Patent GB-512839-A (GB)
Title: Manufacture of azo-dyestuffs and derivatives thereof
IPC: C09B39/00
Filed: 1938-03-17
Abstract: 512,839. Dyes ; dyeing. DU PONT DE NEMOURS & CO., E. I. March 17, 1938, No. 8305. Convention date, March 23, 1937. [Classes 2(iii) and 15 (ii)] Monoazo and dioazo dyestuffs are manufactured by coupling one molecular proportion of a diazotized arylamine or two molecular proportions of the same or different diazotized arylamines with one molecular proportion of a coupling component of the general formula where R is an aryl or aralkyl group, or a straight or branched chain alkyl group, e.g., of 8-15 carbon atoms, or by coupling one molecular proportion of a tetrazotized arylenediamine with one molecular proportion of a coupling component as defined above and one of another coupling component, e.g., a naphthosulphonic acid. When the diazo component, or at least one of them, if there are two, or the tetrazo component, contains a hydroxy or carboxylic group in o-position to the amino group, the products may be converted, in substance or on the fibre, into complex metal compounds by treatment with salts of heavy metals, e.g., chromium or copper. The products are suitable for dyeing animal fibres such as silk, wool and leather. Examples describe the production of the following dyestuffs: (1) 4-chloro-2-aminophenol-6-sulphonic acid#1:3-dihydroxy-4-lauroylbenzene ; the product dyes wool from an acetic acid both chocolate brown and from a sulphuric acid bath yellow brown shades, both dyeings becoming bordeaux when after-treated with dichromate; (3) aniline#1:3 dihydroxy-4- lauroylbenzene ; the product yields a yellow solution in gasoline ; (4) sulphanilic acid #1:3-dihydroxy-4-lauroylbenzene#1-amino-2:4- dimethylbenzene ; the product dyes leather orange shades and also dyes wool; (5) 2- naphthol-6:8-disulphonic acid#benzidine# 1:3- dihydroxy-4-lauroylbenzene ; the product dyes tin weighted silk bluish red shades of good discharge properties. In example (2), the product of (1) is heated in caustic soda solution with chromium fluoride ; the product dyes wool bordeaux shades. The Specification as open to inspection under Sect. 91 comprises in general the manufacture of azo dyes, including trisazo and tetrakisazo dyes, by coupling suitable diazo components with a coupling component of the general formula where R is an aryl, aralkyl or alkyl group which may be substituted, e.g., by halogen atoms or nitro, alkyl, alkoxy, carboxylic or sulphonic acid groups, or, when it is alkyl, by hydroxy or sulphato groups, and in which the nucleus X may contain further substituents, including amino groups. The products may be treated with an alkylating agent, e.g., dimethyl sulphate or an acid halide, e.g., a p-toluenesulphohalide or a nitrobenzoyl halide. An additional example describes the production of -the trisazo dyestuff salicylic acid#benzidine# lauroylresorcinol sulphanilic acid, which dyes silk from an acid bath red-brown shades. Reference is made to the use, as coupling component in example (4) above, of the diketo compound from resorcinol and sebacic, acid, of alpha-ethylhexoylresorcinol, of 2:4-dihydroxybenzophenone or of 2:4-dihydroxy - # - phenylacetophenone. This subject-matter does not appear in the Specification as accepted.