Synthetical applications of activated metal catalysts. XXI. The formation of carbazole from aniline and related compounds in the presence of degassed Raney nickel

Abstract

Trace amounts of carbazole are formed by the action of W-7J Raney nickel on aniline, diphenylamine, 2,2'-diaminobiphenyl, and 2-aminobiphenyl. Aniline yields also N-cyclohexylaniline, diphenylamine, 2,2'-diaminobiphenyl, and 2-aminobiphenyl; 2,2'-diaminobiphenyl gave 2-aminobiphenyl also. Carbazole was not detectably affected by the catalyst. These results suggest that aniline is slowly converted to carbazole (a) by way of diphenylamine; (b) by way of 2,2'-diamino- biphenyl and 2-aminobiphenyl; and (c) by way of 2,2'-diaminobiphenyl. The last route appears to be the most efficient one.