GB815737A - New polyazo-dyestuffs derived from 3,3-dihydroxydiphenylamine and processes for their manufacture - Google Patents

Abstract

The invention comprises dyestuffs of formula <FORM:0815737/IV (c)/1> where R and R1 are benzene or naphthalene residues, at least one of which contains at least one SO2H group, A is a residue of 2-naphthyl-3-hydroxy-6-, -6-hydroxy-8-, -5-hydroxy-7- and -8-hydroxy-6-mono- and -8-hydroxy-3,6-di-sulphonic acids and X is -N=N- or <FORM:0815737/IV (c)/2> where -N=N- is m- or pto -NH-CO-. They may be made by diazotizing an appropriate 2-amino- or 2-(31- or 41-aminobenzoylamino)-naphthol sulphonic acid, coupling with 3,31-dihydroxydiphenylamine and the product with 2 mol. proportions of the required diazo compounds; by coupling a diazotized aniline or naphthylamine in alkaline medium with the naphthol sulphonic acid, the diazotized product is coupled with the diphenylamine and the disazo dyestuff thus obtained is coupled with an appropriate diazo compound; by coupling a diazotized aniline or naphthylamine with the diphenylamine and the product with the diazotized naphthol sulphonic acid with subsequent coupling of the disazo dyestuff thus produced with an appropriate diazo compound and by coupling in an alkaline medium a monoazo dyestuff obtainable by coupling a diazotized aniline or naphthylamine with the diphenylamine and a diazo compound of a monoazo dyestuff obtainable by alkaline coupling the naphthol sulphonic acid with an appropriate diazo compound. The dyestuffs dye leather in yellow to deep brown tints. In examples which illustrate the preparation of the dyestuffs and their use in dyeing leather components used corresponding to R and R1 are 4-nitro-, 2-chloro-4-nitro-and 2-hydroxy-3,5-dinitro-anilines, aniline-4-sulphonic acid and its 2-methyl and -nitro derivatives, aniline-2,5-disulphonic acid, 4-amino-diphenylamine-2- and 4-amino-41-nitropiphenylamine-21-sulphonic acids, 4-amino-1,11-azobenzene-41-sulphonic acid, Cleve's acids and 1-naphthylamine-4- and 2-naphthylamine-7-sulphonic acids, the naphthol sulphonic acids corresponding to A being chosen from those indicated above.