Some unsymmetrical dis-azo dyes have been synthesised from 4,4'-diaminodiphenylamine-2-sulphonic acid in an attempt to find a suitable substitute for benzidine which is now an established carcinogen. The shade, strength and absorption characteristics in the visible region have been compared with the corresponding dyes derived from benzidine.
S YASMIN ,M YOUNAS ,BADR UDDIN ,M A SAEED ,M FAROOQ ,
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