Patent GB-488595-A (GB)
Title: Improvements in azo-dyestuffs
Filed: 1937-05-29
Abstract: Insoluble azo dyestuffs are manufactured by diazotizing an amine of the general formula <FORM:0488595/IV/1> where at least two of the X's represent phenoxy or substituted phenoxy groups, and the Y's and, if desired, one of the X's represent hydrogen, halogen atoms, alkyl or alkoxy groups, and coupling the diazo compound in substance or on the fibre with an arylamide of b -hydroxynaphthoic or acetoacetic acid. The production of the dyestuffs on the fibre is applicable to the dyeing of cotton, viscose or other material or artificial fibres with or without the intermediate formation of nitrosamines, of diazoamino derivatives, of diazo sulphonates or of Schiff's bases. The dyestuffs produced in substance may be used for colouring lacquers, varnishes, organic solvents, plastic materials or rubber.  In examples: (1) cotton is impregnated with 2 : 3-hydroxynaphthoic acid b -naphthylamide and a bluish red dyeing is developed by means of diazotized 1-amino-2 : 4-diphenoxybenzene; (2) cotton is impregnated with b -hydroxynaphthoic anilide and a scarlet dyeing is developed by means of diazotized 1 - amino - 2 : 4 - diphenoxy - 5 - chlorobenzene; (3) cotton is impregnated with b -hydroxynaphthoic p-anisidide and a yellowish red dyeing is developed by means of diazotized 1-amino-2 : 6-diphenoxy-3 : 5-dichlorobenzene.  A table gives the shades of further dyestuffs, the following additional components being specified: diazo components: 1 - amino - 2 : 4 : 6 - triphenoxy-5-chlorobenzene, 1-amino-2 : 4-di-o- and p-chlorophenoxy-5-chlorobenzene, 1-amino-2 : 4-di-o-and p-tolyloxy-5-chlorobenzene and 1-amino-2 : 4-diphenoxy-5-methoxybenzene; coupling components: b -hydroxynaphthoic acid m-nitranilide, 5-chloro-2-toluidide, a -naphthylamide, o - anisidide, o - toluidide, p - chloro - o-anisidide and 2 : 4-dimethoxy-5-chloroanilide, and diacetoacetyl - o - tolidine.  Specifications 6379/12, [Class 2 (iii)], 17279/13, and 210,217, [both in Class 15 (ii)], are referred to.  Amines of the general formula given above are obtainable by reacting a nitro compound of the general formula <FORM:0488595/IV/2> where at least two of the X's are halogen atoms, and the Y's and, if desired, one of the X's are hydrogen, halogen atoms, alkyl or alkoxy groups, with two or three molecular proportions of an alkali phenolate at relatively low temperature, as far as possible in absence of water, and subsequently reducing the nitro group.  In examples: (1) 1-nitro-2 : 4-dichlorobenzene is heated with potassium phenolate, yielding 1-nitro-2 : 4 : 5-trichlorobenzene is heated with potassium phenolate to produce 1-nitro-2 : 4-diphenoxy-5-chlorobenzene, which is reduced to the amine; the diazo compound of the product may be dried and mixed with dehydrated aluminium sulphate to obtain a homogeneous powder; (3) 1-nitro-2 : 3 : 5 : 6-tetrachlorobenzene similarly yields 1-nitro-2 : 6-diphenoxy-3 : 5-dichlorobenzene and the corresponding amine; the amine may be diazotized by treating it in concentrated hydrochloric acid with alkali nitrite, preferably in the presence of acetic or formic acid, and the diazo compound may be stabilized with zinc chloride and dried by admixture with dehydrated aluminium sulphate.  The Specification as open to inspection under Sect. 91 comprises generally the manufacture, and use as diazo components, of amines of the general formula given above in which the Y's and, if desired, one X represent any substituent.  As coupling components are specified components of substantive character, e.g. arylides of o-hydroxycarboxylic acids in general.  Reference is made to the reaction of 1-nitro-2 : 4-dichlorobenzene with the potassium salts of o-cresol and o-chlorophenol, of 1-nitro-2 : 4 : 5-trichlorbenzene with the potassium salts of o-and p-chlorophenol, of 1-nitro-2 : 4-dichloro-5-methoxybenzene with the potassium salts of phenol, cresols, chlorophenols and monoalkyl derivatives of resorcinol or hydroquinone, of 1-nitro-2 : 3 : 5 : 6-tetrachlorobenzene with the potassium salt of o-cresol, and of 1-nitro-2 : 3 : 4 : 6-tetrachlorobenzene with potassium phenate.  The resulting nitro compounds are reduced to the corresponding amines.  This subject-matter does not appear in the Specification as accepted.ALSO:Rubber is coloured by means of insoluble azo dyestuffs obtained by diazotizing an amine of the general formula <FORM:0488595/V/1> where at least two of the X's represent phenoxy or substituted phenoxy groups, and the Y's and, if desired, one of the X's represent hydrogen, halogen atoms, alkyl or alkoxy groups, and coupling the diazo compound with an arylamine of b -hydroxynaphthoic or acetoacetic acid.  Specifications 6379/12, [Class 2 (iii)], 17279/13, and 210,217, [both in Class 15 (ii)], are referred to. p