GB469969A - Improvements in the manufacture and production of vat dyestuffs - Google Patents

Abstract

Vat dyestuffs are manufactured by causing aluminium to act in the presence of sulphuric acid on 1 : 2<1>-dianthraquinonyl sulphide, the compounds of the nature of 1 : 2<1>-dianthraquinonyl sulphoxide obtainable therefrom by oxidation, or halogen or alkyl derivatives of the said substances, advantageously in the presence of nitrosylsulphuric acid or the oxides of acid-forming elements of groups V--VII of the periodic system or the corresponding acids, e.g. the oxides and acids of vanadium, chromium, tungsten or manganese. The products may be purified by precipitation in stages from sulphuric acid, which process may be combined with the preparation of the dyestuffs. In examples: (1) 1 : 2<1>-dianthraquinonyl sulphide is treated with aluminium and sulphuric acid, and the product is precipitated in stages by means of aqueous sulphuric acid; 1-(4-methylanthraquinonyl)-2<1>-anthraquinonyl sulphide may be similarly treated; (2) 1 : 2<1>-dianthraquinonyl sulphide is treated with aluminium and fuming sulphuric acid in the presence of pyrolusite, and the product is precipitated by means of water or dilute sulphuric acid; (3) 1 : 2<1>-dianthraquinonyl sulphide is treated with aluminium and 96 per cent sulphuric acid in the presence of vanadic acid; 1-anthraquinonyl-2<1>-(3<1>-methylanthraquinonyl) sulphide may be similarly treated; (4) 1 : 2<1>-dianthraquinonyl sulphide is treated with aluminium and sulphuric acid, and the product is precipitated with water, treated with nitrobenzene and precipitated in stages from sulphuric acid; 1-(2-methylanthraquinonyl)-2<1>-anthraquinonyl sulphide may be similarly treated; (5) 2-chloro-3 : 1<1>-dianthraquinonyl sulphide is treated with aluminium and sulphuric acid, the mixture is poured into water and the product treated with acetone and precipitated from sulphuric acid. 1 - (2 - and 4 - Methylanthraquinonyl) - 2<1>-anthraquinonyl sulphides are obtainable by reacting 1 - chloro - 2- and 4 - methylanthraquinone respectively with anthraquinone-2-mercaptan sodium salt. 1 - Anthraquinonyl - 2<1> - (3<1> - methylanthraquinonyl) sulphide is obtainable from 2-methylanthraquinone-3-mercaptan sodium salt and 1-chloroanthraquinone. 2 - Chloro - 3 : 1<1> - dianthraquinonyl sulphide is obtainable from 2-chloranthraquinone-3-mercaptan sodium salt and 1-chloranthraquinone.