Patent GB-587348-A (GB)
Title: Manufacture of disazo-dyestuffs
IPC: C09B33/04
Filed: 1943-08-25
Abstract: Disazo dyestuffs are manufactured by coupling 1 mol. of 1 : 3-dihydroxynaphthalene with 2 mols. of a diazo-compound or 1 mol. of each of two different diazo-compounds which is or are free from azo groups and which contains, or of which at least one contains, a lake-forming group (e.g. a hydroxy, carboxyl, alkoxy or alkoxy-carboxyl group in o-position to the diazo group), and, if desired, treating the product in substance, during its manufacture, in the dyebath or on the fibre with an agent yielding metal.  The products may be used for dyeing and printing animal fibres, e.g. wool, silk and especially leather, and vegetable fibres, especially cellulosic fibres.  In examples: (1) 4 - nitro - 2 - aminophenol - 6 - sulphonic acid is diazotized and coupled with 1 : 3-dihydroxynaphthalene in the presence of ferric hydroxide, and the resulting iron compound is coupled with diazotized p - nitraniline, 1 - aminonaphthalene-4-sulphonic acid or 41-nitro-4-aminodiphenylamine-21-sulphonic acid; part of the iron may be replaced by another metal, e.g. copper, and the order of coupling may be reversed; (2) a mixture of 4-nitro-2-aminophenol-6-sulphonic acid and 41-nitro-4-aminodiphenylamine-21-sulphonic acid is diazotized and coupled with 1 : 3-dihydroxynaphthalene in the presence of ferric hydroxide and copper hydroxide; (3) the dyestuff from 6-nitro-1-diazo - 2 - naphthol - 4 - sulphonic acid and 1 : 3 - dihydroxynaphthalene is boiled with an aqueous solution of chromium sulphate, and the resulting chromium compound is coupled with diazotized 4-chloroaniline-3-sulphonic acid, 4-nitraniline-2-sulphonic acid or 21- (or 41-) nitro-4-aminodiphenylamine-41- (or 21-) sulphonic acid; alternatively, the disazo dyestuff is prepared first and then chromed, or the chromium may be replaced by other metals, e.g. iron or manganese; (4) the dyestuff 4 : 6-dinitro-2-aminophenol --> 1 : 3-dihydroxynaphthalene \sM 21 - nitro - 4 - aminodiphenylamine - 41 - sulphonic acid (or 1-aminonaphthalene-4-sulphonic acid) is prepared and heated in aqueous solution with copper sulphate (or a mixture of manganese and nickel sulphates) and sodium acetate; (5) the dyestuff 5-nitro-2-aminophenol --> 1 : 3-dihydroxynaphthalene is boiled with a chroming solution containing chromium hydroxide, tartaric acid and caustic soda, and the product is coupled with diazotized sulphanilic acid or aniline-2 : 5-disulphonic acid; (6) the dyestuff 4-nitro- (or 4 : 6-dinitro-) 2-aminophenol --> 1 : 3-dihydroxynaphthalene is coupled with diazotized 4-nitro-2-aminophenol-6-sulphonic acid, and the product is treated with copper (or nickel) sulphate and ferric chloride; (7) the iron compound of the dyestuff 6-nitro-2-aminophenol-4-sulphonic acid --> 1 : 3-dihydroxynaphthalene is coupled with diazotized 4 : 6 dinitro-2-aminophenol, and the product is heated with a solution of ferric chloride, tartaric acid and caustic soda; (8) a mixture of 4-nitro-and 4-chloro-2-aminophenol-6-sulphonic acid is diazotized and coupled with 1 : 3-dihydroxynaphthalene, and the product is heated with a solution of ferric chloride and sodium acetate; part, e.g. half, of the iron may be replaced by copper; (9) 1 : 3-dihydroxynaphthalene is coupled with 6 - nitro - 1 - diazonaphthol - 4 - sulphonic acid and with diazotized 4-chloro-2-aminophenol, 4 - chlor- or 4 - nitro - 2 - aminophenol-6-sulphonic acid, sulphoanthranilic acid (made by sulphonating anthranilic acid) or 6-nitro-1-aminonaphthol-4-sulphonic acid, and the product is heated with a solution of basic chromium sulphate; the chromium may be partly or wholly replaced by iron. Other diazo components specified are metanilic acid, 4-methyl - 2 - aminophenol - 5 - and 6 - sulphonic acids, 6 - chloro - 2 - aminophenol - 4 - sulphonic acid, 2-aminophenol-6-carboxylic-4-sulphonic acid, 4-nitro-2-aminobenzoic acid, 3 : 6-dichloroaminophenol - 4 - sulphonic acid and 1 : 2 : 4-aminonaphtholsulphonic acid. Specification 445,378 is referred to.