GB469081A - Manufacture of azo-dyestuffs soluble in water - Google Patents

Abstract

Azo dyestuffs soluble in water are manufactured by coupling in an alkaline medium any diazo- or diazoazo-compound with a coupling component of the general formula <FORM:0469081/IV/1> where X is hydrogen, an alkyl or sulphoalkyl radicle and Y is hydrogen or a sulphonic acid group. The products are suitable for dyeing leather. They may be transformed into complex metal compounds by treatment with agents yielding metal. Examples describe the preparation of the following dyestuffs: (1) sulphanilic acid --> 2 - (sulphoethylamino) - 8-naphthol-6-sulphonic acid; chrome tanned calf is deacidified with borax and dyed with the product; (2) 2-naphthylamine-6 : 8-disulphonic acid --> 2-(sulphoethylamino)-8-naphthol-6-sulphonic acid; chrome tanned goatskin is deacidified and dyed with the product; (3) 2-amino-5 : 6 : 7 : 8-tetrahydronaphthalene-3-sulphonic acid --> 2-sulphoethylamino-8-naphthol-6-sulphonic acid; chrome tanned velvet leather is drummed and dyed with the product; (4) 5-sulpho-2-aminobenzoic acid --> 2-(sulphoethylamino)-8-naphthol-6-sulphonic acid; East Indian kips are dyed with the product after drumming; (5) sodium 4-aminoazobenzene-4<1>-sulphonate --> 2-(sulphoethylamino)-8-naphthol-6-sulphonic acid; chrome tanned sheep leather is dyed in the same bath with the product and with an acid or substantive dark brown dyestuff which does not penetrate into the leather; (6) p-toluidine --> 2-(sulphoethylamino)-8-naphthol-6-sulphonic acid; chrome tanned neat's leather is deacidified with sodium bicarbonate, dyed with the product and then top-dyed in the same or a fresh bath with a red-brown basic dyestuff; the diazo-component may be replaced by o-anisidine; (7) p-chloraniline --> 2-(sulphoethylmethylamino)-8-naphthol-6-sulphonic acid disodium salt; leather is dyed with the product by the process of (6); (8) 4-chloro-2-amino-1-methoxybenzene --> 2-(disulphoethylamino)-8-naphthol-6-sulphonic acid sodium salt; chrome tanned neat's leather is dyed with the product by the process of (6); (9) salicylic acid \sM benzidine --> 2-(disulphoethylamino) - 8 - naphthol - 6 - sulphonic acid; leather is dyed with the product by the process of (3). The coupling components in the examples may be replaced by 2-(sulphoethylamino)-8-naphthol-3 : 6-disulphonic acid. The Provisional Specification comprises in general the use, as coupling components, of compounds of the general formula <FORM:0469081/IV/2> where R is alkyl and X is hydrogen or alkyl and wherein the naphthalene nucleus may contain further substituents, especially hydroxyl, sulphonic acid or carboxylic acid groups. Substituted aminonaphtholsulphonic acids of the first formula given above are obtainable by heating halogenethanesulphonic acids with the alkali salts of the appropriate aminonaphtholsulphonic acids in an aqueous medium in the presence of an acid-binding agent.