GB705850A - Manufacture of trisazo-dyestuffs - Google Patents

Abstract

The following N-substituted amides of 3-amino-4-hydroxybenzoic acid may be obtained by the process of Specification 606,872:-N-m-chlorophenyl, N-o-methoxyphenyl, N-p-ethoxyphenyl, N-cyclohexyl and N-methyl-N-phenyl, in addition to those specified therein. The anilide of 4-amino-3-hydroxybenzoic acid can be made similarly. Specifications 455,274, 532,261, 587,110, 619,969 and 649,656 also are referred to.ALSO:The invention comprises trisazo dyestuffs of the formula <FORM:0705850/IV(c)/1> where R1 is the residue of an aromatic m-dihydroxy compound with the hydroxy groups oto the azo linkages and containing at most two fused 6-membered rings, R2 is a salicylic acid residue (which may be substituted) attached pto the hydroxy group, and X is -CO-R attached pto the hydroxy or the azo group, R being alkyl, aryl, <FORM:0705850/IV(c)/2> or <FORM:0705850/IV(c)/3> The dyestuffs are preferably free from sulphonic acid groups. They are made by coupling an aromatic m-dihydroxy compound in either order with (a) a diazotized X-substituted o-aminophenol, and (b) the diazo intermediate from tetrazotized benzidine and a salicylic acid. The dyestuffs are suitable for dyeing and printing wool, silk, leather, cotton, linen and regenerated cellulose. They may be metallized on the fibre or in the dyebath, e.g. by the methods of Specifications 455,274 and 619,969. In examples, (1) tetrazotized benzidine is coupled with one mol of salicylic acid and one mol of the monoazo dyestuff 3-amino-4-hydroxy-benzanilide --> resorcinol or 1 : 3-dihydroxynaphthalene; (2) cotton is dyed brown with the product of (1), followed by after-treatment with sodium copper tartrate. Other suitable diazo components are specified. Specifications 532,261, 587,110, 606,872 and 649,656 also are referred to.