GB490941A - Manufacture of azo-dyestuffs - Google Patents

Abstract

Azo dyes, insoluble in water, are made in substance, on a substratum or on the fibre by coupling the diazo compound of an amine of the formula <FORM:0490941/IV/1> where X = alkyl, alkoxy or halogen, with an arylide of 2 : 3-hydroxynaphthoic acid. In examples: (1)-(2) bleached cotton piece goods are impregnated with the anilide or o-toluidide and printed with a paste containing 2 : 5-diethoxy- or dimethoxy-51-methyl-21 : 41-dinitrodiphenylamine - 4 - diazonium chloride, dried and passed through a hot sodium carbonate solution (blue black); (3) bleached cotton piece goods are padded with the a -naphthalide, passed through a solution of 2 : 5-diethoxy-21 : 41 - dinitro - 51 - chlorodiphenyl amine-4-diazonium chloride in formic acid and steamed (greenish blue black); (4) the diazo compound of (3) is coupled in substance with the 4-chloro-2-methylanilide. A table of further combinations is given. According to the Provisional Specification diazo compounds of amines of the formula <FORM:0490941/IV/2> wherein X and Y, which may be the same or different, stand for alkoxy, aryloxy or aralkyloxy and Z = alkyl, alkoxy, halogen or hydrogen are used. Specifications 329,960, [Class 2 (iii)], and 377,207 are referred to.