GB327860A - - Google Patents

Abstract

327,860. British Celanese, Ltd., Ellis, G. H., Olpin, H. C., and Kirk, E. W. Aug. 1, 1928. Naphthalene, dyes derived from.-Nitrogenous dyestuffs are made by introducing nitrogen into naphthazarin or its nuclear substitution products or reduction products thereof by treatment with ammonia or a substance yielding ammonia in the presence or not of solvents or catalysts. When reduction products are used all the steps, including the oxidation of the leuco compound, may be carried out in the same solution. They are used for dyeing organic substitution derivatives of cellulose, regenerated celluloses and animal and vegetable fibres and may be applied in the reduced state, i.e. by a vat process or in solution, aqueous suspension or in colloidal form. They are also converted either in the reduced or unreduced state into dyestuff preparations, e.g. by grinding in colloid mills, by dissolving in a solvent and mixing with water containing or not containing protective colloids or dispersators, or by treatment with dispersing agents whether alone or in the presence of protective colloids and/or liquids. Preparations for vatting may contain reducing agents, alkali or the products of Specification 262,506, [Class 15 (ii), Dyeing, Processes &c. for]. As dispersing agents may be used, those of Specifications 219,349, 224,925, 242,393,273,819 and 273,820 used alone or in conjunction with the solvents of Specification 242,711 and 269,960. In examples (1) naphthazarin is treated with ammonia and sodium hydrosulphite in methylated spirits and the leuco product obtained oxidized by air. The resulting product dyes cellulose acetate in grey shades, (2) naphthazarin is reduced with sodium hydrate and hydrosulphite, the leuco compound treated with ammonia in presence of copper acetate and the product oxidized with air, (3) monomethylnaphthazarin paste is added to ammonia containing a trace of copper salt, reduced with hydrosulphite, and when then amidation is completed the leuco compound is oxidized. Monomethylnaphthazarine is made from hydrotoluquinone and succinic anhydride according to Specification 315,331.