Patent GB-459894-A (GB)
Title: Manufacture of intermediates and azo-dyestuffs derived therefrom
IPC: C09B29/20
Filed: 1935-07-18
Abstract: Azo dyes, forming upon the material; printing.--Colouring matters are produced on cellulosic fibre by combining a diazotized 4-amino-2 : 5-diethoxyphenylurethane of the general formula <FORM:0459894/IV/1> where X is methyl or ethyl, with 2 : 3-hydroxynaphthoic anilide, o - toluidide, 5 - chloro - o - toluidide or b -naphthalide.  The dyeing may be effected by the following methods: (a) the fibre is padded with the coupling component and immersed in a solution of the diazo-compound or printed with a paste containing it; (b) the material is printed with an alkaline paste containing a soluble derivative of the diazo-compound stable under alkaline conditions and the coupling component, and the print is developed by treatment with a mild acidic reagent.  In examples: (1) cotton skeins are impregnated with 2 : 3 - hydroxynaphthoic anilide and developed with diazotized N-(4-amino - 2 : 5 - diethoxyphenyl) - methyl - carbamate, yielding a blue dyeing; (2) cotton piece goods are printed with a paste containing the diazoamino compound from diazotized N-(4-amino - 2 : 5 - diethoxyphenyl) - methyl - carbamate and piperidine-a -carboxylic acid, 2 : 3-hydroxynaphthoic anilide, turkey red oil, caustic soda and starch-tragacanth thickener and the print is developed by the action of steam containing acetic acid vapour; for the preparation of the diazoamino compound there may alternatively be used other secondary amines containing water-solubilizing groups, e.g. sarcosine, ethyltaurine, proline and methylglucamine. Specification 17279/13, [Class 15 (ii)], is referred to.  Urethanes of the formula given above are obtainable by the following methods: (a) 4-nitro-2 : 5-diethoxyaniline is condensed with methyl or ethyl chloroformate and the product is reduced; (b) the diazo-salt of a water-soluble arylamine, e.g. a sulphonated aniline or naphthylamine derivative, is coupled to 2 : 5-diethoxyaniline and the product is condensed with methyl or ethyl chloroformate and reduced; (c) 2 : 5-diethoxyaniline is condensed with methyl or ethyl chloroformate and the product is nitrated and reduced.  The Specification as open to inspection under Sect. 91 comprises the manufacture, by methods similar to those described above, of carbamates of the general formula <FORM:0459894/IV/2> where X is an alkyl, aralkyl, aryl or hydroaryl radicle which may carry substituents, e.g. alkyl or alkoxy groups or halogen, and each Y represents an alkoxy group, and also the production on the fibre of azo dyestuffs by diazotizing these compounds and coupling with ice-colour coupling components, e.g. the arylamides (e.g. anilides, toluidides, alkoxy- and aryloxyanilides, halogenated anilides, halogenated toluidides, halogenated alkoxy- and aryloxyarylides, trifluoromethylanilides, dianisidides, a - and b -naphthylamides) of hydroxyarylcarboxylic acids (e.g. 2 : 3-hydroxynaphthoic acid, and alkyl, alkoxy, alkylamino and arylamino derivatives thereof, 2-hydroxycarbazole-3-carboxylic acid and 2-hydroxyanthracene-3-carboxylic acid), also various acylaminonaphthols (e.g. 1-benzoylamino-7-naphthol, 2-toluylamino - 3 - naphthol and 1 - (2<1> - chlorobenzoylamino) - 5 - naphthol).  In additional examples: (1) 2 : 5-dimethoxyaniline is condensed with methyl chloroformate and the product is nitrated and reduced; the methylchloroformate may be replaced by ethyl, butyl, or benzyl chloroformate; (2) 2 : 5-diethoxyaniline is condensed with b -methoxyethyl chloroformate and the product is nitrated and reduced; (3) 2 : 5-diethoxyaniline is condensed with n-butyl chloroformate and the product is nitrated and reduced; (4) the n-butyl chloroformate in (3) is replaced by isobutyl chloroformate; and (5) by benzyl chloroformate; (6) sulphanilic acid is diazotized and coupled with 2 : 5-diethoxyaniline and the product is condensed with methyl chloroformate and reduced; (7) and (8) 2 : 5-diethoxyaniline is condensed with methyl chloroformate and the product is nitrated and reduced; in (8), ethyl chloroformate may alternatively be used; (9) cotton is padded with 2 : 3 - hydroxynaphthoic o-toluidide and a blue dyeing is developed with diazotized N-(4-amino-2 : 5-diethoxyphenyl)-b -methoxyethyl urethane; (10) a reddish-blue dyeing is similarly obtained from 2 : 3-hydroxynaphthoic anilide and diazotized N-(4-amino-2 : 5-diethoxyphenyl)-n-butyl carbamate; (11) a navy blue dyeing is similarly obtained from 2 : 3-hydroxynaphthoic b -naphthylamide and diazotized N - (4-amino - 2 : 5-diethoxyphenyl)-benzyl carbamate.  This subject-matter does not appear in the Specification as accepted.