A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS, 393
Oinnamic acid is generally prepared by distilling liquid styrax with
a solution of sodium carbonate, and precipitating the filtered residual
solution with hydrochloric acid. The precipitate is purified by crystallization
or sublimation. It crystallizes from boiling water in fine
needles, and from alcohol in transparent prisms, melting at 133°,
and boiling at 300°. Its salts resemble the benzoates; ferric chloride
produces in a neutral solntion of a cinnamate a yellow precipitate.
Oxidizing agents convert it into benzaldehyde and benzoic acid,
and nascent hydrogen combines with it, forming phenylpropiomc acid
(page 390).
When cinnamic acid is fused wilh caustic potash, it is resolved into
acetic acid and benzoic or phenylformic acid, and when distilled with
slaked lime it yielda carbon dioxide and styrolene.
Ethyl Cinnamate C »%- C i^^} 0 is prepared by dissolving the
acid in absolute alcohol, and passing hydrochloric gas into the solution.
It is a fragrant, oily liquid, boiling at 267°,
C H C HO)
Benzyl Cinnamate,or Cinnamtin Vi 5 Tx 8 nTr f 0, occurs in balsam
of Peru and Tola, and has been prepared Dy sodium ciunamate with
benzyl chloride. It crystallizes from alcohol in small, brilliant prisms,
welting at 39°, and possessing an agreeable odour,
Cinnyl Cinnanwte, or Slyratin c ft C H } °-~~ Tlie Preparation
of this compound has already been described (page 391). It crystallizes
in needles, melting at 50°, and possessing a fragmut odour.
Nttrocinnamic Add COH4(NO2)C8HSO2 exists in two modifications,
which are formed by dissolving cinaamic acid in cold concentrated
nitric acid.
Paranitrocinnamie Acid is but sparingly soluble in boiling alcohol,
and crystallizes in small needles, melting at 265°, Chromic acid converts
it into parauitrobenanc acid.
Metanitroeinnamic Acid is more freely soluble in alcohol, and
melts at 232°; on oxidation it yields metanitrobenzoio acid.
Phenyldibrom&prc^im.ic Acid O6H8.C2HaBr2.CO4H is readily formed
by combining cinuamio acid with bromine. It crystallizes from
alcohol in small rhombic plates, and yields, when heated with alcoholic
potash, two isomeric monobiomocinnamic acids.
Phenylpropiolic Acid C0H5.C2,C0aH stands in the same relation to
cinnamic acid as stearolic to oleic acid, and is obtained by boiling
a lnonobromocinuaroic acid with alcoholic potash, or by suspending
aodium-ethenyl-benxeue in. ether, and passing carbon dioxide into
it;—
C,,H6.Cs=CNa + CO2 = ^H^C^CCO^Na
It crystallizes in white, silky needles, melting at 136°. It combines
with two molecules of bromine or hydrogen, and is resolved by l>eatiug
it with baryta into carbon dioxide and ethinyl-benzene.