had formerly been the case ; and at last no
further separation took place, but on cooling the solution con-
sidenibly, crystalline scales made their appearance. A careful
investigation of this led to the remarkable conclusion that from
9 to 10 per cent, of the normal butyrate had been converted
into the isobutyrate, and that the presence of this latter had
hindered the precipitation of the crystals.*

The fact that calcium butyrate is less soluble in warm
water than in cold has been made use of, as has been stated,
to separate acetic and caproic acid from the crude butyric
acid. According to Lieben and Rossi, this latter liquid is
evaporated with milk of lime, and the solution evaporated down,
when the salt, which is only wetted by water with difficulty,
separates out as a scum, which may then be removed. The
evaporation and skimming is continued until the last mother-
liquors do not yield a pure product.

Zinc Butyrate^ {C^l^O^^^u^ forms pearly scales difficultly

^ Lielien and Rosai, Ann, Cheni. Phann. clxv. 120.
* Ann, Ch:7n, Phann, clxxxi. 126,

THE BUTYRATES. 695

soluble in water. It appears to be most soluble in warm water,
whilst the solubility at 100** is not much greater than at O''.^

Silver BiUyrate, C^H^OgAg, is thrown down as a curdy
precipitate, when a tolerably strong solution of a butyrate is
treated with silver nitrate. It crystallizes from the hot saturated
solution, on cooling, in dendritic prisms. One hundred parts of
water dissolve, at 16°, 0'413 parts of the salt.

Ethers op Butyric Acid.

377 Some of these compounds have been prepared artificially,
and some occur ready formed in the vegetable kingdom. The
following are the most important :

B.P. Sp. Gr. at

Methyl butyrate

lor

09475

4°

Ethyl butyrate

121°

0-9019

0°

Propyl butyrate

143°-4

0-8872

0°

Isopropyl butyrate

128°

0-8787

0°

Butyl butyrate

165»-5

0-8885

0°

Isobutyl butyrate

149°-5

0-8719

0°

Of these, the ethyl ether is obtained by warming a mixture
of two parts of spirit, two parts of butyric acid, and one part of
sulphuric acid for some time to 80", and then pouring the
mixture into water and washing the layer of ether which swims
on the surface with dilute soda solution, drying over chloride
of calcium and distilling. It has a pleasant fruit-like smell,
resembling, especially in dilute condition, that of pine-apples.
A solution of the ether in ten parts of spirits of wine goes by
the name of essence of pine-apple or Ananas-oil. This serves
for the preparation of artificial rum, and is added to the common
sorts of this spirit as well as other liquors ; it is also used in
perfumery and for flavouring cheap confectionery. In place of
butyric acid, a mixture of volatile fatty acids may be used,
obtained by saponifying butter in a current of steam.

The other hutyryl coynpounds are prepared in an exactly similar
way to the corresponding acetyl compounds :

» R. Meyer, Ber, Deutach. Chcm, Ota, xi. 1790.

Q Q 2

BUTYL COMPOUNDS. 697

second is a solid body, crystallizing in oblique rhombic prisms,
melting at about 140**.^

Other chlorinated butyric acids are not formed directly, but
may be prepared from other compounds. These will be de-
scribed hereafter in connection with the bodies from which they
are obtained.

MonobrovibtUi/ric Acid, C^H^BrOj, is obtained by heating
butyric acid with bromine for three to four hours to 150^^ It
may be distilled in a vacuum, and boils under the ordinary
pressure with partial decomposition at 217*. It is slightly
soluble in water, possesses a pungent smell, and at IS'' has a
specific gravity of 1'54. When hydrochloric acid is passed into
its alcoholic solution, the ethyl ether is obtained as a colourless
liquid, boiling at 178^ When heated with alcohol and potassium
iodide, ethyl iodohutyrate is formed, a heavy liquid, boiling with
partial decomposition at about 192^ Free iodobutyric acid is
not known in the pure state.

DibramhUyric Acid, C^HgBrgOg, is obtained by heating the
monobrominated acid with bromine. This crystallizes from hot
water in thin prisms which melt at 65° — 70^ and boil at 227°
with partial decomposition. Its ethyl ether is a liquid smelling
like apples, and boiling between 191° and 193°.

Other isomeric higher brominated butyric acids will be
afterwards mentioned.

ISOBUTYRYL COMPOUNDS.

379 Isobutyraldehyde, (CH3)2CH.CHO, is obtained by oxidiz-
ing isobutyl alcohol with potassium dichromate and sulphuric
acid.^ It is a strongly refracting liquid, possessing a pungent
though not unpleasant smell, boiling at 61°, and having a
specific gravity at 0° of 0*8226. It easily polymerizes, like
acetaldehyde, into the trimolecular para-isobutyraldehyde,
^12^24^3* ^ substance crystallizing from alcohol or ether in fino
needles, melting at 60°, and easily undergoing sublimation.

* Pelouze and Gelis, Ann, Chiin,. Phys, [3], x. 449.

^ Naumann, Ann, Chem. Phann. cxix. 115 ; Friedel and Maclmca, ib. cxx.
282 ; Siippl. ii. 70 ; Schneider, ib. cxx. 279 ; Tupoleff, ib. clxxi. 248.

' Micbaelson, Co7nj)t. Hend, 1. 888 ; Knimer, Bcr. Dctitsch. Chtm. Gcs. vii.
252 : Pfeiffer, ib. v. 699 ; Barbaglia, ib. v. 1052 ; I.ipp. Ann, Chem. Phann.
ccv. 1.

ISOBUTYL COMPOUNDa 599

standard for comparison was obtained by the oxidation of
isobutyl alcohol.

Isobutyric acid has also been prepared synthetically by
Frankland and Duppa by the aceto-acetic-ether reaction
(see p. 181).

Isobutyric acid is found in the free state in the flowers of the
Arnica montana,^ as well as in the carob bean, and amongst the
acids of croton oiL^ Isobutyl ether is one of the constituents
of oil of camomile {AntJiemis ncMlis)}

Isobutyric acid boils at 154**, and at 0'' has a specific gravity
of 0*9598. It has a smell resembling the normal acid, but is
less unpleasant, and is not miscible with water, one part requiring
for complete solution three parts of wat^r at the ordinary tem-
perature. It is distinguished from the normal acid, inasmuch as,
when heated with dilute sulphuric acid and potassium dichromato,
it is easily oxidized into acetic acid and carbon dioxide.

ISOBUTYRATES.

381 The salts of isobutyric acid resemble in general properties
the butyrates, with the exception of the salts of calcium and of
silver.

Calcium Isobuti/i*(Ue, (C^TELjO^^^^ + ^^^O, crystallizes in
monoclinic needles, which dissolve at 1 8** in thirty-six parts of
water, whilst in hot water they are more soluble, and the satu-
rated solution solidifies on cooling to a crystalline magma. If
subjected to dry distillation, isopropyl ketone as well as methyl
isopropyl ketone and isobutyl aldehyde are formed.*

Silver Isobuti/rate, C^H-OgAg, crystallizes from hot water in
transparent scales. One hundred parts of water at 16"* dissolve
0 028 parts of the salt.

Zinc IsohiUt/rate, (C^Hy02)2Zn, crystallizes in monoclinic
prisms, which at 19°'5 dissolve in 5*8 parts of water. The
solubility diminishes quickly with increase of temperature, and
a solution saturated in the cold deposits cr)'stals in large
quantity when warmed.^ *

^ Sicel, Ann. Chtin. Pharm, clxx. 345.

- Scumidt and Behrendcs, Ann, Cli^m, PJuirm. cxci. 101.

3 Kobijj, Ann. Chcm, Phann. cxcv. 92.

* Barbaglia and Gucci, Ber, DciUsch. Chem. Gts. xiii. 1572.

' R. Meyer, Ber, DcuUch, Chem, Gcs. xi. 1790.

ISOBUTYRYL COMPOUNDS. 601

Morisohutyrate, C^HgClOgCCgHg), a liquid boiling at 147* —
150^l

Bromisdbutyric Add, (CH3)jCBr.C02H, is formed by heating
equal molecules of the acid and bromine to 140**.^ It crystal-
lizes from alcohol and ether in white tables which melt at 48*,
and boils with slight decomposition at IDS'* — 200^ Its ethyl
ether boils at 160°.

^ Balbiano, Ber, Dcutsch. Chan. Gea. xi. 1693.
> HeU and Waldbaoer, ih. x. 448.

COMPOUNDS CONTAINING FIVE ATOMS OF
CARBON, OR THE PENTYL GROUP.

383 The compounds of this group are derivatives of the
following isomeric paraffins :

(I.)

Pentane.

(11).

laopentane or Diinethyl.ethyl-metluuie.

CH,
/

CH3 — CH2 — CHj — CH2 — CH3. CHj — CH2 — CH -

0H-.

(III).

Tetramethyl-methane.

CH.

C H J — C — C H3

CH,.

Eight alcohols corresponding to these can exist, viz. :

-S

Primary.

^\^

IVntyl Alcohol, or

Uutyl Carbiiiol

(l>. 603).

CH,

CH.

CH,
I

CHjOH

II.

Methyl Propyl
Carbinol
(p. «04).

CH.

I
CH.OH

Secondary.

111.

Diethyl

Carbinol

(p. 605).

CH.

I •
CH,

TiBTIARV.

CH,

I '
CH,

CH.OH —

CH,

PENTYL COMPOUNDS.

603

/ IV.

Inactive Amyl
Alcohol, or

•

Isobutyl
Carbinol'

(p. 609).

CHj CH3

CH,

, CH^OH

Active Amyl

Alcohol, or

Secondary Butyl

Carbinol

(p. 610).

CH3 CHgOH
CH

VI.

VII.

Methyl

Dimethyl
Ethyl

Isopropy]

Carbinol

(p. 615).

(p. 616).

CH3 CH3

\ /

CH .

^^H

CH.

CH,

H.OH

CH,

VIII.

Tertiary Butyl

Carbinol (p. 617),

CH,

CH- — C — CH«

I
CHgOH

Of these alcohols the first seven are with certainty known.

NORMAL PENTANE AND ITS DERIVATIVES.

384 Peyitane, CgHjg, was discovered by Schorlemmer^ in the
light oil of the tar from cannel-coaL It is also found in the pro-
ducts of the distillation of Boghead cannel (Torbane mineral),
and occurs in considerable quantity in Pennsylvanian petroleum.
It is an easily inflammable liquid, possessing an ethereal smell,
and boiling at 37° — 3D°, and having, at 17^ a specific gravity
of 0 6263, that of its vapour being 2*49.

The first product of the action of chlorine on pentane is a
mixture of the primary and secondary pentyl chloride.

NoBMAL Primary Pentyl Alcohol, C5H11.OH.

This compound, also termed butyl carbinol, or normal amy!
alcohol (No. I. on the list), was first synthetically prepared by
Lieben and Rossi. These chemists, starting from normal butyl
alcohol, prepared the corresponding cyanide, or the nitril of

1 Pha.Traru.W2, 111.

PENTYL COMPOUNDS. 605

in which such an atom occurs, optically inactive. Le Bel, how-
ever, found that if its aqueous solution be brought in contact
with a ferment such as Penidlliuni glaiunim, and allowed to
stand for a short time, it is converted into the laevro-rotatory
alcohol^

The following compounds have been prepared :

B.P. Sp. Gr.

Methyl^propyl carbyl chloride 103-105^ 0 9120 at 0"

Methyl-^propyl carbyl iodide 145-146° 1-5390 0''

Methyl-propyl carbyl acetate 133-135'' 09222 0'

MethyUpropyl Ketone, C8H7.CO.CH3, is formed, together with
dimethyl ketone and dipropyl ketone (butyrone) and other pro-
ducts, in the dry distillation of a mixture of acetate and butyrate
of calcium.^ It has also been synthetically prepared by the
method already described. In smell it resembles common
acetone, boils at 103°, and at 18** has a specific gravity
of 0808. Like dimethyl ketone (p. 568), it yields a nitro-
compound, CH(NO)C2H5.CO.CH3, which crystallizes from al-
coholic solution in prisms which melt at 55**, the liquid
boiling between 183"* and 187**, with partial decomposition.*

Diethyl Carbinol, (C2H5)2CH.0H.

386 This alcohol (No. III. on the list) is formed by heating
ethyl formate with ethyl iodide and zinc ; this reaction corre-
sponding closely to the formation of methyl -ethyl carbinol (see
p. 581.)

The secondary alcohol is a peculiarly smelling liquid, boiling
at 116*''5, and having, at 0°, a specific gravity of 08315. The
following derivatives have been examined : ^

B.P. Sp. Gr.

Diethyl carbyl chloride 103-105' 0916 at 0'

Diethyl carbyl iodide 145-146" 1-528 0'

Diethyl carbyl acetate 132** 0-9090 0'

* Compt. Hend, Ixxxix. 312 ; Bull. Soc. Ckim. xxxiii. 106.
^ Grimm, Ann. Chem, Pharm. clvii. 251.

3 Butlerow, Bull. Soc. Chim. [2], v. 19; Wislicenus, Ann, Chem, Pharm.
elxxxvi. 187 ; cxc. 157.

* Meyer and Zubliii, Ber. Deutsch. Chem. Gcs. xi. 323 and 695.
» Wagner and Saytzeff, LichUja Ann. clxxv. 351 ; dxxix. 321.

THE AMYL ALCOHOLS. 607

that it was a compound standing between tliis latter substance
and an ethereal oil.^ Dumas, who afterwards investigated the
same subject, found that a large quantity of a liquid may be
separated by fractional distillation, boiling at ISl'^'o, and this
possessed tho composition CgHjgO, from which an analogy
between this body, alcohol, and the ethers might be assumed.
Still he thought it more probable and simpler to consider this
substance as a body analogous to camphor or to the ethereal
oils.* Some years afterwards Cahours investigated its chemical
properties, and his experiments led him to conclude that this
substance is isomeric with common alcohol, and belongs to the
natural series of which wood-spirit and common alcohol form the
two first members.* The further investigations of this chemist,*
as well as those of Dumas and Stas,^ and of Balard,^ confirmed
this view. Cahours gave to the compound the name of amyl
alcohol because it had been chiefly found in spirit obtained from
bodies containing starch (amylum). Balard, however, afterwards
proved that it occurs in fusel oils formed in the fermentation of
grape skins, and since that time it has been shown to occur in
all fusel oils.

The amyl alcohol thus obtained was for a long time believed
to consist of one distinct compound. Biot first drew attention
to the fact that this body possesses the power of rotating the
plane of polarized light to the left, but Pasteur pointed out in
1855, that the rotatory powers of different samples of amyl
alcohol vary according to the sources from which they are
obtained. From this he concluded that the body termed amyl
alcohol is a mixture in varying proportions of an optically active
and an optically inactive compound. In order to separate these
two bodies, Pasteur dissolved the mixed alcohols in strong sul-
phuric acid and neutralized with barium carbonate. By this
means he obtained two barium-amyl sulphates ; the one derived
from the inactive alcohol,being 2*5 times less soluble in water than
the other, so that they could be separated by repeated crystal-
lization. He next converted them into the sodium salts by
addition of sodium carbonate ; these he distilled with sulphuric
acid, and he thus obtained the two modifications of the alcohol.^

* Ann. Chim, Ph}j<t. [1], xxx. 221.

- Ih, [1], Ivi. 314 ; Ann, Pharm, xiii. 80.

' Ann. Chim, Phya. [1], Ixx. 31 ; Ann. Pliarm. xxx. 288.

* Ann, Chim, Phys. [1] Ixxv. 193 ; Ann, Chcm. Pharm, xxvii. 164.
' Ann. Chim, Phys, [1], Ixxiii. 128.

« lb. [3], xii. 294 ; Ann, Chcm, Pluirm. Hi. 311.

' Cvmjyt, Jicnd, xli. 296 ; Ann, Chcm. Pharm, xcvL 255.

ACTIVE AMYL ALCOHOL. 609

by oxidation of the inactive amyl alcohol.^ Hence its constitu-
tion is that of No. IV. on the list (p. G03), viz. :

^g^XcH— CH— CH,.OH.

The accuracy of this conclusion was confirmed by the experi-
ments of Frankland and Duppa. They proved that isopropyl-
acetic acid obtained by synthesis is also identical with valeric
acid. 2 Lastly, Balbiano found that the alcohol can be prepared
synthetically from isobutyl alcohol, by the same process as that
adopted by Lieben and Rossi for obtaining the normal alcohol
from primary butyl alcohol.^

The optical properties of the inactive alcohol are almost the
only means by which it can be distinguished from the fermenta-
tion-alcohol. It boils at 131°*4, and has at 0"* a specific gravity
of 08238. It occurs in camomile oil * as the ethers of angelic
and tiglic acids. The following derivatives of the pure inactive
amyl alcohol have been aheady prepared. They may be termed
the a-amyl compounds :

B.P. Sp.gr. at 0".

a- Amyl chloride, C^ll.fil 98'-9 0-8928

a- Amyl bromide, C^Hi^Br 120°-4 1-2358

a- Amyl acetate, CgHiiOCaHgO) 138^-6 0*8838

a-Amyl valerate, C,Hi^O(CXO) 190'.3 0.8700

a-Amylamine, cXiNH^ 9G°5 —

a-Diamylamine, (C^HiOoNH 185*'-0 —

a-Triamylamine, (C5H1J3N 237°-0 —

Active Amyl Alcohol.

389 This was prepared by Pasteur and by Pedler from the
fermentation-alcohol in the mode already described. Accord-
ing to Le Bel it is also obtained from the latter compound
by saturating it with hydrochloric acid, which first acts
upon the inactive alcohol. The chlorides are then distilled

^ Ann. Client. Phnrm. Siippl. v. 337.

- Pedler, loc. cit. : Erleumeyer, Bcr. Dcutsrh. Chem, Ocs, iii. 899,

3 Tier. Deutsch. Chem. Ges, ix. 1437 aud 1692.

* Kobi«^, Liebig's Ann, cxcv. 99.

• Plimpton, Compt. Jlrnd. xci. 433.

VOL. in. R H

610 THE PENTYL GRODP.

off, and the residue heated repeatedly with hydrochloric acid
until about oue-ninth of the original liquid remains unacted
upon ; this consists, to a great extent, of the levro-rotatory
alcohol.^ The first portions of the chloride can bo worked u])
for the inactive alcohol and its derivatives. The above-named
amines were obtained from a chloride obtained in this way.

Active amyl alcohol has evidently not yet been obtained pure,
as the rotfitory power of the different preparations has been
found to be very different. It boils about 128'', and smells like
the fermentation-alcohol, but has rather a more fruitv flavour.
The remarkable fact that the derivatives of this levro-rotatory
amyl alcohol turn the ray of polarization to the right lias been
observed by Le Bel. Another interesting fact is, thfit the
aqueous solution of the levro-rotatory alcohol is converted by the
action of a mucor into the dextro-rotatory alcohol which boils
at 127**, and yields a levro-rotatory amyl iodide.^ 'When the
levro-rotatory alcohol is heated for some time with soda or
potash, or when it is converted into sodium amylate, the
regenerated alcohol is found to have lost its optical activity ;
the same change occurs when it is heated under pressure. It is
not improbable that a part of the alcohol is here converted into
the dextro-rotatory modification, and that then a condition of
equilibrium is attained, so that the optical properties of the two
physical isomerides neutralize each other. The constitution of
the active amyl alcohol is probably represented by the formula
(No. V. on the list, page 603) :

and for the following reasons. Theoretically, four primary
pentyl alcohols may exist independent of optical isomerides.
Of these only the one possessing the above constitution cont^iins
an asymmetrical carbon atom, a well-known characteristic of
optically active b^xlies. In addition to this, the active alcohol
yields on oxidation an acid which closely resembles syntlietically
prei)ared mothyl-ethyl-acctic acid, CII^(C2ir5)CH.C02lI, which
has not yet been thoroughly investigated. It is, however, dis-
tinctly (lifftTont from the three other known iK*ntylic acids who.so
possible existence is i)ointed to by theory.

> Bull. Soe. Chhii, XXV. 545.

- \jc IJcl, Ball, Soc, Chitn. xxxl KM.

THE AMYL COMPOUNDS. 611

The following derivatives of the active alcohol, which may be
termed /9-amyl compounds, have been prepared : ^

B.P. Sp. Or. at 0".

/9-Amyl chloride, CgH^iCl 97-98" 0 886
/9-Amyl bromide, C,Hi,Br 117-120° 1225
i8-Amyl iodide, cXiI 144-145" 1*540

THE AMYL COMPOUNDS.

390 The amyl compounds derived from the fermentation- alcohol
have been much more fully investigated ; but inasmuch as this
liquid is a mixture, its derivatives are not pure substances, the
compounds of the inactive alcohol being present in largest
quantity. These may be simply termed the amyl compounds.

The Amyl Ethlus.

Ethyl'Amyl Ether, C2H5(CsHii)0, was first prepared by
Balard, by heating amyl chloride w^ith alcoholic potash. It
was, however, believed by him to be amyl oxide, until William-
son showed that the same compound is obtained by acting on
amyl iodide with sodium ethylate * (see p. 329). According to
Guthrie, ethyl-amyl oxide is best prepared by dissolving caustic
potash in boiling amyl alcohol, and then adding ethyl iodide,
when a considerable evolution of heat takes place, but at last
the reaction must be aided by heat.* It is an ethereal-smelling
liquid boiling at 112°, the vapour of which has a specific gravity
of 4-042.

Methyl'Amyl EfJur, CH3(C5Hii)0, is obtained in a similar
manner, and boils at 92** (Williamson).

Diamyl Ether, or Amyl Oxide, (0511^)20, was first prepared
by de Glaubry,* and afterwards by Rieckher,* by heating the
alcohol with sulphuric acid, when the oxide is formed together
with a number of by-products. Williamson ® obtained it by
acting on sodium amylate with amyl iodide, and Wurtz ^ pre-
pared it together with amylene, by acting on the iodide with

^ Lc Bel, Bull. Soc. Chim. [2J, xxv. 545.

- Quart, Joum. CJum. Soc. iv. 233. ' Phil. Mag. [4], xir. 186.

* Ann. Chcrn. Pharin. xliv. 128. « lb. Ixiv. 336.

« Quart. Joum. Chem. Sec. 108, 234. ? Ann. Chim. Phjs. [3], xlvi. 222.

R R 2

612 THE PENTYL GROUP.

silver oxide. According to Friedel, it is best obtained by-
heating 10 parts of the alcohol with 1 part of amyl iodide,
for several hours, to 100°^ (see p. 331). It is an unpleasantly
smeUing liquid, boiling at 176", having at 0" a specific gravity
of 0*7994, that of its vapour being 5535.

Amyl Haloid Ethers.

« Amyl chloride, C,ll,fil
^ Amyl bromide, CgH^^Br
* Amyl iodide, C^HijI

Amyl Ethers of Inorganic Acids.

^ Amyl sulphite, (CgHiJ^SOs —

® Hydrogen amyl sulphate, H(C5Hji)S0^ —

B.P.

Sp. Gr.

100°-9

0-8859

118°-7

11G58

IG"

147°-2

1-467G

^ Amyl nitrite,

CjHuNOg

99°

0-902

* Amyl nitrate,

C,H„N03

148°

1000

►-3

• Amyl phosphite,

(C,U,,),VO,

** Amyl phosphoric acids

" Amyl borate,

{C,ll,,),BO,

254°

0 872

^- Amyl silicate.

(C,H,0.SiO,

322-325°

0-8G8

so"*

"Ainyl carbonate.

(C,H,^),C03

226°

0-914

Amyl Nitrite. This important compound is obtained by
passing nitrous fumes, obtained by the action of nitric acid on
starch or arsenic trioxide, into amyl alcohol ; or by dissolving
amyl alcohol in its own volume of sulphuric acid, and heating
the mixture, after it has become cold, with a solution of 2G
parts of potassium nitrite in 15 parts of water, and then

* Ber. DcutKh, Chem. Ges. ii. 715.

- C'ahoui-s; Bulard; BufF, Ann. Chcm. Pharm. cxlviii. 350.
' Cahouw ; ElketotF, Ber, DcuUch. Chen, Ocs. vi. y2:*S.

* CahuUFH ; Fraiikland, Qiinrt. Journ. Chem. Soc. iii. 30.

' Carius and Fries, Ann. Chcm. Pharm. cix. 1 ; Cahouis, cxi. 03.

* Caliours ; Kckule* Ann. Chem, Pharm. Ixxv. *275.

' UalanU Guthrie, Quart. Joitrn. Chem, Sue. ^xi. 215; Nmller, Ann. Cficrn,
Pharm. cxvi. 17t> ; Hilgor, Hennard, Jahresb. 1874, 352.

8 llitJikher, Ann. Chem. Pharm. Ixiv. 336; llofiuaiiii, ih. Ixviii. 332 ; Cliapmaii
and Smith, Juurn. Chem. Site. xx. 5S1.

* AVillianis>on and Railton, Proc. Po^f. Soc. vii. 131 ; Mcnschutkin, Ann. Chcm.
Pharm. cxxxix. 348.

^^ (Juthrii!, Jmtrn. Chem. Soc. ix. 131 : Krant, Ann. Chem. Pharm. cxviii. lo2.

" Schitr, Ann. Chem. PJuirm. Suppl. v. 187.

^^' Kh,quii.n, ib. Ivii. 331.

*^ Medlock, Qaarl. Juuni. Chcm. Sue. i. 370 ; Bruce, ib. v. 131.

THE AMYL COMPOUNDS. C13

B.I'.
116°

Sp. Gr.

0-874

137°

0-8837

1 - -'O

176°

0-852

15^

distilling, Amyl nitrite is a light yellow liquid possessing a
peculiar stupefying smell, and its vapour, when inhaled in
small quantity, produces a flushing of the countenance, rush
of blood to the head which may increase up to insensibility, and
a quickening of the pulse due to an increase in the area of the
blood-vessels, and a diminution of the controlling-power of tho
contractile fibres. These symptoms disappear again very quickly.
On account of its peculiar physiological action amyl nitrite is
employed in medicine, and is said to have been beneficially
employed in epilepsy, asthma, in certain cases of hypochondriasis,
and in angina pectoris.

Amyl nitrite has a peculiar disagreeable smeil, and its
vapour, like that of ethyl nitrite, is very explosive.

Amyl Ethers of the Fatty Acids.

1 Amyl formate, C,HiiO(CHO)

2 Amyl acetate, C.R.fii^fiP)
^ Amyl propionate, C^HiPCCaH.O)
^ Amyl butyrato, C5HiiO(C^H70)

Amyl Acetate is obtained by warming a mixture of one part
of sulphuric acid, two parts of amyl alcohol, and two parts of
acetic acid, and distilling. It has an aromatic ethereal smell
which, when the ether is diluted with alcohol, resembles the
smell of Jargonelle pears. Hence it is used for the preparation
of pear-essence. It is usually prepared for this purpose from
l)otato fusel-oil, and 10 parts of the ether are mixed with one
part of acetic ether and 80 parts of rectified spirit, and a few
drops of oil of lemons or oil of bergamot added.

Amyl Sulphur Compounds.

B.P. Sp. Gr. at

•• Amyl hydrosulphide, C.Hi^.SH \W\> 0-835 21'

« Amyl sulphide, {Gr^i^, S213-214' — —

- Ethyl-amyl sulphide, aHsCCXi)^ 160" - — '

* Kopp, Ann, CJiem. Pharm. Iv. 183. ' Cahoura ; Kopp, ih. xcir. 294.
3 Wrightsou, ib. xc. 45. * Deltfs, ih, xcii. 278.

* Balanl ; Knitzsch, Joum, Prakt, Chem, xxxi. 1

* lialanl ; Beckniann, ih. [2], xvii. 440.

^ Saytzfff, Ann. Chan. Pharm. cxxxix 361 ; Beckinanu.

CM THE PENTYL GROUP.

Amyl Telluridc, (CgH^jj^Te, was prepared by Wohler and
Dean by heating potassium telluride with a solution of potas-
sium amyl sulphate. It is a reddish yellow heavy liquid, having
a most unpleasant smell. It boils with partial decomposition
at 198^ and is converted, on exposure to air, into the oxide
(C,H,,)jTe0.i

Amyl Nitrogen Compounds.

n.p.

8i>. Gr.

* Amylamine,

(C,H„)NH,

95°

0-7503

18"

Diamylamine,

(C5Hi^)3NH

170°

0-7825

Triamylamine,

(C,H„),N

257°

^ Amyl carbamine,

C,H„.NC

137°

* Amyl carbimide.

CjHijN.CO

100°

^ Amyl thiocyanate, C^HijS.CN lOT 0-905 20**

» Amyl thiocarbimide, C^HiiN.CS 183-184** — —

NitropentaTU, CgHjiNOj, is formed by the action of amyl
iodide on silver nitrite. It has, however, not been obtained ia
the pure state, as it is difficult to separate it from the amyl nitrite
formed at the same time, although the latter boils 60** lower.
It is a light liquid, smelling like the rest of the amyl com-
pounds, and boiling between 150" and 160**, and dissolving only
with difficulty in caustic potash.*

Amyl Phosph(;hus Compounds.**

B.P.

Amylphosphine, (C^Hii)PH, 106-107'
Diamylphosphinc, (( \,H,i),PH :>1 0-21 5"
Triamylphosphine, (C^Hj^r^P 300°

' Ann. Chcm, Pharm. xcvii. 1.

- Wurtz, ib. Ixxi. a2() ; Ixxvi. 317; Hofniann, ib. Ixxiv. 118; Ixxv. 364;
Ixxviii. 27y ; Ixxix. 2o ; Silvn. Comjtt. Rend. Ixiv. 1209.

* Hufiiuuiii, Ann, Chan. Pharm. cxliv. 114 ; cxlvi. 107 ; Gautitir, ib. cxlvi
110, 121.

* Wurtz, Compt. Rend. xxix. 186.

* M^Mllm^k, Ann. Chcm. Phann. Ixix. 214; Quart. Journ, Chenu Soc. i. 373 ;
llcnry, Journ, Prnet. Chcm. xlvi. 161.

* riofmann, Brr. Ikntsch. Chcm. Gcs, i. 178.
" V. Mover, Ann. i'hrm. Phann. *0.xxi. 43.

' llofmami, Per, DeuUch, Ckcm, Gcs. vL 2U7.

METHYL-ISOPROPYL CARBINOL. G16

Amyl Antimony Compounds.^

Antimony-diamyl, (CgH^J^Sbj.
Autimony-triamyl, (CjHjJjSb.

Amyl Metallic Compounds.

B.P.

Sp. Gr.

^ Zinc-amyl,

(C.HJ^n

220°

1022

^ Mercury-arayl,

(C,H„).Hg

1-6663

0°

* Lead-sesquiamyl

(P&^nX^^a

^ Tin-tetramyl,

(C,H,,),Sa

^ Amyl-tin iodide,

(C,H„)3SnI

302-305°

Auiyl-tin hydroxid<

3. raH„),SnOH

335-338°

Methyl-isopropyl Carbinol, (CH3).jCH(CHOH)CH3.

391 This secondary alcohol (No. VI. on the list) is formed by
the action of sodium amalgam on an aqueous solution of the
corresponding ketone,^ as well as when bromacetyl bromide is
treated with zinc-methyl. A thick liquid is formed after stand-
ing for several weeks, and this is decomposed by water, with
formation of the secondary carbinoL The mechanism of the
last reaction has not yet been explained.® The carbinol is a
sweetly smelling liquid, boiling at lll^-llS**, and having at 0"*
a si>ecific gravity of 0*819.®

Hygroscopic substances easily split it up into water and
trimethyl ethylene, (€113)20 = CH(CH3), and for this reason,
on treatment with phosphorus chloride, hydriodic acid, «&c., it
yields the tertiary alcohol, and not the corresponding ethers.
Its haloid ethers may be obtained, however, by combining the
hydracids w4th isopropyl ethylene, (CH3)2CH.CH = CHg, which
can be obtained, together with an isomeric olcfine, by heating
common amyl iodide with alcoholic potash.

^ Rorle, Ann. Chcni. Phann, xcvii. 316 ; Cramer, Jahresb. 1855, 590.

* Fraiikland, Quart, Joum, Chcm. Hoc, vL (54 ; Frankland and Duppa, Jouni,
Chi'in. Sue. xvii. 32.

'" Frankland and Duppa, ib. xvi. 420. *• Klippel, JaJircsh, 1860, 383.

^ Grinini, Ami. Chnn, Phann. xcii. 383.

• ('iihours and Dcniar^ay, Comjrf. JUncf. Ixxxix. 68.
^ Miinch, Ann. C/Min, Pharm. clxxx. 339.

^ 'NViuugi-adow, ib. cxci. 125. • '\Vysoliuegrads>ky, ib. cxc. 338.

CI 6 THE PENTYL GCOUP.

n.P. Sp. Gr. at

Secondary arnyl chloride, C5H11CI 9^ 0-883 —

Secondary amyl bromide, CgHijBr 115-116" — —

Secondary amyl iodide, C^H^jI 137-138" — —

If these are heated with water and silver oxide, or lead oxide,
the tertiary alcohol is foniied.

Mdhyl-propyl Ketone, (CH3)oC.H.CO.CH3, is prepared by the
usual method from calcium isobutyrate and calcium acetate;
and also by the decomposition of dimethyl aceto-ac etic ether. It
is a liquid boiling at 95", and having at 0" the specific gravity
0 822.

Dimethyl-ethyl-Carbinol, (CH3)2(C2H5)C0H.

392 This tertiary alcohol (No. VI I. on the list) is formed in
an analogous way to tertiary butyl alcohol by acting ujx)n
propionyl chloride with zinc-methyl, and decomposing the
crystalline product by water/ It may be more easily prepared
from commercial amylene, obtained from the fermentatiou-
alcuhol, which contains, together with the above-mentioned
isopropyl ethylene, its isomeride, trimcthylethylene. This
latter conil ines with slightly dihitcd sulphuric add on shak-
ing in the cold, and if the solution be then distilled with
water, the tertiary carbinol is obtained.'-^ The carbind was
obtained at an earlier date by Wurtz, but mixed probably
with an isomeric alcohol. He obtained it by treating the
above-mentioned mixture of amylenes with hydriodic aci<],
and acting upon the products with moist silver oxide in
the ct)ld.*'^ He calletl this new isomeride of the fermentation-
alv'ohol amylene hy finite. It was afterwards considered to bo
a secondary alcohol, until further investigation revealed its
true nature.

Tertiary amyl alcohol is a peculiar aromatic-smelling liquid,
bailing at lOi'*;"), solidifying in a freezing mixture, forming long
white needles which melt at 12", and having a specific gravity
at 0" of 0 827.

' Vo\\of(, Aun. Chcin. Vhinn. v\\\\ 2*.»2 ; Wv.Hrlinc;:rR<I>k\. ih. r\c. iVAil.
' WyHchnef^nulsky, hn: ,//. ; Klawitzkv, it*, clxxix. ;U3 ; Osii>otr, /Ar. Ihuts.-!,.
Chan, (wrs, viii. .'i4i\ 124t).
» Ann, Chem. rhann. ixw. lU, cxxvii. •«»:;«; rxxix. 365.

TETBAMETIIYL METHANE. C17

U.P. Si.. Gr. at

Tertiary amyl chloride, CjHuCl 86' 0-889 0

Tertiary ainyl bromide. C,H,iBr 108-109° — 0

Tertiary amyl iodide, CjHjJ 127-128° 1-524 0

Tertiary amyl acetate, C^K^fiiC^Hfi) 125° — 0

Tertiary amylamine, OjHuNHg 7S-5 — 0'

TETRAMETHYL METHANE AND ITS

DERIVATIVES.

393 Tdramethyl MetJiane, C(CH3)^, is formed by acting with
zinc-methyl on tertiary butyl iodide or on propidenc dichloride,
(Cli.^.jCC\2f a body obtained by treating dimethyl ketone with
phcspliorus pentachloride. It is a mobile liquid boiling at 9°*5,
and solidifying when placed in a freezing mixture to a mass of
delicate crystals which melt at —20°.^

The derivatives of this paraffin have not as yet been directly
prepared from the hydride. By the action of chlorine, the first
substitution-iiroduct is said to be a primary chloride from which
other compounds might be prepared, such as the alcohol
(0113)30. CHoOH, whoso corresponding acid, trimethylacetic
acid, is known and will be subsequently described.

THE PENTOIC OR VALERIC ACIDS.

394 Fentoic, or Normal Valeric Acid, C^Hg-OOgH, was prepared
by Lieben and Rossi by heating one of the haloid ethers of
normal butyl with alcohol and potassium cyanide for two days to
100°— 101°, when pentonitrll, O^H^CN, is formed, a liquid which
has a specific gravity at 0° of 0 '81 04, and boils at 140°*4. ^ For tho
purpose of prej)aring the acid it is not necessary to obtain the
nitril in the pure state, but the product of tho reaction is dis-
tilled in order to remove potassium iodide, and the distillate is
boiled with caustic potash in connection with an inverted con-
denser as h)ng as ammonia is evolved. The alcohol is then
removed by distillation, and the acid separated from the residue
by means of sulphuric acid.^ It is also obtained, together with
j)araffins and normal homologous acids, when fats are distilled

^ Lwow, Ztitsch, Chem, vi. 520 ; vii. 257.
* yinn. Chem. Phann. dviii. 171.
^ Ami. Chan. Phann, clix. 58.

THE PENTOIC OR VALERIC ACIDS. 619

Valeric acid was formerly obtained by distilling valerian root
with water. The distillate which, in addition to the acid,
contains an ethereal oil, is neutralized with soda, the aqueous
solution concentrated and decomposed by sulphuric acid. The
acid is now obtained by oxidizing fermentation amyl-alcohol
when it is obtained with a larger or smaller admixture of
optically active acid ; and this, for the objects for which it has
to be employed, does not signify. In order to prepare it, a mix-
ture of one part of amyl alcohol and 3 9 parts of sulphuric acid,
is gradually added to a mixture of 51 parts of potassium
dichromato and four to five parts of water, and the mixture
distilled. An aqueous solution of the acid comes over, to-
gether with valeraldehyde and amyl valerate, which separate
out as a light oily layer. The whole distillate is then neutral-
ized with carbonate of soda and shaken up until the aqueous
solution has a slightly alkaline reaction. This is then separated
from the upper layer, concentrated by evaporation, and valeric
acid liberated from the residue by means of sulphuric acid.^ In
order to obtain the pure acid, either the pure inactive alcohol
must be used, or the acid nmst be synthetically prepared from
isobutyl iodide, which is first transformed into the nitril, and
this then decomposed by alkali.^ For this purpose the follow-
ing is the best process to adopt. The iodide ia dissolved in half
its weight of strong alcohol, and water added until an opales-
cence occurs, which is then again removed by the addition of
some alcohol. Ten parts of this solution are then heated in a
water-bath for two days with three parts of powdered potassium
cyanide, w^hen a thick crystalline magma is produced owing to
the formation of potassium iodide. The nitril is removed from
this by a vacuum filter, the filtrate distilled, and again heated
in an upright condenser with caustic potash as long as
ammonia is evolved, the alcohol distilled off, and valeric acid
prepared from the residue by the addition of sulphuric acid.
It is then dried over dehydrated glauber-salt, and afterwards
over phosi)honis pentoxide.^

Inactive valeric acid is a mobile oily liquid boiling at 17o°
and having a specific gravity at 0° of 0"9o3G. It has a strongly
acid taste and caustic action. It has an unpleasant. pungent
smell resembling old cheese, and dissolves in about thirty

' I^wroso and Jazukowitsch, Zfitsdi, Chem. 1864, 83.

- Erlenm«jyer and Holl, Ann. Chrm, Piutrm. clx. 264.

' Schmidt and Sachtlebeu, Ann. Chan, Phann. cxciii. 87.

620 THE PENTYL GROUP.

parts of water. The specific gravity of its vapour at tem-
peratures considerably removed from its boiling-point is 3 67
(Dumas and Stas). Like acetic acid, it possesses, at lower
temperatures, a higher specific gravity, though it does not
exhibit so great a divergence as the latter acid.

The ethereal oil obtained by distilling valerian root which
occurs together with other bodies in the process of preparing
valeric acid, is used in medicine, whilst the acid obtained from
amyl-alcohol is used for preparing the ammonium and zinc
salts, which arc also employed in pharmacy.

The Valerates.

395 Many of the older statements respecting the salts of valeric
acid arc found to bo contradictory, inasmuch as it frequently
happened that for their preparation the acid containing the
active compound was emi)loyed. The investigations of ErJen-
meyer and Hell as well as those of Schmidt and Sachtleben
have, however, placed this subject in a clear light. The salts of
the alkali- and alkaline-earths-metals are easily soluble in water,
whilst those of the other metals are less soluble. When freshly
prepared they are, in the dry state, almost odourless, but on
keeping, especially on access of air, the smell of the acid becomes
noticeable, as they are partly decomposed into basic salts, a
decomposition which also takes place when they are heated with
water.

Calcium Valerate, {G^^O^j^Ok -f 311.^0, crystallizes in lung
needles on evaporation of the solution.

Barium Valerate, (C^H^0o)2Ba, easily crystallizes in triclinic
scales or tables.

Zinc Valerate, {C^fi^^n -f 2H2O, forms large glistening
lamina).

Silver Valerate, CgH^O^Ag, is difficultly soluble in water, and
crystallizes from the hot saturated solution in glistening scales.

Ethers of Valeric Acid.

B.r.
Methyl valerate, C H30(C5H90) \Wo
Ethyl valerate, CgHjOfCjIIaO) 134'"-5
Amyl valerate, CjH„0(C5H/)) 188'

Sp. Cr.

0-88o

17'

0 866

18°

0 879

THE VALERYL COMPOUNDS. C21

The last named of these compounds is obtained as a by-
product in the preparation of valeric acid from amyl-alcohol
(sec p. 619), and it is also easily produced when the acid or the
soclium salt is warmed with amyl-alcohol and sulphuric acid.
Its dilute alcoholic solution has a pleasant smell of apples, and
is used as an apple-essence in cheap confectionery.

Valeryl Compounds.

\ Valeryl oxide, {0,11^0^)20.

2 Valeryl chloride, CgH^OCl.

3 Valeryl bromide, C^H^OBr.
* Valeryl iodide, CgHgOI.

Divaleryl, {G^J^)<i, is formed by the action of sodium on
valeryl chloride diluted with ether, and is a yellow oily liquid
possessing a fruity smell, and it may be distilled under
diminished pressure without decomposition.^

Valeryl Cyanide, C^fiifJii), is produced when the chloride
is heated with silver cyanide. It forms a thick liquid, which
smells like celery, boils at 145° — 148°, and is slowly decomposed
by water into valeric and hydrocyanic acids.®

Valeramide, G,TigO{N}I^, is formed by the action of concen-
trated aqueous ammonia on the methyl or ethyl ether,^ and also
by heating the acid with ammonium thiocyanate.® It is easily
soluble in water, alcohol, and ether, crystallizes in large thin
tables melting at 126° — 135°, and sublimes below its boiling
point at 230°— 232°.

Valeronitnl, C^HgCN, was first discovered by Schlieper
amongst the products of oxidation of glue.^ Dumas obtained it
by heating the amide with phosphorus pentoxide, or by passing
the vapour of the former compound over red-hot lime.^® For
its preparation the method already mentioned (see p. 619) may
be employed. The alcohol is first distilled off and the residue
thun heated more strongly in order to drive over the nitril,
which contains small quantities of the iodide. It is, therefore,

* Chiozza, Ann. Ch(m. Pharm. Ixxxiv. 106.

2 Bechamps, Coinj)t, Rend. xlii. 224 ; Moldcnlmuer, Ann. Cliem, Phurm,
x?iv, 100 ; briilil, Bcr. Dcutsch, Chcm. Gcs. xii. 314. * Bechamps, loc, ciU

■* Cahours, Ann» CJieui. Pharm. civ. Ill ; Compt. Rend. xliv. 1262.

* Briihl, loc. cit. • llilbnor and Cunzo, Ann, CJum. Pharm. cxxxL 74.
^ Dumas, Malan:iiti, ami LeUaiic, Co-mpt. JUnd. xxv. 475, 658; Schmidt and

Sachtloben, Ann. Clicin. Pharm. cxciii. 102.
** Letts, Per, Lhutsth. Chcm. Ors. v. 672.

* Ann. Chan. Pharm. lix. 1. *<* Loc. cit.

022

THE PENTYL GROUP.

re-distilled in a current of steam, when the latter compound
passes over first. Yaleronitril is a liquid having a smell
resembling oil of bitter almonds, boiling at 126"* — 128^ and
having a specific gravity at 0° of 0 8826.

396 Active Valeric Acid, C^Hj^^Oo, is formed by the oxidation
of the lipvro-rotatory amyl alcohol and turns the plane of polariza-
tion to the right.^ It has a smell resembling ordinary valeric
acid, but boils at a temperature 2° — 3° lower, and is easily con-
verted by oxidation into acetic acid, carbon dioxide, and water.
The barium salt is the most characteristic. This, on account of
its solubility, remains behind as a thick syrup, in which, on
standing for some time, small crystals are formed, consisting
probably of the salt of the inactive acid which may be present,
whilst the mother-liquor dries up to an amorphous varnish.

Active valeric acid appears to possess an identical constitution
with methyl-ethyl-acetic acid, (CHJCgHyCH.COaH. But tliis
latter, obtained by the aceto-acetic-ether reaction is, like other
synthetically prepared compounds, not optically active. It boils
at 175°.* If this be the case, as appears extremely probable
for a variety of reasons, it follows that the inactive and active
alcohols and valeric acids are derivatives of isopentane.

AMYL ALCOHOLS.

Actiye.

CH, CH4.OH
CH

CH<

CHj.

Inactive.
C'Xi» Cfi.

I
CH.

CH4OH.

VALERIC ACIDS.

CHg CO.OH

CHj

CH« CH.

I
CH,

CO.OH.

' Frankland and Duppa, Jinirn. Chrm. Sue. xx. 110 ; PcJler, Ann, Chem,
r/iann. cxlvii. 243 ; Krli-nnicviT ami Hell, il>. clx. 282.
' Ahh. Vhetn. t'harm. clxxx'viii. 257.

TERTIARY VALERIC ACID. 623

397 Tertiary Valeric Acid, or THmethylacetic Acid,
(0113)30.00211. This acid is the first example of a fatty acid
which contains a tertiary alcohol radical (dibutyryl). It was
discovered by Butlerow, who obtained it synthetically from
tertiary butyl iodide.^ This is first converted into the nitril by
bringing it in contact with the double cyanide of mercury and
potassium in the cold, and allowing it to stand until the
reaction is complete. If the mixture becomes heated, iso-
butyleiie and its polymerides are formed, together with other
products, such as tertiary butylamine, the formation of which
can never be completely prevented. Pure trimethyl acetariitril,
(OH3)3C.ON, has a pungent smell resembling that of bitter-
almond oiL It boils at 105° — 106°, and solidifies on cooling to a
crystalline mass which melts at 15° — 16°. In order to prepare
the acid, the crude nitril is heated with an equal volume of
fuming hydrochloric acid in a closed vessel to 100°, the pro-
duct diluted with water in order to dissolve the sal-ammoniac,
the oily acid drawn off, and the aqueous liquid distilled, as
it contains some acid which can then be recovered from the
distillate by the addition to it of glauber-salt The crude
acid is then treated with caustic soda, the insoluble portion re-
moved, and the solution evaporated to dryness. The residue is
next treated with alcohol, the filtrate again evaporated, and the
pure sodium salt thus obtained decomposed with tolerably con-
centrated sulphuric acid. Tlie acid which is thus liberated is
dried over anhydrous glauber-salt, and then over phosphorus
pentoxide and afterwards rectified. It boils at 163°'7 — 1C3°'8,
and solidifies on cooling to a mass of crystals which appear to
belong to the regular system as they do not produce any action
on polarized light. They have, however, not been obtained in
very definite form, as the fused salt absorbs air, and this, on soli-
dification, is evolved in small bubbles. "When cooled down to
0° it is converted into a snow-like mass of needles, which at
the ordinary temperature gradually changes into a transparent
amorphous mass. It melts at 35°*4, has a strongly acid taste,
and smells of acetic and valeric acids. Its specific gravity at
50° is 0*905, and its coefiScient of expansion for 1° between 50°
and 75° is 000112.

Trimethylacetates, Those of the alkali-metals are very easily
soluble in water, and form, like acetic acid, so-called acid
salts.

* Ann. Chan. Phann. clxv. 322; clxx. 151 ; clxxiii. 355.

■;»i"i, izji il*r pa£^7 iLis TrLi-i-ti if :.c=ei Lii & scri-czij acid
rsa^r.; -^ If ar. e5cac*i of •iir f:c^ vH»i is Tc»cTeiL»cti, ifce zs&ss
fe:^:c:>=s ^Iiir'jr: jerf-ectlj cl-ear •:^l ci»]fiL:^. Tbc sal: is t.:!er:iWjr

SJicer Tfiiii^UMla^aU, CrHjO*A^. 15 tiijEcGliIy solable in
»at»ir, cnrnaJiziiig oa ffpjii:iiii«t:»>"i5 eT^pjnuioa in giistening

CoMPOL'XD Ethers.

R p. 5p- Gr. a: 0.

Methvl trimetfivlacetate, X'H.O C.IL.0 1C»«>10*^ —

Plthyl tririjeihyIxtr;eiaUr, (C^H/J^C^HjO llS'o 0-S773

Ifj ad'litiori th^; following compounds Lave btren prepaid bv
Butlc-row :

a P.

Trirnoihylacetyl oxide .... 190"'

Triincthylac^Hyl chloride . . . 105-106*
Trimethylacetauiide

• • • •

COMPOUNDS WITH SIX ATOMS OF CARBON,

OR THE HEXYL GROUP.

398 According to theory five parafiSns may exist of the
formula CgHj^, and the whole of these are known :

I. Hexanc.

CHj— CH^— CH^— CHg— CH— CHj.

II. Isohexauc, or Dimethylpropyl Methane.

CH3

CH« — CHa — CHo — CH

\
CH3.

III. Methyl-diethyl l^Fcthane. IV. Tetrametliyl Ethane.

CH3 — CH2 — CH — ^H2 — CH3 CHg CHj

'3*

\ /

H CH— CH

/ \

CH3 Ctlg.

y. Trimethyl-etbyl Methane.

CH,

I
C H3— ^C — v/Hg — C H 3

CHj.

NORMAL HEXANE AND ITS DERIVATIVES.

399 Hexanc, C^Hj^ was first observed by C. Greville Williams
in the products of the distillation of Boghead cannel, and was
believed by him to be the free radical propyl.^ Cahours and
Pelouze next found that this same hydrocarbon occurs in large
quantities in the volatile portions of Pennsylvanian petroleum,
and they termed it " hydrure de caproylinc " or ** hydrure

» Journ. Chem. Soc. xv. 130,
VOL. III. » S

626 TUE HEXYL GROUP.

d'hexyla"^ Lastly, Schorlemmer proved that it occurs in the
naphtha from cannel coal.^

Normal hexane is also formed when suberic acid, CgH^^O^ is
heated with caustic baryta.* The yield is, however, in this
case only small, owing to the large number of by-products
formed.* It is likewise produced by heating secondary hexyl
iodide, obtained from mannite, with zinc and water or alcohol.^
This decomposition takes place, however, more satisfietctorily
when the iodide is brought in contact with zinc and water, and
hydrochloric acid gradually added. In this way some hexylene,
CgHjj, is always formed together with dihexyl or dodecane,
CjgHjg (see p. 138). The latter compound, which boils at 202**,
can readily be removed by distillation. The two other hydro-
carbons, both of which boil at 69°, may be separated by addition
of br9min8 when the diflScultly volatile hexylene bromide is
obtained, and the hexane can be distilled off, and afterwards
obtained in the perfectly pure state by allowing it to remain
for some time in contact • with a mixture of concentrated
sulphuric and nitric acids. It is then washed with water, dried
over caustic potash, and lastly rectified over sodium.*

Hexane can be synthetically obtained by heating primary
propyl iodide with sodium.^ It is a mobile liquid, possessing a
weak but pleasant smell, boiling at 69^ and having at l?"* a
specific gravity of 0 663, whilst that of its vapour is 2 '98. If
chlorine be allowed to act upon it in diffused daylight, the first
product obtained is a mixture of the primary and secondary
chlorides.® Bromine on the other hand yields only secondary
hexyl bromide.®

Primary Hexyl Alcohol, C^H^gOH, was first prepared by
Pelouze and Cahours, but mixed with the secondary alcohol.
Tliey regarded this, as well as the other derivatives of hexane,
as pure compounds. Schorlemmer, however, proved that this
is not the case.

Hexyl alcohol occurs in the form of ethers in nature. Thus
the oils of the seeds of Heracleum yiganteum consist principally

• Ann, Chem, Pharm. cxxiv. 289 ; cxxvii.
' Joum, Chein, Soe. xv. 422.

« Riche, Ann. Chim, Phy$. [3], lix. 432.

• Dale, Joum. Chem. Soe. xvii. 258 ; Ann. Chem, Pharm. cxxxii. 248.

• Erlenmeyer and Wankl}Ti, Joum, Chem. Soc, xvi. 227 ; Ann. Chem. Pharm,
cxxxv. 136. • Schorlemmer, Phil. Trans, 187^ 118.

' Schorlemmer, ib. ; Briihl, Ann, Chem. Phann. cc. 183.

• Schorlemmer, Inc.. cil. and Lieh. Ann. cxcix. 139.

• Schorlemmer, Phil. Trans, 1878, p. 1.

THE HEXYL ALCOHOLS. 627

B.r.

Sp. Gr.

134-137'

loo 0

11935

0°

isi"-*

1-4607

169''o

0-8890

of the isomeric ethers, hexyl butyrate, and octyl acetate,
which cannot be separated by distillation as they boil at
almost the same temperature. By collecting the portion boil-
ing between 201'* and 206**, and heating ^it with caustic potash,
the alcohols are obtained, and these may then be dried over
ignited carbonate of potash, and easily separated.^ Hexyl
alcohol may also be obtained from normal caproic acid by
reduction.* It is a pleasantly aromatic-smelling liquid boiling at
157^ and having at O'' a specific gravity of 0 8333. The follow-
ing derivatives are those wliich have been most accurately
examined :

Ethyl-hexyl ether, C.HgCCeHiOO
Hexyl bromide, CgHijBr
Hexyl iodide, CgH^jI
Hexyl acetate, CgHijOCCaHjO)

400 Methyl'hUyl Carhinol, (CH3)C4Hg.CH.OH, was first pre-
pared by Erlenmeyer and Wanklyn,* and termed by them jS-hexyl
alcohol. They obtained it by acting upon the iodide, which is
about to be described, with silver oxide and water, when, together
with the alcohol, hexylene and secondary hexyl oxide are formed.
A better method is to convert the iodide into hexylene by heating
with alcoholic potash, and then to shake up this with an equal
volume of a mixture of three volumes of sulphuric acid and
one volume of water until the hydrocarbon is dissolved, taking
care to keep it cool during the whple operation. On the addi-
tion of water the larger portion of the alcohol separates out,
and a further quantity is obtained by distilling the aqueous
liquid. It is an oily liquid, possessing a pleasant, refreshing
smell, boiling at 136^ and having a specific gravity at 0"* of
0-8327.

Secondary Hexyl Iodide, CgHjgl. This compound, which is
the starting-point for the hexyl compounds derived from methyl-
butyl carbinol, is formed on heating mannite or its isomeride
dulcite with concentrated hy dried ic acid : *

CgHi.O^ + 11 HI = CgHijI 4- 6 H2O + 5 Ij.

As the presence of free iodine acts delete riou sly in this re-
action its formation is prevented by the addition of amorphous

* Franchimont and Zincke, Ann. Chnn, Pharm. clxiii. 193.

* liiel)en and Janecek, ib. clxxxvii. 126. ' Joum. Chem, Soe, xvL 280.

*• Elrlennieyer and Wanklyn, loe. eit. ; Hecht, Ann. Chetn. Phartn, clxv. 14tf.

S 8 2

628 THE HEXYL GROUP.

phosphorus. According to Hecht, 95 7 grams of iodine are
covered with 86 cc. of water, and 20 grams of yellow phos-
phorus are gradually added, and then a further 10 grams of
red phosphorus. The air is displaced by carbonic acid, and the
whole gently warmed, and 50 grams of mannite ordulcite added
gradually in small portions ; 10 grams of amorphous phosphorus
are then introduced, and the whole is distilled in a current of
carbon dioxide. It is perhaps simpler to gently warm a mixture
of mannite and red phosphorus with an excess of fuming hydri-
odic acid, to distil the iodide off, and again to add mannite and
phosphorus. In this way the operation may be conducted for
some time, care being taken to pour back again from time to
time the hydriodic acid which comes over (Schorlemmer).

The secondary iodide is a colourless liquid, which soon becomes
brown on exposure, boils at 167°, and at 0"* has a specific gravity
of 1-4526.

Secondary Hexyl Compounds.

B.P. Sp. Gr. at

1 Hexyl oxide, (G^^is)^^ 203"-5-2 ? —

« Hexyl chloride, CgHiaCl 125-126' — —

« Hexyl bromide, CeH^gBr 143-145" — —

1 Hexyl hydrosulphide, CeHjaSH 142° 0-8856 0'

'Hexylamine, C^HiyNHg 116' 0 7638 — -

« Hexyl thiocyanate, CeHig-SCN 206-207''5 — _

a Hexyl thiocarbimidc, CoHjjN.CS 197-198' 0 0253 —

1 Hexyl acetate, CoH^O(C2H30) 155-157' 08778 0'

Ethyl-hutyl Kctoiu, C2H5(C4Hq)CO, is formed by oxidizing
the secondary alcohol, and was formerly described as y8-hexyl-
aldehyde. It is a pleasantly -smelling liquid, boiling at 127*,
and being converted by further oxidation into acetic acid arid
normal butyric acid. This fact supplies the means of ascertain-
ing the constitution of the hexyl alcohol from mannite. The
ketone forms a crystalline compound with sodium sulphite.

EthyUprojnjl Carhinol, C2H6(C3H7)CH.OH. This second
normal secondary hexyl alcohol is formed by the action of
sodium amalgam and water on the corresponding ketcne,* de-
scribed hereafter. It boils at 134', and at 0' has a specific
gravity of 0*8343. It has a pleasant aromatic smell. When

* Eriennipyer and Wanklyn, loc. cU, ' Schorlemmer.

* U|»I»enkamp, Ber, Detttsch, Chan, Get, viii. r»5.

* Volker, Ber. Deutsch, Cfum. 0<n, viii. 1019 ; Oochsner tic Coninck, Bull
Soc, C'Aim. [2], XXV. 7.

SECONDARY IlEXYL COMPOUNDS.

C29

heated with hydriodic acid the iodide is formed, boiling at
164° — 166°. The acetate is a pleasantly - smelling liquid,
boiling between 149° and 151°.

EthyUpropyl-mrhyl Ethyl Ether, ^'^f^^^^^^ has been

already described as biethyl ether (page 339). It is formed by
heating dichlorethyl ether with zinc-ethyl under pressure :

CHoCLCHCi 1 04.Zn(C2H,)2 =C!H2(C2H5).CH(C^H,) | o^ZnCl^.

The product gives the pure ether on heating with sodium.
This boils at 131°, and at 0° has a specific gravity of 07856.
When heated with fuming hydriodic acid under pressure, ethyl
and hexyl iodides are formed, which latter is converted by the
action of acetic acid and silver acetate into hexyl acetate, a
body boiling at 154° — 157°. When heated with caustic potash
this does not yield ethyl-propyl carbinol, but methyl-butyl
carbinol. Consequently in the reaction an intermolecular in-
terchange takes place, which may be explained in a variety of
w^ays. Thus, by the action of silver acetate a small quantity
of hexylene is always formed, and it is probable that in this
reaction the iodide is first converted entirely into this hydro-
carbon, which is methyl-propyl ethylene, and that this latter in
the nascent condition, when brought in contact with acetic acid,
unites with it to form the acetate of the mannit^ alcohoL The
following equations show these reactions :

(1)

(2)

/CH,

I
CH,

CH,

CHI

I
CH,

CH,

/CH,
CH,
CHj

+ AgO.CjHjO =

il
CH

I
CH.

+ H.O.C2H3O

CHj

I
CH,

CH,

II
CH

I
CH,

CH,

I
CH,

+ HO.C,H,0 + Agl.

H.O.C-H3O
CH,.

METHYL-DIETIIYL METHANE. 631

According to theory, isohexane yields two secondary alcohols,
which, however, have not as yet been prepared, although the
ketones corresponding to them are known.

Isdbutyl'methyl Ket(me, (CH3)2C2H3.CO.CH3, was prepared
by Williamson, though not in the pure state, by distilling a
mixture of potassium valerate and sodium acetate.^ Frankland
and Duppa obtained it by decomposing isopropyl-aceto-acetic
ether with baryta-water.* It is a liquid having a strong smell
of camphor, boiling at 114**, and having a specific gravity of
0-819 at 0^

Dirnethyl'propyl Carhinol, (0113)203117 .COH, was obtained by
the action of zinc-methyl on butyryl chloride. It is a thick
liquid which has a faint smell of camphor and boils at 122*'*5 —
123°'5. Its chloride boils at 100^ and its iodide boils with
decomposition at 142°.*

METHYL-DIETHYL METHANE AND ITS

DERIVATIVES.

402 MethyUdieihyl Methane, OH3(02H5)2CH, was obtained by
Le Bel by acting on a mixture of methyl iodide and active
amyl iodide with sodium. It is a liquid boiling at 60°, and
is optically inactive, not containing any assymetrical carbon
atom.*

Methyl'diethyl Carhinol, OH3(C2H5)200H, is prepared by the
action of zinc-ethyl on acetyl chloride. It is a thickish liquid,
smelling of camphor, boiling between 121° and 125°, and yielding
only acetic acid on oxidation.

TETRAMETHYL ETHANE AND ITS

DERIVATIVES.

403 Tctramethyl Etluine, (CH3)^02H2, was obtained by Schor-
lemmer by heating secondary propyl iodide with sodium in
presence of ether, and he tenned it di-isopropyl,^ It is a liquid
smelling like normal hexane, boiUng at 58°, and at 10°

* Quart Journ. Chem, Soe, iv. 238. ' Joum, Chem, Soe. [2], v. 106.

3 Butlerow, Zeilsch. Chem. 1865, 617 ; Jawein, Ann, Chan. Phann. cxcv. 253.

* Bull. Soe. Chim. [2], xxv. 546. * Proc Jttoy, Soe. xvl 34.

TRIMETHYL-ETHYL METHANE. 633

This body will be treated of more fully hereafter. When it is
dissolved in moderately dilute sulphuric or hydrochloric acid, it
is converted into pinacoline, CgHj20, and this is capable of unit-
ing with nascent hydrogen to form pinacolyl alcohol. This latter
body is a liquid smelling like camphor, boiling at 120° — 121**,
and having at 0° a specific gravity of 0*8347. On cooling it soli-
difies to long silky needles melting at 4**.^ On oxidation it is
converted into pinacoline, which is its ketone.

B.P. Sp. Gr. at 0'.

Pinacolyl chloride, C^HijCl ll2''-5-114°-5 08991

Pinacolyl bromide, CgH^^Br 1 40-1 44^ 1 '4739

Pinacolyl acetate, C^^KJiiC^Kfi) 140-143^ —

Pinacoline or Trimethylcarhyl-inethyl Ketone, (CH3)3C.CO.CH3.
This liquid has a smell resembling peppermint, boils at 105***5
to 10G°'5, and has a specific gravity at O"* of 0*83.^ On oxidation
it yields, together with carbon dioxide, an acid which was first
called pinacolinic acid,'^ until Butlerow showed that it is
trimethylacetic acid * (see p. 623). The formation of the acid in
which three methyl groups are linked to one carbon atom from
pinacoline, the constitution of which has been already given,
appears at first diflBcult to understand, although similar inter-
molecular interchanges are known. Ethylene alcohol or com-
mon glycol is converted into aldehyde by hygroscopic bodies, a
reaction which is quite similar to the formation of pinacoline :

Ethylene Alcoliol. Aldehyde.

CH2.0H CH3

CHj.OH = CO + H,0.

I
H

Pinacone. Piuacoliue.

C(CH3),0H CCCH,),

I I

C(CH3).,0H = CO + HjO.

CH,

^ Frkdel and Silva, Cmnpt. Jlend. Ixxvi. 226.

- Fitti^, Ann. Cheni. Phann, cxiv. 57.

' Compt. Rend. Ixxvii. 48.

* Ann. Chctn, Phann. clxx. 162; clxxiii. 358.

THE HEXOIC ACIDS. 635

the acids occurring in fats, and certainly in those produced by
fermentation, as the properties of these bodies exactly coincide
with those of the substance obtained by oxidation of normal
hexyl alcohol as well as with those of the synthetically prepared
acid. Tills latter substance was obtained by Lieben and Rossi
by heating normal pentyl iodide with potassium cyanide and
alcohol. The solution of the nitril thus obtained was boiled
with caustic potash until no more ammonia was evolved, and
the potassium salt obtained on evaporation was decomposed by
sulphuric acid.^

Normal caproic acid is best obtained from the crude fermenta-
tion-butyric acid by fractional distillation, the portion passing
over above 180** being separated and washed repeatedly with six
times its volume of water, when butyric acid alone passes into
solution. The pure acid may be obtained from the residue by
fractional distillation.* It boils at 205** and has a specific gravity
at 0' of 0 9450.

Calcium Caproate, (CoEl^fi^^^^'^^i^* crystallizes in long
very thin glistening laminae. 100 parts of a solution saturated
at 18**'5 contain 27 parts of the anhydrous salt. When mixed
with calcium formate and heated, caproyl aldehyde, CgH^.COH,
is obtained together with other products. This substance has
a pungent smell, boils at 127***9, has a specific gravity at 0'
of O'SoO and readily absorbs oxygen with formation of ozone.

Barivm Caprodte, (C^H^fi^^BsL This deposits in six-sided
laminae often united in coxcomb-libe tufts. 100 parts of the
solution saturated at 18° "5 contain 8*49 parts of the anhydrous
salt. The acid derived from hexyl alcohol yields a salt crystalliz-
ing in scales or thick tablets containing one molecule of water
of crystallization.^ Kottal, however, obtained a salt from the
fermentation-acid which contained three molecules of water
and crystallized in bushy needles.*

£thf/l Cap7'oate, CgHjiO(C2HgO), separates out as a light layer
of liquid when a mixture of two parts of absolute alcohol and
two parts of the acid is allowed to stand for some time together
with one part of sulphuric acid. It is a pleasantly- smelling
liquid boiling at 167°, and having at 0° a specific gravity of
0-8898.

^ Ann. Chan. Pharm. clix. 75 ; clxv. 118.
- Grillone, Ann. Chcm. Phann. clxv. 132 ; Lieben, ih. clxx. 80.
' Franchimont and Zincke, Ann. Chmi. Phann, clxiii. 193.
* Ann, Chcm. Pharm. clxx. 97.

ISOCAPROIC ACID. C37

the preparation of the above compounds. Very probably it
Avas that obtained from amyl alcohol.

Isoca'proylamide, CgHjjO.NHg, is formed by the action of
ammonium carbonate on the chloride. It crystallizes in small
pearly glistening scales which have a fatty smell and boil at
about 255"*^

Isocaproyl Nitril, C^H^jN, was first prepared by Balard ^ by
heating amyl oxalate or potassium amyl sulphate with potassium
cyanide. He termed it dther ci/anhydramylique^ but did not
investigate it more fully. Frankland and Kolbe prepared it by
the latter reaction, and ascertained its properties.* Williamson
showed later on that it can be obtained by heating amyl iodide
with potassium cyanide and alcohol ; * and Wurtz, who obtained
it in a similar way, proved that it, like all the derivatives of the
common laevro-rotatory alcohol, turns the polarized ray to the
fight.^

It is a colourless liquid, having a pungent smell, boiling at
155** (Wurtz), and its vapour has a specific gravity of 3*335
(Frankland and Kolbe). Like other nitrils, it unites with
various metallic chlorides to form crystalline compounds,^ and
by the action of potassium a base corresponding to cyanethine
(p. 562) is formed.^

407 Diefhylacetic Acid, (C2H5)2CH.C02H, was first prepared by
Frankland and Duppa ® by the successive action of sodium and
ethyl iodide on acetic acid. SaytzeflF^ obtained it from diethyl-
carbinol by converting this into the iodide and then heating
it with alcohol and potassium cyanide. The product was dis-
tilled, and the distillate boiled with caustic potash. The
potassium salt thus prepared was decomposed by sulphuric acid
after the alcohol had been driven off.

Diethyl-acetic acid is a liquid possessing a pleasant smell,
but slightly resembling that of caproic acid. It boils at 190"*,
and at 0** has the specific gravity 0*9355.

The calcium and barium salts of this acid crystallize only
with difficulty. The silver salt forms glistening needles, and
is more readily soluble than are those of the two preceding

* Henry, Ber. DexUach. Chan. Ges. ii. 494.
« Ann, Chim. Phys. [3], xii. 294.

» Jnn. Chan. Phami. Ixv. 297.

* Phil. Mag. [4], vi. 205. » Ann. Chim. Phya. [3], li. 858.

• Henke, Ann. Chan. Phann, cvi. 280.

' Me<llock, Qiiart. Jmim. Chnn, Soe, i. 379 ; Ann. Chein. Pharm. Ixix. 229.

• Phil. Trans. 1860, 50. » Ann. Chrm. Phann. cxciil 360.

638 THE HEXYL GROUP.

acids. Its ethyl-ether boils at 151**, and at 0° has a specific
gravity of 0-8826.

Methyl'propyl-acetic Acid, CH3(C3H7)CH.C02H, is prepared
from methyl-propyl-carbinol in a corresponding manner. It
boils at 193**, at 0** has the specific gravity 0*9414, and both it
and its salts closely resemble diethylacetic acid. Its ethyl-
ether boils at 153**, and at 0** has a specific gravity of 0*882G
(Saytzeflf).

ZHniethyl-ethyl-acetic Acid, (CH^gCgHg.CH.COgH, is prepared
from dimethyl-ethyl carbinol exactly as trimethylacetic acid is
got from tertiary butyl alcohol (p. 623). It is a colourless
liquid, boiling at 187°, having a faint smell of the fatty acids,
and on cooling in a freezing mixture forms crystalline scales
which melt at — 14^

Barium DimethyUethyl'acetate^ {C^^fi^^Rsk+SU^^ crystal-
lizes in scales or transparent tablets which effloresce on ex-
posure to air.

The very soluble calcium salt forms long, thin, glistening
needles.^

Markownikoflf* obtained a caproic acid from amyl iodide
obtained by the combination of ordinary amylene and hydriodic
acid and subsequently making use of the nitril reaction. This
acid he believed to be methyl-isopropyl-acetic acid, as the iodiile
from which it was obtained must be looked upon as secondary
amyl iodide. This, however, as has been stated, is a tertiary
compound, and the acid obtained from it, which has not been
more nearly investigated, ought, therefore, to be identicAl with
dimethyl-ethyl acetic acid. As, however, ordinary amylene is
itself a mixture of isomeric bodies, it is probable that this is
also the case with the caproic acid obtained from it. Hence it
therefore merits further investigation.

As has been stated (p. 630), hexyl alcohol from oil of camomile
yields a caproic acid by oxidation, which is different from the
other known acids. Its calcium salt crystallizes in small silky
needles, which do not contain any water of crystallization ; 100
parts of the solution saturated at 15** contain 16*5 parts of the
salt, which is partly deposited on warming the solution.

' Wischne^?rad«ky, Ann, Chem, Pharm. clxxiv. 56.
» ZeOseh. Chem. 1866, 502.

COMPOUNDS CONTAINING SEVEN ATOMS OF
CAEBON, OR THE HEPITL GROUP.

408 Nine paraffins of the formula C7HJQ may exist according
to theory. Of these only the following are, however, known
with certainty :

Normal Heptane.

CH^.CIi^.CM2.CM2«CIj^{.Oii2.0xi3.

Ifioheptane, or Dimethyl-butyl Methane.
p^* yCH.CH2-CH2.CH2.CH3.

Triethyl Methane. Dimethyl-diethyl Methane.

CH3.OH2.CH.CH2.CHg CH3

CHg CHg — CHg — C — CH2 — CH3

I * 1

CH3, CH3.

NORMAL HEPTANE AND ITS DERIVATIVES.

409 Heptane, C^Hj^ was first discovered by Schorlemmer
in cannel-coal naphtha/ and he afterwards showed that this
paraffin is contained in large quantity in the Pennsylvanian petro-
leum ;* this liquid, however, contains another isomeric heptane
boiling at 90°,* the presence of which renders the purification of
the normal compound boiling 8"* higher very difficult.* The
heptyl hydride obtained by Pelouze and Cahours * from the same
source, and boiling at 92° — 94"*, is a mixture of these two
heptanes.

Normal heptane also occurs largely in the distillation-products
of lime-soaps of the Menhaden oil, and together with other

^ Joum. Chem. Soe. xv. 423. ' Jmim. Chtm. Soe. xvi. 216.

• W^arren, Chem, Xr,wa. xiii. 74 : Schorlemmer, Proc, Roy, Soe, xvL 3f 7.

* Schorlemmer, Phil, Trans, 1372, [1], 120. » AmuChim. Phya. [4], i. 1.

640 TIIK IIBPTVL GROl'P.

products in the dry <listillnti<iii of a mixtiire of azclaic acid,
C;Hn(C02H)j, and caustic baryta.^

A remarkable nctiirrence of tliia paraffin in the vegetable
kingdom remains to be noticed. On the low mountain chains run-
ning parallel to the coast of California, as well as on the slopes of
the foot-liills of the Sierra Nevada, the nut-pine or digger-pine
(Pinus Sabiniana. Doujl) grown in magnificent profusion. This
tree, the fruit of which is used na an article of food by tlie Digger
Indians, yields a turpentine which lias become an article of com-
merce. For the purpose of procuring the exudation, the tree
is notched and guttered during winter at a convenient height
{tow. the ground, and the resin obtained subjected to distillation.
This yields a very volatile liquid which was recognised by
Wenzcl as a hydrocarbon, to which he gave the name of abu-ttne.
It has also received the names of aiirantinc and tluoline in the
San Francisco market, and it is used instead of benzoline or
petroleum benzene for the removal of grease-stains and also
as an insecticide. The crude hydrocarbon is a mobile, almost
colourless liquid, having a smell resembling oranges, and ita
vapour pmhices amcsthetic effects on inhalation. When sub-
jected to distillation it begins to boil about 100°, by far the
larger portion coming over at 101°. The residue leaves on
further evaporation a brown resin, which has a strong and per-
sistent smell of oranges. When the liquid is shaken up for
some time with sulphuric acid this smell disappears, and the
purified nhirfene consists entirely, as Tliorpe has shown, of pare
normal heptane whose physical constants be has most catefullj
determined.' It boiLi at 98°4, and at 0° has a spedfic graTity
of 0-70048, whilst that of its vapour is 3464. It is reinarkaUa
tJiat the substance obtained from petroleum and purified as
carefully as possible, exhibits a higher specific gravity th&n tbafe
from I'inus Sabiniana. This appears to dtpcud upon the facfc d
that petroleum purified by the action of sulph'iric and nitric
aci<l, though consisting principally of the nnrntitl paraffins, lUao
contains small quautities of isomeric and hotnologotis hydro-
carbons which cannot be removed, and that the heptane t'
biiiicd from this source containing some of ihoae. thus 1
higher specific gravity.

Heptane behaves towards chlorine and hnirnino exaeUjp t
liesanc (p. C2G).^

ri;lMAltY llEPTi'L ALCOIKil.. C41

410 I'rimm-y llq)!^! Ah>hd, t'jl[,,,OII. Tlic jXHiit of
dipiiture fur tliia coinpouud is the correspijiidin<; aUt'lijiIe which
can 1)0 easily obtained by the distillation of rastor-oil, and is
known uodor the name of oeiiantbyl alcohol. The first attempts
to convert this body into ccnanthyl alcohol were made by Fittig.
By heating aciianthdl with slaked-limc he obtained, together
witli ceiianthylic acid and other products, a liquid which
undoubtedly contained the alcohol in question, but he did not
suceccd in preiKiring it in the pure etivte.'

Bouis and Carlut then heated oenaiithol with glacial acetic
acid and zinc under somewhat increased pressure and thus
obtained an acetate, which, when heated with alkali, yielded
ail alcohol-like liquid, aud this, according to their description,
wjis probiibly an impure hcxyl alcohol.*

Tho pure alcohol was first prepared by Grimsbaw and
Schorleuimer, who employed Lieben aud Ros.si's method for the
reductiijn of the aldehyde. The aldehyde was brought into
contact with water aud sodium amalgam, care being taken that
the liijuid should always remain neutral by aildition of dilute
sulphuric acid.^ By this process large quautities of condeiiHation-
products of cenanthol arc also obtained. The quantity of these
may, however, bo diminished, as Schorlemnier has shown, if
instead of using water, strong acetic acid in which cenanthol
has been dissolved be employed.* This method was worked
out first by Cross ^ and afterwards by Jounlan."

According to this latter observer, a solution of two parts of
cenanthol in one port of acetic acid is taken, and to this is added
a small quantity of 50 per cent acetic acid. From 170 to 180
parts of a 2 per cent sodium amalgam is next gradually addi^l
to the cold liquid, whilst &om time to time a sm^l quantity of
glacial acetic acid is poured in. The whole is then diluted with
water, neutralized with carbonate of eod*, end the oi^ btyer
which separates out twice heated with icetic ecid end lodium
amalgam, and the oil then ( "'^'^^^^^^^^^^^^^^^^^^™
in order to decompose the acotS^woic^nOTSea^^ra^iquKI,
is then dried over ignited caibonate of potash and the produc
fractionally distilled under diioinished pressure.

Heptyl alcohol is a colourless pleasantly smelling liquid

' An*. Ohtn. Pharm. extii. T«.

■ lb. cxzIt, 353 : Compia Xtniiu, k

■ CVm. Boa, Jaum. xxvi. 107S.

■ r«<M. Snt. Jeurn. ]gr7. iL MX

VOL. in.

G42 THE llEPTYL GROUP.

boiling at 175°*5, and having a specific gravity of 0"838. Cross
prepared th6 following derivatives :

B.P. Sp. Or. at 1««».

Heptyl-ethyl ether, C^Tl^^(CJi;)0 165'' O'TOO

Heptyl chloride, C7H15CI ISO'^S 0-881

Heptyl bromide, CyH^gBr 178°-5 1 133

Heptyl iodide, C7H15I 20r 1*346

Heptyl acetate, C^H^fiiC^Iip) 19V'd 0874

Methjl'perUyl Carhinol, CHj(C5Hii)CH.0H. This is prepared
from normal heptane, but has not as yet been obtained in the
pure state. It boils at 160° — 162"*, and yields a ketone boiling
at 150"* — 152^ It is converted on oxidation into acetic and
normal pentylic acids (Schorlemmer). The chloride boils at
about 145"*, and the bromide at 165** — 167^

Dipropyl Carhinol, (C3H7)2CH.OH, is obtained from the
corresponding ketone. Water is added to the ketone and then
sodium in small pieces, the whole being well shaken up. It
is a peculiarly smelling liquid boiling at 149" — 150**, and
having a specific gravity of 0814 at 25^^

Dipropyl Ketone^ (C8H7)2CO, Chevreul was the first to
obtain this compound in the impure state by the dry distillation
of certain salts of butyric acid. It was then described as a
liquid oil having a smell of certain species of Labiatce. Chancel
investigated it more exactly, and recognised it as a ketone of
butyric acid, giving to it the name of bnfyrade.^ In order to pre-
pai'e it, calcium butyrate is subjected to distillation in small quanti-
ties and at as low a temperature as possible. The crude product
always contains other ketones,* from which butyrone is separated
by fmctional distillation. It is a highly refracting liquid, having
a pleasant smell and a burning taste. It boils at 144°, and at 20*
has a specific gravity of 082, whilst that of its vapour is SDO.
It does not yield any compounds with the acid sulphites of the
alkali metab, and decomposes on oxidation into propionic acid
and butyric acid. By the action of hot concentrated nitric it
in converted into dinitropropane, C3Hg(N02)2, a body which was
formerly supposed to be nitro-propionic acid.*

* Friedcl, Ann, Chim. Phys. [41, xvi 810 ; Kurtz, Ann. Chcm Pharm. clxL

• Ann. Chim. Phys. [.3], xii. 146. » Friedel ; Kurtz, loe. eft.

« dmncfl, Ann. Chern Phnnn, Ixiv. S31 ; Compl. JUnU. Ixxxri. 1405; Kurtz,
^MH, CKcPi, Phaivi, clxi. 209.

ISOllEPTANB. G43

ISOHEPTANE AND ITS DERIVATIVES.

411 Isoheptaiie, ox Dimcthyl-hityl Methane, (CHj)jCH.C^H^, was
first obtained by Wurtz by acting with sodium upon a mixture of
ethyl and amyl iodides, and was termed by him cthyl-amyl} In
order to prepare it, a mixture of equal parts of ethyl bromide
and amyl bromide is gradually treated with the requisite quantity
of sodium, care being taken that the temperature does not
rise above 25** and does not fall below 20^ As soon as all the
sodium has been added, and the reaction slackens, the mixture
is heated to 1 00^ and kept for some time at this point. It is
then distilled, and the distillate fractionated in order to separate
the tetramethy I methane (diamyl) which is formed at the same
time. During this process more sodium is added in order to
remove more completely the bromides which are formed. The
ptjrtion boiling from 85° to 90° is then further purified by shaking
with sulpliuric acid, with which it is allowed to remain in contact
for some time. It is then washed with water, dried over caustic
potash, and afterwards rectified over sodium.*

Isoheptane boils at 90°'3, and at 0° has a specific gravity of
0*6969 (Thorpe). Chlorine acts easily upon it in diffused day-
light; as a first substitution-product a mixture of the primary
and secondary chlorides Ls obtained. These cannot be separated
by fractional distillation, but the alcohols obtained from them
may be thus separated.

Primary Isoheptyl Alcolwl, (CH^jCgHgOH, boils at 163°— 165^
has a smell like fusel-oil, and on oxidation yields isohep-
tylic acid, which will be afterwards described. Faget' has
separated out heptyl alcohol boiling at 155° — 165° from the
fusel-oil of wine brandy, and this perhaps is the substance under
consideration.

Secondary Isoheptyl Alcohol, or MethyUamyl Carhiiwl, (CH)2
C3H5(CFI.OH)CH3, boils about 148°, and on oxidation yields
methyl-amyl ketone, (CH3)2C3H5CO.CH3, boiling at 148° (Grim-
shaw). This may also be easily obtained in the pure state by
treating isobutyl acetic ether with baryta water. In contact

^ Ann, Chim. Phys. fS], xliv. 275.

' Grimshaw, Chfm. Soc Jaum. xxvi. 309.

' Ann. Chem Pharm. cxxiv. 355 ; BuU, Soe. Chim. 1862, 59.

T T 2

CU THE HEPTYL GROUP.

with nascent hydrogen it is again converted into the secondary
alcohol, which has a sweetish smell and a specific gravity at 17*
of 0-8185 1 (Faget).

It has been already stated that American petroleum not only
contains normal heptane, but also an isomeric paraffin boiling at
90**. This substance has been investigated by Schorlemmer, who
found that the derivatives obtained from it closely resemble
those of isoheptane, but differ inasmuch as the ketone obtained
from the secondary alcohol yields on oxidation only acetic acid.
Hence it is evident that the above paraffin is not isoheptane.-

TRIETHYL METHANE AND ITS DERIVATIVES.

412 Triethyl Methane, CH(C2H^3, was discovered by Laden-
burg,^ by the action of zinc-ethyl on sodium and ethyl
orthoformate :

2 CHCOC.H,), + 3Zn(C,H5)2 = 2 CH(C,H,)3 + 3Zn(0CH)^

This reaction however does not occcur so simply as above
described, inasmuch as several by-products are formed. In order
to separate the paraffin, the portion boiling at about 100"* is treated
with concentrated sulphuric acid, and the li(iuid which is not
attacked is purified by washing with water, then dried and rectified.
Triethyl-methane has a faint smell of petroleum, boils at 96*,
and at 27° has a specific gravity of 0 689.

Triethyl Carhiiiol, (C2H5)3COH, is obtained by the action of
propionyl chloride on zinc-ethyl> It is a liquid having a smell of
camphor, boiling at 140"^ — 142°, and having a specific gravity at
0** of 0'8593. When oxidized by potassium dichromate and
weak sulphuric acid, acetic and propionic acids are obtained ;
the greater part, however, is converted by loss of water into
heptylene, which may be looked upon as diethyl-methylethylene
(C,H^,C = CH.CH3.

Diethyl'dimcihyl Metliane, 0(0113)2(02115)2. The compound
03HgOl2 is obtiined by the action of phosphorus pentachloride
on acetone, and this when warmed with zinc-ethyl gives the
above-named paraffin together with other products :

* Rohn, Ann. Chem. Phann, cxc. 309.
' Joum. Chnn, Soc. xxvi. 319.

' Bcr. IkuUch. Chnn, Ors. v. 752.

* Ladenburg, Dcr, DtrutteK. Chan. Gts. v. 752.

DI-ISOPROPYL CARBINOL. C45

I ^^2^6

H3 CH3

By careful rectification, the pure product is obtained, boiling
at 8G**— 87^ and having a specific gravity of 07111 at OV

413 The other heptyl compounds which have been prepared
are derived from unknown paraffins.

Di'isopropyl Carhinol, [(CH3)2CH]2CH.OH. This secondary
alcohol is prepared from the following ketone, which is dissolved
in benzene, the solution poured upon water, and sodium gradually
added, the whole being kept cool. Di-isopropyl carbinol is a
liquid with a pleasant smell resembling peppermint, boiling at
13r— 132°, and having at 17"* a specific gravity of 0-8323.

I>i'isopropyl Ketone, [(CH3)2CH]2CO, is obtained by the
fractional distillation of the product of the dry distillation of
calcium isobutyrate. It is a liquid having a strong ethereal
smell somewhat resembling that of camphor, boiling at 124° —
12G°, and having a specific gravity at IT^'of 0*8254.^

Isohutyl'dimethyl Carbinol, (CH3)2C2H3(CH3)2C.OH, was first
prepared by MarkownikoflF from isopropyl-dimethylethylene,
(CH3)2CH.CH = C(CH3)2, by combining this with hydriodic
acid and treating the iodide with moist silver oxide. The
tertiary alcohol is also formed by the action of zinc-methyl on
valeryl chloride, the product being treated with water.* It boils
at 129° — 131°, smells like camphor, and yields isobutyric acid
and acetic acid on oxidation.

Propyl - ethyl ' victhyl Carbinol, C3H7(C2H5)(CH3)C.OH, is
obtained by the action of zinc-methyl and zinc-ethyl on butyryl
chloride, and boils at 135°— 138°.*

Isopropyl-ethylmcthyl Carbinol, (CH3)2CH(C2H5)(CH3)C.OH,
is prepared in a corresponding way from isobutjrryl chloride,
and boils at 124°— 127° (Pawlow).

Trimethylcarbyl-dimethyl Carbinol, (CH3)3C(CH3)2C.OH. This
tertiary alcohol was first prepared by Butlerow, and termed by

^ Friedcl ami Ladenlmrg, Ann, CJicm, Pharm. cxlii. 310.

' Miinch, Lichig's Ann. clxjcx. 327.

' Pawlow, Ann. Chnn, Pharm. clxxiii. 102. ■♦ IK clxxxviii. ll*2.

IlEPTALDEHYDE OR (ENANTHOL. C47

chemists found that the body in question can be obtained in
large quantity from wine-lees, and they showed that it is the
ethyl-ether of an acid having the formula Cj^Hj^Og -f- HgO, and
to which they gave the name oicenanthic acid {blvo^ wine).^

Tilley, in 1841, obtained an acid by the oxidation of castor-
oil, to which he gave the formula C^^H^Og + HgO, and sup-
posed that it contained the same radical as oenanthic acid, and
gave it therefore the name of ananthylic acid, suggesting that
the acid whose ether is contained in wine should be termed
cenanthylous acid,^

Further investigation has shown that Tilley's acid is normal
heptoic acid, and that oenanthic ether is a mixture of the ethyl
ethers of higher acids, especially of capric acid, under which
heading a further description will be found.

Hcptaldehyd^, (Enanthaldehyde, or (Enantlwl, CgHj3.CH0, was
first prepared by Bussy by distilling castor-oil,* and then further
investigated by several other chemists.* Castor-oil consists
essentially of the glycerin ether of ricinoleic acid, and on heat-
ing, it undergoes a somewhat complicated decomposition by
which, in the first place, acraldehyde and oenanthaldehydo
are formed, and these may be separated by fractional distillation
owing to their diflference in boiling point

According to Erlenmeyer and Sigel the best mode of pre-
paring heptaldehyde is to distil 500 grams of the oil quickly in
a large glass retort, the operation being stopped when the mass
becomes resinous. The distillate is rectified, and the portion
coming over between 90° — 180"* shaken up with a solution of
acid sodium sulphite. The whole is then warmed on the water-
bath, and the hot solution filtered ; on cooling, the compound
CyHj^O + HNaSOj + HgO separates out in fine scales. These
are freed on a filter-pump from the mother-liquor, and dried
between filter-paper. On distillation of these crystals with soda
solution, pure oenanthol is obtained, and this may be dried over
anhydrous glauber-salt.

A better yield is obtained when the castor-oil is distilled under
a diminished pressure of 100 mm. In this case it is almost
completely converted into oenanthal and hendecatoic acid :

^13^3403 = C7H14O + CuII^oOy

* Ann. Ciumi. Phann. xix 241. ' Chcm, Soe, Mem. i. 1.
' Ann, Chnn, Fharm, Ix. 246.

* Tillcy, Phil. Mag. [3], xxxiii. 81 ; Schiff, Zcitseh, Chan. 1870, 74 j Erlcn-
iinycr aiid Sigel, Ann. Chcm. Phann. clxxvL 341.

648 THE HEFPYL GROUP.

These bodies may be separated by two or three rectifications
under diminished pressure.^

When castor-oil is distilled under ordinary pressure hendeca-
toic acid remains behind as a spongy mass, which on more
strongly heating splits up into heptane and its homolo^es.*

(Enanthol is a highly refracting liquid boiling at 154^
having a specific gravity at 16° of 0 823, and possessing an
aromatic pungent smell. It absorbs dry ammonia with evolu-
tion of heat, a thick liquid having the composition C7Hj^O,NHj
being formed (Erlenmeyer and Sigel).

415 Noi^mal Hcptoic Acid, or (EnarUhylic Acid, CgH^.COgH.
This acid was first obtained in the impure state by oxidizing
oleic acid with nitric acid, and termed by Laurent * " acide
azoleique.'* Tilley then obtained it in a similar way from castor-
oil,* and Bussy by the oxidation of cenanthol.* It was then in-
vestigated by various chemists,® and synthetically preparetl by
Franchimont,^ as well as by Lieben and Janecek,® from normal
hexyl alcohol by the nitril reaction.

For its preparation crude oenanthol boiling at 150** — 160*' is
used, and 300 grams of this are gradually added to a warm mix-
ture of 300 grams of potassium dichromate, 450 grams of sul-
phuric acid, and 900 grams of water. As soon as the action has
moderated, the mixture is heated for some hours in a flask with
a reversed condenser. When cold, the oily liquid swimming on
the top is dissolved in caustic soda. The acid aqueous liquid,
which also contains oenanthylic acid in solution, is distilled, and
the product also neutralized with carbonate of soda The solu-
tions of sodium cenanthylate are then evaporated, and the acid
liberated from the residue by sulphuric acid. The pure arid
may be readily obtained by repeated fractional distillation and
rectification of the distillate over phosphorus pentoxido (Grim-
shaw and Schorlcmmer). CEnanthylic acid is also found amonsrst
the products of the distillation of fats in superheated steam. It
is an oily liquid which when cold has a faint smell, but on
heating acquires a more puncjent odour. It boils at 223° — 224°,
and solidifies at a low temperature, either in tablets or in broad

* Krain, Ber. Deutsch. Chnn. Gcs, x. 2034 ; xi. 2218.

» Amato, Gass, Chim. 1872, 6. ' Ann, Chim. Phys. [2], Ixvi. 173.

< Loe cH. * Ann. Chrm. Pharm, Ix. 246.

• Williamson, %b, Ixi. 38 ; Tilley, loc. cit ; Uedtenlmcher, Ann, Chnn, Pharm.
Hx. 41 ; Schneider, ih, Ixx. 107; Ar/Kichcr, i7>. Ixxiii. 199; GrinuHhaw and
Stthoriemmer, Chcm, Sor. Jown. xxvi 1073.

' lb. clxv. 237. * Jb. clxxxvii. 126.

NORMAL HEPTOIC ACID. 649

needles, melting at — 10**o. It has a specific gravity at 0'' of
0-9345.

The heptoates of the alkali-metals arc easily soluble in water,
and separate after concentration or cooling, usually in the form
of a jelly. The sodium salt can be obtained in thin interlaced
needles.

Calcium Hcptoate, {C^Yi^jd^j^o, + HgO, crystallizes from
hot-water in thin bushy needles.

Barium Heptoate, (C7Hi302)2Ba, crystallizes in bright needles
or in thin scales.

The heptoates of zinc, lead, and silver are white precipitates.
The two latter may, however, be crystallized from boiling water,
in which they are slightly soluble.

Copper Htptoale, (CSR^jd^fiw. This characteristic salt is
insoluble even in boiling water, but crystallizes from absolute
alcohol in short silky lustrous needles or short prisms.

Ethyl Hcptoatc, C^HjaOgCCoH^), i?> obtained like the hexoate.
It has a pleasant fruity smell, boils at 189**, and has a specific
gravity of 0-8879 at 0°.

ITcphjl Heptoatc, G-^1^P^{Q^^^^, boils at 270'*— 275", and has
a pleasant fniity smell.

ITcptoijl Oxide, (CyHj^O).,©. This anhydride, obtained in the
usual way,^ is a liquid boiling at 268° — 271°, and at 21° having
a specific gravity of 0*932.

Hcptamide, CyH^jO.NHg, is prepared by the action of ammonia
on the anhydride as well as by heating the acid with potassium
thiocyanate. It crystallizes in needles, which melt at 94° — 95°,
and when quickly heated it distils between 250° — 258°.

Iffpfonitril, C7H^3N, is obtained together with the amide in
the second method of preparation of the latter body. It is a
slightly aromatic smelling liquid boiling at 175° — 178°, and
have at 22° a specific gravity of 0895 (Mehlis).

Isoheptoic Acid, or Isoa^tianthylic Acid, {Q]1^^^^,C0^, is
obtained by the oxidation of the corresponding alcohol. It is an
unpleasantly smelling acid liquid, boiling at 210° — 213°. The
barium salt forms an amorphous mass, whilst the calcium salt,
(C-Hi30.,).3Ca 4- 2 HgO, crystallizes in small needles.

Methyl'htifyl -acetic Acid, CH3(C^Hg)CH.C02H, is prepared
from secondary liexyl iodide, obtained from mannite. It is
converted into the nitril by the action of cyanide of potassium,
and this decomposed by boiling with caustic potash. Tlie acid

* Chiozza. Ann. Chnn. Pharm. xc. 102; Mehlis, ih. clxxxv. 370,

rUTMAUY OCTYL ALCOHOL. 651

sjphondyHum), This consists chiefly of octyl acetate, but also
contains the free alcohol together with the caproic ethers, and
its higher homologues, as well as some hexyl acetate.^ It has
already been stated that octyl acetate occurs together with
hexyl butyrate in the fniit of Jleracleum gigantcum (p. 626),
whilst the oil from the seeds of the common parsnip {Pasti-
nacca saliva) chiefly contains octyl butyrate * Several of these
oils also contain small quantities of methyl and ethyl compounds.

In order to prepare octyl alcohol, the portion of cow-parsnip
oil, boiling between 206° — 208° is heated with caustic potash,
the crude liquid dried over fresh caustic lime, and purified
by fractional distillation. It is a colourless, oily, pungently
aromatic-smelling liquid, boiling at 196° — 197°, and having a
specific gravity at 16° of 0 830.

The following derivatives of primary octyl alcohol have been

more accurately examined :

B.r.
3 Ethyl-octyl ether, (C2H5)(C8Hi-)0 182-184,
» Dioctyl ether, {Q'^'S.^^\0

* Octyl chloride, CgHi.Cl

* Octyl bromide, CgH^-Br

* Octyl iodide, CgH^.I

* Octyl acetate, CgHiyOCCgBLjO)

* Octyl valerate, CgH^OCCsH^O)

^ Octyl caproate, C^HiyOCCgHuO)
3 Octyl sulphide, {O^'S.^^X^

* Octyl nitrite, CgHi70(N0)

* Nitro-octane, C^Hj^NOj
^ Octylamine, CgH^^.NH^

* Octylphosphine, CgHi^PH.,

* Mercury-octyl, (CgHi7)2Hg

417 Secondarji Odyl Alcoliol, or MethyUhcxyl Carhinol,
CH3(CgHj3)CH.Ori, was discovered in 1851 by Bonis, who
obt^ained it by the distillation of castor-oil or of ricinoleic acid
with caustic soda, and termed it caprylic alcohol, CgH^gO.^ Soon
afterwards he came to the conclusion that this liquid is oenan-
thylic alcohol, C-Hj/3 ;^ and this appeared to be confirmed by

' Zincko, ih. clii, 1 ; ^Idsliuger, il. clxxxv. 26.

^ lIoiK'sse, Ann, Chiia. Phanii. clxvi. 80,

' AlosUngor, loc. ciL * Ziiicko, Joe, cit.

' Kichlcr, Jicr. JkuMi. Chrm. Gen. xii. 1S70.

• Ann, Clinn. Phunn. Ixxx. 304. ~ /.'*. ;H)6.

B.P.

Sp. Gr.

► 182-184*

0-7940

17°

280-282°

0 8050

17°

170°-5-lS0°-5

0 8802

10°

198-200°

11160

16°

220-222°

1138

16°

206-208°

08717

16°

249-251°

08624

16°

2G8-271°

0-8419

17°

175-177°

08620

17°

205-212°

——

185-187°

184-187°

0-8209

17°

1-342

17°

SECONDARY OCTYL ALCOHOL. 663

chiefly of the sodium salt of ricinoleic acid, and this, under the
above conditions, undergoes the following decomposition :

CisHgjNaOj 4- NaOH + HgO = C^U^fi + CioHi^NagO^ + H^.

The crude alcohol contains octylene, boiling at 125^ and other
bodies, together with the products of the decomposition of the
sodium suberate, and these occur in larger quantities if the heat
has been applied for any length of time (Schorlcmmer).

Neison,^ who has also investigated this subject, obtained
chiefly methyl-hexyl carbinol when he distilled castor-oil
soap by itself. Another preparation yielded large quantities of
oenanthol, and on distilling with excess of alkali, only products
containing eight atoms of carbon were formed, varying quan-
tities of the ketone being produced ; this, according to Schor-
lcmmer, not being the case when the distillation is carried on
rapidly. In place of castor-oil, the oil obtained from the fruit
of the Curcus jpnrgaris may be used for this preparation.^

In order to purify the crude alcohol, it is subjected to re-
peated fractional distillation, with addition of caustic potash,
and then rectified over sodium. It is an aromatic-smellinor
lic[uiJ, boiling at 179°'5, and having at 20"* a specific gravity
of 0 8913.

The following derivatives have been obtained :

B.P.
3 Methyl-capryl ether, CH8(C8Hi.)0 160-161**

3 Ethyl-capryl ether, CaHfiCCgHiyjO 177°

* Capryl chloride, C3H17CI 175° _ _

* •' Capryl bromide, CgHiyBr 190-191** — —

* <^ Capryl iodide, CgCiyl 220-221** 1*338 10*
^ Capryl sulphuric acid, CgHjySO^H — — —
2 Capryl nitrate, CgH^^NOj — — —

* "* Capryl acetate, CgHi^CC^HjOg) 191-192** — --

* Capryl sulphide, (C8Hi7)2S — — —
* « 8 9 Caprylamine, (C8Hi7)NH2 165** — —

» Capryl thiocyanate, CgH^y.SCN 242** — ~

» Capryl mustard oil, CgHjyNCS 234° — —

' Joum. Chan. Soc. 1874, 301, 507, 837.

- Silvn, Compt. llcnd, Ixvii. 1251. » Wills. < Bonis.

• IVerthelot, Ann, Chan. Fftarvi, civ. 185 ; Comptes Jtendtts, xliv. 1350.

• Squire. ^ Dacliaucr

• Cahours, Ann. Chan. Phann. xoil 399 ; Comptes JRenduSf xxxix. 254.

• Jahii, JJrr, Jkutsch. Chttn. Gev. viii. 803.

Sp. Gr.

0-830

16'

0791

16°

0-680

20'

TETRAMETHYL BUTANE. C66

gated by Carleton-Williams,^ who obtained the hydrocarbon by
the action of sodium on isobutyl bromide. By passing chlorine
into the vapour of the boiling paraffin he obtained a mixture of
chlorides which could not be separated by fractional distillation.
The chief portion, boiling between 170° — 180°, was then heated
with potassium acetate and glacial acetic acid, when the acetic
ethers, as well as an octylene, CgHjg, boiling at 122°, is formed.
The acetates, boiling between 170° — 205°, cannot be separated
by distillation, but on heating them with concentrated caustic
potash the alcohols are obtained, and these can be fairly well
separated by repeated fractionation.

Pnmary Isodyl Alcohol, (CH3)2C^Hg(CH3)CH20H, is a liquid
smelling like oranges, boiling at 179° — 180°, and^ having a specific
gravity of 0 841 at 0°. It yields an acid on oxidation which
will be described hereafter.

Seco)idary Isodyl Alcolwl, or Isopropyl-iscbutyl Carhinol,
(CH3)2C2H3(CH.OH)CH(CH3)2, is only formed in small quan-
tity. It has a fainter smell than the primary alcohol ; boils at
160°— 163°, and has a specific gravity at 15° of 0-820. On
oxidation it yields the corresponding ketone, boiling at 159° —
161°, which on further oxidation chiefly yields acetic acid,
though at the same time a small quantity of another acid
which appears to be isobutyric acid is formed. According to
theory, the latter acid should bo produced, and that this is
not the case is probably due to the fact, as Erlenmeyer has
shown, that isobutyric acid is easily oxidized to acetic acid and
carbon dioxide, and this naturally takes place more easily when
the acid is in the nascent condition.

TERTIARY OCTYL COMPOUNDS.

419 Didhyl'prapyl Carbinol, (C2H J 2(^*3117)0011, is formed
by the action of zinc-ethyl on butyryl chloride. A sticky mass is
obtained, which is decomposed by water. It yields a liquid
smelling like camphor, boiling between 145° — 155°.^

Isodihutol (CH8)30.CH2.0.0H(OH3)2. The iodide of this ter-
tiary alcohol is formed by the union of hydriodic acid with
di-isobutylene, OgH^g, which will be described under the octylenes.
By the action of moist oxide of silver on the resulting iodide
it is converted into the carbinol, a thick liquid smelling like

^ Jouni. Chan, f^'oc. 1877, i. 541 ; 1870, i. 125.
•'* Butlerow, ZeiUch. Chem, 1865, 617.

C5G THE OCTYL GROUP.

camphor, boiling at 146° '5 — 147**"5, and solidifying in needles at
— 20^ and having at 0° a specific gravity of 0 8417.^

HEXMETHYL ETHANE, C(CH3)3C(CH3)3.

420 This hydrocarbon is formed by the action of sodium on
tortiarv-butvl iodide. It is a crystalline substance meltinsr at
0(5' — 97*, and boiling from 105** — IOC'*.* No derivatives have as
yot boon prepared.

THE OCTOIC ACIDS.

421 Xornwl Odaicov Caprylic Acid, CyHij.COgH. The volatile
fatty acids which occur in cow*s butter, and were discovered by
rhovroul, have since been carefully investigated by Lerch.* He
found a new acid amongst them which, according to its com-
jHv^ition, stands between caproic acid and capric acid, and to
this he gave the name of caprylic acid. The same acid is
found, together with other fatty acids, in large quantity in
coooa-nnt oil,* and it has also been detected in other fats, as in
human fat. It is also found, together with its homologiies, in
old cheese, and in the products of distillation of the fats in
superheated steam ; it also occurs, partly in the free state and
partly in the form of ethers, in various fusel oils and in the
acid aqueous distillate from Arnica molilalia.

That the eight-carbon acid contained in fats, «S:c., is normal
caprylic acid is proved by the fact that its properties are iden-
tical with those of the acid obtained by the oxi<:lation of the
primary alcohol.^

In order to prepare it, cocoa-nut oil is treated with caustic
soda having a specific gravity of 11 2, and after the soap which
swims on the surface is solidified, it is removed and well mixed
with dilute sulphuric acid, and the mixture quickly distilled in
a oopjwr retort. The distillate, which chiefly consists of caproic
<\\\k\ caprylic acids, is neutralized with baryta, and the solution
oxnjH^rated to crystallization. After cooling, barium caprylate
*\*|wM'atos out, whilst the mother-liquor, on further concentration.

THE OCTOIC ACIDS. 657

yields barium caproate. Both salts are purified by recrystal-
lizatiou and decomposed by dilute hydrochloric acid. The oily
layer which separates is dried, and the acid obtaiued in the pure
state by repeated fractionations.

Pure caprylic acid is a liquid which, especially when hot, has
a smell resembling that of sebacic acid and of perspiration. On
cooling it crystallizes in needles or scales, which melt at 16° —
17°. It boils at 235°— 237°, at 0° has a specific gravity of
0 9139, and is soluble in 400 parts of boiling wator, separating
out almost completely in crystalline scales from this solution on
cooling.

The octoates or caprylates of the alkali-metals, and those of
he alkaline-earth metals, are soluble in water; those of the
other metals are sparingly soluble or insoluble in water, but, as
far as they have been investigated, are all soluble in alcohol.

Calcium Odocttc, (CgHj502)2Ca+H20, is a salt diflicultly
soluble in cold water, crystallizing in long, thin, silky needles.

Barium Ocloate, (G^^^^fi^^iiJ^^* ^s somewhat more soluble, and
forms fatty tablets or thin flat needles, or, when slowly
crystallized, yields long prisms.

Methyl Octoate, 0311^502(0113), is a strongly aromatic-smelling
liquid.

Efhj/l Octoate, OgH^gOoCOgH^), possesses the smell of pine-
apples, boils at 208°, and has a specific gravity at 16° of 0*8728.

Octyl Octoate, C^UyO^iC^n^^l is a liquid boiling at 297°— 299'
and having a specific gravity at 16° of 0*8625.

Caprylamide, C^^fii^TS^, is fonned by the action of aqueous
ammonia on ethyl octoate. It forms pearly glistening scales,
melting at 110°, and boiling with decomposition above 200°.

Octoyl Oxide, or Caprylic Anhydride, (03Hj,jO)2O, was prepared
by Ohiozza by acting with phosphorus oxychloride on barium
octoate. It is an oily liquid which boils with partial decom-
position at 280 — 290°, is slowly acted upon by water, and has a
disagreeable smell resembling that of the carob.^

Octonitrd, or Capi^lonitril, OgH^gN, is a liquid smelling of
camomile, obtained by heating the ammonium salt with phos-
phorus pentoxide. It boils at 194"* — 195°.*

Isoctoic Add, (0H3),0^Hc(0H3)00oH. This, as has been
stated, is the oxidation-product of isoctyl alcohol. It is an oily
liquid which, when warmed, has a smell of old cheese. It

^ Ann. Chcm. Phann. Ixxxv. 229 ; Comptrs Rcndus, xxxv. 865.
= Felletar, JaJircsb, 1868, 624.

VOU III. U U

658 THE NOXYL GROUP.

boils at 218°— 220', and does not soldify at —17'. At 0' it
possesses a specific gravity of 0*926.

Calcium Isocioate, (CgHj502)2Ca + HoO, crystallizes in scales
-which have a stellated form, and is more easily soluble in cold
than in warm water.

The barium salt does not crystallize, but the solution, on
drying, gives an amorphous mass.

The ethyl etJur boils at 175°, and has a peculiar penetrating
smell.

A third octoic acid is formed in small quantity, together
with trimethyl-acetic acid and acetone, by the oxidation of
di-isobutylene. It has a smell resembling trimethyl-acetic acid,
but somewhat weaker, and boils at 21 5^ Its constitution has
not been satisfactorily determined, but the mode of its forma-
tion is strictly analogous to that of isobutyric acid from
trimethyl carbinol.^

COMPOUNDS CONTAINING NINE ATOMS OF
CARBON, OR THE NONYL GROUP.

422 The compounds of this group have been but imperfectly
investigated. Pelouze and Cahours obtained nonane, C^H^
a body boiling at 136** — 138**, from petroleum, and termed it
'palargyl hydride. This substance is, however, evidently a mix-
ture, as, indeed, were all the paraffins obtained by them from
petroleum (p. 132). On the other hand, Thorpe and Young
obtained a series of liquid paraffins by the distillation of solid
paraffin, and as the lower members of these certainly belong to
the normal series, the higher homologues, doubtless, are also
normal.

Noi^mal Xonane, C^Hj^, is a liquid boiling at 147' — 148"*, and
having at 13°*5 a specific gravity of 0 7279, whilst that of its
vapour is 4*587.*

l^ctramethyl'pentane, (CH3)2C5Hg(CHj)2, was obtained by Wurti
by acting on a mixture of amyl iodide and isobutyl iodide with

* Butlerow, Lirhig's Ann. clxxxix. 70.
' Chcm, Soc. Journ, xxiv. 842.

THE NOXOIC ACID& 659

sodium, and described by him as butyl-amyl. It in a liquid
boiling at 132**, and having at 0** a specific gravity of 0*7247.^

Pentamethyl'hUane, (CH3)2(C2H2(CH3)CH2.CH(CH3)2, was ob-
tained by Silva, together with a small quantity of di-isopropyl
(p. 565), propane, and propylene, by heating secondary propyl
iodide with sodium amalgam.^ In order to explain the forma-
tion of this paraffin, which boils at 130^ it must be assumed
that the radicals propylene and secondary propyl combine
together when in the nascent conditions

ptr^yCH .... CH — CHp. . . . CH^pTT*

CHj

The Konyl Alcohols have been only slightly investigated. The
alcohol obtained from petroleum-nonanc, and boiling at about
200", is certainly a mixture.

By acting on amyl valerate with sodium, and treating the
residue with water, Lourenqo and d'Aguiar obtained an oily
liquid which, according to them, is a mixture of various homo-
logous alcohols, the lowest member consisting of nonyl alcohol,
CjjHgoO, boiling at 205^—212".*

Di'isdbntyl Ketone [(CH3)2C2H3]2CO. This compound, com-
monly kno^vn as valeronc, is formed in small quantity, together
with a larger amount of valeraldehydo and other products, by
the dry distillation of calcium valerate. It is an ethereal
smelling liquid which boils at 181** — 182^ has a specific gravity
at 20° of 0^ 833, and does not combine with the acid sulphites of
the alkali metals.*

Dinitro-isdbutane, {GH^Ju^^O,^^^ first obtained by the
action of hot nitric acid on this substance, has acid properties,
and was originally described as nitro-butyric acid.

THE NONOIC ACIDS, CgHi^COgH.

423 In 1827 Recluz showed thdX Pelargonium roseum owes its
peculiar odour to an ethereal oil ; ^ and this was more accurately
examined in 1846 by Pless, who, by distilling the plant with
water, obtained an acid distillate which, on saturation with

' Ann. CJutm, Pharrti. xcvi. 371 ; Ann, Chim, Phya. [3], xliv. 290.

- Bcr. Dcutach. Chtin, Grs. v. 984.

> Zcilsrh. Chem, 1870, 404. < E. Schmidt, Her. DeiUsch. Chan. Ocs. v. 600.

• Joum. Pharm. xiii. 629.

U U 2

4n> rEz y:xYL gbijup.

burr-ii T i-cr Izzz x z.oz'zznl iz^solable ofl. whikt the aqueous
Ii':_"iji :-:ii"ii.zLiii -l.f cilttizi sil: of ;i new acid.^ Almost simul-
Zisuc-.j-^l-r T^i^Lz^z^^ztn^hir 5:riZii An acid having the same com-
r< =111' III jjz.i.tLCf': •^'T T^.•i:;•:^!:5 -.t the action of nitric aciil on
:-*=£': ui'jL iz-d :: *:> > i-r rive ?be name oi pelargonic acid?
CmrbLrli.' A5 -vzZ. is Cilocr?,* aLso obtained an acid bv the
:x:Lkzi':c :c :C :i rii fr:ci R'tu'i -rrririiuViw' , and this substance
tl'fj'rtfli'f'r'i i^* ce ii-z^-d'-^ widi pelar^onic acid. The same
bo I J TTis AficraraLrii ziore exactiv examined by Fittig and

El 7 sc^tTELL-ents c^:iicemicLZ the melting-points and boiling-
pi-:? -•: :lrr rtlir^::!:': acids obtained fir«>m these various
Si:vir:*f< :j:\r ~:: jcnxri^ki::. It 15, however, probable that they
a^ C'juJLi: •:: in-e n-:r" •■■•>. ai::i.

3^1 •;■..:." -V- v;.--J;:o"wA5 synthetically prepared by Zincke and
Fn2.:cii:io-t toni octjl ivtiiie : this substance being heateii for
sozie .:avs in contact ^ith spirit of wine and potn^ium cyanide,
ai-i the crude nitril fcmir=d beicg decomposed by aL^oliolic
piiMc-h. The acii is :hen prepared from this and purified by
\i"vll-kr.own pr>.>:S5f:s.*

T^v sac.e acid is obtained tojether with other products by
iLv oxii.U'oa of stearoiic acid, C, jH^^O*," as also by the action
of Loxvl i.>iido ou the sodium compound of aceto-acctic ether
and djcv'U.p.'siti^'a of the prcduct by means of potash.^

It is :\n oily. sli-:htly smelling liquid bc»iling at 253' — 254'.
and ha\ iu,: a spe. iiic irravity of 0 00G5 at 17'*5. On cooling
it crvst iilizos to a scalv mass, which melts at 12' — 12'-5 and
solidities airain at 11'.

The salts of nonoic acid are very similar to those of the
diiVcrent ivlargonic acids. They are most of them difficultly
soluble iu water. Those of the heavy metals dissolve readily
in alcohol The salts of the alkali metals on the other hand
are readdy soluble, and crystallized in tablets.

Couiuhi XviuMtU, (CjHj.O^^^Ca, crystallizes from hot alcohol
in glistening scales and is very difficultly soluble in watL»r.

L'arium yononte, (C^Hi702)iBa, separates out from a hot
aqueous or alcoholic solution in similar scales.

£fhi/l A\moatc, C,H,,0,(C^J, boils at 227^— 228^ and at

• .i.nu Chnn. Phar.n. lix. 54 (foot-not!;),

a jl, lix. 52. ' Compt. R nd, xxvi. 226.

« lb. xxvi.'iGi ; xxxi. 143. * ZrUsch, Chtm. 1870. 420.

• Ann. CU.n. rhann. clxiv. 103. ' Limiwicb, Licbig* Ann. cxc. £»4.

• Jounljii, Ann. Chan. Phunn. cc. 107.

THE NONOIC ACIDS. 661

IT* '5 has a specific gravity of 0*8635 ; whilst methyl nonoate,
Cj^Hj^OgCCHa), boiling at 213"* — 214°, has at the same tempera-
ture a specific gravity of 0*8765.

The peculiar odour of the quince is duo to an ethereal oil/
which, according to R. Wagner, is perhaps ethyl pelargonatc;
and this ether is obtained on the large scale by oxidizing the acid
contained in oil of rue. It is employed in the manufacture
of common brandy and wines, &c.^

From this pelargonic acid the chloride, C9H17OCI, is obtained
by the action of phosphorus pentachloride. It is a liquid fuming
in the air and boiling at 220°.* If the sodium salt be acted
upon by this chloride, nonoic anhydride, (CqHj70)20, is obtained,
and this is purified by solution in ether. On evaporation the
anhydride remains as a slightly rancid oil, which on cooling
crystallizes in needles melting at -f- 5°.*

If mcthyl-nonyl-ketone obtained from oil of rue be heated
with nitric acid of specific gravity 1*2, and the oily layer which
remains when the action is completed be removed and shaken
up with concentrated potash, a crystalline precipitate is formed
which is increased on the addition of water. If this be then
filtered off and washed with ether in order to remove any
neutral oil and crystallized from hot alcohol, glistening yellow
rectangular tables are obtained which decompose on addition
of a dilute mineral acid with separation of a yellow liquid,
known as nifrous-oxidc-pelaryanic acid, CgHjg02(NO)2.^ There
can however be little doubt that this compound is dinitro-
nonnne, Gq'^i'^0sO^2' I^ decomposes on heating with evolution
of nitric oxide and combustible gases, whilst its diflBcultly
soluble and yellow salts deflagrate when heated. The formation
of this compound is analogous to that of dinitro-propane from
dipropyl ketone (p. 642.)

424 Isononoic Acid, or McthyUhcoyl-acetio Acid, GR^i^^^^
CH.COoH. If secondary octyl iodide be boiled with alcohol and
potassium cyanide, isonononitril separates out on the addi-
tion of water as a brown oil. On heating the crude product
for some time with alcoholic potash isononamide, 0113(0^11^3)
0H.C0(NH2), is produced, which crystallizes from hot water in
scales or needles melting at 80° — 81°. Boiling alcoholic potash
only acts slowly upon this with formation of isononoic acid.

^ Wohlcr, Ann. Chan. Pharm. xli. 239.

' Journ. Prnkt. Chcm. Ivii. 440. • Cahoiirs, Compt. Rend, xxxix. 257.

•• Chiozza, Ann. Chcm. Pharm. Ixxxv. 231.

* lb. Ixxxv. 235 ; Alczeyoff, Zrit. Chrm. 18C5, 73G.

CC2 THE KOKYL GEOUP.

This substance is a liquid boiling at 244** — 246^ anJ does
not solidify at — 11^ At 18"* its specific gravity is 0*9032.

The salts of the alkali-metals are easily soluble in water,
and separate out as a saponaceous mass on the addition of
common salt

Calcium Isonoiwaie, (C^yjO^J^ + H^O, is obtained as a
flocculent precipitate on the addition of calcium chloride to the
s^xlium salt. This however soon becomes crystalline, and may
be obtained in fine needles fix>m hot alcohol.

Ethyl Isonoiioate, CgU^jO^lC^W^), is a liquid having a pleasant
fruity smell, boiling at 213'' — 215°, and having at 17' a specific
gravity of 0 8640.* On heating wdth concentrated ammonia
it yields nonamide, a body analogous to that obtained from the
nitril, but not melting below 105°.*

Isoheptyl-acrfirAcid, (CHj^CfiHu.CH.CHyCOjH, was obtained
by Venable by heating isoheptyl-malonic acid, CH3(C5Hjj)
CiI.CH(C02H)j, a body which will be subsequently described.
It decomposes into carbon dioxide and isohcptyl-acetic acid, a
li([uid boiling at 232^.'

COMPOUNDS CONTAINING TEN ATOMS OF
CARBON, OR THE DECATYL GROUP.

425 Xurmal Diaitane, C^^H^, also doubtless occurs in Pennsyl-
vauian petroleum and other li(^uids containing its lower homo-
logues, although it has not been obtained from this source in the
pure state. On the other hand, a hydrocarbon, having the com-
position Ci^jHjj^, was obtained by Thoq>e and Young by the de-
composition of the solid paraffins, and this is no doubt normal
decatane. It boils at 16G^— 168°, and at 13' 5 luis a specific
gravity of 0 731)4, that of its vajjour being 503.* It also appears
to oicur in loinmoii coal-tar naphtha.*

IHrnvtlnjUhptyUrnethane, CH(CH3)/\H,,^ was prepared by
\\ urtz by the electrolysis of a mixture of potassium valerate

* Kullhcin, Ana, Chan, Vharm. dxxiii. ;.lt».

- ib. clxxvi. 308.

' Jhr. DnUwh, Ch4^n, Grs, xiii. 16r>2.

ThoriM- ami Youn;,% Ann. Chrm, Plmna, c!xv. i»U.
•' liicobjk'ii, ib. clxxxiv. 202.

DECATYL COMPOUNDS. 6G:)

and potassium cenanthylate, and termed by him hiUyl-caproyl ;
it is a liquid boiling at 160V

TdramethyUhccane, (CH3)2CgHi^(CH3)2, was first prepared by
Franltland, and described as amyl. It is obtained together with
amylene and amyl hydride (isopentane) by heating amyl iodide
with zinc to 160'— 180^2

Brazier and Gossleth obtained the same hydrocarbon by the
electrolysis of sodium isocaproate,* and Wurtz showed that it is
also easily formed when amyl iodide is warmed with sodium/ In
place of the iodide, amyl bromide may be employed.^

Diamyl, as this paraffin is usually termed, boils at 160°, and
has at 0"" a specific gravity of 07413.

The action of chlorine on the hydrocarbon has been investi-
gated by Schorlemmer ® and Grimshaw. As first product, a mix-
ture of monochlorides is obtained, boiling between 198° — 21 7^
By heating this with acetate of lead and glacial acetic acid it
is converted into acetates, which on treatment with concen-
trated potash are retransformed into the alcohols, and these may
with difficulty be separated into two parts, the larger boiling at
202°— 203**, and the smaller at 211°— 213°. They possess an
agreeable smell, especially the higher boiling portion, somewhat
resembling the flowers of the DapJuie odorata. Besides these
two other decatyl alcohols have been briefly described.

Isocapric Alcohol, Cj^Hgi-OH, is formed, together with amyl
alcohol, valeric acid, and other products, by the action of sodium
on valoraldehyde. It is a pleasantly smelling liquid boiling
at 203° 3, and having at 0° a specific gravity of 0 8569. When
heated with glacial acetic acid under pressure, an aromatic
smelling acetate, boiling at 220°, is formed. The oxidation-
products of this alcohol show it to be a primary compound.^

An isomeric alcohol is also formed, together with other pro-
ducts, by the action of sodium amalgam on amyl valerate
(p. 620) ; it boils at 225°— 230°.

Isoctyl-methyl Ketone, CH3(C5Hii)CH.CH2.CO.CH3, was pre-
pared by means of the acetic-ether-reaction from secondary
hc'ptyl bromide. It is a pleasantly smelling liquid, boiling at
196°— 19S°.8

' Ann. Chim. Phys. [3], xliv. 291 ; Ann, Chcm. Phann, xcvi. 371.
' Quart. Jouni. Cfwni. Soe. iii. 33. • lb. 222.

* Ann. Chan. Pharrn. Ixxv. 249.

* Grimshaw, Jouni. Chein. Soc. 1877, ii. 260. • Joum, Chem, Soc xvl 427.
7 lioiwlin, Jnhrcah. 1864, 338 ; Zcit. Chcm, 1870, 416.

* Yeiiable, Bcr. IkiUscK Chcm. Ges, xiii. 1651.

664 THE DECATYL GROUP.

THE CAPRIC OR DECATOIC ACIDS.

426 Capric Acid, CgHjy.COgH. This acid, as has been stated,
was discovered by Chevreiil (p. 634), but more accurately
examined by Lerch.^ It is found not only in butter, but in many
other fats, as, for instance, in cocoa-nut oil,^ and generally occurs
together with caproic and caprylic acids. In combination as
the ethers of various alcohol radicals, as well as in the free
state, it forms one of the constituents of the high-boiling por-
tions of the several fusel oils.' Hungarian wine also contains
a considerable quantity of amyl caprate.* It is also formed
together with other acids in the products of the distillation
and oxidation of oleic acid,^ as well as in the oxidation of the
higher fatty acids.^ The synthesis of capric acid has been
effected by the introduction of normal octyl in place of one
atom of hydrogen in acetic r.cidJ

Capric acid is a crystallme mass of scales or needles. It
possesses a goat-like smell, which is faint when cold, but be-
comes strong on heating the acid. It melts at 30^ and boils
at 268** — 270°. It is somewhat soluble in boiling water, but
separates out, almost completely, in scales on cooling.

The caprates of the alkali metals arc easily soluble in water.
Those of the other metals are difficultly soluble or insoluble. A
few, however, dissolve with difficulty in alcohol.

Calcium Caprate, (Ci^i^O^fiii, crystallizes from hot water or
alcohol in fine, glistening, thin plates.

Barium Capraie, {Ci^if>^^fi'Ji, separates out from the same
solvent in nacreous needles.

Methyl Caprate, OioHj^OglCH^, has a pleasant, fruity smell,
and boils at 223^—224°.

Ethyl Capratc, CioHigOjCaHJ, boils at 243°— 245^ and has
a specific gravity of 0 862. It has already been stated that
this ether forms the chief portion of cenanthic ether (p. G47),
occurring in old wines, and obtained on the lar^j^o scale by
the distillation of wine-lees ® or the after-brandy • of grape-

* Ami. Chnn. Phorm. xlix. 223. • Gorgey, ih. Ixvi. 290.

' Kowiiry, Kdin. Phil, Trans, vol. xx. part ii. ; Fehlinp, Dinrjl, Polyt. Jottm,
rxxx. 77 ; Wetlierill, Journ, Prakt, Chem, Ix. 202 ; Johnson, i6. IxiL 252 ;
ris<lu'r, .inn. Chrm, Phnnn, cxviii. 307.

* (Jriinin. ib. clvii. 254. » Gottlieb, ib. Ivii 68.

* luMlti'iiIuichtT, lb. Ivii. 150 ; lix. 54.

' Cliithz.'it, Jnn. Chnn. Phann. c.civ. 1.

* l.i»M^ ami IVlouzo, Ann. Chvm, P/uirm, xix. 241.

* Schwarz, ib. Ixxxiv. 82.

THE CAPRIC ACIDS. 665

marc. These lees coutaining wine are diluted with half their
volume of water and distilled, and the distillate, which contains
about 32 per cent, by volume of alcohol, is distilled again,
when a liquid containing 60 per cent, of alcohol first passes
over, and then the oenanthic ether. Four thousand parts of
wine contain about one part of this ether (Liebig and Pelouze).
The commercial product is an oily liquid, frequently coloured
green by copper, and possessing a strong alcoholic smell. It
is used for the preparation of artificial brandy, and for giving
an aroma to common wines.

Delffs, who investigated a sample of oenanthic ether which
had been prepared in Kreuznach, came to the conclusion that
the chief constituent was the ethyl-ether of pelargonic acid.^
On the other hand, Fischer who examined another sample
obtained from Neustadt, could not detect this acid, but found
that the ether contained chiefly capric acid, together with small
quantities of caprylic acid.^

Isocapric Aldehyde, C^jHig.CHO, is obtained by the gradual
oxidation of isocapric alcohol. It is a mobile, aromatic-smelling
liquid, boiling at 160°, and having a specific gravity of 0'828.*

Isocapric Acid, CgH^g-GOgH, is obtained by the further oxida-
tion of the aldehyde as an oily, slightly-smelling liquid, having
an lUip^easant, burning taste. It boils at 241***5, and does not
solidify at — 37^ and its specific gravity is 0*9006.

Its salts usually crystallize with difliculty. Tho barium salt
forms an oily or wax-like mass.

Ccdcium Isocnprate, {G^QU^QO^fio,, is a white precipitate,
crystallizing from hot water in needles.

COMPOUNDS CONTAINING ELEVEN ATOMS OF
CARBON, OR THE HENDECATYL GROUP.

427 Hendecatane, Gifi^v also probably occurs, together with its
isomerides, in petroleum and other oils containing the paraffins;
but it has not yet been prepared in the pure state. Amato
obtained a body, boiling at 180° — 185**, which is probably the
normal compound, by distilling the spongy residue left in the

* Pofjg, Ann. Ixxxiv. 505 ; Ann. Chan, Pharm, Ixxx. 290.
^ Ann, Chcm, Plmrm. cxviii. 3C7. • Borodin, loe, cil.

666 THE HENDECATYL GROUP.

preparation of oenanthol from castor-oil (p. 647). Louren^o
and d'Aguiar obtained an hendecatj 1 alcohol, boiling at 245** —
255°, from amyl valerate.

Mcthyl'Twnyl Carbinol, CH3(CgH JCH.OH, is formed by the
action of sodium amalgam and water on the corresponding
ketone. It is a very thick liquid, wliich boils at 228** — 229**,
and at 19° has a specific gravity of 0*8628.^

Mcthyl-nonyl Ketone, ClI^{CgH^^)CO, forms the chief consti-
tuent of the essential oil of rue from JRuta graveolens, occurring
together with hydrocarbons and other bodies. This oil was first
examined by Will, who first ascertained its chemical constitu-
tion.^ According to Gerhardt' and Cahours* it chiefly consists
of capric aldehyde, as on oxidation it yields an acid w^bich they
believed to be capric acid. If this has really been produced, it
shows the presence of an admixture. Greville Williams also
examined this oil, and came to the conclusion that it contains
liendecatoic aldehyde, CjiHogO, together with lauraldehyde,
C^Jiofi,^ The analytical numbers obtained by Hallwachs
indicate the existence of the former compound, but he con-
sidered it to be a ketone rather than an aldehyde.® Strecker
then threw out the suggestion that it is methyl-nonyl ke-
tone (iiiethyl-caprinyl) ; and this view was confirmed by the
investigations of Fittig and Giesecke,^ as well as those of
Gonip-Besiiuez and Grimm.® The two first of these chemists
distillod 500 gmms of the oil, which contained scarcely any hydro-
carbons, and thus obtiiined 300 grams of a liquid boiling at 225**
— :i-(r, and this on oxidation yielded acetic acid and pelargonic
or nouoic acid. The two other chemists obtained the ketone
synthetically by submitting calcium acetate and calcium capmte
to dry distillation, the product being repeatedly rectified. The
l)t)rtion boiling between 210^ — 245° is mixed with liquid am-
monia, and the solution siiturated with su'phur dioxide, when
it becomes warm, and on cooling the compound Cj^H^O +
H(NH^)S03 h HgO septu-ates out in shining, white, jiearly
crystalline scales, and these are decomposed by warming with
a solution of carbonate of soda. The ketone thus obtained is
an oily, hi^^hly refracting liquid, possessing a pleasant smell

> (Jiejwckc ami Fittig, ^fif- Chnn. 1870, 428.

•-• Ann. rh*in, Phann. xxxv. 235.

» l\mntt. Rtmi. xxvi. 226 ; Ann. Chim. Phya. [3], xxiv. 96.

4 ffiisr pr^si'nii d la fuctdU lU* ikicncrn, Ic 15 Janvitr, 1846 ; Camjil. Jicml

^ ^ Ph a. Trans. 1858, 100. * Ann. Chnn. Phnrm. cxiii. 107.

" /t'itiich, Chctti. 187U, 428. •* Ann. Chan. Pharm. chiL 275.

THE DODECATYL GROUP. 607

resembling that of garden rue. It boils at 224**, and at 17° has
a specific gravity of 0 8295. On cooling it solidifies, as also
does that obtained from oil of rue, to crystals which melt at
15"— 16^

I>Uimyl Ketone, or Caprone, {C^^^)fiO, is obtained by distil-
ling calcium isocaproate. It is a liquid having a pleasant smell,
boihng at 220° — 221°, and having at 20° a specific gravity of
0 822.^ On warming with concentrated nitric acid it yields a
crystalline compound which deflagrates on heating, and possesses
acid properties, and is probably dinitro-isopentane.

Heiidecatoic or U)idecylic Acid, Ci^H^.COgH, was first pre-
pared by Erafft by heating hendecalenic acid, CjoH^g-COgH,
with phosphorus and hydriodic acid,^ and he afterwards prepared
it by oxidizing undecatyl-methyl ketone.* It forms a scaly,
crystalline mass, having a faint smell of caproic acid, is insoluble
in water, and melts at 28°"5. Under diminished pressure it
distils without decomposition, and it boils under a pressure of
100 mm. at 212°'5. Its salts and derivatives have not as yet
been examined.

Dipseudo-hutyl-methyl'dcetic Acid, [(0113)30] gCHg.C.COgH,
wjis obtained by Butlerow by the oxidation of tri-isobutylene.
Ci^H^^. It is a crystalline mass, fusing at 66° — 70°, easily
soluble in alcohol, and boilinsr at 266° without decomposition.*

COMPOUNDS CONTAINING TWELVE ATOMS OF
CARBON, OR THE DODECATYL GROUP.

428 Normal Dodecatane, CigH^g, was first prepared by Brazier
and Gossleth ^ by electrolysis of potassium oenanthylate. A hydro-
carbon identical with this appears to be formed as a by-product
in the preparation of normal hexane from secondary hexyl
iodide (p. 626). It also appears to occur in petroleum (Pelouze
and Caliours), and in the distillation-products of Boghead caimel
fGreville Williams). It is a mobile liquid, boiling at 202°,
and having a faint ethereal smell (Schorlemmer).

^ E. Schmidt, Bcr. Deut^h. Chcm. Gca, v. 604.

- Her. Dc}a.Hch, CV//i. dot, xi. 2218. » lb. xiL 1664. ** Ih.

* QuHrt. Juunir, Ch-^n, Svc. iii. 224 ; see also Wurtz, Ann, Chem. Phaitn,
xcvL 372.

THE TETRADECATYL GROUP. 6G9

COJ^IPOUNDS CONTAINING THIRTEEN ATOMS
OF CAKBON, OR THE TRIDECATYL GROUP.

429 Neither paraflSns nor alcohols containing thirteen atoms
of carbon have hitherto been prepared.

Bihcxtjl-ketone, or (Enanthone, (CflH^3)2CO, is formed, together
with other bodies, in the dry distillation of calcium heptoate.
It crystallizes in scales melting at 30°, and boiling at 264?°.^

Methyl'Undecyl Ketone, or Mcthyl-hendccatyl Ketone,
CH3(C||H^C0, is formed when a mixture of calcium acetate
and calcium laurate is distilled under diminished pressure. It
is a crystalline mass, melting at 28**, and boiling at 263°.^

TridcccUoic or Tridecylic Acid, Cj2Ho5.C02H, obtained by the
oxidation of methyl-tridecatyl ketone fp. 674), is a scaly crystal-
line body, insoluble in water, but dissolving in alcohol. It melts
at 40°'5, and boils, under a pressure of 100 mm., at 230°.*

COMPOUNDS CONTAINING FOURTEEN ATOMS
OF CARBON, OR THE TETRADECATYL GROUP.

430 The following acid, occurring in nature, is the only ono
of this series known :

Myristic Acid, C13H27.CO0H. This body was discovered by
Play fair* in the nutmeg-butter of Myrlstica moschata. It also
occurs, together with other fats, in the otoba-fatof the Myristica
otaha, which contains the glycerine ethers of oleic acid and
myristic acid (Uricochea).'* According to Oudcmans, one half
of the fatty acid contained in Dika- bread consists of myristic

* Uslar and Seelcamp, Ann, Chcm. Phann. cviii. 179,
^ Kmirt, Bcr, Dcutsch, Chcm. Ges, xii. 1667.

' Jb. 1668.

* Pk:i. Mn4j, [3], xviii. 102.

* Ann, Chan. Phann, xci. 369.

THE HECDECATTL GROUP. 671

An acid of the same composition occurs in a fungus {Agaricus
integer). It crystallizes in small needles, which melt at 69°'5
— 70° ; its properties have not been more particularly examined.^

COMPOUNDS CONTAINING SIXTEEN ATOMS OF
CARBON, OR THE HECDECATYL GROUP.

432 Normal ITecdecatane, or Di-octyl, C^fi^, is formed, together
with octane, by the action of sodium-amalgam and water on
octyl iodide. It boils at 278**, and solidifies on cooling to pearly
glittering scales, which melt at 21*".*

This paraffin is probably a constituent of oil of roses. Dios-
corides mentions such a poBivov iXcuov ; this, however, was only
olive -oil, in which rose-leaves had been steeped in order to give
it an agreeable odour. Up to the end of the last century this
preparation was known in Europe under the name of Okum
rosatcum.

An odoriferous water, obtained by distilling the flowers with
water, is frequently described by Oriental poets, and appears
first to have been prepared on the large scale in Persia. It was
prepared in such quantities that, in 1772, 20,100 gallons of
rose-water, of the value of 3,500t, were imported into Bombay.
The traveller Kampfer, who visited Persia in the year 1683-4,
states that a kind of fat, in appearance like butter, was obtained
from rose-water, and that this was known under the name of
cettrgyL That a volatile oil is obtained by distilling roses was
first stated by Geronimo Rossi * in 1582, and Baptista Porta in
1589 says, " Omnium difficiUimaB extractionis est rosarum oleum
atque in minima quantitate sed suavissimi odoris." * In the
price lists of the German apothecaries in 1614 this substance is
also mentioned.^ The discovery of otto of roses in the East is
thus described by Langles. " On the occasion of the marriage
of the Great Mogul Jehan Ghir with the Princess Nur-jehan,

* Thomer, Bcr, Deiitsch. Chan. Ges. xii 1635.

' Zincke, Ann, Chcm. Pharm. clii. 1 ; see also Schorlemmer, Phil, Trans.
1872, 122.

* Hicronyvii Ruhci Rav. Dc Dcstillaiionc, Ravennse, 1582.

* Dc Distillatione, Komoe, 1 608.

^ Faior 81VC Titxatio mnnivm materierum medicaruvi . , . qua in officind
phamuuxuticd sw^vphordiand venundantur, Giessen, 1614.

672 THE HECDECATYL GROUP.

in the year 1612, a canal in the garden of the palace was filled
-with rose-water, and the bride noticed that a scum deposited on
its surface. This, having an admirable fragrance, was collected,
and to it the name Atar-jchanghiri, or the perfume of Jehan
Gliir, was given/* ^ The Arabic word dtr (or more properly
Ktr) is used throughout the East, and, combined with the
Persian word gul (rose), is atrgul, or otto of roses. Oil of
roses is still made in the East, wherever the flower grows in
abundance ; and that which comes into the English market
chiefly comes from Roumelia and the lower slopes of the
Balkans. There the peasants cultivate the Eosa dnmascijui,
and this plant flowers in April and May. The flowers are
cut off before sunrise, and distilled in a rough copper stilL
The first portion of the distillate is used for a second operation,
and from this second product the oil separates out on standing.
One part of rose-oil is obtained from about 2,500 parts of
the flowers.*

Rose-oil is a varying mixture of liquid oil, and a solid,
odourless body, known as rose-camphor or solid rose-oil. This
latter substance was analyzed by Saussure in 1820, and by
Blanchct in 1833, and shown to belong to the family of the ole-
fines (CnHjn). This fact has been since confirmed by Fliickiger.'
Analysis, however, can only decide with difficulty whether a
body containing a largo number of carbon atoms belongs to the
define or to the paraffin series. The fact that it is only slowly
attacked by boiling and fuming nitric acid would rather point to
its belonging to the latter class. It melts at 32^5, and begins
to boil at 272°, but soon becomes brown and carbonizes ; from
tbis it wou!d seem that it is a mixture, and the boiling-point
indicates that it contains normal hecdecane.

433 Ifecdecatf/l Alcohol, or Cetyl Alcolwl , C^^jHjjjOH. Spermaceti
is found in peculiar cavities in the head oiPhyseter 7)iacrocephahiS,
P. Tarsia, and in Di'lphinus edentulus. During the life of the
animal the spermaceti is kept in solution in the sperm oil by
the animal boat, but it crystallizes out after death. It is freed
as much as possille from oil by filtration and treatment with
potash -lye, and then melted. The commercial product is a
white, scaly, brittle mass, soft to the touch; and from this
the pure spermaceti fat (cetin) was obtained by Chovreul by

' rrclurches sur la dtcouvrrtf dc V esse nee de rosf, Paris, 1804,
■•' Flucki«;or ami llunbury, rhfirmacvifrtiphin, 233.
* Phann. Journ. lSt)J»» 1>. 74.

CETYL ALCOHOL. 673

repeated crystallizations. Spermaceti is also found in small
quantity in the blubber of the Balccorcca rostrata^ and also in
the oil of Delphinus glohiceps.

In 1818 Chevreul found that this fat is decomposed, by
heating with caustic potash, into an acid wliich he had already
observed in other fats, and a neutral body. This latter sub-
stance he analyzed, and gave to it the name ethal, a name
composed of the first syllables of the words ether and alcohol,
because he believed this body to be composed of olefiant gas and
water.^ Ethal was first recognised to be an alcohol by Dumas
and Peligot.^

Spermaceti consists chiefly of the cetyl-ether of palmitic acid,

CjgHjoO ; but it also contains small quantities of lauric, myristic,

and stearic acids, in the form of the ethers of the following

alcohols, which have not yet themselves been obtained in the

pure state : *

Lethal, CjgHggO.

Methal, Ci^Hg^O.

Stethal, C18H33O.

In ORler to prepare pure cetyl alcohol, a solution of 10 parts
of purified spermaceti in 30 parts of alcohol is boiled for some
time with 4*5 parts of caustic potash, and then precipitated with
barium chloride. The whole is next filtered, and the hot residue
pressed and moistened two or three times with alcohol, and again
pressed. The alcoholic residues are then distilled, and the cetyl
alcohol which was dissolved is found in the residue, and this is
then dissolved out by ether. The ethereal solution is again
distilled, and the residual compound purified by repeated
crystallizations from alcohol.

Cetyl alcohol crystallizes from hot spirit of wine in small
scales, melting at 49°'5, and solidifying on slow cooling in
glistening laminae. It boils at about 400^ but evaporates per-
ceptibly at the temperature of boiling water. Heated with
caustic potash to 250*^, it forms potassium palmitate :

CieH3,0 + KOH = CieHgiKOg + 2 H^.

434 Cetyl Oxide, or Dicetyl Etiur, {G-^^^jd, was obtained by
Fridau by dissolving sodium in fused cetyl alcohol until the
evolution of hydrogen ceased, and heating the product with
cetyl iodide to 110^ Cetyl oxide crystallizes from alcohol or

^ ^7171. Chim. Phys. [1], vii. 157. » Ih. IxiL 5.

' Ileintz, Pogg. Ann. Ixxxi. 267, 553.

VOL. in. X X

PALMITIC ACID. G75

TricetT/lamine, (CigH33),N. This was obtained by Fridau by
passing ammonia over cetyl iodide, heated to 150**, the tempera-
ture being gradually raised to 180^ It crystallizes from alcohol
in white needles, melting at 39*, and forms salts which are
insoluble in water. The hydrochlorate, (C,gH33)3NHCl, crystal-
lizes from hot alcohol in glistening needles. Its solution yields
with platinic chloride a cream-coloured precipitate, having the
formula, 2(CigH33)3NHCl + PtCl,.

Falmitaldehyde, CjgHggO, is formed, according to Friedel, by
heating cetyl alcohol with potassium dichromate and sulphuric
acid. A better process is to distil a mixture of calcium palmi-
tate and formate under diminished pressure. It crystallizes
from ether in glistening scales which melt at SS'^'S, and boils
under a pressure of 100 mm. at 289° — 240°.^

Palmitic Acid, CigHj^.COgH.

435 So early as the year 1813, Chevreul pointed out that the
soap obtained by saponification of pig*s lard yields on decom-
position two fats having acid properties, one of which is solid
and the other liquid. The former of these, on account of
the pearly character of its potash salt, he tenned vmrgarin
(j^pyapo^, pearl-shell). In a subsequent investigation in
181G, he came to the conclusion that saponification depends
on the combination of a fatty acid with the alkali and the
simultaneous separation of glycerin. To the two above fatty
acids he then gave the names of acide margarique and acide
oUique. The subsequent investigation of many other fats
show^ed that the consistence of these bodies depends on the
proportion of the solid and of the fluid fat which they con-
tain. To the first of these he gave the name of stearin
(from aredp, tallow) and to the other that of eliene (from eXaiop,
oil). Lastly, in 1820, he distinguished two kinds of fatty acids,
namely, acide margariqtu and adde margaretix, to the last of
which he afterwards gave the name of acide sUarique, Chevreul
did not, however, believe that any real distinction between the
two acids existed, and he threw out the idea that margaric acid
would after all turn out to be a mixture of stearic acid with
some easily fusible acid. Nevertheless, margaric acid was usually
considered to be a definite compound, and to it the fonuula

» Krafflt, Bcr. Deutseh. Chan. Ges, xiii. 1416,

X X 2

PALMITIC ACID. G77

bodies of men and animals. Other fatty acids are also contained
in this material. The first mention of this substance is found
in a letter, dated November 17, 1664, from Henry Oldenburg,
then Secretary of the Royal Society, to Robert Boyle. "Mr.
Howard produced a substance taken out of the grave of a man
who had been dea^l thirty years, and was in a manner all
wasted, but that a piece of fat remained about the place of his
belly, of which this present was a small portion, which being
jjut upon the fire, burned and smelled like fat." ^ The above
name was given to this substance by Four^roy as standing half-
way between fat and wax.

Eikyl Palmitate, CigHgiOgCCgHJ, is obtained by passing
hydrochloric acid into a hot saturated alcoholic solution of the
acid. It crystallizes in hard prisms, melting at 24^

Ccfi/l Palmitatc, CigHgiOoCCigHgg), is the chief constituent of
spermaceti ; from which it may be obtained by repeated crystal-
lizations from hot alcohol and ether, when it is deposited in the
form of thin glistening scales, melting at 53°'5.

Is^palmitic Acid, or Dihepyl acetic Add, (C7Hj5)2CH.C02H,
is obtained by the decomposition of the diheptylacetic ether.
It forms a white, hard, crystalline mass, melting at 26'' — 27**,
and boiling under a pressure of 80 — 90 mm. between 240**
and 250°.2

COMPOUNDS CONTAINING SEVENTEEN ATOMS

OF CARBON.

436 PentadcccUyl'Tncthyl Ketone, CH3(C^5H3i)CO, is obtamed by
the dry distillation of a mixture of barium acetate and barium
pulmitate under diminished pressure. It yields colourless
crystals which melt at 48°, and boils under the normal pressure
at 310"— 320 (Krafft).

Maryaric Acid, CjoHgyCOgH, was obtained synthetically by
distilling a mixture of potassium cetyl sulphate and potassium
cyanide. The crude margaronitril thus obtained was decom-
posed by boiling with alcoholic potash, and the acid separated
from the product.^ Krafft obtained this acid by the oxidation

* Boyle, Opera, vi. 176. - Jourdan, Ann, Chcni, Phann. cc. 112.

' Becker, Ana. Chcm. Phann, cii. 209 ; Heiiitz, Pogfj. Ann. cii. 272.

STEARIC ACID. 679

is also suitable for the preparation of stearic acid, inasmuch as
the substance only contains stearic and oleic acids. ^

Stearic acid crystallizes from hot alcohol in nacreous laminae
or needles, which melt at 69^'2, to a colourless oil, again solidify-
ing on cooling to a fine, white, scaly, crystalline mass. It can be
distilled, but under the normal pressure suffers partial decom-
position. Under a pressure of 100 mm. it boils constantly at
287'' (Krafft). Its specific gravity from O** to 11** is equal to
that of water (H. Kopp).

Potassium Stearate, C^^Tl^sfy^K., crystallizes from hot alcohol
in needles or scales. It dissolves in ten parts of water at the
ordinary temperature, forming a mucilaginous mass. On heat-
ing, however, the solution becomes clear, and when poured into
a large volume of cold water the so-called acid stearate,
CjgHjjgOgK + CjgHggOg, scpoxates out in delicate white pearly
lamiuse.

Sodiuvi Stearate, CigHj^OgNa, forms the chief constituent of
ordinary tallow soap. It crystallizes from hot alcohol in forms
similar to the potassium salt, and like this is decomposed by a
large volume of cold water into free alkali and the acid salt.
This method may be employed for the preparation of pure
stearic acid by dissolving good tallow soap in six parts of hot
water and adding to this fifty parts of cold water, when a mixture
of sodium palmitate and sodium stearate is precipitated. This
is then dissolved in hot alcohol, and on cooling the stearate first
separates out, and this is decomposed by hydrochloric acid, and
the acid purified by recrystallization.

The stearates of the alkaline earths are crystalline precipitates
insoluble in water. The magnesium salt, which is obtained in
the form of a white flocculent precipitate, crystallizes from alco-
hol in delicate laminae. The stearates of the other metals form
imperfectly crystallized or amorphous precipitates.

By the dry distillation of a mixture of the pure calcium
salts of acetic and stearic acids methyl-heptdecatf^l ketone,
CU.JC^^I{^C0, is formed. This body melts at 55°-5, and
distils at 266°5 under a pressure of 100 mm.

Wlien calcium stearate is distilled alone, a variety of products
are formed, amongst which stearone, (^17^135)200, occurs. This
body crystallizes from ether in laminae which melt at 87***8.*

■

* H. L. Buff, Gniclins Ilaiidhookf xvii. 1041 ; OudemannA, Jotiim. Prakt, Ch^n,
Ixxxix. 215.
*"* Bussy, Aiin, Chan. Phann. ix. 270.

THE WAXES. 681

Lignoccric Acid, CajH^y.COgH, is found in paraflSn and in
bcechwood tar. It crystallizes from hot alcohol in interlaced
needles melting at 80°'5.^

An acid of the same composition, but melting at 45"* — 47°,
was obtained by Pouchet by oxidizing solid paraffin with fuming
nitric acid. He gave to this tlie name of paraffinic acid.^

IDjccruidc Acid, C24H40.CO2H, was found by Carius in the anal
glandular pouches of tlie striped hyaena {Hyocna stricia). It
crystiillizcs from alcohol in granules consisting of microscopic
curved needles, and from ether in more distinct crystals. It
molts at 77^*5.3

The existence oi these acids, with the exception of arachic
and lignoccric acid, is somewhat doubtful.

THE WAXES.

439 Professor John, in Berlin, who in 1812 was the first to
examine beeswax, found that it could be separated into two
constituents by boiling alcohol. The easily soluble portion he
termed cerin, and the more insoluble myricin. Other chemists
occupied themselves with investigations of the various kinds of
wax, but Brodie's investigations first threw a clear light upon
this subject.*

Ccrijl Alcohol, G^Ti^O. Chinese wax is produced by the
puncture of an insect {Coccus ccrifcrus) on the various species
of EIlus, Zigvstrum, and Hibiscus, and that of Coccus Fela,
on FrcLvinns chincnsis. Chinese wax consists almost entirely
of cerotyl cerotate, G^^sf^^ip^H^. It can be purified by
rocrystallization from solution in the lighter tar-oils and alcohol.
It melts at 82°.

In order to obtain the alcohol from this substance, the wax is
melted with caustic potash, the fused mass treated with boiling
water, and barium chloride added, the solution filtered, and the
washed precipitate, consisting of a mixture of barium cerotate,
and ceryl alcohol, washed and dried. The latter substance is
then dissolved out by boiling alcohol, to which a small quantity
of benzol has been added, and crystallized from a solution in a
mixture of alcohol and ether. It forms a waxliko mass

^ lIi-11 an«l Hermanns, Bn'. Duf^h. Chem. Gf^s. xiii. 1713.

' Bull. Sn,\ CUim. xxiii. 111. * Ann. Cficm, Phann. cxxix. 168.

* Phil. Trans. 1848, i. 150.

MELISSVL ALCOHOL. 683

resinbus body with myricyl- and probably ceryl-ethers.^ By
repeated treatment with strong alcohol at 20° — 25" the colouring
matter is removed, and the residue is then heated with alcoholic
potash. The residue remaining on evaporation is boiled with a
solution of acetate of lead, and the mixture of lead salts and
wax-alcohols thus obtained is well dried, and treated with pure
ether free from alcohol. On cooling, myricyl alcohol separates
out, and is purified by recrystallization.

Myricyl alcohol is a crystalline silky mass, melting at So**, and
solidifying as a fibrous crystalline mass on cooling. It is scarcely
soluble in cold ethyl alcohol.

Melissyl Chloride, Cg^Hg^Cl, is formed by heating the alcohol
with phosphorus pentachloride, when the ether separates out
as a waxlike mass, melting at 64'*'5.

Melissyl Iodide, CjoHgil, is obtained by the action of iodine
and phosphorus on fused melissyl alcohol. It separates out
from alcohol in the form of crystalline grains, melting at 67^
When heated in a current of ammonia to 120'' a mixture of the
primary, secondary, and tertiary bases is obtained, which have
not as yet been obtained pure.

Melissyl Hydrosidphide, Cj^^H^^SH, is formed by boiling the
chloride with alcohol and potassium sulphide. It is a yellow
amorphous powder, without taste or smell, and melting at 94 5"*.

Mclissic Acid, CggHgj^COgH, does not occur in nature, but is
obtained as a crystalline mass by heating the alcohol with
potash-lime to 220° as long as hydrogen is evolved (Brodie,
Pieverling). It crystallizes from alcohol in small, fine, silky
needles, which melt at 88°'5. Its alcoholic solution has a
faintly acid reaction.

Potassium Melisscite, Cg^Hg^OjK, crystallizes from alcohol in
glistening needles, and dissolves in about 20 parts of water,
forming a turbid, gummy liquid, from which the acid salt is
precipitated on addition of an excess of water.

Lead Melissate, (02Q^so0.^^h, is formed as an amorphous pre-
cipitate, but crystallizes from boiling toluol in glistening needles.

Fthyl Melissate, C^HfJ^/C^S^), is obtained by boiling the
silver salt with ethyl iodide. It is easily soluble in alcohol
and ether, and is a waxlike, odourless mass, melting at 73°.

442 TJieobromic Acid,CQ^}l^^.C02fi, is found, together with
other acids, in cocoa-butter. It crystallizes from alcohol in

^ Maskelj-ne, Journ, Chcm, Soc, [2], vii. 87 ; Pieverling, Licb, Ann. clxxsiii.
344.

OF THE FATTY ACIDS.

685

latter can be separated by a repetition of the method of partial
neutralization, and the valerianic acid can be removed by distil-
lation. By a repetition of these operations a mixture of two,
or even more, of these volatile fatty acids can be completely
separated from one another.

In the oxidation of the ketones which contain methyl, acetic
acid is formed together with another fatty acid. If the dilute
aqueous solution be distilled, the latter acid passes over first,
the acetic acid remaining almost completely in the residue. By
a repetition of this operation it is also possible to separate these
acids completely from one another.^

The solid fatty acids can be separated by the method oi frac-
tional precipitation proposed by Heintz.^ An alcoholic solution
of acetate of barium, magnesium, or lead is added to the alcoholic
solution of the acids, when the fatty acid richest in carbon is
first precipitated, care being taken that the precipitant is added
in quantity sufficient only to throw down a small portion of the
acids present. The filtrate is then treated in a similar way, and
the various precipitates thus obtained are decomposed by hydro-
chloric acid. The acids thus separated out are again treated in
a similar way, until a pure compound is obtained, this being
ascertained by the melting-point. If the melting-points of the
different finctions are found to be identical, and correspond with
that observed in the previous partial precipitation, it may be
concluded that the pure acid has been obtained, especially if
the point of solidification is identical with the melting-point, for,
in the case of a mixture, the melting-point and point of solidi-
fication do not fall together, the first being generally lower than
that of the more easily fusible constituent. Besides, the texture
of the mixture is a totally different one from that of the pure
acid. The following examples illustrate this :

Mixture of

stearic «,

Palmitic

Acid.

100

Point of

Texture on

M.P,

Solidification.

69°-2

69*°2

Crystalline scales.

65°-3

60°-3

Fine needles.

60°-3

56°-5

Non-crystalline.

oQ''-5

64°-3

Large plates.

So"!

54°-0

Non-crystalline.

57°-5

53°-8

Ill-defined needles.

62°0

Scales.

1 Schorlemmer, Phil, Trans. 1872, i. 121.

*** Jaurn, FrakL C/icm. Ixvi. 1 ; Pogg, Ann, xcii. 588.

OF THE FATTY ACIDS.

087

It was formerly believed that the melting-point in this series
also regularly rose with the increase of molecular weight ; but
Baeyer ^ has shown that this takes place in an irregular manner,
inasmuch as an acid with an uneven number of carbon atoms
always possesses a lower melting-point than the preceding
member of the series containing an even number of carbon
atoms. The following table is arranged to show this periodic
increase and diminution of melting-point

GSnanthylic acid,
Caprylic acid,
Pelargonic acid,
Capric acid,
Hendecatoic acid,
Laurie acid,
Tridecatoic acid,
Myristic acid,
Pentadecatoic acid.
Palmitic acid,
Margaric acid,
Stearic acid,
Nondecatoic acid,
Arachidic acid,
MeduUic acid,
Behenic acid,
Lignoceric acid,
Hyajnasic acid,
Cerotic acid,
Melissic acid,
Schalfejew's acid,

CyHigOj

C14H28O2
C15H30O2
C10H32O2

^'20^40^2

C22H44O2

^25^60^2
C27H64O2

^84^68^2

- 10'-5
+ Wo

ir-o

SO'O
28°-5
43''-3

si-o

62'0
69°-9
69°-9
66°-2
75»0
72°-5

80°-5

7r-5
oro

Wc have already seen that most of these acids occur in nature,
especially those which contain an even number of carbon atoms
in the molecule. !Many are found in the free state, although the
larger number occur as ethers of the various alcohols, especially
as those of glycerin, CjH5(0H)j. The fats and oils occurring in
the vegetable and animal kingdom usually consist of mixtures
of the normal ethers of this alcohol, and, together with the
fatty acids, they also usually contain acids of the series
CnHj^-jOj, and especisUly oleic acid, CjgHj^Oj.

* Ser. Deuftch. Chem. Ocs. x. 1286.

HISTORY OP SOAP-MAKING. C89

second century, and ascribed to Gebcr, we find the statement
that soap was prepared from various kinds of tallow with potash-
lye and lime. German soap is described as the best and most
fatty ; and then came the Gallic. It is stated that soap is used
as a medicine, and that by means of it all dirt could be removed
from the body and clothes. That the German soap was softer
depended, of course, upon the fact that it was prepared from
wood-ashes containing potash, whereas the French soap was
made from the ashes of sea-plants containing soda.

It was only, however, by slow degrees that soap came into
general use as a cleansing agent. In place of soap potash-lyes
were frequently used, the ancients cleansing in this way not
only their wine and oil casks, but also the marble statues of
tlieir gods. Natural carbonate of soda and the ashes of sea-
plants were also used for this puq)ose, but the cheapest
material used as a cleansing agent was imtrid urine. The
fullers in Rome were obliged to live beyond the walls, or in
districts removed from the fashionable portion of the city, in
consequence of the disagreeable nature of their trade.

That the Romans, at least in later times, employed soap is
rendered certain by the discovery at Pompeii of a complete
soap-boiling establishment, together with some soap in a perfect
stAte of preservation.

Certain jJants were employed for washing, such as the
Saponaria, Gypsophila, <S:c., in early days, and are used even at
present in certain localities. The juice of these plants forms a
kind of soap-like lather with water, produced by the saponin
which is contained in the substance.

Little is known concerning the soap industry up to the seven-
teenth century. The use of soap had then become pretty general,
and its manufacture has increased from year to year. It received
an important impetus from ChevreuVs discovery of the decom-
position of the fats, and from Leblanc's discovery of the artificial
preparation of soda on the large scale.

In former days soap was prepared in northern countries
entirely from tallow, whilst in other places olive-oil was em-
ployed. When, however, soap came to be used not merely for
washing purposes, but was needed in very large quantities in
many industries, such as in bleaching and calico-printing, it was
necessary to seek for other sources of the fatty acids, and these
were found in cocoa-nut oil, palm-oil, and other vegetable
fats and oils.

VOL. III. Y Y

MANUFACTURE OF SQAP. 691

becomes saponified, after which the soap is separated by the
addition of common salt. In France, Spain, and England, the
kelp was frequently used in place of wood-ashes.

In the year 1823 artificial soda was first employed in the
making of soap. The alkali was manufactureil from common salt
on the large scale in England according to Leblanc's process by
James Muspratt. The Lancashire soap-boilers were long before
they would believe that this artificial soda could replace that to
which they had so long been accustomed, and Muspratt had to
give away his soda by scores of tons in order to convince them
that by using his purer article both time and labour were spared.
After a time, however, the tide turned, and so great was the
demand for the new and purer soda, that it was packed off
to the soaperies in iron waggons whilst still hot from the
furnace.

Up to within a recent period soap-boilers made their own
caustic lye from soda- ash. At present, however, caustic soda
prepared in the alkali-works is almost entirely used for the pre-
paration of soap. The process employed in the manufacture of
soap depends greatly on the character of the fat and the nature
of the soap which has to be prepared. When a fat is boiled
with caustic alkali and the whole well mixed together, an
emulsion is formed when a certain degree of concentration is
reached. If common salt be then added to this, the soap
separates out as a liquid layer, solidifying to a granular or
imperfect soap, whilst glycerin and the alkali salts, termed the
spent lyes, remain in solution. This imperfectly-made soap is then
boiled with water or weak alkali, when the contents of the pan
are brought into a state of homogeneous mixture called the
close-state. In this process the soap takes up more water, and,
on addition of common salt, it separates out as card fizap.

After the spent lyes have been removed from under the curd
soap, it is boiled again with an excess of caustic soda solution to
insure perfect saponification. The soap is now allowed to settle
for about twelve hours. The excess of soda solution is removed
and the curd soap is boiled with a small proportion of water till
the whole is " close " and homogeneous. This process is called
"fitting." After this the pan of soap is left at rest for two or
three days, during which time an impure and dark-coloured
soap (called " nigre ") separates out at the bottom, and a light
and frothy portion (termed the "fob") rises to the top. The pure
(or upper soap) is removed into forms (frames), cooled and cut

Y Y 2

SOIjT soaps. 093

is much more soluble in salt-water than the other soaps, and
it is therefore used on board ship, and receives the name of
marine soap. This soap is very similar to cador-oil soap^ which
is hard but very brittle.

Ecsin Soaps. The resin left behind in the distillation of
tuq^entine contains a number of compounds having acid
jjroperties, and these when heated with alkalis form resin soaps.
These are usually mixed with fatty soaps, and are commonly
employed in soap used for bleaching.

Silicate Soap is prepared by stirring up a solution of silicate
of soda or soluble glass with the liquid soap in the forms before
solidification sets in. The addition of silicate of soda greatly
lessens the price of the soap without diminishing, at any rate
in the same ratio, its detergent properties, as silicate of soda,
like the fatty acid, holds the alkali in a feeble state of
combination.

449 Srft Soaps are obtained by the saponification of a cheap
oil or fat with caustic potash, oleic acid or fish oil being usually
employed. Soft soap forms a thick transparent emulsion, which
is more or less darkly coloured. It contains an excess of alkali,
and also all the glycerin which is contained in the fat. The soft
soap obtained from Belgium and Germany is green, and as this
green soap is in many places in demand, common brown soft-
soaps are frequently coloured with indigo. Soft soaps made from
clear fish-oil are also commonly coloured brown artificially.
Soft soap is chiefly used for fiiUing, and for scouring, and in
the cleaning of woollen goods and wooden vessels; it is also
employed in linen-bleaching works.

Lead Soap. If oxide of lead be employed for the saponifica-
tion of fats, a mixture of the lead salts of the fatty acids is
obtiiined, and this is used in phannacy, and serves as diachylon
plaster. Such a preparation has been known f »r a long time.
The ordinary lead-plaster, which is obtained by boiling olive-oil
witli litharge, was said to be discovered by the Roman phy-
sician Menecrates, in the middle of the first century. It was
likewise known to Pliny, who writes as follows : '• Moli/hdama
coda cum oho, jccinoris colorevi trahit. . . . Usiis in liparas, ad
hnienda rcfrigerandaque hulccra ; evqjlast risque quca non alH-
gantur. Composito ejus est lihris trilus^et cera^ libra unas old
trihas hi minis.*^

Tlie i)urifyin<j: action of soap depends upju tlic fact that it
is deconip>yed by a large quantity of water into free alkali and

694

COMPOSITION OF VARIOUS SOAPa

an insoluble acid salt. The first of these takes away the fatty
dirt on washing, and the latter forms the soap lather, which
envelops the greasy matter and thus tends to remove it.

A solution of soap in dilute alcohol is used for the determina-
tion of the liardness of water (Vol. 1. p. 250), as when the
whole of the salts of calcium and magnesium are precipitated
a permanent lather is obtained, and this point can be readily
ascertained.

Soap is also employed in medicine, both internally and
externally. As an internal medicine it should be prepared
from the best olive-oil and pure caustic soda* It acts like
a mild alkali, and is sometimes mixed with other medicines in
the form of pills. Soap- water, which can readily be prepareil,
acts as an excellent antidote in the case of poisoning with tlie
stronger acids.

Externally it is use^l in many forms of skin diseases, soft soap
being most firequently used for this purpose.

The soaps which occur in commerce vary very much in
their composition, as is showti in the following table :

I. Hard Soaps—

Old mottled soap

New tallow soap

Marseillefl soap

Palm-oil 80;ip, vellow

Do. bleached

Tallow soap

Cocoa-nut oil soap (mariDe

soap)

Palm-oil soap

II. S<>FT SiV\rs—
Common soft ft>ap...
Ix>ndon do.
Belgian gn»on »**^

Fatty
Adds.

Potash,
K,0.

Soda.
Sa,a

Water.

Sslt Slid
other sd-
niixtures.

81-26
61 0
67 0
65*2
61-2
42*8

22*0
49-6

its

1-77 I 8-M

— ! 8-4

— ! 7-8

— 9*8

— 9-7

— i S-S

— 4-5

— S-0

r 0

8*43
28 8
21-2
19-9
24-8
S91

73-5
35*4

48 0
46-5
5:0

2 3
4 0
11
1-3

4c*^*«/<^«**^'i^^''*^*^^^^^' '*• Vxu^ll known soap manufiMMuior,
,h,7Uk^ Air. Wiu. Uv^-^-vv^c ^luvv-. iliat in 1852, when the excise
,|mv oa soap was UxukIU ^k^U.^sI. (he totil production of »iVii>
itt Great Bntaui ssh. l.ii^K* Iouk jkt week, less than one-balf
of which wa^j pnHluvHHl ia the Lancashire district He abo

STATISTICS OF THE BUITISH SOAP TRADE. 695

concludes that the production in Lancashire in 1870 is fully equal
to the total production in the year 1852, and that hence during
the eighteen years the production of British soap ^as doubled.
From information furnished us by his son, Air. Frederick H.
Gossage, we learn that the British make at the present time
(1881) has reached the enormoujs amount of 4,500 tons
per week, or taking fifty weeks to the year 225,000 tons per
annum.

INDEX.

INDEX TO VOL. III.

Abel ; fla^hing-point of petroleum, l46
Abeljanz ; substitution products of ether,
S38

Absolute alcohol, 397
Acetaldehyde, 47S ; preparation, 475 ;
properties, 477

Acetates, or the salts and ethers of acetic
aci<l, 496

Acetdiamine, 520

Acetic acid, 12, 483

Acetic acid, constitution of, 115

Acetic acid, ethers of, 507

Acetic aciil, pure, 491 ; properties, 494 ;
acetates, 496

Acetic acid, reactions of, 506

Acetic acid) substitution products, 533

Acetic add and trichloracetic acid, re-
semblance of, according to Dumas, 17 s
dissimilarity between^ according to
Berzelius, ib.

Acetic anhydride, 511

Acetone, or dimethyl ketone, 568

Acetone bases, 574

Acetone condensation products, 573

Acetonitril and its derivatives, 521

Acetyl anhydride, 5<.^

Acetyl bromide, 515

Acetyl carbamide, 520

Acetyl chloride. 13, 513

Acetyl comjx>unds, 473

Acetyl cvanide, 520

Acetyl dioxide, 512

Acetyl disulphide, 517

Ace^l iodide, 515

Acetyl oxide, 509; properties, 511

Acetyl peroxide, 512

Acetyl sulphide, 516

Acetyl thiocyanate, 521

Acetyl urea, 520

Acid cetyl sulphate, 674

Acid ethyl pyrophosphite, 363

Acid potassium acetate, 497

Acide soonique, 485

Acidum radicale, 484

Acids, molecular formube of, 105

Acids, Tegetable, discovered by Scheelc,6

Aetiye amyl alcohol, 609

Acthe valeric acid, 622

; flvrt distillating apparatus, 389

Adipic acid series, 37

Adulterated wine, 316 ; liquor, 319

uEtheran phosphoratux, 335

Alcarsin, 237

Alchemy, 4

Alcohol ; history of its preparation, 285 ;
derivation of the word, ib.\ manufacture
of, 286 ; grain spirit, 287 ; mashing, ib.\
rectification of spirit, 289 ; apparatus
for rectifying spirit, 290 ; Pistonus still,
291 ; Ck)ffey's stUl, 293 ; the French
column apparatus, 295 ; its occurrence,
.296 ; preparation of absolute, 297 ;
properties of, 299

Alcohol nomenclature, Kolbe, 171

Alcohol radicals, see Monad alcohol radi-
cals.

Alcohol radicals, isolation of, 19

Alcohoktes, 321

Alcoholometry ; processes of, 301 ; pow*
der^ and oil- tests, ib.; proof -spirit,
i^. ; hydrometers, 303; Sykes*s hy*
drometer, 305; tables for calculating
the real strength of alcohol by the ap^
parent strength observed with a glass
alcoholometer, 306, 307 ; determination
of alcohol in beer and wines, 308 ; the
ebullioscope, 309, 311 ; the vaporimet^,
313 ; the dilatometer, 314 ; percentage
table of alcohol contained in various
wines and other fermented liquors,
ib. ; uses of alcohol in the arts, 316 ;
methylated spirit, 317 ; detection of
alcohol, 318 ; decompositions of alcohol,
320

Alcohols and their derivatives, 169;
primary alcohols and fatty acids, ib. ;
aldehydes, 172; haloid compounds of
the acid radicals, 173; anhydrides or
oxides of the acid radicals, 176 ; thio-
compounds of the acid radicals, ib.\
amides, 177; substitution products of
the fatty acids, 178 ; synthesis of the
primary, 179 ; secondary alcohols and
ketones, 182 ; constitution of secondary
alcohols, 185; tertiary alcohols, 186;
oxidation of tertiary alcohols, 187
Aldehydes, 13, 172, 473; preparation,

475; properties. 477
Aldehyde-resin, 481
Alexandrians ; distillation, 28^

700

INDEX.

Alexejeff ; zinc cthide, 457

AlfreUm petroleam spring, 143

AUophanates, 165

Alosa menhaden, oil of the finh, 140

Aluminium acetates, 504

Aluminium-i'thyl, 405

Aluminium-ethyl iodide, 406

Aluminium ethylate, 323

Alumininm isobutyl, 585

Aluminium-methyl, 252

Aluminium propyl, 555

American oil wells, 144

American petroleum, 132

Amidacetic acid, 28, 29

Amides, 177

Amines, primary, secondary, tertiary,
160 ; isomerism amongst, 101

Ammonia, formation of, 65

Ammonia (compound), molecular for^
mula of, 109

Ammonias (compound) or amines, 23,
159

Ammonio-boric ethide, 449

Ammonium acetates, 498

Ammonium diacetate, 499

Ammonium ethyl sulphate, 353

Ammonium ethyl sulphouate, 396

Ammonium formate, 274

Ammonium fulminuratc, 5S1

Ammonium sesquiacetate, 499

Ammonium silver fulminate, 526

Ammonium trichloracetate, 542

Ammonium xanthate, 390

a-Amyl acetate, 609

Amyl acetate, 613

Amyl alcohols, 606; inactive, 608; ac-
tive, 609

Amyl antimony compounds, 615

Amyl borate, 612

Amy] bromide. 612

a-Amyl bromiae, 609

Amyl butyrate, 613

Amyl-capryl ether, 653

Amyl carbamine, 614

Amyl carbimide, 614

Amyl carbonate, 612

ft-Amyl chloride, 609, 612

Amyl compoimds, 61 1

o-Amyl compounds, 609

/9-Amyl compounds, 611

Amyl ethers, 611

Amyl ethers of inorganic acids, 612

Amyl ethers of the fatty acids, 613

Amyl formate. 613

Amyl haloid ethers, 612

Amyl hydrosulphide, 613

Amyl iodide, 612

Amyl metallic compounds, 615

Amyl nitrate, 612

Amyl nitrite, 612

Amyl nitrogen compounds, 614

Amyl oxide, 611

Amyl phosphite, 612

Amyl phosphoric adds, 612

Amyl phosphorus compounds, 614

Amyl propionate, 613

Amyl silicate, 612

Amyl sulphioe, 613
. Amyl folphHe, 612

Amyl sulphur compounds, 613

Amyl telluride, 614

Amyl thiocarbimide, 614

Amyl thiocyanate, 614

Amyl-tin hydroxide, 615

Amyl-tin iodide, 615

Amyl valerate, 620

cT'Amyl valerate, 609

a-Amylamine, 609

Amylamine, 614

Amylphosphine, 614

Analysis, methods of: Lavoisier'a, 40;
Saussure's, 43 ; Th^nard's, BerthoUet'a,
Gay-Lussac and Th^nard**, t^. ; Berse-
lins*s, 45 ; liebig's, 48 ; Kopfer's, 62

Ancients, chemical facts known to the^ 3 ;
first attempts at distillatioa, t^. ; prepa-
ration of salts, ib» ; manufacture of aoap
known to the, ib, ; their aoquaintance
with resins, colouring matters, &c., H. ;

Separation of wine, ih. ; preparatioti of
cr from malted grain, ib. ; grouping
of chemical compounds, 4; art of
brewing, 282
Anderson ; methylamine, S19
Antiromeda lesckenaultiif oil from, 195
Angelica archantjelicaj valeric acid in,

618
Anhydrides or oxides of the add radicals,

176
Anhydrous alcohol, 297
Anhydrous ethyl sulphuric acid, 352
Anhydrous formic acid, 272
Anilme, 18

Anquillula aceti (vinegar eel), 490
Anthemis nobiliSf isobutyl ether from

599
Anthriscus cerefolium, oil from seed of,

195; alcohol in, 297
Antimony compounds of eth}'!, 443
Antimony-diamyl, 615
Antimony pentamethyl, 244
Antimony-triamyl, 615
Ants, acid emitted by, 209
Aqua ardens, 285
Aqua vita, 285
Aqua vitis, 285

Arabians inventors of the retort, 283
Arachidic add, 680
Arendt and Knop; bulb-apparatus in

estimation of nitrogen, 66
Aristotle ; distillation, 282
Arnica montana, trimethylaminc in, 221 ;
isobutyric add from, 599; caprylic
acid from, 656
Aromatic group of carbon eompounds,

129
Aromatic vinegar, 495
Arouheim ; acetic add, 512
Arsen-ilimethyl, 235
Arsenates, 367

Arsenic compounds of ethyl, 440
Arsenic compounds of meUiTl, 234
Arsenic ethyl phosphate, 364
Arsenic xanthate, 9M)
Arsenites, 366
Arsonmonoethylic add,
Athamantia wrtif$flinwM^
618

-• 1

INDEX.

701

Atoms of carbon, 34

Atoms, law of the linking of, 112

Atomic weight of carlx>n and other

elements in early times, 32
Aurin, molecular formula of, 111
Aurin, percentage composition of, 81
Azonium iodides, 162

Babo ; gas-furnace, 54

Baeyer ; methylchloride, 202 ; arsen-mo-
nomethyl compounds, 235 ; di-iodomc-
thane^ 259 ; mesityl oxide, 573

Baku oil springs, 143; sacred fire of,
102

Balard ; amyl alcohols, 607 ; isocaproyl
nitrol, 637

Balbiano ; alcohol, 609

Bardy and Bordet ; methyl formate, 276

Barium caprate, 664

Barium caproate, 635

Barium dimethylH^hyl acetate, 638

Barium ethyl phosphate, 364

Barium ethyl phosphite, 362

Barium ethyl sulp)iat«, 353

Barium ethyl sulphonate, 396

Barium ethylate, 322

Barium formate, 275

Barium heptoate, 649

Barium isocaproate, 636

Barium methme trisulphonate, 265

Barium methyl sulphate, 208

Barium methyl sulphonate, 216

Barium monochloracetate, 535

Barium nonoate, 660

Barium octoate, 657

Barium trimethylacetate, 624

Barium valcrrate, 620

Bases, molecular formulae of, lOS; caf-
feine, ib. ; compoimd ammonia, 109

Basic copper acetate, 503

Basic lead acetate, 501

Basse's hyrlrochloric ether, 343

Bathgate oil mills, 144

Baume*s Dissertation sur VtiheTf 326

Beaimi^ ; ethylchloridc, 343

B^hamp; occurrence of t-thyl alcohol,

297

Becher, organic researches, 5; acetone,
568

Beckurts ; propionic acid, 558

Beer from malted grain, prepared by the
Egyptians, Gauls, and Gc;rmans, 3 ; de-
termination of alcohol in, 308; table
giving percentage of alcohol in, 314

Beetroot sugar mdustry and methyl
alcohol, 196

Beheuic acid, 680

Behrend; formamide, 277

Beilflt(?in ; riiic ethide, 457 ; ethyl iodide,

347
Belohoubek ; methyl propyl carbinol,

6)4

Beniine, 146

Bemok acid, molecular formula of, 106
BaiiMie add, vapour density of, 99. 102
U

Bergmann ; organic researches, 6 ; alcohol

test, 301
Berthelot; polyvalent radicals, 27;
parafiin, 138 ; distillation of mixtures,
153 ; properties of marsh gas, 190 ;
methyl chlori<le, 202; methylamine,
218; spirit from coal gas, 296; ethcr-
ification, 330; sodium acetate, 498;
mercury fulminate, 528 ; propane, 548 ;
isopropyl alcohol, 563

BerthoIlet*8 method of analysis, 43;
properties of marsh gas, 190; adde
zoonique, 485

Bertoni ; ethyl nitrate, 360

Beryllium ethide, 455

Beryllium propyl, 554

Berr^lius; investigations of, 8; the
name »therin given to olefiant gas,
11; radical theory, 12; benzoyl, (7/.;
chemical constitution of organic com-
pounds, 13 ; theory of substitutions,
15 ; dissimilarity between acetic and
trichloracetic acids, 17 ; the copula^ 18 ;
radicals containing oxygen, 19 ; copu-
lated compoimds, 29 ; method of analy-
sis, 45 ; rational formulae, 112 ; racemic
acid and tartaric acid have same com-
position, 120; isomers, 121; isomerism,
th. ; gases, 191 ; wood - spirit, 195 ;
etherification, 327; acetic acid, 486;
green verdegris, 503; propionic acid
556

Binney ; peat bog petro eum, 144

Bischoff ; trichloracetone, 571

Bismuth compounds of ethyl, 447

Bismuth mercaptide, 380

Bissel ; American oil wells, 144

Black ; nitric ether, 357

lilagden ; tables giving the composition
of aqueous spirit from the specific
gravity, 301

Iknly, temperature of, effected by alco-
hol, 315

Ik)erhaave ; acetic acid, 484 ; acetone, 568

Boghead cannol, paraffin from, 140;
pentane, 603

Boghead gas coal, 144

}k>Ius and Groves; tctrabrom methane,
258

Bomhyx procefsionea (catiTpillar), at id
found in, 269

Borates of ethyl, 367

Itorates of methyl, 211

Borethyl, 448

Boron compounds of ethyl, 448

Boron diethylethoxide, 448

Boron diethylhydroxide, 449

Boron etho-diethoxide, 449

IU)r(»n ethyl-bydroxethoxide, 449

Kormcthyl, 244

Bonis ; hexyl alcohol, <U1 ; methyl hexyl
carbinol, 651 ; trichloracetone, 571

Boullay; ether, 326, 332, 335; ethyl
chloride, 343 ; ethyl sulphuric acid, 350

Boyle ; organic researches, 6 ; adia-
phorous spirit, 194; distiUation of
spirits of vi iue, 284 ; spirit of wine
and snow, 300 ; ethyl perchloratc, 348 ;
acetic acid, 484 ; acetone, 568

INDEX.

Gaproyi alcohol, 630

Caprovl aldehyde, 635

Capryl acetate, 653

Capryl bromide, 653

Capryl chloride, 653

Capryl iodide, 653

Capryl mustard oil, 653

Capryl nitrate, 653

Capryl sulphide, 053

Capryl sulphuric acid, 6.53

Capryl thiocyanate, 653

Caprylamide, 657

Caprylamine, 653

Cnprylic add, 656

Caprylic anhydride, 657

Caprylonitril, 657

Carbamines, 163

Carbimides, 164

Carbon and hydrogen, determination off
40

Carbon, and other elements; atomic
weight in early days, 32 ; atoms, 34

Carbon, a tetrad element, 113

Carbon compounds, 38 ; classification of
the, 128; fatty group, ib.; contain-
ing relatively less hydrogen than the
foregoing, ih. ; the aromatic group,
129 ; compounds of unknown constitu-
tion, tA. ; methods of classification, ih.

Carbon ; compounds containing three
atoms, 548; four atoms, 576; five
atoms, 602; six atoms, 625; seven
atoms, 639; eight atoms, 650; nine
atoms, 658 ; ten atoms, 662 ; eleven
atoms, 666; twelve atoms, 667; thir-
teen atoms, 669 ; fourteen atoms, ih. ;
fifteen atoms, 670 ; sixteen atoms, 671 ;
seventeen atoms, 677 ; eighteen atoms,
678

Carbon; fatty acids containing from
nineteen to twenty-four atoms of, 680

Carbon dioxide discovered by Lavoisier, 6

Carbon monoxide, 36

Carbon tetrachloride, 257, 487

Carbon tetra-io<lide, 261

Carbonates, derivatives of marsh ga5), 36

Carbonates of methyl, 211

Carbonate of methylamine, 220

Carbonate of potash, production in
French distilleries, 196

Carbonyl amines. 164

Carius; determination of chlorine, 76;
determination of sulphur, 78; deter-
mination of phosphorus, 79; methyl
benzoate, 197 ; ethyl methyl sulphide,
381 ; triethylphosphine oxide, 435

Carlet ; hexyl alcohol, 641

Carleton- Williams ; tetramethyl butane,
654

Castor oil soap, 693

Ceroticacid,682

Ceryl alcohol, 681

Ceryl palmitate, 682

Cetyl aceUtc, 674

Cetyl alcohol, 672

Ceiyl bromide, 674

Ce^l chloride, 674

Cetyl hydrosulphide, 674

Cetyl iodide, 674

Cetyl oxide, 673

Cetyl oxv-dithio-carbonic acid, 674

Cetyl palmitate, 677

Cetyl sulphide, 074

Cetylacetic acid, 680

Champion ; ethyl nitrate, 360

Chancel; primary propyl alcohol, 548;
propyl oxide, 551 ; acetone, 569 ; di-
propyl ketone, 642

Chapman ; ethyl nitrate, 360 ; zinc ethide,
458

Chemical compounds, ancient grouping
of, 4

Chemical constitution, Laurent's theory
of, 16

Chemical types, Dumas^s theory of, 16

Chenevix ; acetone, 568

Chenopodium vulvarioy trimethylamine in,
221

Chevrcul ; butyric acid, 591 ; isopentoic
acid, 618 ; caproic acid, 634 ; dipropyl
ketone, 642 ; caprylic acid, 656 ; capric
acid, 664 ; ethal, 673 ; margarin, 675

Clievrier ; ethyl monotbioposphate 388

Chinese wax, 681

Chiozza ; acetone, 569 ; octoyl oxide, 657

Chloracetic acid, 29

Chloral hydrate, 539

Chloraldid. 538

Chloral, 537

Chloraniline, 18

Chlordibromuitromethane, 263

Chloride of diethylphosphoric acid, 365

Chloride of ethyl phosphoric acid, 364

Chloride of ethyl phosphorous acid, 363

Chlorinated anilines, 18.

Chlorine, bromine, and iodine, deter-
mination of, 75 ; Carius's method 76

Chlorine substitution products of ether,
338 ; monochlorethyl oxide or mono-
chlorether, ih.; Dichlorethyl oxide,
339; trichor-ethyl oxide, ib.; tetra^
chlor-ethyl oxide, 340 ; pentachlorethyl
oxide, ih. ; perchlorinated ether, 341 ;
methyl-ethyl-ether, ib.

Chlorine substitution products, 533

Ch lor iodoform, 261

Chlomitromcthane, 261

Chloroform, 13, 26, 254 ; vapour density
of, 102

Chromic salt, 390

Circular polarization, 127

Claesson ; ethyl sulphuric acid, 351 ;
anhydrous ethyl sulphuric acid, 352;
ethyl chlorsulphonate, 355

Classification of chemical compounds, 4

Classification of carbon compoimds, see
Carbon compounds.

Clermont ; trichloracetic acid, 541

Cloez ; ethyl cyanate, 414 ; trichloracetic
acid, 541 ; trichloracetamide, 543

Coal gas, methane in, 192

Cocoa-nut-oil soap, 692

Coffey : still, 291, 293

Colin : hydrochloric ether a compound
of hydrochloric acid with olefiant gas,
10 ; acetone, 194; ethyl chloride, 343

Combustion of bodies containing sul-
phur, 59

r{V4

INDEX.

Combitftioo of nitrogctioas sabstaooes,
58 ; vae of lead chromste in, 59

Combostion in a current of oxygen, 55

Compound ethers, 6S4

OMnpountl rsidicads, 11 ; definition of the
term, 14

Coiupoiin>U containing three atoms of
cariwn or the propyl gronp, 543 ; four
atoms of carbon or the butyl group,
576; fire atoms of carbon at the
pentyl group, 9DS ; six atoms of carbon,
0^:' seven atmns of carbon cr the
heptyl group, 639; eight atoms of
camn or the octyl group, 65<) ; nine
atoms of carbon or the nonyl group,
tf5S: tiiii atoms of carbon or the
decatyl group, 0dS: eleven atoms of
carbon or the hendecatyl group, 665;
twelve atoms of carbon or the dode-
catyl group, 667 ; thirteen atoms of
caHk.«n or tbe triilecatyl group, 669;
fourteen atoms of carbon or the te-
tnM^levatyl group, lA. ; fifteen atmns of
carbon or the pentadecatyl group, 670 ;
wventeen atoms of carbon, 677 ;
eighteen atoms of carbon, 67S

Compounds of ethyl and selenium, 397 :
ethyl hydnjselenide, t6. ; ethyl se-
knide, ;S^ : triethyl seleniodide, 399 ;
etbyl diselenide, t^.

Com^iiMuids of ethyl and tellurium, 399 ;
ethrl telluride,'iA.; eth^l tellurium
o^^, <liK>: ethyl tellurium nitrate,
f>. ; ethrl tellurium chloride, ih. ;
ethyl tellurium sulphate, 401 ; ethyl
ti-^ruriimi carbonate, ih. : ethyl ditel-
luri^le. iK : triethyl tellurium iodide,
iS.

Oompounils of ethvl with the metals,

4.'yi

Com^H^un^^» of isoprt>pyl with phos-
phorus, .'W57

Com}Hnm«ls of isi>pcopyl with sulphur,
5-M

r«mi{^ninds of methyl with antimony,
rJl;^: trimt'thylstibioe, iV.. ; trimetbyl-
stil'ino o\idt', if:: trimrthylstibonium
iiHlitlt', r7.. ; antimony pentamethyl, 244

l'omi»»nu»iU of methyl with boron, 244 ;
U^nuoiliyl or trimt*thylborine, i6.

('om)HMuurs of mt'thyl with silicon, 245 ;
siluNMi-mothyl. f''.

I '.>m)iimiids of*lea«l with ethvl. 4<W

C.^iij^nuuN of tin isith rthyl 4<ft>

I'oni^touutN of th«* monadalc >hol ladicals,
ft ( \Um:i<i iiKn>h«)l railii'alrt.

1\muiku«uU of t«'tniethylan»mnr.:um, 4»>8

ri»mvntrattM a«vtio acitl, 491

rondon>ation-pnHluct!» of a'.ntone, ^1*2

Conine cvanide, 5«W

Const it uti.Minl fonnulA\ 114

i'oplMT aivtati'. r»«»2

C«»i»i*«T nvti»nrj«t'nite, ."WM

<'<»pmr format!', :2'h

CopI»»*r fuhninatt', ."tiJO

CopptT hi'ptcatt'. 649

CopptT nicrcaptidi', 370

Copnlat*^! ooni|MmniN, l-J>

Co(iulatod radirals. -jii

Cordus, Valerius ; preparation of etbert
323

Couper ; atoms of carban, 34 ; linking of
atoms, 113

Cottrs de chymie of Nicolas Leroefy, 5

Crafts; tnethylsulphine oxide, 435;
siliooheptyl oxide, 453

Cranston ; normal ethyl carbonate, 370

Crockford ; spirit indicator, 311, 312

Cross ; heptyi alcohol, 641

Crum ; aluminium acetates, 504

Cuprammoniiim fulminurate, 531

Cupric oxide as an oxidiaog agent. 4*^

Curd soap, 691

Cyanacetic acid, 547

Cyanethine, 562

Cyanides of the alcohol radicals, 163 .

Cyanides, derivatives of marsh gas, 3«l

Cyanmethine, 523

Cyanogen discovere<l by Gay-Lussac, 9

Cyanogen oompounib, 33, 580

Cyanogen compounds of ethyl, 413;
ethyl carbamme, ih.; ethyl cyauate.
414; diethyl amidocyanurate, 415;
ethyl diamidocyanurate, i6. ; ethyl
isocyanate or ethyl carbimi<le, th.;
ethyl isocyan urate, ib.; diethyl-iso-
cyanuric aad, 416 ; ethyl ferrocyanide,
ib. ; ethyl platinocyanide, ih. ; ethyl
cyanamidc, 417 ; ethyl thiocyanate.
r^. ; ethyl thiocarbimide, 418

Cyanogen compounds of methyl, 224;
methyl carbamine, ib. ; methyl
cyanate, 225; methyl isocyanate or
methvl carbimide, ib. ; trimethyl
tricarbimide, 226 ; methyl thiocyanate,
r6. ; methyl thiocarbimide or methyl
mustard oil, 227

Cymogene, 146

Dabit ; ethyl sulphuric add, 350 ; ether,
474

Dalton ; isomerism, 119 ; gases, 191

Davy ; gases, 191 ; fulminate's. 529

Dean ; ethyl diselenide, 299 ; methyl m -
Icnide, 216

Debus; determination of sulphur, 7H;
methylamioe, 218; ethyl trithiocar-
bonate, 388 ; xanthic disulphide, 391

Decatoic adds, 66t

DtH^atyl group, 662

Decomposition of alcohol, 320

Definitions of organic chemistry, 'M
ft Sfg.

Dehn : tnethylsulphine compoimds, 382

De Liivnes : butyl alcohol, 576 ; methyl-
ethyl carbinol, 581

Delffs ; oenanthic ether, 665

Iklphinw* glohictp$ ; isopentoic add from.
618 ; D.phoccPMa^ isopentoic aci«l from.
I*.

Derivatives of methyl, 253: dii*hlnr-
mrthanr or methylene dirhloride, »/«. :
trichlorroethane or chloruform, 254 :
tetrachlorm thane or carbon teUra-
chloride, ar>7 : dibntmmethane or

in'i>p:x.

7<V

.'>

niothene ilibromidi'f ///. : trihroiu-
methanu or bromofonii, //*; tetra-
broniiiR'thani' or carlx)!! tctrabroinid',
2')^ ; <li>i()ilomettmiio or nuitliylrmi «li-
iudidc, ifi.; tri-ioilomcthane or io<lo-
foriQ, 259 ; chloriotloform, 2(il ; t^^tra-
io<ioin('tiianu or carhjii tt-tra-iotliiU',
ib. ; chl- ruitromethauo, ift. ; triclilor-
iiitromethane, iiitruc'hlorof(»rm, or chlo-
ropieriii, ih. ; (liclilonlinitronietliaiio.
2(J2 ; luonobroinnitrometliaiio, 2(53 ; tli-
bromnitrjuK^thunc, ///. ; tribromiiitrf)-
Dietliane or broniopicrin, ib. ; chlonli-
broiniiitromethaiic, ih.; trinitrouu'-
tliane or iiitrofornn, i7». ; tt-traiiitro-
in«t!iaii(\ 2)4 ; metheao (lisulphouic
ac*i<l, iff. : iimthino trisulplioiiic add,
20 > ; potassium m<.'thiue trirtulphouatx*,
if}.; methyl -me rcaptan trisulphouij
acid» ih.

Den)sne ; acetone. 50S

Desains ; xauthic disulphidc, 301

DcHiToizelles ; appanituH for determina-
tion of alcohol in beers and wines, 30.S

Detiiction of alcohol. 318

Doutsch ; ethyl orthoformate, 37t5

Deville ; determination of vapom* density,
94

Devillier and Biiisine ; trimethylcne, 222

Diacctamide, 519

Diacetonamine, 574

Diacotone alkamine, 574

Diacetyl carbamide, 52«J

Diamyl, (303

Diamyl ether, Oil

Diamyl ketone or caprom*, 0 »7

a-Diamylamine. (J09

Diamylamine, 014

Diamylphosphine, 014

Diazo-othoxane, 431

Dilxiron ethopentethoxide, 4l!>

Dibromaeetic acid, 544

Dibromacetyl aldehyde, 54 1

Dibromacetyl broniiile, 544

Dibrombutyric acid, 597

Dibrommethane, 257

Dibromnitroethane, 42<5

Dibronmitroroethane, 203

Dibrom-nitro-ucetonitril, 52: >

Dibromnitropropane, 553

Dibrompropionic acid, 5*J0

Dibutyl oxide, 579

Dibutyril, 596

Dicacodyl, 239

Dicetyl ether. 073

Dichloracetaniide, 5!J7

Dichloracetic aci<l, 530

Dichloracetcme, 571

Dichlonlinitromethane. '2ti2

Dicldorethyl format*'. 370

Dirhlor-ethyl oxide, 339

Dichlorethylamine, 4<.>5

Dichlorfomiic ether, 19

Dichiormethane, 253

Dicthylacetic jicitl, (J37

Diethyl anmlocyanurat**. 415

Diethylamine. 4<^

Diethylarsine, 442

Diethyl c^irltamide, 42 )

VOL. III.

Diethyl carbinol, ()«»5

Diethylcurlx>xydisulpl;id«-, 392

Di(!thyl carbyl acetate*, (J('5

Diethyl carbyl ddoride. (;'»5

Diethyl carbyl iodide, Cn 5

Di-ethyl conv»Tted by chloriui? into butyl

chloride, 132
Ditthylcyanamide, 47
Di«;tliyl cy.iuamidooarlMmaU*. 374
Diet'iyl-dimethyl methan(>. 014
Diethyl- diHulpho-<lit)xi«le, 3lr5
Di-ethyl ether, 339
Diethyl forutamide, 4r)7
Diethyl guanidine carbauate, 37 1
Diethyl hydrazine, 411
J diethyl hilico-ketone, 451
Diethyl-isocyannric acid, 410
Diethyl ketone. miS
Diethylmethylarsine. 442
Diethylmethylsulphine compounds, 3^3
Diethylmethylsulphine mercuric chloride.

38:

Diethylmethylsulphine platinic chloride

3«3
Diethyl phosphine, 433
Diethyl phosphinic acid, 433
Dietliyl phosj)horic acid, 305
Diethyl -propyl carbinol, ({55
Diethyl 8eniic;»rbazi<le, 421
Diethyls! licon dichloride, 454
Diethylsilictm-iliethylate, 454
Diethyl silicon-diethyl-oxide, 4il
Diethyl Kul hine comixiuuds, 3S2
Diethyl sulphine oxide, 3^2
Diethyl sulphonate. 3f)0
Diethyl sulphone, 382
Diethyl thiocarbamide, 422
Diheptylacetic uc'id. 077
Dihexyl ketone or C£nanthoiit>. (}<i9
Di hydrazines, 1(J2
Di-iodacetic acid, 517
Di-iodoethylamine. 405
Di-io4lomethane, 1:58
Di-i(Klo- nitro-a-etonitril, 529
Di-isobutylamine, 583
Di-isobut ylphosphine. 585
Di-isobutyl ket^^ne, 059
Di-isopropylaniiue, 5(>0
Di-is.ipropyl cirbinol. (}45
Di-isoprojiyl ether, 5(54
Di-isoprnpyl ketone, (545
Di-isopropylphoRphiue, 5(57
Dilatometer, Silbermann's, 314
Dime thy larsenic a"i<l, 241
Dimethylamiue, 22(J ; hydrochloride tif.

221
Dimethyl-ammonium chloride, 221
Dimethylarsine compounds, 237
Dinu^thylarsine oxide, 238
Dimethyl-butyl methane, (543
Dimethyldiethylammonium iodide, 4 9
Dimethyl-ttliyi-ac^tic acitl, 038
Dimethylethylarsine, 442
Dimetbyl-ethy 1-carbinol, 01 0
Dimethyl-heptyl-methane, 002
Dimcthyl-isopropyl carbinol, (5^52
Dimethylphosphine, 229, 231
Dimethyl-propyl carbinol, 0151
Dimethyl-sulphine compounds. 213

Z Z

iiliHtpB "f mi'tliyl, il: : inelliyl arwiiiti;,
(A. : RH-thvl >^M■D*U^ i'>.: bunilc!i of
iiii-tliyl, m'lno-iiM'tbyl burat.-, 311;
mi-tli;'! nrtlumlimtv. i7>. ; rHrbunutM
of idi^IitU ill.; mi'lliyl nrbiiiiiili! iir
iK-thy! ucilliuo'-, tXi- iiu-tlijl alio-

KiCS;

>:> Kiuiule and mixMl cthrn. 15(1;
ki'.1 I'thrn and llii<i-alniliul», Ifti i
Iphiiti^K ortliio-vthtTH, 139 i carbaiuii;

Kthvl
Kthyl
Etl>jl
Rtliyl
Ethyl
Ethyl

EtUjl
Stbyli
Blhyh
Ethyii

Ethyl.
Etlijl-
Ethtli

vUmide.eia

:huhiil ^ .liRtiUaticm, ib.

coho! deriT»tive of i-lliauo,
alcohol OD oliiLiition. 12
septate. fiOT

jJcoliol iu ustare nml iliy <!
in of Drgaaii: fiilmtaiii'i'^ 'Si'i
■llophaoato, 373
tniiiloiDothyl rnclxuioti-. :17:!

uiinoal ithyl nirlxiunU-. i(S: ilhyl
intboi-M-buDut*, -UTl : etJijI cbtarucaT-
bouate, ik. ; ettiyl corlauoatp, il. :
ctbyluDiilometliyl csrboiute, 3'3

EthylcarbotUG dcid, 'iua

Ivtiivl (vu-l-^uyl buiiuiuium cliluride, 41!l

Ethyl . . : . ■; . r 1,7-1

!':tli>'l Us <k-rlvative of Gtbane, 114

Elliyi diluiiJv. 51:>; v^'parntioii, ^MSj

El.'.' ....,n!n.371

KthjJ cLkirsiilvlicmBte.arw

Kthjl coiDpouiidB witli tho metal*. AZ^

Ethyl ryaDsniide.JlT

Ethyl cyanale, i\i

Etliyl. tjaaos'^ (omponDilH uf, 4

Ethylt " -----

Ethyl
Ethyl
EthyJ
Ethyli
Ethyl
Etiiyl
Ethyl
Eihyl
Ethyl
Ethyl
Ethyl
Eihyl
Ethvl
Ethyl ._ , . .

Ethti .iiti I ; . -, i I. 3^a

;Tuictlianluni bydroxiili', aOi
■tucetaiuide, SlU
diamrdocyaanratp, 41*i
diliromacelatr, 544
BDs dibromiiLe, l?ti
itJCBrbotbioDate. 3(13
dichloncetate, 5S7
dicyBtiuniilc, 417
di-iodacetntr, 647
iliQiytbioairboiiktt', 'JUl
ctiwleuule, 399
(liiiiliote, 3(IS
aimluhide, SS6
"■ "liiride,40I

inilphll

itli<>t>hUi

m carlwiiatc, 4M
m (Jiloraurati' 4>>1
a, rhIciHilp 4113
■n clhylthiii-i'atbaniu'

-maniiilo, ViO

matn, 3T5 : dirlilorvlhyl torawtp,

wrcIJoR^lhyl chhirturniatr. ih.;
nrthoforiniitp. .A : rthyl orth..-

■Iif lyl ethrr, 1127
hydranne, 410
hydranne Drr>.431
hydiDCpleni.!?, 307

ElhylaDiioiiuiuiii hylronojphuie, 4tVi \t.fi

EthjIaniiDOtiiuin nitrate. ii^ KtLy!

EthylniDmnniuiii platiuliblori.!.'. 4'^l Ktliyl

Eth^lanilliullioin Bii1|ilintf . 4I» >^lhy1

EthTliimyl rthrr, (11 1 Etl.yl

EtUyUmy uljh Jr.tiia 37'!;

Ethyl arMTuati--, ;HiJ itl.j

Bthyi nnriiitc. IMW hIki

Ethyl ami upUniiim compounds. ;i97 Eihyl

Ethyl an.1 trlli.rium .■i.iii|K>i'iid». 3ffll Ethyl

Ethyl baaeii 4trJ Ethyl-

Eth*)-I>iiimuth cWori.ip. 44T Ethyl

EtlirMHnunth iodhlf. 44» Rthyl

Ethyl-liinnutb Dilmtc. 44S Ethyl

Etby1-Ili^>nluth nxUk-, 447 Ethyl

JM^lmB)»e.»KI •'-thyl

■OijWHrtylta.tone.liS'* EWiyl

Ethyl hntyn.lp..W.1 Ethyl

Ethjl.-a.wlyl. 4-13 Ethyl

Ethyl c«™lylic a.i.l. 413 Ethyl

Ethyl ni|4'n|p. «M Ethyl

Ethyl caiiroBti'. 63S Ethyl

E'hyl-cHirryl ether, 053 Ethyl

Ethyl carbsroidf, 410 Ethyl

Kthvlcarb!WuiM.-.413 Ethyl

Eihyl cnrliainatr-. 371 Ethyl mrtaborate, 3H7

Etliyl rarliinulp. 41.1 Ethyl mcUnlicatr, 309
Ethyl rurhnuatm. 3131 : hydr(.g<'ii i-thyl Ethylinclhyli-lhy1iiul|ili!n(-

inrhimotfi or fthyl i-arbciijc xiil, iK; 'AM

ioillde, 34d
itnlobutyrat*, 5!t7
' ihiityl ahor tM
icniiTDoti 038

INDEX.

700

Kt]iylat<'«l iirtMS. 41i>; rtbyl o:irkiini<l(>,
it>.\ a-(li(!tliyl cjirlMimiilr, 4J0; /S-^li-
ethj'l carbaiiiiile. i/». ; trirthyl car^a-
iiiiilo, ifi. ; tftra'-'thyl carlmmiile, ih.

Ktliyl.itos, ',\±1 ; potassiimi. Rodiiim,
thallium, kiriuin, ziui*, //'. ; alumi-
nium. 323

KthylfUii, 31), 117

KtlivleinMiLoln)!. I'S

Krlivh'iie clilorhvlratr. 28

Kttliug ; normal ethyl curbuuato, 3J1)

Eupioii, 139

I''a<jk.t; hoxyl alcohol, 03<»; primary i«o-
h<>ptyl alcohol, (m

" Faiats " from |X)tjito-»pirit, MO

Fara-lay; isomcriism, 120; spirit from
(*oal-gaM, 2iHi ; iohulation of ether, 337

Fatty a.-icl sirrics from morftli gas hydro-
carlxms, 37

Fatty acifls, molfcular formula; of, 108 :
paraffin obtained from. 137, 139; sub-
stitution products of, 178

Fatty acids and primary alcohols, 1(19 :
8yutheMi» of, 179

Fatty acids containing from nineteen to
twenty-four atoms of carbon, 080 ; non-
dccatoic, arachi<lic, medullir, bchenic,
//'. ; lignoceric. hyjcnasic, G&l

Fatty acids ; general projHjrtics of the,
()>t: separation of, ih. ; partial neutra-
li/zitiou, //'. ; fractional precipitation,
{}<* I boiling point, G8>J ; melting point,
<kS7

Fatty group of carbon compounds, 128

Fehling; paraldehyde, 479; metalde-
hyde, ISO

Kerric a etat*', 5^^') ; xauthate, 390

FtTHJUS iicctate, 5iC>

Filhol : i<»«loform. 2'.9

Fis:-hei' ; azide compounds, 421 : formic
aciil, 2(>!) ; capric aci<l, (i<i5

Fittig; i)rimary propyl alcohol, 549; di-
choracetone, 571 : pelargonic acitl, tSM);
metiiyl-uonyl ketone. (Uid

Fitz : propionic acid. 5>7, ooS; butyric
acid, 593

** Flashing i>oint" of petroleum, 14ij

Formamide. 277

Format«*s, 274: ivitajv^ium, sodium, am-
monium, calcium, ih. ; barium, lead,
copper, silver, mercuric. 275; merru-
r.)U8. nn'thvl, 27«»; methvlorthofor-
mat*'. 277 ; formanude. //•. ; methyl for-
mumido, 278 : reactions of formic acid
and the format s, ih.

l\,nii\?. acid. 12,113,209; Kynlhosis of,
271 ; preparation of anhydrous formi;*
a-id, 272 ; propcTtii'S, 273

Formic acid and the formates, reactions
of. 278

Formic aldihvde. 200

Ft>rn7yl group, 2>h)

FormuI:i.-, cali-ulation of. 83 ; mcdecular.
y-X. 1*13 ti .«(-'/.; empiriiral and rational.
1 12 (/ 51'/. ; e(ui«<titutiiinal, 114

jMUircroy: ether, 326 ; properties of etiier,
334 ; wine-oil and ether, 351

Fractional distillation, 147

Franchimont ; normal ht?ptic acid, 048 ;
normal nonoic acid. &M1

I'Vaukland ; hydrocarbons, 19 ; some acida
conjugate componnds, 30; action of
zinc, 1,*J0 ; chloride of ethyl hytlride,
132; synthetic method, 180; arsen-
dimethyl, 235: ** chemical valency,**
ih. ; zinc-methyl and ethyl, 240 ; mer-
cury-methyl, 250 ; ethane, 279 ; boron
compounds of ethyl, 448; zinc ethyl,
450, 40f.) ; mercury ethidOf 403 ; leail-
tetraethyl, 400 ; acetic ether, 507 ; pro-
pionic acid, 550; cyanethine, 502; bu-
tane, 577 ; butyric ackl, 593 ; isobutyric
acid, 599 ; isopentane, 00({ ; isopentyl
alcohol, 000 ; isobutyl methyl ketone,
031 ; isocaproic acid, 030; diethytacetio
acid, 037 ; isocaproyl nitril, ih. ; tetra-
methyl-hezanc, 0^)3

Frapoli ; monochlorether, 333

Freund ; ketones, 182 : dibutyryl, 500

Freezing-machine, Vincent, 204

Fritlau ; dicetyl ether, 073 ; tricetylamine,
075

Friedi'l : secondary alcohols, 182 ; silico-
heptyl oxide, 453 ; silicon acetate, 512 ;
isopropyl alcohol, 50;^ ; methyl propyl
carhinol. 0(U

Friedel and Crafts; ethyl orthosilicate,
30s ; ethyl metasilicate, 309

Friedlan<ler ; niethyltriethyl stibonium
compounds, 447

Frobt nius. Sigismund Augustus ; ether,
324, 320, 357

Fruit in the mauufa?ture of alcohol, 280

Fuel, alcohol as a, 310

Fulnunat<-s, decompositions of the, 529

Fulminic acid, 524

Fulminuric acid, 530

Fimk ; bored the first flowing oil-well,
144

Furnaces, 53 et .««'/.

Fustd-oil, 148, 288

(1.

Gai. : trihrdmaoetic acid, 545

(iallic s<mp, 0^9

Clamgi-e ; exijeriment* with mercur}'-
niethyl, 251

Cas-burner, ]>unsen*s non-lumiuous, 53

Gas-combustion fmnaces, 53 t^ .-mi.

(i:is-springs, 145

G "S'vs ahsurheil by alcohol, 317

(ianltht ria jn'octnuhi ii:i ; ethi-real oil of,
VXt ; punctntti^ methyl Mdts obtained
from, ih. ; h urruttrjm^ methyl salt*
obtained from, .7*.

( lautier ; propi(»nitril. otJi'i

Gay-Lu«sa^ ; di.scovers cyanogen, 9 ; ex-
periments on weight «)f vapour, 10;
method of analysis, 43; composition
of acido, 59 ; determination of vapour-
density, 87 ; example of methml, 88 :
alcoholomt'tric tables, 302; wine-tester.

INDEX.

phiiie ami di methyl pliosphine, 2'2i) ;
tctraclilorinothanc, 257 ; ohloropicriii,
202; niftliine disulplumic iiciil, 2(U;
formic aUit.'liy<1cs 2(Jt>; foriiiuiindfs
277; ethylamiuc, 4()l, 402; tri-
icxlide, 4<.H) ; <'tliyl phoHphine, 431 ;
triethyl phospliiue, 4X\; parathiul-
dehyde, 4j<l ; ucotonitril, 522; niouo-
chloracetii^ acid, 5o3 ; propionitril,
54U ; secuudary butyl thiocarbiiniilo,
5.S3
Homologous si^rioR, 38
Howtird ; f ulniiuiu acid, 524
HugeuA; ethyl nitrite, 3o(J
Husemanu ; ethyl trithiocarbouatc, 3^8
Uywnasic acid, 0^1
Hydnizine comiM)uuds, 1<>1
Hydrides and nidieals. 132
Hydrocarbous aud their derivatives, 37
Hydrocarlxms from alcohol radicals, 10
HydnvarbouH of th«j ixirallin series, 13' J
Hy<lrochloric ether, 10
Hydrochhmde of dimethylamiue, 221
Hydrochloride of methylamine, 220
Hydrochloride of trimcthylamiue, 223
Hydrogen amyl Hulphat<\ (jl2
Hydrogen ethyl carbonate, 309
Hydrogen ethyl phosphite, 3(>1
Hydrogen ethyl seleuate, 350
Hydrogen ethyl sulphate, or ethyl sul-
phuric acid, 350 ; preparation, ih. ; pro-
perties, 351
Hydrogen mc^thyl sulphate, 207
Hydrogen silver fuluiiuate, 520
Hydrometers, 303 ; Sykes's, 305

Iatuo chemistry, 4

Imidoilimethyl-aoetodiuietiiyl -propionic
acid, 575

Inactive amyl ahrohol, <K1S

Io<liue, determination of, 75

Iodine substitution produits, 540

Iodoform, 250

Isubutane and its derivatives, 5j*3

Isobutyl acetate, 5h4

Isobiityl alcohol, IS7, 5S3

Isobutylamine, 5^5

Isobutyl borate, 5^ I

Isobutyl bromitle, .'si

Isobutyl butyrat*'. 505

Isobutyl carlKimine. 5S'»

Isobutyl carbinol, &*S

Isobutyl carbonate. oS-l

Isobutyl chloride. 5M

Isobutyl compounds, 507, <>'H>; isobutyr-
aldehyde, 507 ; isobutyric arid, 508 ;
calcium isobutyrat**, 500 ; silver iso-
butyrate, ih. ; zinc isobutyrate, /A. ;
ethers of u^obutyric acids, iSOO ; isobu-
tyryl com]>ounds, ib. : isobutyramide,
ih.; isobutyronitril, ih.; substitution
products of isobutyric acid, ih. ; brom-
isobutyric acids, 001

Isobutyl-<li methyl carbinol, 045

Isobutyl formate, 58-1

I v»butyl hydrosulphide, 5*^5

Isobutyl iodide, 584

Isobutyl-methyl ketone, 031

Isobutyl muhtard oil. 585

Isobutyl nitrate, 5^4

Isobutylphosphine, 5S5

Isobutyl propionate, bbA

Isobutyl silicate, 584

Isobutyl sulphide, 585

Isobutyl thioeyanate. 5sr>

Isobutyl trithiocarI>ouat4*, 5f<5

Isobutyraldchyde, 507

Isobutyramide, (HH)

Isobutyrates, 500

Isobutyric acid, 187, 508

Isobutyric adds, ethers of, 000

Isobutyric acid, substitution products of,

0«X)
Ibobutyrouitril, <J00
Isocapric acid, 0(J5
Isoirapric alcohol, 003
Isocapric ahlchyde, 005
Isocaproic a<'id, 030
Isocaproyl aldehyde, O^iO
Isocaproyl anhydride, <)30
I.«»ocapn>yl chloride, 030
Isocaproyl nitril, 037
Isocaproylamide, (W7
Isoceryl alcohol, 082
I.«o:'toic acid, 057
Isiictyl alcohol. 055
Isoctyl-methyl ketone, 003
Tsocyanates, 1<J4
Isocyanides, 103
Is^K'yauuric acid. 53*)
Isodibntol, 055

Isohe]itane and its derivatives, 043
Isoheptoic acid, 040
Isoheptyl-acetic aci<l. 002
Isoheptyl alcohol, primary and seiuudary,

043
Isohexaue and it.s derivatives, 030
Isohexoic acid, ({30
Isomeric compounds, 123
Isomerides, 122
Isomerism, 110 ; in the restricted senM>,

121
Isomerism ; physical, 120; unexplained,

127
Isomers. 121
Isononoic acid, 0(>1
iKoconanthylic acid, OiO
Isopalmitic acid. 077
Iso-(>arafl[ins, 135

IsojMMitane and its dcrivativt-h 0<>0
Tsopentnio acid. 018
Iso|ientyl alcohol, ii^Hi
Isopropyl acetattJ, 5(^5
Isopropyl alcohol, 5(ht
Isopropyl Isjrate, 505
Isoi)ropyl bromide, 504
Isopropyl butyrate, 505
Isopropyl carbamiue, 5({(>
Isopropyl chloride, iiCA
Isopropyl cyanate, 600
lsoproi»yl-ethyl-methyl carbinol, 645
Isopropyl io<lide, 504
Isopropyl -isobutyl carbinol. 055
Isopropyl nitrate, 5<»5
TxtprtJpyl nitrite, 5*15

INDEX.

713

IjttWlauc; synthesis of primary alcoholfl,
170 ; acctamidu, 517 ; acetoiiitril, r>21 ;
moDOchloracetic aciil, 5^{3: propionic
acid, Sort ; butyronitril, 59<J
Lemcry, Nicolas; his Cmin df Chf/mie. 5;
hiri system of classifiration, ih. ; a:;ctii:
aciil, 4 So ; acetoni*, 50S
I^erch; caprylic acid, (3oG; capric acid,

6(i4
lA'thal, 073

Libavius ; exphwive fire-damp, 190 ; alco-
hol, 285 : acetone, 5(J8
Liel)en and Kossi; synthetic method,

180
Tiioben ; properties of ether, 335 ; substi-
tution products of ether. 338 : diehlor-
ethyl oxide, 330 ; aldehjrde, 537 ; butyl
alcohol, 577; isobutyric acid, 508;
pentxiic acid, 617 ; normal heptoic
acid, 048;
I^ebig; on the radical of benzoic acid,
11 ; radical theory, 12 ; grouping com-
pounds, 13 ; definition of a compound
radical, 14 ; metal in permanganic acid,
17 ; his attack on the French chemists,
18; theory of polybasic acids, '20;
compound ammonias, 23; original
method of analysis, 48 ; improved, 51 ;
relative determination of nitrogen, 67 ;
determination of sulphur, 78 ; methyl
alcohol, 194 ; chloroform, 2&i ; raethene
disulphonic acid, 264 ; formic acid, 270 ;
etherification, 327; substitution pro-
ducts of eth(;r, 338 ; sulphoviuate of
wine-oil, '^A; ethyl phosphoric acid,
i^; ethyl hydrosulphide, 378; acetyl,
475 ; aldehyde, ih. ; metaldehyde, 480 ;
f ulminic acid, 524, 525 ; silver fulmi-
nate, i7). ; mercury fulminate, 526 ;
fulminuric acid, 530 ; chloral, 537 ;
acetone, 560 ; dichloracetone, 571 :
heptoic acids, 616; consumption of
Koap, (MK)

Lifbig and "Wohler; ethyl allophanate,
373

Lielircich; chloral hydrate, 539

Ijignoceric acid, 081

liigroin. 140

Limprioht; aldehydes, 180; butyro acetic
acid, 557

Linnemann: apparatus for fractional dis-
tillation, 149; ]»rimary propyl alcohol,
540 ; projiyl ak>oh(»l, 550 ; monochlor-
aoetone, 570 ; trimethyl carbylamine,
r>dO ; butyric acid, 593 ; butyronitril,
590

Linkiug of atoms, 112

Liffiior avoihfiiHs Hojfinnni^ or llofTmau^s
ilrops, 3-1

JJqttnr luminnsiif^ 324

L >ng : ether »8 an au:L'<thetic agent, 'X\1

Loriu ; fonnamidis 277

T<iun'U(;o ; uonyl alcohol, 659

1/iiwig ; tribruni methane, 2-57 ; ethyl bro-
mide, 340 ; ethyl formate. 375 ; ethyl
sul phonic acid, 304 ; ethyl seleuide,
IJI»> : bromal, 54 \ ; bromal hydnite. 515

l.fiwitz ; ali-fihol. 207 ; aidiydrous nlcoh'»l,
2!»7 ; ntetic a(i<l, \^ t

Lully; distillation, 283; alcohol, 207;
alcohol test, 301; ethyl ether, 323;
ethyl nitrite, 356; potassium acetate,
406

Macaire; methyl alcohol, 194
Macquer ; acetic acid, 485
l^Iagnesium ethide, 455
Magnesium-methyl, 245
l^Iagnus^s green salt, 404
Maiaguti ; substitution productii, 15 ; di-
chlorformic ether, 19; synthesis of
primary alcohols, 179; substitution
protluirts of ether, 338 ; ti'trachlor-ethyl
oxide, 344); acetamide, 517; aceto-
nitril, 521 ; trichloracetic acid, 540 ;
propionic acid, 556 ; butyronitril, 596
Mallet; ethyl tell uride, 399
Malligand ; ebullioscope, 309
Malt vinegar, 488
^^ Manufactured " wine, 316
Marcet; methyl alcohol, 194
Marchand ; wine oil, 354
Margaric acid, 677

Marignac ; dichlordiuitro methane, 20 J
Marine soap, 693
Markownikoff ; isobutyric acid, 598;

caproic acid, 638
Marseilles soap, 692
Marsh gas, 28 et seq.
Marsh gas hydrocarbons, fatty acid series

from, 37
Marsh gan, properties of, 190 ; not poison-
ous, 191
Marsson ; isobutyric acid, 598 ; lauric

acid, 668
Mashing in manufacture of alcohol, 287
Maumene ; dichloracetic acid, 536
Meconic acid, molecular formula of,

106
M(Hlullic acid, 680

Melseus; r;.'ver8e substitutions, 18; tri-
chloracetic acid, 487 ; glacial acetic acid,
407
Melissic acid, 683
Melissyl alcohol. 682
Melissyl chlt)ride, 6S3
Melissyl hydrosulphide, 683
Melissyl ioili«le. 6S3

Mendelejeff ; origin of pt>troleum, 143 ;
properties of pure alcohol, 299; pri-
mary propyl alcohol, 548
Meudius ; synthetic method, 179 ; methyl-

amine, 218 : propylamine, 552
Menecrates ; lea«l plast<T, 693
Jfercuria/i* anttua^ methylene occurs in,

210 ; triinethylamine in, 221
Mrrnirialif pirennis, methylene occurs in,

210
^It?rcuric acetate, 5iU
Mercuric fonnate, 275
Mercuric mercjiptide. 370
Mercurous acetate, 5(>1
Merct irons formate, 276
l^I-rcury acetamide, 518
^l«Toury-amyl. (»15
Mercury ethide, Iri'l

714

INDEX.

Mercury-ethyl bromide, 4(J4
Mercury-ethyl chloride, 4<U
Mercury-ethyl compouiids 404
Mercury-ethyl cyanide, 4(J5
Alercury-ethyl hydroxide, 464
Mercury-ethyl iodide, 4(U
Mercury-ethyl nitrate, 4*io
Mercury-ethyl sulphide, 465
Mercury ethyl sulphate, 4U5
Mercury fulminate, 526
Mercury iaobutyl, 5d5
Blercury-methyl, 250
Mercury-methyl chloride, 251
3Iercury -methyl io<lide, 251
Mercury-methyl ralphate, 252
Mercury-methyl sulphide, 252
Mercury-octyl, 651
Mercury propyl, 555
Merrill ; methyl bromide, 205
Mesiuo ; myristic acid, 670
Mesityl oxide, 572, 573
Mesityleuc, 572
Meso-paraffiiiR, 136
Metachloral. 538
Metaldehyde, 480
Metalepsy, 14

Metallic compounds of methyl, 245 ;
magnesium methyl, 245 ; zinc-methyl
or zinc methide, 246 ; mercury methyl,
250 ; mercury-methyl chloride, 251 ;
mercury-methyl iodide, 251 ; mercury-
methyl sulphate, 252; aluminium
methyl, ib. ; lead-methyl, 252; tin
tetramethyl, 253; tin dimethyl or
ntanuo-tetramethyl, ih. ; tin dimethyl
iodide, ib.
Metallurgy, 4
Metamctric bodi s, 121
fthttamerism, 12 >
Methal, 673

Metliane (methyl hydride), lOt); ob-
served by the ancients, ih. ; pri>|)erti«?>,
191 ; preparation, 192 ; nyuthesis of,
193
Methene disulphonic acid, 264
Metheue dihromide, 257
Mcthine trisulpliouic acid, 2((5
Meth'.Hls of analysis, a* < Analysi** inethotls

of.
Methyl acetate 607
Methyl alcohol on oxidation, 12
Methyl alcohol, 113, 194 ; comincrcial
prci>aration, 195; pure preparation,
197; properties of, 198
Methvl allophante, 212
Methyl-amine, 2S, 37, 113, 218; hydro-
chlorate of, 220 ; sulpliiite of, ih. \
nitrate of, ih. ; carbonate of, »7».
Mcthyl-amnionium carbonate, 220
Methyl-ammonium chloride, 22<>
Mt^thyl-ammoniuni nitrate, 220
Mt'thyl-aminonium sulphate, 220
Methyl-amyl ether, 61 1
Metliyl-anthraccne, molecular formuho

of, 103
Methyl-anthracene, vajxMir <lensity of, 97
Methylarsen diohlorid*', 212
Methyl arsenate, 210
Methyl, arsc>uic comiiomids of. 231

Methyl arseuite, 210

Methylarsenoxidi;, 242

Methyhurseusulphide, 242

Methylated spirit, 317

Methyl bromide, 205

Methyl-butyl-acetic acid. 649

Methyl-butyl carbinol. 627

Methylbuty Iketone, 5^52

Methyl butyrate, 595

Methyl caprate, 664

Methyl-capryl ether, 653

Methyl carl^mine, 224

Methyl carUmide, 225

Methyl carbonate, 212

Methyl chloride, 113. 2ii2

Methyl cyanate, 225

Methyl cyanide, 521

Methyl, cyanogen compoiud^i of. 224

Methylene dicbloride, 2'>3

Methyl-diethyl-acetic arid, 6-30

Methyl-diethyl carbinol, <;31

Methyl-diethyl methane and its derivr.-

tives, 631
Methyl disulphide, 215
Methylene di-io<lide, 258
Methyl ether, 27
M(»thyl, ethereal salts of, 202, tt frj. ; n4

Ethereal salts of methyl
Methyl-ethyl acetic acid. 182
Methyl-ethyl carbinol, 581
Mcthyl-ethyl-ether, Ml
Methyl-ethyl sulphonate, 396
Methyl fluoride, 207
Methyl formamidc, 278
Methyl formate, 276
Methyl group, 190
Methyl-guanidine, 224
Methyl-hendecatyl ketone, 66J)
Methyl-beptdecatyl ketone, 679
Methyl-hexyl-acetic acid, 6(U
Methyl-hexyl carbinol, 651
Methyl-hexyl ketone, 654
M«*thyl hydrosulphide, 212
Mrthyl iodide, 206
Methyl isocyanate, 225
Methyl-isopropyl carbinol, 615
Methyl mercaptan, 212
Methyl-mercaptan-tlisulphouic acid. 2ii5
Methyl-mercaptan trisulphoutc aci«l, 265
Methyl, metallic coinptmnds of, 245
Methyl mustani oil, 227
Methyl nitrate, 2tl9
Methyl nitrite, 2j>8
Methyl-nunyl carbinol, (UM
Methyl-nonyl ket<me, iHiO
Methyl octoate, 657
Methylorthoformate, 277
Mtrthyl oxide or di-methyl ether, pre)>Ara-

tioM of, 200
Mt'thyl-pi'ntyl carbinol, 642
Mothyl phosphine. 229
Methyl phosphinic acid, 231
M«!thyl phosphonium chloride, 231
Methyl phosphonium io<lide, :^1
Methyl, phoR|}horus compountb of, 229
Methyl propionate, 559
Methyl-propyl-acetic acid, 638
Methyl-propyl carbinol, 604
Methylpropyl ether, 551

INDEX.

715

Methyl-proiiyl ketonp, (Wo, 010

Mt-thyl flelenitlo, 210

Metbylseloni-diohloriile, 217

Mcthylselciii-nitrnte, 217

Methyls$c>letii-|jlatmic chloride, 217

Methyl, seleuiuni cumpouuds of, 210

MoDiyl seleuonic acid, 217

Methyl, some dcrivates of, 253 ; see alro
Derivat^is of methyl

Methyl st*»arito,OSO *

Methyl siiliihide, 2i:t

Methyl sulphonic add, 21o

Methyl sulphonic chloride, 210

Methyl, sulphur comp>unds of, 212

Methyl sulphuric acid, 2(J7

Methyl tellurido, 217

Methyl. tcUuriuui compounds of, 217

Metliyl tellurium oxide, 217

Methyl thiocarhimide, 227

Methyl thiocarbouatv, 212

Methyl thiocyanate, 220

Methyl-tridecatyl ketone, 070

Methyl trimethylacetate, (^24

Methyltriethylanmiouium iodide, 44)0

Methyltricthyl stibonium compouuds,
447

Methyl-undecyl-ketoue, 009

Methyl-urauiue, 224

Methyl urea, 220

Methyl urethaiie, 212

Methyl valerati», 020

Methyl with autimouy, compouud.s of,
243

Methyl with borou, compounds of, 244

Methyl with silicon, compounds of, 245

Meyer, Carl ; determination of vapour
density. 100

Meyer, E. von ; cthylarainc salts, 4i.d ;
ferric acetate, 5<f0; cyanethiue, 502

Meyer, J. F. ; sotlium acetate, 497

Meyer, Victor ; determination of vapour
density (Method No. 1), 04 ; (Methoil
No. 2) 97 ; nitro-methane, 207 ; ethyl
dicarbothionato, 302 ; nitro-ethano,
423; ethyl nitrolic acid. 428; tiu-
diethyl, 400

Millon ; ethyl nitrate, 350; methyl
nitrate, 209

Minderer ; ammonium acetate, 408

Mineral sperm, 140

Mineral tallow, 140 ; wax, ih.

Mitchell ; properties of ether, 3;i4

Mitscherlich ; etherificatiou, 327

Mixed types. 29 et sej.

Mixtures, distillation of ; various ex-
amples, 153

Mohr ; wine tester, SOS

Molecular formul», S4 ; determination
of, 103 ; of volatile bodies, ih. ; of
acids, li)5 ; of bases, 108 ; of nou- vola-
tile and neutral boilies, 109

Molecular weight determination, 81

Monad alcohol radicals, compounds of,
151 ; nature of alcohols, ib.\ ethereal
suits or compound ethers, ih. ; haloid
ethers, 155 ; simple and mixed ethers,
150; hydrosulphides and sulphides,
157; sulphine compounds, 158; sul-
phonic acids, (7'. ; comimmid ammonias

or amines, 159 ; primary, secondary,
and tertiary amines, hiO ; hydrazine
compounds, 101 ; cyanides of the alco-
hol radicals, 102; cyanat^s and isocy-
auatos, 103; isocyanat^^'S, carbarn ides,
or carbonylamines, 104; compound
ureas or carbamides, ih. ; urothanes or
cnrbamic ethers, 105; allophantes, ih.;
compound ^uanidines, 100 ; thiocy-
anates and isothiocyanates, ih.; com-
pound thio-ureas, 107 ; nitro-paraffins,
ih. ; phosphorus bases or phosphines,
108; compounds of alcohol radicals
with silicon, ih. ; compounds of alcohol
nidicals with metals, ih.

Monctliylarsinc comimuuds, 443

Monethyl etl.er, 374

Mon«.'thyl silicic ether, 454

Monioda'*etamide, .>tO

M-.ujioilucetic arid, 540

M(mol>asic melissic acid, molecular for-
mula of, 105

Monobromacetic acid, 5-13

Monobromat*etyl bromide, 644

Monobromacetyl chloride, 54 1

Monobrombutyric acid, 507

Monobromnitroethane, 425

Monobromnitromethane, 203

Monobromnitropropane, .553

Monochloracetaldehyd<N 533

Monochloracetimide, 535

Monocldoracetic acM. 110, 533

Monochloracetone, 570

Mnnochloracetyl bnmiide, 535

Monochloracetyl chloride, 110, 535

Monochloracetyl phosphamide, 530

Mouochlorether, 338

Momichlor-ethyl oxide, 338

Monoiodo.acetone, 570

Monomethyl arsine compoimds, 242 ;
methylarsjjn-dichloride, ih.; nieth}-!-
arsen-oxide, //•. ; methylarsen-sulphi<le,

Monomethylaisenic acid, 213
^lononn-thyl borate, 211
Monomethyl phosphiue, 220
^lortimer ; receipt for ether, 324
Morton and Jackson ; inhalation of ether,

337
Mottled soap. 002
Miilier ; ethyl chlorsulphonatc, 355 ;

ethyl trisulphide, 3>f(5 ; (N>tassium ac«f-

tate, 400 : momvhlnracetic acid, 533 ;

dichlonicetic ariil, 530
Muspraitt ; manufacture of artificial

soda, 001
Mustard oils, 107, S-bO
Mvricvl. 082
Myrisitaldohytle, 070
Myristic acid, 009

Naphtha, 140
XufihOut vitrioii, 320
Xauiiiann ; determination of vapour den-
sity, 0!)
NaviiT ; Fn>l»eniui>'etlier, 357

716

INDEX.

XtrisoD ; distillation uf castor-oil soap,

($53
Neo-i)araffin<«, 136
Neutral bodies, molecular formulae of,

Nickles ; butyro-acetic acid, 55t5

Nitrate of methylamine, 220

Nitrils, 1G3

Nitro- acetonitril, 524

Nitrobutane, secondary, 5S3

Nitro-compounds of ethyl, 423 ; nitro-
ethaoe, ih. ; 8o<Hummtroethane. 424 :
moDobromnitroethaue, 425 ; dibrjm-
nitroethane, 426; diuitroethane, iVi. ;
bromdinitroethane, 428 ; ethyl nitrolic
acid, ib. ; dinitroethylic acid, 43<3 ; di-
azoethoxaue, 431

Nitro-compountis of isopropyl, 566

Nitro-compounds of methyl, 227 ; nitro-
methane, ih. ; methazonic acid, 228

Nitro-compounds of primary butyl, 580

Nitro-compounds of propyl, 553

Nitroethane, 423

Nitroform, 263

Nitrogen bases, 580

Nitrogen bases of ethyl, 401

Nitrogen bases of methyl, 218 ; methyl-
amine, ib. ; dimethylaminc, 220 ; tri-
methylamine, 221 ; tetrajnethylam-
monium compounds, 223

Nitrogen compounds of acetyl, 617

Nitrogen, determination of, 64; "Will
and Varrentrapp's metho<l, 65 ; Tjiebig*s
relative metho<l, 67 ; Bunscn's relative
method, 68 : Dumas's abwlute methoil,
7<>: Maxwell Simpson's method, 71;
l*liuger'8 methoti, 75

Nitrogenous substances in combustion,
58

Nitro-isobutane, 5S5

Nitrolic acids, 172

Nitro-raethane, 227

Nitro-octane, 651

Nitrtv paraffins, 169, 187

NitrojH.'utune, 614

Nitrofiotriacetonamine, 574

Nitroso-acetoue, 572

Nitrous-oxide-iH'largonic a:M(l, 661

Nollner ; propionic acid, 5>6

Nonane, 6'iS

Xondecatoio acid, 680

Nonoir a 'ids, (>.">!)

Nouoie anhydride, 661

Non-saturated compt)uudH, formuliu of,
117

Non-volatile bodies, molecular f<»rniu!:»'
of, 101>

\:inyl alcohols, 6r>:l

X »uyl group, 6^)^

Nnnn-il butane and its derivatives.

577
Normal butyrahh'ijyde, 5:X>
Nonniil bityric; a'.'i«l, 51)1
Normal copiwr ao'tate, 5i)J
N(»nnal deeatane, ()&2
Normal do«lfL*ataij<', 6 57
Normal <-thvl ejirlK>nat«'. 1>»I'>
N<»rmal ethyl phosphate. ;»'»•"»
Normal i-thyl phosphite, 3i»J

Normal ethyl sulphate, 353 ; history and

properties, 354, 355
Normal hecdecatane or di-octyl, 671
Normal heptane and its derivatives, 639
Normal heptoic acid, 648
Normal hexane and its derivativen. G2-'»
Normal methyl sulphate, d'^S
Normal methyl sulphite, 207
Normal nouane, 658
Normal nonoic a?id, 660
Normal octoic acids, 656
Normal octyl compounds, 650
Normal parafi&ns, 135
Normal pentane and it-s derivHti%-pK. (in;<
Normal primary pentyl alcohol, 6.^3
Nucleus theory, 16

OCTA>XE,650

Octoic acids, 656

Octonitril, 657

Ojtoyl oxide, 657

Octyl acetate, 651

Octylamine, 651

Octyl bromide, 651

Octyl caproate, 651

Octyl chloride, 651

Octyl group, 650

Octyl iodide, 651

Octyl nitrite, 651

Octyl octoate, 657

Octyl phosphinc, 651

Octyl sulphide, 651

Oi-tyl valerate, 651

Odling; chemical compoun<ls, 2tl; alu-
minium-ethyl, 465

Oefele ; triethylsulphine compounds, 3^2

CEnanthaldehyde, 647

CEnanthic acid, 647

(Enanthol, 647

(Knanthone, 669

(Enanthylic acid, 647.648

(Enanthylous acid, 647

Oil, 141 ; early use of, 142 ; varioun
springs, 143; manufacture in England,
ih.: American wells, 144; yield of
Peniisylvaniau wells, ih.

Oil-gas, 120

< >il of roses, paraffin from, 14(^
Oil of turpentine, 34
Oil-test of alcohol, 301

Olive oil soap, 602

Organic analysis by means of platinum.
60

Organic compounds, early theorr con-
cerning the iH)mposition of, 10; formt-tl
in nature, 31

Organic chemistry, definitions of, 31 ff

< )rganic chemistry, definition of, adopt«t|,

35
Orthosilico-acetic acid, 455

< )rthosilico-]>ropionic ether, 454
Ossokin; methyl-ethyl carbiuol, 5*^1
Otto: d(>termiuation of 8ul)>hiir, 'i^i

]>ropiouic acid, 558
i )tt<) of rosi.*, di»c»overy of, 071

< htdenians ; myristic add, 66R

inl>p:x.

Oxiilatiuu of alcoliolfl, 12
Oxidatiou of tertiary nlcuhuls, l^7
< >xi(U*8 of acetyl, 5()y
Oxygeu, combustion in a current of, i>5
Oxygen, determination of, HJ
Ozokerite, 144)

rATJkPOTL hyib-itle, C')"^

I*ahn oil soap, 002

Pahnitaldehyde, U7d

Palmitic acid. C75
Palmitouc, 070
Famicea citrifi/i\ 324
Tapin ; ethyl nitrite. ;r»<J
rarucelsus ; ether. '62'S

PaniflinN; in cold and htat, V.VA; a
generic t^^rm, »/».; ]>rop«?rtieH of, I'M:
couHtitution of, 1X> : the nonnal. ih. ;
the iso-paraffin?, ib. ; nieNO-par::tfiriK,
V6ii', neo-parafiins, //'. ; ]irepiiration of,
//'. ; formation of. I'M)', oci-urrmi e of
140 ; application of, if'.; and {)etroIeun)
oil mauufactnro, 143; preparation of
the normal from i>etroh>nm, 14({

Paraffin hydrocarbons, 13* i; mohcular
formulae of, »/i.

ParnformaMehydt>, 2<)7

Paraldehydi-, 4*79

I*arat]iialdehyde. 4»1

a-Parathialdehyde, 482.

/3-Parathialdchyde, 4.^2.

Parathioformaldehyde, 2<JS

Past<>ur : alcoholic fermentation of sugar,
288; amyl alcohols, 007: actii'e amvl
alcohol, 009

J'a.*tinara snlii-a, alcohol fron),'2l)7

Pe^t Iwg petmleiim. 144

l*el)a1 ; zinc ethid(>. 4i>7

Ptdler; amyl alcohols, 0 x ; active amyl
alcohols, 009

Pelargonic acid. 0({i)

Peligot; wootl-spirit and alcohol. ]!)'»;
methyl aw*tate, iViJ

Pelouze; American petroleum hydr;)-
car1x>us. 132 : ethyl phosphoric acid,
H($>i; propiouitril. r>00; butyric acid,
.Wl ; hexane, 025 ; prinuiry hexyl
alcohol, 020; heptyl hydri.h', 4i3J» ;
heptoic acids, (^10 ; nonane, O-^S

Pi-nnsylvania petroleum, 1 in, 142

Peutachloracvtone, 572

Pmtachlor-ethyl oxide, 310

Pentadecatoic acid, 070

Penta<lecatyl grtmp, 070

Pi-ntadecatyl-methyl ketone, 077

iVntamethylarsine, 237

Pentamethrl-bntane, r»59

Pentamethyl-ethyl chl(»ride, 04«J

Pentamethyl-ethyl iotlide, 0-10

Pentrine. G<»3

Pentoic or valeric acids, 01 7

Pentyl acetate, iVW

Pentylic ncid. 1P2

P. iityl alcohols, 123. 0f»3

PeiitVl bromide. I Hi

Pt-ntvl chloride, f>!4

Pentyl comitouiids, C^Ki
I'eutyl group, ii<)2
Peutyl i.)dide, 004
Peroldoracetic ether, o**?)
Perchorethyl chlorformate, 370
IVichloriuated ether, 341
l*erLhloniiethylformate, 277
Perchlorniethyl mercsptan, 205
Pt'rkin ; dichlormt>thane, 2.'vl ; mono-
bromacetic acid, 543 ; tlibromacrtii!
ncid. 514; mnuio<lacet ic acid. 54(i ;
diiodacetic acid, 547
Penwune: ethyl bronn'de, 3-10; ethvl

iodide, 317
Persoz ; ethyl nitrate, 300
IVtroleum, 132

Petroleum (oleum potra)) occurrence of,
142; origin of, 143; manufacture in
England. ///. ; American oil wells, 144 ;
pn^paratiou of normal paraffins from,
140
Petn)leum contains {jjiraffin. 140
Petroleum-spirit, 14<J
Pttiiger ; determination of nitrogen, 75
Piiorone, 572.573

Phospljat<.-8 of ethyl, 303; ethyl jhos-
phoric aci«l. 3<,'4 ; bitrium ethyl pho<<-
phati*. 'ft.; lead ethyl phosphate, lA. ;
arseni.-* ethyl j^hosphate. if: ; chloride
of ethyl phosphoric acid. ift. ; diethyl
phosphoric acid, 'M'to : lead diethyl
phosphate, //«. : chloride of diethyl
phosphiiric acid, iA. ; normal ethyl
l>liosphate, if'. ; ethyl pyrophosphate,
'ii6ij
Phosphates of methyl, 21(>
Pliosphit«'S of ethyl, 301 ; hydrogen
ethyl phosphiti;, or ethyl phosphorous
acid, iff. : iMttas.sium ethyl phosphite,
barium ethyl, lead ethyl, normal ethyl,
302 ; chloride of ethyl phosphorous
acid, 3'J3 ; ivcid ethyl pyrophosphite,
if>.
Ph;'sphite of methyl. 210
l*hosphorus bases of ethj'l, 431
Phosphorus bases, or phcspl lines, 108
Phosphorus compounds of methyl, 2l9 ;
methyl phosphiue, /A. ; methyl jihos-
phouium chloride, 231 ; mt^thyl phos-
phonium io«lide, /A. ; methyl phosphinic
aiiil. if'. ; dinu-thylphosphine, if'. ; tri-
methyl phosphinc, 232: tetramethyl
phosphonium io<lide,233; tetramethyl
diphos] hide, 234
Phosphorus, det^^rmiuntion of, 79
Physical isomeriMu, l:;;ii
Physic dogical action of alcohol, 315
Pierre and l*uchot ; distillatim of nnx-

tures, 153
Piern* ; nifthvl bromide. 2''5
Pinacoliiic, VyiM
Piuacolyl art-tate, 033
l*iuacolyl alcohol, (»32
Ptuacolyl bromide, 033
Pinacolyl chloridi-. (J;i3
l*inner; pro]>yl alcohol, 540
/ tints S,t>'.i;iit)a iC'alifoniian Pine), 14<)
J i.ni.H .ViA//#/,f;/rt Doviff^ heptane from,
040

INDEX

719

of mercury vapour, 91 ; methyl sul-
phide, 213; dichlcNrmethane, 253 ; chlo-
roform, 254, 255; tetrachlormethane,
257 ; substitution products of eth(T,
338; ethvl mtrcaptao, 378; ethyl
sulphide, 380 ; chloral, 537

Rcichenbach ; crystalline solids in wood-
tar, 133; iKiraffiu, ib. ; eupion, 139

Resin soairn, G93

Restricted isomerism, 121

Retort, invention of by the Arabians, 283

Reverse substitutions, 18

Rice-spirit, Japanese plan of preparing,
2>5

Richardson ; dichlormethane, 254

Itiche ; monocliloracetone, 570

Ricliter ; anh^droiu alcohol, 297

Rieth ; ethyl iodide, 347 ; zinc cthide, 457

Rhil^olene, 146

Robiquet ; hydrochloric ether a com-
pound of hydrochloric acid with ole-
iiant gas, 10 ; ethyl chloride, 343

Romans, soap use<l by the, 0S9

R4>mer ; propyl hydrosulphide, 552; tctra-
propylammoniimi iodide, 553

Ronalds ; propane, 548

Roscoe ; lead tctraethyl, 460

Rose-oil, 672

Rose ; sulphuric ether, 3:?6

Rossi; propyl alcohol, 55^1 ; butyl alcohol,
577 ; isobutjTic'acid, 598 ; i»eutoic aci<l,
617; caproyl alcohol, (J30

RoueJlc ; organic researches, 6

Russell ; determination of sulphur, 78

Salts containing compound radicals, 31

Salts, ethereal, 175

^alts of the oxyacids, 20

Salts and ethers of acetic acid, 496

tSamlfUcus nigral valeric acid in, 618

Sapiwhis sapnnaria (soap-nut tree), acid
found in, l'69

Saussure's method of analysis, 43 ; analy-
sis of ether, 326 ; acetic acid, 486

Savalle ; apparatus for determination of
alcohol in beer.s and wiur;s, 309

Savonarola : alcohol test, 301

Snytzeff; propyl alcohol, 55<"); methyl-
ethyl carbinol, 581 ; diethylat:etic acid,
637

Sihafarik ; aluminium-ethyl, 465

Schiiffcr ; bromal, 544 ; tribromacetic acid
salts, 545

S^heele ; organic researches, 6 ; discovers
important vegetable acids, ib. ; formic
acid, 270 ; ethyl fluoride, 348 ; oxide of
manganese, 473 ; acetic ether, 507 ;
amyl alcohols, 606

Scheurer-Kester ; acetic acid double salts,
506

Scliiel : alcohol radicals, 38

Scliischkoff ; nitruform, 263 : fnlminic
acid, 525 ; fnlminuric acid, 530

Schmitt and Glutz; ethyl dithioxycar-
bonate, 393

Schorlemmer; action of chlorine upon

ethyl-amyl and di-amyl, 132; methyl
identical with hydride of ethyl, ib.\
cannel coal hydrocarbons, ib. ; ethane,
281 ; propane, 548 ; primary propyl
alcohol, 549; pentane, 603; hexaue,
626 ; primary hexyl alcohol, ib. ; tetra-
methyl ethane (di-isopropyl), 631;
heptane, 639 ; heptyl alcohol, Wl

Schiiyen ; di-ethyl convertetl by chlorine
into butyl chloride, 132; butane, 577

Schrick ; oil-test of alcohol, 301

Schi'itzenbach ; quick vinegar, 488

Sohiitzenberger ; ethane, 281 ; acetic acid,
512

S;-hweizer ; ethyl trithiocarlnmate, 388

Secondary amyl bromide. 616

Secondary amyl chloride. 616

StH*oudary umyl iotlide, 616

Secouilary butyl compounds, 581

Secomlary butyl iodide, 582

Secondary butyl oxide, 582

Secondary butyl thiocarbimide, 583

Secomlary hexyl ioiUde, 6i*7

Secondary isoheptyl alcohol, 643, 655

Secon<lary nitropropane. 5(KJ

Secondary octyl alcohol, 651

Secomlary propyl alcohol, 563

Seleniiun and ethyl compounds, 397

Solenium compounds of methyl, 216 ;
methyl selenide, ih.\ metliylseleni-
nitrate, 217 ; methylseleni-dichloride,
ib. ; methyl-selenonic acid, j7i.

SfTtiiruer; etherification, 328; sulpho-
vinic acid, 350

Senillas: tri-iodomethane, 259; ethyl
bromide, 346 : ethyl iodide, ib. ; ethyl
sulphuric aci<l, 350; wine-oil, 354

Sosijuibasic copper acetate, 503

Shea-butter, 678

Siemens ; ethyl hydrosclenide, 397

Sigel ; heptaldehyd(!,6t7

Silbermann ; dilatometer, 314

Silicate soap, 693

Silico-acetic anhydride, 512

Silicoheptane, 451

Silicoheptyl alcohol, 452

Silicoheptyl bromide, 454

Silicoheptyl chloride, 453

Silicoheptyl compounds, 451

Silicoheptyl oxide, 453

Silico-nonyl com|)ounds, 451

Silicopropionic acid, 455

Silicon acetate, 512

Silicon compounds of ethyl, 450

Silicon-diethyl compounds, 454

Silicon diethyl-ethiT, 454

Silicon ethyl, 451

Silicon hexethyl, 451

Silicon-methyl, 245

Silicon-monethyl compounds, 454

Silicon tctraethide, 450

Silva : triethylsulphine oxide, 435 ; pcnta-
methyl-butane, 659

Silver acetate, 504

Silver acctamide, 618

Silver butyrate, 595

Silver ethyl sulphate, 353

Silver ethyl sulplumate, 396

Silver formate, 275

INDEX.

721

TABI.BS for calculating tho true ptsrcent-

hge of alcohol in any spirit at any

given temperature, 300, 307
TacheniuH ; ammonium acetate, 49S
Tallow curd soap, tS92
Tamarinds, acid found in, 209
T&uret ; properties of etlter, 334
Taylor ; pyroligneous ether, 194
Tellurium com^unds of methyl, 217;

methyl tellunde, ib. ; methyl tellurium

oxide, ib.
Tellurium and ethyl compounds, 399
Temperature of body affected by alcohol,

315
Tertiary amyl acetate, 017
Tertiary amylamine, 617
Tertiary amyl bromide, 017
Tertiary amyl chloride, 01 7
Tertiary amyl iodide, 017
Tertiary butylamine, 590
Tertiary butyl chloride, ,^SS
Tertiary butyl compounds, 55*(i
Tertiary nitrobutaue, 5:^9
Tertiary octyl compoundK, 055
Tertiary valeric acid or trimethylacetic

add, 623
Tetrabroram^'thane or carbon tetra-

bromide, 258
Tetrachloracetonc, 571
Tetrachlor-ethyl oxide, 340
Tetrachlormctbane, 257
Tetradecatyl group, 009
Tetraetbylammonium bromide, 40t$
Tetraethylammonium chloraurute, 409
Tetraetbylammonium chloride, 4o8
Tetraethylammonium compounds, 44)8
Tetraethylanmionium hydroxide, 408
Tetraethylammonium iodide, 4k)8; tri-

iodide, 409
Tetraethylammonium platiniclilorido,

409
Tetraethylarsonium compounds, 441
Tetraethylarsonium hydroxide, 442
Tetraethyl carbamide, 420
Tetraethylphosphonium compounds, 430
Tetraethylphosphouium ioiUdc, 439
Tetracthylstibonium chloride, 440
Tetraethylstibonium compounds, 440
Tetraethylstibonium hydrosulphide, 447
Tetraethylstibonium hydroxide, 440
Tetraethylstibonium io<lidc, 447
Tetraethyl-tetrazone, 412
Teti-a-iodomethnne, 201
Tetra-isopropylphosphonium iodide, oliS
Tetramethylammomum compounds, 223 ;

methyl-guanidine, 224
Tetramethylarsonium compounds, 230
Tetramethyl butane and its derivatives,

654
Tetramethyl diphosplude, 234
Tetramethyl ethane and its derivatives,

631.
Tetramethyl-hexane, 063
Tetramethyl methane and its derivatives,

617
Tetnunethyl-pentane, 058
Tetnunethylphoiiphonium iodide, 233

VOL. III.

Tetrane, 577

Tetranitrom ethane, 204

Tetrapropylammouium iodide, 553

Totrazones, 102

Thallium-diethyl chloride, 473

Thallium-iliethyl compounds, 473

Thallium-diethyl hydroxide, 473

Thallium ethyhitc, 322

Thenard's method of analysis, 43

Thenard ; phosphorus compounds of
methyl, 229 ; arsenical methyl com-
pounds, 234 ; properties of ether, ib.

Theobromic acid, 083

Theophrastus ; copper acetate, 502

Theories of Types and Radicals, 22

Theory of substitutions, 15

Thia?etic acid, 515

Thiacetic anhydride, 510

Thio-acids, 170

Thio-anhydrides or sulphides of the acid
radicals, 170

Thiobutyric acid, 590

Thiocarbonates of ethyl, 393

Thiocyanates, 100

Thio-ureas, compoimd, 107

Thomson, Thomas; speeitic gravity of
methane, 191

Thorpe, distillation of solid paraffin,
137; normal heptane in Califoruiau
pine, 14(^ ; distillation of mixtures,
153 ; normal decatane, 002

Tielebein ; nitric ether, 357

Tilley ; normal heptoic acid, 048

Tin-diethyl chloride, 472

Tin-diethyl compounds, 472

Tiu-<liethyl iodide, 472

Tin-diethyl nitrate, 472

Tin-<liethyl sulphate;, 472

Tin-diethyl sulphide, 473

Tin dimethyl, 253

Tin dimethyl iodide, 253

Tin propyl compounds, 555

'iin-tetraethyl, 409

Tin tetramethyl, 253

Tiu-tetramyl, 015

Tin-tetrapropyl, 555

Tin-triethyl, 409

'nn-triethyl-animonium-iodide, 471

Tin-triethyl bromide, 47(»

Tin-triethyl compounds, 470

Tin-triethyl chloride, 470

Tin-triethyl cyanate, 471

Tin-triethyl cyanide, 471

Tin-triethyl ethyl sulphonate, 471

Tin-triethyl hydrosulphide, 471

Tin-triethyl hydroxitle, 47U

Tin-triethyl iodide, 470

Tin-triethyl nitrate, 471

Tin-triethyl sulphate, 471

Tin-triethyl thiocyanate, 471

Tin with ethyl, coni{)Ounds of, 409

Tinctura ferri acvUrtis^ 500

Titusville oil wells, 1-14

Triaoetamide, 519

Triacetonalkamine, 575

Triacetonamine, 574

a-Trianiylainine, 009

Triamylamine, 014

Triamylphosi>hinc. 014

INDEX.

72:j

vini), 285; alcohol tcftt, 301; ethyl
ether, 3:>3; ethyl chloride, 342 ; acetic
acid, 483, 485; vinegar, 403; lead
acetate, 490
Valeraldchyde. 618
Valeramidc, 621
Valerates, 620; calcinm, barium, zinc

and silver valerates, ih.
Valeriana officinalis^ acid from, 618
Valerianic add, 182
Valeric acids, 617 ; inactive, 618
Valeric acid, active, 622
Valerone, 659
Valeronitril, 621
Valeryl bromide, 621
Valeryl chloride, 621
Valeryl compounds, 621
Valeryl cyanide, 621
Valeryl ioilide, 621
Valeryl oxide, 621

Vauquelin; ether, 326; properties of
ether, 334 ; wine oil and ether, «$54 ;
act^tic a^-id, 486
Venetian soap, 692

Vapour density ; determination of, 84 ;
Dumas*B method, 85; Gay-Lnssac^s
metho<l, 87 ; Uofmann*s method, 89 ;
"Wichelhaus's barometer tube, 92;
Victor Meyer's metho<ls, 94, 97 : Carl
Meyer*s method, 100 ; literature on the
subject, 102
Vaporimeter, Geissler*s, 312, 313
Vegetable acids, important, discovered by

Scheele, 6
Vegetables in the manufacture of alcohol,

286
Vihernum opulus^ valeric acid in, 618;

isopentic acid in, ib.
Vieille ; mercury fulminate, 528
Villier^s acetates, 498
** Vinasse,^ or spent wash, distillation of,

196, 222
Vincent ; dry distillation of spent wash
(vinames), 196, 222; methylamine,
219 : dimethylamine, 221 ; freezing
machine, 304
Vinegar; or dilute acetic acid, the only
acid known to the ancients, 3 ; solvent
power of, accordinff to the ancients,
483 ; manufacture of, 487
Vinegar eel, 400
Vinegar fly, 400

Vinegar-lamp, Dobereiuer*s, 320
Vinvm alcalisatum^ strong alcohol, 285
Vinyl chlorid*', 13
Vogel ; sul phonic acid, 350
Vugeli ; normal ethyl phosphate, 365
Volatile liquid, percentage compohition

of, 81
Volatile bodies, molecular f ormul« of, 103
Volckel ; pure acetic acid, 401
Volhard ; methyl formate, 276
Volta ; intiammability of marsh gas, 190
Van Lauraguais; acidum radicale, 484

"Waonkk ; ethyl pclargonate from quince,
661

AVallach ; ethyl ether, 536
AVankl^ ; distillation of mixtures, 153 ;
pro{Honic acid, 556 ; acetone, 569 ; pro-

Wpione, 606 ; methyl-butyl carbinol, 627
arren ; apparatus for fractional distil-
lation, 140

AVatts, Henry ; paraffin a generic term,
133

Waxes, 631

AVeidcubusch ; metaldehyde, 480 ; acetyl
mercaptan, 481

Weidmann ; ethyl sulphine add, 304

AVeith ; methylamine, 218

W'eltzien ; tri-iodide, 400

"NVestendorf ; acetic acid, 484

Westrumb ; acetic acid, 270

Wetherill ; normal ethyl sulphate, 353

Wicfaelbans; barometer tube in deter-
mining vapour density, 02 ; zinc ethide,
458

Wiegleb ; wine-oil and ether, 354

Will and Varrentrapp ; determination of
nitrogen, 65

Will ; oU of rue, Qm

Williams, G. ; distillation of Boghead can-
nel, 131 ; dichlormethane, 254 ; hexano,
625 ; oil of rue, 666

Williamson ; theory of types, 26, 31 ;
synthesis of alcohols and adds, 180;
etherificatiou theory, 320; methyl-
ethyl-ether >41 ; ethyl-chlorsulphonate,
355 ; ethyl orthoformate, 376 ; isobutyl-
methyl ketone, 631 ; isocaproyl uitril,

637

Willm ; ethyl monochloracetate, 535

AMne ; acquaintance of the andents with
the preparation of, 3, 282

Wine ; determination of alcohol in, 308 ;
table giving percentage of alcohol in,
314 ; ♦* manufactured," 315

Wine-tester, Gay Lussac's, 308

Wine vinegar, 487

Wischin ; zinc ethyl sulphinate, 307

WohliT; discovery of the artificial for-
mation of urea, 10 ; radical of benzoic
add, 11 ; ammonium cyanate con-
verted into urea, 120; preparation
of pure methyl alcohol, 107; methyl
selenide, 216 ; ethyl diselenide, 399 ;
ethyl telluride, 399

Woo<l ; manufacture of methylated siiirit*

Wood-tar 133

Woulfe ; hyilrochloric ether, 343
Wurtz ; discovery of the compound am-
monias, 23; the formula ethylamine,
24; theory of types, 27: isolation of
radicals, 131 ; apparatus for fractional
distillation, 148; aldehydes, 180; me-
thylamine, 218 ; monochlortfther, 338 ;
ethylamine, 401 ; ethylated chloride
of nitrogen, 405 ; ethyl carbimide, 415 ;
ethyl diacetamide, 519 ; butyl alcohol,
576 ; isobutane, 577 ; methyl propyl
carbinol, 604; amyl alcohol, 608;
dimethylethyl-carbinol, 616 ; isohexane,
630 ; isocaproyl nitril, 637 ; isoheptane,
(U3 ; tctramethyl butane, 654 ; tetra-
niethylpentane, 658

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Full text of "A Treatise on chemistry v. 3, 1884"

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