Trisazo Direct Black dyes based on nonmutagenic 3,3′-disubstituted benzidines

Abstract Using 3,3′-di-n-propoxybenzidine, 3,3′-di-n-butoxybenzidine and 3,3′-di-(β-hydroxyethoxy)-benzidine as diazo components, and 2,4-diamino-n-propoxybenzene, 2,4-diamino-n-butoxybenzene and 2,4-diaminophenyl-β-hydroxyethyl ether as coupling components, a series of new black trisazo dyes were prepared as homologues of C.I. Direct Black 38. Assessment of the resultant dyes indicated that their color and the dyeing properties were comparable or slightly better than the properties of C.I. Direct Black 38.