GB633492A - Manufacture of dyestuffs - Google Patents

Abstract

A vat dye or anthraquinone intermediate is reduced to the metal salt of its leuco body or a complex compound comprising the metal salt with a metal in presence of ammonia, or a primary or secondary amine which will form a co-ordination compound with copper hydroxide in aqueous suspension. The leuco body may be converted to the leuco-sulphuric ester by reacting with sulphur trioxide or the addition compound of sulphur trioxide with an organic amide or tertiary base of any substance actually used in practice for or known from the literature to be capable of, forming sulphuric esters from vat dyestuffs in the presence of metals, from leuco compounds or metal salts thereof, comprising the metal salts thereof. Inorganic or organic salts may be present during the reduction, e.g. sodium b -naphthalene sulphonate, potassium ethyl sulphate, ferric chloride, and magnesium chloride. Diluents specified for the reduction are benzene, chlorobenzene, acetone, pyridine, acetonitrile, ethylene dichloride, dimethylformamide, and diethylformamide. An amide derived from a secondary amine may be present during the sulphation step, e.g. dimethylformamide, diethylformamide, dimethylacetamide, formylpiperidide, tetramethylurea, N : N - diethyl - p - toluene sulphonamide. In examples, zinc dust is used together with a diluent and an organic or inorganic salt as specified above to reduce the following dyestuffs in presence of the amines indicated, the product being then sulphated with dimethylformamide-sulphur trioxide: (1) 6 : 61 - diethoxythioindigo, with methylamine or ethylene diamine; (2) 2-(1-amino-2-anthraquinonyl) - anthraquinone - 21 : 31 - oxazole, with methylamine, ethanolamine or ammonia; (3) 5 : 51 - dibenzoylamino - 1 : 11 - dianthrimidecarbazole with methylamine; (4) 2-chloro - 3 - acetylaminoanthraquinone, with ethylene diamine; (5) dimethoxydibenzanthrone, with diethanolamine; (6) an anthraquinonylamino - benzanthrone - pyrazolanthrone according to example 1 of Specification 344,147, with methylamine. Dyes of the indigoid series also are referred to. Specification 274,156, [Class 2 (iii)], and 610,117 also are referred to.