GB995502A - Reactive mono- and dis-azo dyestuffs - Google Patents

Abstract

The invention comprises azo dyes which in the form of the free acids are of formula <FORM:0995502/C4-C5/1> wherein R is a hydrogen atom or C1- 4 alkyl group; R1 and R2 are methyl groups and R3 and R4 are each independently a hydrogen atom or a methyl group, or when R3 and R4 are hydrogen atoms R1 and R2 are joined together to form a tetra- or penta-methylene radical, or R1 and R3 and R2 and R4 are joined togethe to form in each case a trimethylene radical; D is the residue of a diazo component of the benzene, naphthalene or stilbene series or a benzene or naphthalene radical substituted by a phenylazo or naphthylazo group; n is an integer from 1 to 6; E is a 1,4-phenylene or -naphthylene radical which may be substituted by ureido, acetylamino, methyl, methoxy, carboxylic or sulphonic acid groups and X is a divalent mono- or di-chloropyrimidyl, or 5-cyanochloropyrimidyl radical or a divalent 1,3,5-triazinyl radical substituted in the 6-position by a hydrogen atom or a C1- 4 alkyl, phenyl, C1- 4 alkoxy, phenoxy, amino or substituted amino group. The dyes are prepared by reacting an azo dye of formula <FORM:0995502/C4-C5/2> with a hydrazine of formula <FORM:0995502/C4-C5/3> Specified hydrazines include N:N:N1-trimethyl and N:N:N1:N1 - tetramethyl - hydrazine, N - aminopiperidine, N - aminopyrrolidine, 1,5 - diazabicyclo - (0,3,3) - octane and, preferably, N,N - dimethylhydrazine. The dyes may be used to colour wool, silk, synthetic polyamide and preferably cellulose materials by the usual reactive dye processes. The preparation of the dyes is described in examples.