GB908202A - Process for the production of asymmetrical polyazo dyestuffs - Google Patents

Abstract

In a process for making asymmetrical polyazo dyes a diazoamino-diazo compound of formula <FORM:0908202/IV (b)/1> where R1 and R2 are benzenic residues, R3N is the residue of a primary or secondary amine of the aliphatic, cycloaliphatic or aromatic series, and X is a single bond or a bridge member, is coupled with an azo component and the diazoamino group is split in the resulting product and coupled with a coupling component different from the first coupling component. R1 and R2 may carry substituents such as halogen, nitro, alkyl, alkoxy, sulphone, sulphonamide, sulphonic acid or carboxylic acid groups. Bridge members indicated for X are -N=N-, -NHCONH-, -NHCO, -SO2-, -CO-or -CH=CH-. Examples of indicated amines are sarcosine, diethanolamine, 5-sulpho-2-alkylaminobenzoic acids and phenyl-glycine-carboxylic acid. Indicated coupling components are pyrazolones and their sulphonic acids, acetoacetic anilides, arylides of 2,3-hydroxynaphthoic acids, naphthols, naphthylamines, aminonaphthols and sulphonic acids of the last three types of compounds. The starting diazo amino compounds are made by coupling appropriate tetrazo compounds and amines, tetrazo compounds with low coupling energies being preferably coupled with aliphatic amines. The starting compounds may also be made by splitting on one side bis-diazoamido compounds obtained by treating appropriate tetrazo components in two steps with different amines. The latter process is of advantage when special demands are made on the stability of the remaining diazoamino group. Examples are provided of the preparation of the dyes and their use in colouring cotton and wool in a variety of colours.