BENZENE. 271 



Dibromdiphenyl, C^IPBr 2 , is produced by the ac- 

 tion of bromine on diphenyl under water. Large, 

 colorless prisms, that fuse at 164, and can be distilled 

 without decomposition. Insoluble in cold alcohol, diffi- 

 cultly soluble in boiling alcohol, easily in benzene. 



Dinitrodiphenyl, C 12 H 8 (N"0 2 ) 2 , is formed by pour- 

 ing cold fuming nitric acid on diphenyl. Fine, color- 

 less needles, difficultly soluble in alcohol. Fuses at 

 213. A compound of the same composition, isodini- 

 trodiphenyl, is formed at the same time with dinitrodi- 

 phenyl ; it is more easily soluble in alcohol, and forms 

 large colorless crystals that fuse at 93.5. 



Diamidodiphenyl (Benzidine), C I2 H 8 (FH 2 ) 2 . Is 

 obtained by the reduction of dinitrodiphenyl with am- 

 monium sulphide or tin and hydrochloric acid. Is 

 further formed by the treatment of the isomeric hy- 

 drazobenzene (p. 269) with acids ; by heating azoben- 

 zene with concentrated hydrochloric acid at 115 ; by 

 treating monobromanilin with sodium ; and, together 

 with anilin, by conducting sulphuretted hydrogen into 

 an alcoholic solution of nitrobenzene in the presence of 

 copper or lead. Colorless laminae of a silvery lustre, 

 fusing at 118, but slightly soluble in cold water, more 

 readily in hot water, and easily in alcohol. Sublimable, 

 but undergoing partial decomposition. Benzidine sul- 

 phate, C 12 H 12 N 2 .H 2 S0 4 , is almost insoluble in water and 

 alcohol. 



Carbazol, C 12 H 9 N (probably Imidodiphenyl 

 C 6 H 4 ) 

 C 6 H 4 f ^-^-)' ^- s obtained as a secondary product in 



the process for the purification of crude anthracene on 

 the large scale. Can be artificially prepared by con- 

 ducting the vapor of anilin or diphenylamine through 

 red-hot tubes. Crystals, that resemble those of anthra- 

 cene ; fusing point, 238 ; boiling point, 338. By 

 the action of hydriodic acid on carbazol, there is formed 

 a base carbazolin, C 12 H 15 ^N", that crystallizes in large, 

 white needles, fuses at 96, and boils at 286. 



