Patent GB-701241-A (GB)
Title: Manufacture of new disazo-dyestuffs
IPC: C09B33/12
Filed: 1951-10-29
Abstract: Compounds of the formula R-CO-NX-R1-SO2OH where R and R1 are benzene nuclei, the former carrying hydroxyl and amino groups ortho to each other, and X is hydrogen or alkyl, are made by (1) sulphonating an arylide of a hydroxynitrobenzoic acid and then reducing the nitro group to amino, or (2) condensing a hydroxynitrobenzoic acid or functional derivative thereof (e.g. chloride) with an arylamine sulphonic acid and then reducing the nitro group.  In examples, (1) 2-nitrophenol - 4 - carboxylic anilide is sulphonated and then reduced; (2) similarly the N-methyl-derivative of (1); (3) 2-nitrophenol-4-carboxylic acid is converted into its chloride and reacted with sulphanilic acid; finally the nitro group is reduced; (4) as in (3) using metanilic acid.  Other starting materials are specified.  A pyrazolone derivative is made as follows:-4 - (p - aminobenzoylamino) - aniline is tetrazotised and reduced to give the di-hydrazine, which is then condensed with ethyl acetoacetate.  A similar compound is made from 3-(m-aminobenzoylamino)-aniline.ALSO:The invention comprises disazo dyestuffs of the formula <FORM:0701241/IV(c)/1> where R1-R6 are benzene residues, the hydroxyl groups on R1 and R2 being oto the azo linkages, X1 and X2 are hydrogen or alkyl and Y is a direct linkage, -CO-NH-, -NH-CO-, -NH-CO-NH- or -CH=CH-; at least one of the residues R1-R4 contains a sulphonic acid group and the whole dyestuff is free from salicylic acid residues. These are made by (1) coupling 2 mols of diazotized R3NX1-CO-R1 (OH)NH2 (containing a sulphonic acid group) with the appropriate bis-pyrazolone, or (2) coupling 1 mol of the diazo compound of (1) with an aminophenyl-pyrazolone and treating the product with phosgene.  In method (1) a mixture of two different diazo compounds in any proportion may be used, provided that at least one contains a sulphonic acid group.  Similarly in method (2) phosgene may react with 2 mols of different components, with the same proviso.  The products can be metallized in substance, in the dyebath or on the fibre to give e.g. copper, chromium, iron, cobalt or nickel p  compounds; the processes of Specifications 455,274 and 619,969 are applicable.  The dyestuffs are suitable for dyeing and printing wool, silk, leather, cotton, linen and regenerated cellulose.  In the examples, (1) diazotized 2-aminophenol-4-carboxylic anilide sulphonic acid is coupled with diphenyl-4 : 4\sv-bis-(3-methyl-5-pyrazolone); (2) as in (1) using similar pyrazolones derived from 3 : 3\sv-dichloro-, 3 : 3\sv-dimethyl- and 3 : 3\sv-dimethoxy-diphenyl, diphenylurea and benzanilide (m- and p-isomers); (3) diazotized 2-aminophenol-4-carboxylic anilide sulphonic acid is coupled with 1-(p-aminophenyl)-3-methyl-5-pyrazolone and the product phosgenated; (4) diazotized 2-aminophenol-4-carboxylic anilide sulphonic acid is coupled with stilbene-4 : 4\sv-bis-(3-methyl-5-pyrazolone)-2 : 2\sv-disulphonic acid and the product coppered; (5) cotton is dyed with the product of (1), coppering taking place in the dyebath, giving a brown-orange shade.  Other suitable components are mentioned.  Specification 606,872 also is referred to.