GB679604A - Manufacture of new azo-dyestuffs - Google Patents

Abstract

4 : 41 - Diacetoacetylamino - stilbene - 2 : 21-disulphonic acid is prepared by reacting 4 : 41-diaminostilbene-2 : 21-disulphonic acid with an acetoacylating agent. An example is given of the reaction using diketene, the product being isolated as its disodium salt.ALSO:The invention comprises dyestuffs of the formula <FORM:0679604/IV (c)/1> where R1 and R2 are each the residue of a diazo component containing a metallizable group in the o-position. These are prepared by coupling 4 : 41 - diacetoacetylaminostilbene - 2 : 21 - disulphonic acid with 2 mols. of a suitable diazo compound, preferably derived from an o-carboxyamine free from further solubilizing groups. The metallizable group may, however, be hydroxy or carboxymethoxy. Other substituents in the diazo compound may be halogen, alkyl, alkoxy, nitro, acylamino and arylazo; suitable compounds are listed. The dyestuffs may be used for dyeing and printing animal fibres such as wool, silk and leather and also cotton, linen and regenerated cellulose. They may be metallized by normal methods in substance, in the dyebath or on the fibre, to give compounds of, e.g., copper, chromium, iron, cobalt or nickel. The processes of Specifications 455,274 and 619,969 are suitable. In the examples the diazo derivatives of the following amines are coupled with 4 : 41-diacetoacetylamino - stilbene - 2 : 21 - disulphonic acid:-2 - amino - 5 - benzoylaminobenzoic acid, 2 - amino - 5 - chlorobenzoic acid and 4 - nitro - 2 - aminophenol. A further example is given of the dyeing of cotton, with three alternative coppering treatments.