GB491496A - Improvements in the manufacture and production of azo dyestuffs - Google Patents

Abstract

Azo dyes are made by coupling diazo compounds of amines of the general formula R-NH-CO-R1-NH2 (in which R is the residue of a sulphosalicylic acid in which the carboxylic group is in m-position to the -NH group and R1 = phenyl) with amines capable of coupling (including heterocyclic amines) and treating the resulting dyestuffs with phosgene, or by coupling a diazo compound of an amine of the above formula (2 mols.) with a urea capable of coupling derived from two molecular proportions of an amine (1 mol.) Instead of the amines, there may be used compounds which are capable of being converted into amines, e.g. the diazo compound may be coupled with a nitrophenyl pyrazolone and the nitro-azo dyestuff reduced. They dye vegetable fibres and regenerated cellulose or mixtures thereof with wool in yellow to red shades; the dyeings may be after-treated with metal salts. In examples: (1) the dyestuff 3- or 4-aminobenzoyl-21-hydroxy-31-carboxy- 11 - aminobenzene - 51 - sulphonic acid --> m - toluidine, p-cresidine or aminohydroquinone dimethyl ether is treated with phosgene; 3- or 4-aminobenzoyl- or 4-chlor-3-aminobenzoyl-41-hydroxy-31 - carboxy - 11 - aminobenzene - 51 - sulphoni acid may be used as diazo component; (2) the dyestuff 4 - chlor - 3 - aminobenzoyl - 21-hydroxy - 31 carboxy - 11 - aminobenzene-51 - sulphonic acid --> (1-41-aminophenyl)-3-methyl-5-pyrazolone is treated with phosgene. A sample has been furnished under Sect. 2 (5) of the dyestuff: 3-aminobenzoyl-31-amino-61 - hydroxy - 51 - sulphobenzene - 11 - carboxylic acid \sQ J acid urea. Specification 348,680 is referred to. Other components specified are chlor-, methyl- or methoxy-3-aminobenzoyl - 21 - or 41 - hydroxy - 31 - carboxy - 11 - aminobenzene - 51 - sulphonic acids; aminophenylpyrazolone carboxylic acids and their esters and amides.