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balsam (concerning which Lehmann had already stated in his
Dissertation de balsamo peruviano (1709), that on decomposition
it yields flowers resembling flowers of benzoin), Mecca balsam
(BalsamvdtndronOpolakamum et gilcadensis), myrrh (B. Myrrlia),

* Ann. Chem. Pharm. iii. 249.

Kolbe and Lautemann, ibid. cxix. 136 ; FlUckiger, Pharmacographia.
3 Aschoff, Jahresb. 1861, 400.



OCCURRENCE OF BEMZOIC ACID. 153

liquid styrax, acaroid resin (Xanthorrheo hastilis), dragon's blood
and other resins. Benzoic acid has also been found in the per-
fume known as hilan-hilan or ilang-ilang, which is prepared
from the flowers of Unona odoratissima, 1 as well as in plums
(Prunus domestica cldorocarpaf and the cranberry. 3 It also
occurs in vanilla, the fruit of the clove-tree, the seeds of the
spindle-tree (Kuonymus europaeus) and the root of the sweet
flag (Acorus calamus), &c. The coumarin which occurs in
Holcus odoratus, Anthoxanthum odoratum (sweet-scented venial
grass), and woodruff was at one time mistaken for benzoic
acid.

In the year 1776, Rouelle stated that the urine of the cow
and the camel contains a salt similar to flowers of benzoin, and
Scheele, in 1785, obtained a substance, the properties of which
agreed with those of benzoic acid, by extracting with alcohol
the solid residue left on the evaporation of urine and treating
the " soapy extract " with nitric acid. Fourcroy and Vauque-
lin found, in 1797, that the urine of graminivora contains
benzoic acid, but Liebig, in 1829, showed that this substance is
a new nitrogenous acid, which he named hippuric acid, and
which splits up when the urine is allowed to stand, yielding
benzoic acid. According to some observers, however, benzoic
acid frequently occurs along with hippuric acid in the urine,
and it has also been found in a gland in the beaver,* and in the
kidneys of the ox. 5 It is probable that in all these cases the
acid is formed by the decomposition of hippuric acid.

It has also been observed as a decomposition product of
various alkaloids, such as atropine, cotoine, &c., and is formed
in small quantity by the oxidation of albuminoids. It may be
obtained in large quantities by the oxidation of those aromatic
compounds which possess a side chain containing carbon
(Part III. p. 13). It also occurs in coal-tar. 6

The various synthetical methods by which it has been pro-
duced have already been given (Part III. p. 34).

2 95 It was formerly prepared exclusively from gum benzoin,
and the acid used in medicine is still obtained from it by sublima-
tion ; it always contains a small amount of an ethereal oil, which

Gal, Ber. Dcu'sch. Chcm. Oes. vi. 824.
Ducheek, Gmcliriti Org. Chem. v. 332.
Loew, Journ. Pmkt. Chem. [2] xix. 312.
Wohler, Ann. Chem. Pharm. Ixvii. 360.
Seligsohn, Chem. Centralbl. 1861, 241.
Schulze, Ber. Deutsch. Chem. Gcs. xviii. 615.



154 AROMATIC COMPOUNDS.

gives it its peculiar smell. 1 In order to obtain it in this way,
the coarsely powdered resin is heated to about 1 70 in a flat
iron vessel ; this is covered with filter-paper and fitted with a
conical cap of strong paper, in which the acid collects. 2 Accord-
ing to Wohler, the gum benzoin is dissolved in an equal volume
of absolute alcohol and fuming hydrochloric acid added to the
hot solution until the resin commences to separate out ; it is
then distilled, water being added at intervals, and the distillate,
which contains ethyl benzoate, warmed with caustic potash and
then heated to boiling and saturated with hydrochloric acid.
Benzoic acid separates out on cooling and is found to possess
precisely the same smell as the sublimed acid. 3

In order to extract the acid from the resin by Scheele's
method, it is well mixed with an equal weight of slaked lime,
repeatedly boiled out with water, the filtrate evaporated to
one-sixth of its original bulk, treated with bleaching-powder
solution, and then boiled with hydrochloric acid until all the
chlorine has been removed. The acid separates out on cooling
and is re-crystallized from hot water. 4

It is prepared from the urine of cows or horses by allowing it
to stand for several days, clarifying with milk of lime, evaporating
the liquid to one-fourth of its bulk and precipitating the benzoic
acid with hydrochloric acid. Since the evaporation produces
a very unpleasant smell, it is better to precipitate the excess
of lime by carbonic acid and add ferric chloride, to precipitate
ferric benzoate, which is then decomposed by hydrochloric acid.
The acid thus obtained is purified by being redissolved in milk
of lime with the addition of a little bleaching-powder solution,
separated by hydrochloric acid and re-crystallized from hot water.
The final product (acidum benzoiciim ex urina) still smells of
urine, and is not employed for pharmaceutical purposes. The
smell may, however, be disguised by the addition of some of the
sublimed acid. About two kilos, of acid are obtained from
1,000 kilos, of urine. 5

P. and E. Depouilly have proposed to obtain benzoic acid
from phthalic acid, 6 which is obtained by the oxidation of

1 Jacobsen found in it methyl benzoate, benzyl benzoate, vanillin, guiacol,
catechol and other aromatic compounds (Ber. Dcutsch. Chcm. Gcs. xvii. lief.

2 Mohr^ ^7i7i. Chcm. Pharm. xxix. 117 ; Lowe, Journ. Prakt. Chcm. cviii.

3 Ann. Chcm. Pharm. xlix. 245. * Stenhouse.

5 Hofmaon, Bcr. Entw. Chem. Ind. ii. 431.

6 Jahrcsb. Chcm. 1865, 323.



PREPARATION OF BENZOIC ACID. 155

naphthalene and is now manufactured on the large scale.
When its calcium salt is heated to 330 350 with slaked lime
in absence of air, calcium benzoate and calcium carbonate are
formed :

2C 6 H 4 (C0 2 ) 2 Ca + Ca(OH) 2 = (C 6 H 5 .CO 2 ) 2 Ca + 2CO 3 Ca.

According to the method of Laurent and Castelhaz, 1 acid
ammonium ph thai ate is converted into phthalimide by heating,
and this is then distilled with lime, benzonitril being formed :



m\ > + Ca ( H )-2 = C 6 H 5 CN + CaCO, 4 H 2 O.

^6 n 4 \ /

CO

The benzonitril is then converted into benzoic acid by boiling
with caustic soda solution.

Benzoic acid is now generally prepared from toluene ; this may
be simply oxidized by boiling with dilute nitric acid, but it is
more advantageous to first convert it into benzyl chloride, 2 and
then boil 100 parts of this with 300 parts of nitric acid of
sp. gr. 1'313 and 200 parts of water for about ten hours in an
apparatus connected with an inverted condenser, until the
smell of benzyl chloride and benzaldehyde has disappeared, and
the liquid solidifies on cooling to a crystalline mass, no oily
drops being formed. 3

This method, according to A. von Rad, is not adapted for
the preparation of the acid on the large scale ; it can, however,
be readily obtained by heating benzotrichloride or benzenyl
chloride with water under pressure : 4

C 8 H 6 .CC1 S + 2H 2 = C 6 H 5 .C0 2 H + 3HC1.

Since it is difficult to prepare pure benzeiiyl chloride, the acid
obtained always contains chlorine substitution products, which
adhere to it very obstinately.

Espenschied proposes to boil benzenyl chloride with milk of
lime or caustic soda and whitening, and then to proceed as in the
preparation of benzaldehyde from benzal chloride (p. 136).






1 Jahrcsb. Chem. 1868, 459.

2 Grhnanx and Lauth, Bull. Soc. Chim. vii. 100.

8 Lunge and Petri, Bcr. Dcutsch. Chcm. Ges. x. 1275.
4 Dinglcr's Polyt. Journ. ccxxxi. 538.



156 AROMATIC COMPOUNDS.

Jacobsen obtains benzole acid, together with acetyl chloride,
by heating benzenyl chloride with glacial acetic acid and some
zinc chloride :

C 6 H 5 .CC1 3 -f 2CH 3 .CO.OH = C 6 H 5 .CO.OH + 2CH 3 .COCl + HC1.

In order to avoid the evolution of hydrochloric acid, which
carries off acetyl chloride with it, half of the acetic acid is
replaced by zinc acetate.

Benzoic acid can also be prepared without the formation of
acetyl chloride, by heating benzenyl chloride with a little acetic
acid and zinc acetate, and gradually adding the amount of water
necessary for the formation of the acid. 1

Since benzaldehyde is now manufactured, it can readily ba
employed as a source of benzoic acid.

2096 Properties. It crystallizes in lustrous, flat, monoclinic
plates or needles ; by the gradual evaporation of its solution it iz
obtained in larger tablets, which however are always thin, while
when Guichard allowed a mixture of benzoin resin and carbon
disulphide to stand for a long time, tolerably large crystals
were formed, which had exactly the appearance of crystals of
gypsum. 2

Benzoic acid has a sharp acid taste and produces a peculiar
irritation in the throat ; it melts at 121'4, and boils at 249
(Kopp), but volatilizes at 1.00, and sublimes rapidly at 140.
It also volatilizes with steam, one gramme passing ever with
two litres of water (Nolting). Its vapour has an aromatic, pene-
trating odour, produces coughing and attacks the eyes violently,
more mildly when it is mixed with steam. The specific gravity
of its vapour is, according to Mitscherlich, 4'27; according to
C. and V. Meyer, who determined it in diphenylamine vapour, it
is 4'24, 3 the calculated number being 4'229.

1,000 parts of water dissolve : ' :

at 10 20 30 40 50 60 70 80 90 100
170 2-10 2-90 410 5-55 775 H'55 1775 2715 40 75 5875
parts of the acid.

100 parts of absolute ether at 15 dissolve 3V35 parts ; 100
parts of 40 per cent, alcohol, 41'62 parts ; and 100 parts of

1 Ber. Dcutsch. Chem. Gcs. xiii. 2013.

2 Ibid. vi. 453. 3 nidm xL 2258.
4 Bourgoin, Ann. Chim. Phys. [5] xv. 168.



SALYLIC ACID. 157



absolute alcohol, 46'68 parts of benzoic acid ; x boiling alcohol
dissolves about twice this quantity. It also readily dissolves in
chloroform, carbon disulphide, volatile and fatty oils and con-
centrated sulphuric acid.

It is characteristic of benzoic acid that certain impurities, even
when they are present in extremely small quantities, alter its
physical properties to a very considerable extent ; so largely in
fact, that the impure acid has been mistaken for an isomeride.
Thus, E. Kopp, by the oxidation of gum benzoin with dilute
nitric acid, obtained the amorphous parabenzoic acid as a white
powder, which melts at 113; it is converted into ordinary
benzoic acid by distillation. 2 Another so-called isomeric acid
was named salylic acid by Lautemann and Kolbe, because they
had obtained it from salicylic acid, C 6 H 4 (OH)COOH. 3 The
latter was converted into a chlorine compound by phosphorus
pentachloride and this was decomposed by water into hydro-
chloric acid and chlorosalylic acid or orthochlorobenzoic acid,
C 6 H 4 C1.C0. 2 H. Salylic aid was obtained from this by the
action of water and sodium amalgam. This compound crystal-
lizes from hot water in indistinct needles or small plates, which,
on drying, form an odourless sandy powder, while the soft, light
plates of benzoic acid have a faint but distinct aromatic odour.
When its aqueous solution is boiled, however, the characteristic
smell becomes perceptible. It melts at a lower temperature
thnn benzoic acid, from which it also differs in fusing when
heated with a quantity of water insufficient to dissolve it, and in
the fact that its hot, saturated solution becomes milky on
cooling and then again clear, crystalline flocks being deposited.
Its salts also differ from the benzoates in crystalline form and
in solubility.

Kekule confirmed these resul ts, 4 and Griess obtained a substance
which he found to be identical with salylic acid, by decomposing
azo-amidobenzoic acid suspended in boiling alcohol with nitrogen
trioxide. 5 Kolbe and Lautemann put forward the suggestion
that the isomerism of these acids was due to a difference be-
tween their radicals, 6 but Cannizzaro showed that on distillation
with caustic baryta they both yield the same substance, viz.,
benzene. 7

The two acids were then assumed to be physical isomerides,

1 Bourgoin ; Bull. Soe. C'him. xxix. 242. 2 Compt. Etnd. Chim. 1849, 154.
3 Ann. Chem. Pharm. cxv. 187. 4 Ibid, cxvii. 158.

5 Ibid, cxvii. 34. 6 Ibid. cxv. 169. 7 Ibid. Suppl. i. 247.



158 AROMATIC COMPOUNDS.

until Reichenbach and Beilstein showed that salylic acid is
nothing but a more or less impure benzoic acid. 1 If the acid ob-
tained from salicylic acid be subjected to distillation with steam,
a perfectly pure benzoic acid passes over which possesses the
correct melting-point and all the characteristic properties. Kolbe
has confirmed this result, and finds that his salylic acid contains
a small quantity of a yellow, resinous substance, which is not
volatile in steam. When some of this is added to a hot, satu-
rated solution of pure benzoic acid, the liquid on cooling deposits
crystals of salylic acid. The admixed substance can be destroyed
by the addition of potassium permanganate to the hot solution. 2

The salylic acid obtained from azo-amidobenzoic acid con-
tains a little nitrobenzoic acid, as does the benzoic acid which is
prepared by the oxidation of toluene with dilute nitric acid. 3
When this acid is distilled, a trace of the nitro-compound vola-
tilizes with it and prevents it from crystallizing well, while when
a little of the nitro-compound is added to a hot saturated solution
of pure benzoic acid, it becomes milky on cooling and deposits
flocks, which are much more soluble than the pure acid and
melt at a lower temperature. Pure benzoic acid cannot be
prepared from this either by sublimation or re-crystallization, but
the impurity can readily be removed by dissolving in concentrated
ammonia, saturating with sulphuretted hydrogen, heating to boil-
ing, and then evaporating off the ammonium sulphide on the
water- bath. Hydrochloric acid now precipitates pure benzoic
acid, while amidobenzoic acid remains in solution (Reichenbach
and Beilstein).

An admixture of cinnamic acid, which melts at 133'3, also
lowers the melting-point of benzoic acid considerably, 4 so that a
mixture of equal parts of the two acids melts at 84'3, an excess
of either acid raising the melting-point. 5

Benzoic acid is employed in the manufacture of colouring
matters and in medicine. It has antiseptic properties, but
exerts a more feeble action than salicylic acid. 6 The observation
that cranberries withstand fermentation and putrefaction better
than most other fruits, gave the clue to the discovery of benzoic
acid in them.

Ann. Ghem. Pharm. cxxxi. 309.

Journ. Prakt. Ghem. [2] xii. 151.

Fittig, Ann. Chem. Pharm. cxx. 214.

Kolbc and Lautermann, Ann. Ghem. Pharm. cxix. 136.

Kachler, Bcr. Deutsch. Chem.. Ges. ii. 515.

Kolbe and v. Meyer, Journ. Prakt. Ghem. [2] xxii. 133, 178.



DECOMPOSITIONS OF BENZOIC ACID. 159

2097 When benzole acid is distilled with slaked lime or
caustic baryta, it is decomposed into benzene and carbon
dioxide (Mitscherlich). It also undergoes this decomposition
when heated with caustic soda, 1 and when its vapour is passed
over heated pumice stone 2 or iron. 3 Some diphenyl is always
formed in this way, and at a very high temperature the acid is
decomposed with separation of graphite and formation of carbonic
oxide, carbon dioxide, hydrogen and diphenyl, C 12 H 10 . 4 When
its vapour is passed over heated zinc-dust, it is reduced to benz-
aldehyde. 5 Sodium amalgam reduces its boiling solution with
formation of benzaldehyde, benzyl alcohol, a crystalline com-
pound, C 14 H 14 O 2 , and benzoleic acid, C 7 H 10 2 , which is further
described below. On heating with concentrated hydriodic acid
to 275 280, it is first reduced to toluene, but heptane and
hexane are formed on further heating, the latter being derived
from the benzene, which is formed by the decomposition of the
acid. 7

It is not attacked by chromic acid solution ; ozone converts it
in alkaline solution into carbon dioxide and water. 8 It is con-
verted in the animal organism into hippuric acid and appears
in this form in the urine ; 9 a portion is simultaneously oxidized
to succinic acid, which is also formed when an aqueous solution
of benzoic acid is treated with lead dioxide and sulphuric acid. 10
On oxidation with manganese dioxide and sulphuric acid, Carius
obtained carbon dioxide, formic acid, and some phthalic acid, 11
while Oudemans also detected a small quantity of the isomeric
terephthalic acid. 12 When the solution of its calcium salt is
electrolyzed, the acid is not decomposed in a similar manner to
the fatty acids, but the nascent oxygen exerts an oxidizing
action, with formation of carbon dioxide, carbonic oxide, and
some acetylene. 13

Benzoleic acid, or Hydrobcnzoic acid, C 7 H 10 2 , is formed when
sodium amalgam is allowed to act on a boiling solution of benzoic

Barth and Schreder, Ber. Deutsch. Chcm. Cfcs. xii. 2555.

Barreswill and Boudault, Journ. Pharm. Chim. v. 265.

F. d'Arcet, Journ. Prnkt. Chem. xiii. 427.

Schulz, Ann. Clicm. PJiarm. clxxiv. 202.

Baeyer, ibid. cxl. 295.

Kolbe, ibid, cxviii. 122 ; Herrmann, ibid, cxxxii. 75.

Berthelot, Jahrcsb. Chem. 1867, 364.

Gnrup-Besanez, Ann. Chcm. Pharm. cxxv. 207.

Wohler, Bcrzclius' Lchrb. Ed. 4, iv. 376 ; sec also hippuric acid.

I Meissner and Shcpard, Jdhrenb. Chcm. 1866, 397.

II Ann. Chcm. Phiirm. cxlviii. 72.

12 Zcitschr. Chcm. 1869, 84.

13 Berthelot, Bull. Soc. Chim. [2] ix. 103 ; Bourgoin, ibid. 431.



130 AROMATIC COMPOUNDS.

acid, hydrochloric acid being added at intervals benzyl alcohol
and a crystalline substance, C U H U O 2 , 1 are simultaneously formed.
Otto obtained the same acid from hydrobenzuric acid, 2 and,
together with other compounds, by the action of sodium amalgam
on benzoyl glycollic acid (p. 165). 3 It is an oily liquid, which has
a repulsive odour resembling that of valerianic acid, and is
rapidly altered in the air. When hydrochloric acid is passed
into its alcoholic solution, the ethyl ether is formed and resembles
ethyl valerate, but has a sharper smell ; in the air the smell
becomes exceedingly disagreeable, and, since it clings persistently
to the clothes, increases the difficulty of the investigation of the
compound and the free acid.



SALTS AND ETHERS OF BENZOIC ACID.

2098 Benzoic acid decomposes carbonates in aqueous solution,
but when a current of carbon dioxide is passed into an alcoholic
solution of potassium benzoate, potassium carbonate separates
out. Most of the benzoates are soluble in water and alcohol ;
some, such as the sodium and barium salts, are withdrawn from
their solutions by animal charcoal, and calcium benzoate is
decomposed by it, so that free benzoic acid can be extracted by
ether.*

Potassium benzoate, C 7 H 5 KO 2 -f-3H 2 O, crystallizes with diffi-
culty in small plates which effloresce in the air and are very
soluble in water and alcohol.

Sodium benzoafe, C 7 H 5 Na0 2 + H 2 O, crystallizes in needles,
which also effloresce in the air and are very soluble in alcohol.
It is used in medicine.

Ammonium benzoate, C 7 H 5 (NH 4 )O 2 , separates from a solution
containing an excess of ammonia in deliquescent rhombic
crystals ; it is also employed medicinally. Large crystals of
the less soluble acid salt, C 7 H 5 (NH 4 )O 2 + C 7 H 6 O 2 , are, obtained
by the gradual evaporation of its aqueous solution (Berzelius).

Calcium benzoate, (C 7 H-O.,) 2 Ca + 2H 2 O, crystallizes from hot
water in long lustrous needles which form fascicular aggregates ;
they dissolve in 29 parts of cold water and effloresce in the air.



1 Herrmann. Ann. Chcm. Pharm. cxxxii. 75.

2 Tbid. cxxxiv. 115. 3 Ibid. oxlv. 350.
* L. Licbermann, Her. Wicn. ATcad. 1877, 331.






ETHYL BENZOATE.



Barium benzoate, (C 7 H 5 O 2 ) 2 Ba -}- 3H 2 O, is only slightly soluble
in water, and crystallizes in needles or hard, lustrous tablets.

Lead benzoate, (C 7 H 5 2 ) 2 Pb 4- H 2 O, is obtained by the addi-
tion of lead acetate to a solution of the potassium salt ; it is a
crystalline, difficultly soluble precipitate.

Copper benzoate, (C 7 H 5 O 2 ) 2 Cu + 2H 2 O, crystallizes in light
blue plates united in spherical masses or in needles.

Silver benzoate, C 7 H 5 Ag0 2 , is a curdy precipitate, which is
soluble in alcohol and crystallizes from hot water in flat
needles.

Mercuric benzoate, (C 7 H 5 O 2 ) 2 Hg + H 2 O, crystallizes from hot
water in needles which are almost insoluble in cold water.

Ferric benzoate, (C 7 H 5 O 2 ) 6 Fe 2 . Berzelius obtained this salt in
yellow needles by dissolving ferric hydroxide in aqueous benzoic
acid ; it is decomposed by water and alcohol with formation
of an insoluble basic salt. Sestini was unable to prepare this
compound. 1 "When a soluble benzoate is added to neutral ferric
chloride, a reddish yellow precipitate is thrown down, which is
decomposed by washing with water into a soluble acid salt and
an insoluble basic salt. If the iron solution has been previously
treated with sufficient ammonia to produce a dark red coloura-
tion, soluble benzoates give a voluminous, hydrated, flesh-coloured
precipitate of (C 7 H 5 O 2 ) 3 Fe 2 (OH) 3 , which is not altered by cold
water.

These reactions are employed for the separation of iron from
manganese and for the detection of benzoic acid and its separa-
tion from other acids.

Methyl benzoate, C 6 H 5 .CO.OCH 3 , is best prepared by passing
hydrochloric acid into a solution of benzoic acid in methyl
alcohol, distilling, and then precipitating the ether with water. 2
It is a liquid which possesses an aromatic odour and boils
at 199.

Ethyl benzoate was prepared by Scheele as long ago as 1785, by
the distillation of a mixture of alcohol, benzoic acid and hydro-
chloric acid. It is not formed when an alcoholic solution of the
acid is allowed to stand in the cold, but the ether is gradually
formed if a little hydrochloric acid be added, or if the liquid
be heated to 100. In order to prepare it, the method adopted
for the preparation of the methyl ether may be followed, or the
alcoholic solution of the acid may be heated with sulphuric or

1 Zcitschr. Chem iv. 6t 8.
- Carius, Ann. Chem. Pharm. ex. 210.
VOL. III. PART IV. M



162 AROMATIC COMPOUNDS.

hydrochloric acid. It is a liquid which has a pleasant aromatic
smell, and boils at 213.

Ethyl benzoate is also readily formed by the action of benzoyl
chloride on alcohol (Wbhler and Liebig), which is more readily
attacked by it than water. The presence of alcohol even in very
dilute aqueous solution can therefore be detected by warming it
with a little benzoyl chloride and removing the excess of this by
caustic soda; even when only 01 per cent, of alcohol is present,
the characteristic smell of ethyl benzoate can be distinctly
recognized (Berthelot ; see Part I. p. 318).

Boiling-point.

Isopropyl benzoate, 1 C 6 H 5 .CO.OCH(CH,) 2 . 218

Propyl benzoate, 2 C 6 H 5 .CO.OC 3 H 7 . . . 229'5

Butyl benzoate, 3 C 6 H 5 .CO.OC 4 H 9 . . . 247'3

Amyl benzoate, 4 C H 5 .CO.OC 5 H n . . . 260 7

Octyl benzoate, 5 C 6 H 5 .CO.OC 8 H 17 . . . 306

Allyl benzoate, 6 C 6 H 5 .CO.OC 3 H 5 . . . 228

Benzyl lenzoatc, C 6 H 5 .CO.OCH 2 .C 6 H 5 . Cannizzaro obtained
this compound by the distillation of benzyl alcohol with benzoyl
chloride or benzoic anhydride. 7 It boils at 323 324, has the
sp. gr. of T1227 at 39, and solidifies in a freezing mixture to
lustrous, compact crystals, melting at 21 . 8 As already mentioned,
it is also formed by the action- of sodium methylate on benz-
aldehyde (p. 93) and is a constituent of Peru balsam 9 and of
Tolu balsam, 10 but has not yet been obtained from them in the
pure state. If the ether be submitted to distillation while it still
contains water, it is decomposed with formation of beazoic acid,
benzyl alcohol and toluene.

Ethyhne lenzoate, (C 6 H 5 .CO 2 ) 2 C 2 H 4 . Wurtz prepared this
compound by the action of silver benzoate on ethylene
bromide ; n it crystallizes from ether in lustrous, rhombic prisms, 12
melting at 67.

Silva, Ann. Chcm. Pharm. cliv. 255.

Linncmann, ibid. clxi. 28.

Ibid. clxi. 92.

Rieckher, ibid. Ixiv. 336.

Zincke, ibid. clii. 7.

Hofmann and Cahours, ibid. c. 358 ; cii. 297.

Ibid. xc. 254.

L Claisen, private communication.

Kraut, Ann. Chem. Pharm. clii. 129 : Bcr. Deutsch. Chem. Ges. ii. 18-

Busse, ibid. ix. 830.

Jahresb. Chem. 1859, 676.

Bodewig, ibid. 1879, 676



PHENYL BENZOATE. 103

The following propylene ethers have been prepared in a
similar manner :

Melting-point.
Propylene benzoate : l
C 6 H 5 .CO.OCH 2

, viscous fluid .....
C 6 H 5 .CO.OCH.CH 3
Trimethylene benzoate : 2



Dimethylmethylene benzoate : 3

CH 6 CO O / C \CH 3 ' monoclinic Pyramids . G9 71

The last of these yields acetone on saponification.

Benzidene benzoate, (C 6 H 5 .CO.O) 2 CH.C 6 H 5 , is formed by the
action of benzidene chloride on silver benzoate, and crystallizes



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