GB442873A - Manufacture of azo dyes on the fibre - Google Patents

Abstract

Azo dyes are made on the fibre by coupling the diazo compound of an amine of the formula <FORM:0442873/IV/1> (in which Z = a furyl or substituted furyl group, X = H or OR and R = alkyl) with an arylide of 2 : 3-oxynaphthoic acid, both components being free from solubilizing groups such as SO3H or COOH. The diazo compound may be applied in the form of a diazoimino compound, e.g. in a printing paste, the colour being developed by acid treatment. Violet and blue shades are obtained. In examples, the following dyes are produced on cotton: (1) 2-furoylamino-5-aminoanisole --> the b -naphthylamide; (2) 4 - furoylamino - 2 : 5 - diethoxyaniline --> the o-toluidide; (3) chlorofuroyl - 4 - amino - 2 : 5-dimethoxyaniline --> the o-toluidide; (4) a paste containing the o-toluidide and the diazoimino compound from diazotized 4-furoylamino-2 : 5-diethoxyaniline and piperidine-a -carboxylic acid is printed on cotton and developed with steam containing acetic acid. Specifications 303,838 and 313,865, [both in Class 15 (ii)], are referred to. Chlorofuroyl-4-amino - 2 : 5 - dimethoxyaniline is made by refluxing furoic acid with sulphuryl chloride, condensing the chloro-furoyl chloride thus obtained with 4-nitro-2 : 5-dimethoxyaniline in presence of benzene and potassium carbonate and the product reduced by hydrogenation at 100 DEG C. in methyl alcohol using a reduced nickel catalyst. The Specification as open to inspection under Sect. 91 comprises the production of azo dyes in substance or on the fibre by coupling the diazo compound of an amine of the formula <FORM:0442873/IV/2> (Z and R as above) with an arylide of 2 : 3-oxynaphthoic acid or an acyl-acetyl derivative of an aromatic mono- or diamine. This subject-matter does not appear in the Specification as accepted.