Patent GB-578964-A (GB)
Title: Manufacture of disazo-and polyazo-dyestuffs
IPC: C09B35/00
Filed: 1943-08-26
Abstract: Azo dyes; dyeing regenerated cellulose.-Dis- or poly-azo dyes are made by coupling any components with a 3-oxy-31-alkoxy-4 : 41-diaminodiphenyl, and, if desired, performing a further coupling or linking reaction or reactions.  Coupling components may be benzene, naphthalene or heterocyclic derivatives and may contain the carbon atom capable of coupling in an open chain, the following being specified: phenols, salicylic acid, resorcinol, naphthols, naphthol mono- or di-sulphonic acids, aminonaphthols and sulphonic acids thereof, 1-aryl-3-methyl- or carboxy-pyrazolones with or without substituents such as sulphonamido, nitro, amino or salicylic acid groups in the aryl nucleus, and acetoacetic arylides.  Especially valuable dyes are obtained by using a pyrazolone as one component and/or a component containing the salicylic acid grouping.  These two features may be present together, e.g. by using 1-(31-carboxy-41-oxyphenyl)-3-methyl-5-pyrazolone. Tris- and poly-azo dyes are made by using components (a) containing a further diazotisable amino group or a group capable of conversion thereto, (b) capable of coupling more than once or (c) suitable for producing polyazo dyes by other reactions, e.g. by formation of ureas or reduction of two nitro-groups.  The dyes are suitable for dyeing or printing animal fibres, e.g. wool, silk and leather and cellulosic fibres, e.g. cotton, linen, artificial silk and staple fibre of regenerated cellulose.  The dyes may be reacted with agents yielding metal, especially copper, e.g. complex copper tartrates, in substance, in the dyebath or on the fibre.  In examples (1) to (8), disazo dyes are prepared from 3-oxy-31-methoxybenzidine and the following: salicylic acid and 1-(31-sulphonamidophenyl) - 3 - methyl - 5 - pyrazolone, the latter component alone, salicylic acid and 1-(41-oxy-31 - carboxyphenyl) - or 1 - (31 - nitrophenyl)- or 1 - (41-b -oxyethoxyphenyl)-3-methyl-5-pyrazolone or 3 - methyl - 5 - pyrazolone, 1 - amino - 8 - naphthol - 4 - sulphonic acid, 5 : 51 - dioxy - 2 : 21-dinaphthylamine - 7 : 71 - disulphonic acid and 1 - (41 - oxy - 31 - carboxyphenyl) - 3 - methyl - 5 - pyrazolone; polyazo dyes from 3-oxy-31-methoxybenzidine and the following: salicylic or o- or m-cresotinic acid and 1-(31- or 41-aminophenyl)-3-methyl-5-pyrazolone --> 1-(41-oxy-31 - carboxyphenyl)- or 1 - (41 - b  - oxyethoxyphenyl) - 3 - methyl - 5 - pyrazolone, 2 - amino- or 2 - (41 - oxy - 31 - carboxyphenyl) - amino - 5 - oxynaphthalene - 7 - sulphonic acid or 2 - aminophenol - 4 - sulphonamide --> resorcinol, and 2-aminophenol-4-sulphonamide or 4-nitro-2-aminophenol --> resorcinol and 1-(41-oxy-31-carboxyphenyl) - 3 - methyl - 5 - pyrazolone.  In example (9) cotton is dyed with salicylic acid \sM 3 - oxy - 31 - methoxybenzidine --> 1 - (41-oxy-31-carboxyphenyl)-3-methyl-5-pyrazolone and treated with complex copper tartrate in the dyebath. Specification 455,274 is referred to.  3-Oxy-31-methoxybenzidine is made by the partial saponification of dianisidine with moderately concentrated (e.g. 65 per cent) sulphuric acid.  The crude product, containing some 3.31-dioxybenzidine, may be extracted with chlorobenzene and the extracted 3-oxy-31-methoxybenzidine purified by recrystallisation from benzene.