C12H9N

CARBAZOL  , a chemical constituent of coal-tar and crude anthracene . From the latter it may be obtained by fusion with caustic potash when it is converted into carbazol-potassium, which can be easily separated by distilling off the anthracene . It may be prepared synthetically by passing the vapours of diphenylamine or aniline through a red-hot tube; by heating diorthodiaminodiphenyl with 25 % sulphuric acid to 200° C. for 15 hours; by heating orthoaminodiphenyl with lime; or by heating thiodiphenylamine with copper powder . It is also obtained as a decomposition product of brucine or strychnine, when these alkaloids are distilled with zinc dust . It is easily soluble in the common organic solvents, and crystallizes in plates or tables melting at 238° C . It is a very stable compound, possessing feebly basic properties and characterized by its ready sublimation . It distils unchanged, even when the operation is carried out in the presence of zinc dust . On being heated with caustic potash in a current of carbonic acid, it gives carbazol carbonic acid C12H$N• COOH; melted with oxalic acid it gives carbazol blue . It dissolves in concentrated sulphuric acid to a clear yellow solution . The potassium salt reacts with the alkyl iodides to give N-substituted alkyl derivatives . It gives the pine-shaving reaction, in this respect resembling pyrrol (q.v.) .