A Manual of the Chemistry of the Carbon Compounds

THE CARBON COMPOUNDS. 415
It has also teen produced by heating a mixture of potassium
phenate and benzoate.:'—
COH6.OK + C9H6.C02K = C9H6.C6H6 + CO8K2
Diphenyl crystallizes from boiling alcohol in large, brilliant, thin
plates, melting at 70 o> 5. It boils at 240°, and possesses a peculiar,
aromatic smell. By heating it with a solution of chromic trioxide in
glacial acetic acid, it is oxidized to benzoic acid.
Monohomodiphcnyl C12H0Br is obtained by adding bromine to a
solution of diphenyl in carbon disulphide. It forms thin, large
plates, melting at 89°, and boiling at 310°. Oxidizing agents convert
it into parabromobenzoic acid.
Dibromodiphenyl C,2H8Br2 is formed by acting with bromine on
diphenyl in the presence of water. It crystallizes from benzene in
large colourless prisms, melting at 164°. and volatilizing at a high
temperature. On oxidation it yields also parabromobenzoic acid.
Linitrodipkenyl C,2H8(NOj)2.—When diphenyl is dissolved in cold
concentrated nitric acid, two isomeric eomponuds are formed. One
crystallizes in slender, colourless needles, melting at 213"; and the
other, called tsadinitrodiphcnyl, which is more soluble in alcohol,
forms large colourless crystals, melting at 93 O> 5.
Diamidophnyl, or Benzidine, C12H8(NHa)2, is not only produced
by reducing the first of the dinitro-componnds with ammonium sulphide
or tin and hydrochloric acid, but also by the action of acids on
hydrazobenzene (page 328), the following molecular change taking
place :—
CflH6.NH ^ C0H,NH4
CflH6.NH " 00
It is therefore conveniently prepared by passing sulphur dioxide
into an alcoholic solution of azohenzene:—
C0H6.N C9H4.NH2
||+2H2O+S0.3= | +H2SO.
CflHf,N CA-NH,
Benzidine has also been obtained by acting witli sodium on bromaniline.
It forms silvery scales, melting at 118°, and subliming, when more
strongly heated, with partial decomposition.
Benzidine Sulphate C12H8(NH,,)2 is a white powder, which is almost
insoluble in water and alcohol.
Imidodiplicnyl, or Carbazol Cj2H8.NH.—This body was first found
in crude anthracene; it is produced synthetically by passing phenylaniline
through a red-hot tube;—
CaIL CCH4
^NH | )NH + Ha