GB820950A - New disazo-dyestuffs of the stilbene series, complex metal compounds thereof and process for making them - Google Patents

Abstract

The invention comprises dyes of formula <FORM:0820950/IV(c)/1> where R is a benzene residue free from sulphonic and carboxylic acid groups and X is OC-CH= CH-CO or, advantageously, CO, and their nickel and copper complexes. They are made by coupling, advantageously in an alkaline medium, appropriate pyrazolones with diazo compounds of the required 4-acylamino-2-aminophenols, or by linking 2 mols. of appropriate monoazo dyes or metal complexes thereof by means of phosgene or a fumaric acid dihalide, with subsequent metallization, if desired. Preferably ammine complexes in aqueous media are used as metal-yielding agents. Substituents such as alkyl, alkoxy, hydroxyalkyl and sulphonamide groups may be present in R. The metal-free dyes dye animal fibres, e.g. wool, silk and leather and especially cellulosic material such as cotton, linen, artificial silk and regenerated cellulose. Advantageously the dyeings are treated on the fibre, or partly on the fibre and partly in the bath, with the metal-yielding agents. Precipitation of the sparingly soluble metal complexes may be prevented in a neutral or alkaline dye-bath by the addition of an aliphatic amine containing at least one amino group separated from an hydroxyl group by 2 carbon atoms, the dye, the metal-yielding agent (which should be resistant to alkali) and advantageously phosphoruscontaining anions. Dyeing with the complexes formed in substance may be effected in the presence of the amines and anions of the last sentence. Examples are provided of the preparation of the dyes and their complexes and the use of the latter in the dyeing of cotton in red and yellow shades. Specifications 455,274, [Group IV], and 619,969 are referred to.