GB540578A - Improvements in or relating to dyestuffs - Google Patents

Abstract

540,578. Photographic sensitizing dyes ; dyeing cellulose esters. KENDALL, J. D., and FRY, D. J. April 19, 1940, No. 7078. [Classes 2 (iii) and 15 (ii)] [Also in Group XX] Dyestuffs which may be used for sensitizing photographic silver halide emulsions or for dyeing textiles, particularly cellulose acetate artificial silk, are made by condensing a compound of the general formula where R, is a hydrocarbon group and R 2 is a hydrogen atom or hydrocarbon group, with an alkyl or aralkyl ester and condensing the product with a quaternary salt of a heterocyclic nitrogen compound containing a reactive methyl group in the x- or y position to the heterocyclic nitrogen atom. The alkyl ester used is preferably an alkyl-p-toluene sulphonate, and the process may be carried out by mixing the compound of the general formula with the heterocyclic nitrogen compound and with sufficient alkyl-p-toluene sulphonate to convert both compounds to quaternary salts, the condensation being effected by heating the fused mixture with an acid-binding agent, e.g. pyridine. The products, when obtained as p-toluene sulphonates, may be converted into salts of inorganic acids by treating them with a solution of a salt of the desired acid, e.g. an alkali metal halide. The parent materials of the general formula may be made by the process of Specification 540,577. Heterocyclic nitrogen compounds which may be used include thiazoles, oxazoles, and selenazoles, pyridines, quinolines, naphthaquinolines, indolenines, diazines, diazoles, oxazolines, thiazolines and selenazolines. In examples, compounds of the general formula in which R 1 is methyl or ethyl, and R 2 is methyl are condensed with methyl or ethyl-p-toluene sulphonate and 1-methylbenzthiazole, quinaldine or 1-methylbenzoxazole. In the use of the products for dyeing cellulose acetate fabrics, the dyebaths may be simple aqueous solutions, where the dyestuffs are sufficiently soluble, or the dyestuffs may be dispersed with the acid of the usual dispersing agents, e.g. Turkey red oil, sulphoricinoleic acid, naphthenic and sulphonated naphthenic acids, sulphonated naphthalene-formaldehyde condensation products, and sulphonated long chain fatty alcohols. Examples of the dyeing process are given. The Provisional Specification describes also the use as parent materials of compounds of the general formula in which R 1 is hydrogen, and in which the ring sulphur atom is replaced by oxygen. It also comprises the condensation of the parent materials with any of the seven types of compounds described in Specification 489,335. The products containing thione groupings may be treated with alkyl or aralkyl salts and further condensed with compounds of these seven types. Specifications 426,718 and 438,420 also are referred to.