GB457534A - Manufacture of 4-amino-3:4-dinitro-diphenylamine and of azo-dyestuffs therefrom - Google Patents

Abstract

Azo dyes insoluble in water are made in substance, on the fibre or on a substratum by coupling diazotized 4 - amino - 3 : 4<1> - dinitrodiphenylamine with an arylide of 2 : 3-oxynaphthoic acid. Black-currant to black shades are obtained. They may be used for the production on the fibre of mixed shades with other dyes derived from 2 : 3-oxynaphthoic arylides, e.g. with those from diazotized 4-aminodiphenylamines. According to the examples: (1) cotton is impregnated with the a -naphthylamide by the usual process and developed with the diazo solution; (2) the material is prepared with the o-toluidide, printed with a paste containing the diazo compound, dried, treated with hot soda solution, rinsed and soaped; (3) crude, desized cotton piece goods are impregnated with the o-anisidide, passed through an acetic acid solution of the diazo compound, steamed, rinsed and soaped; (4) bleached cotton material is grounded with the o-anisidide, dried, passed through a solution containing diazotized 4-amino-4<1>-methoxydiphenylamine, diazotized 4 - amino - 3 : 4<1> - dinitrodiphenylamine and ammonium sulphate, steamed, rinsed and soaped; (5) the diazo compound is coupled in substance with the anilide. Other arylides are also specified. Specification 329,960, [Class 2 (iii)], is referred to. 4 - Amino - 3 : 4<1> - dinitrodiphenylamine is obtained by condensing 4-nitro-1-chlorobenzene-2-sulphonic acid with 1 : 4-diamino-3-nitrobenzene and splitting off the sulphonic group from the 4-amino-3 : 4<1>-dinitrodiphenylamine-2<1>-sulphonic acid thus obtained. According to the example, the condensation is effected under pressure in the presence of water and calcium carbonate and the sulphonic group is split off by heating with sulphuric acid. The Specification as open to inspection under Sect. 91 describes the preparation of 4-amino-6-methyl - 3 : 4<1> - dinitrodiphenylamine and mentions 6<1> - bromo - 2<1> : 3<1> - hydroxynaphthoyl - (1 - amino - 2 : 4 - dimethoxybenzene) and 6<1> - methoxy - 2<1> : 3<1> - hydroxynaphthoyl-(1-amino-2-methoxybenzene as coupling components. The use of the condensation product of oleyl alcohol and ethylene oxide in the printing paste of example 2 is also mentioned. This subject-matter does not appear in the Specification as accepted.