Patent GB-518902-A (GB)
Title: Process for the manufacture of azodyestuffs
IPC: C09B31/065
Filed: 1938-09-08
Abstract: 518,902. Dyes ; dyeing. I. G. FARBENINDUSTRIE AKT.-GES. Sept. 8, 1938. No. 26282. Convention date, Sept. 8, 1937. Sample furnished. [Classes 2 (iii) and 15 (ii)] Azo dyes are manufactured by diazotizing initial components of the formula where X is a diphenyl linkage or a -CH=CH- bridge, Y is hydrogen, any neutral substituent or a nitro or acylamino group, and,at least one of the nuclei A contains a sulphonic acid group, coupling with aniline or o- or m-toluidineor their #-methanesulphonic acids, saponifying when the #-methanesulphonic acids are employed, further diazotizing, coupling with phenol or a cresol and alkylating the hydroxy group of the phenol. The products dye cotton orange to brown shades, which are capable of being discharged. When a nitro or acylamino group is present it may be converted into an amino group by reduction or saponification, whilst an amino group so formed, or present in the initial component in place of an acylamino group, may be acylated, e.g., benzoylated, nitrobenzoylated or treated with phosgene, or reacted with cyanuric chloride. Products containing a free amino group may be further diazotized in substance or on the fibre and coupled with any coupling component, e.g., salicylic acid, pyrazolones, resorcinol or its monoazo dyestuffs which may contain metal, naphtholsulphonic acids, aminonaphtholsulphonic acids or derivatives thereof or their monoazo dyestuffs capable of coupling a second time. In examples : (1) monoacetylbenzidine-3:3<1> disulphonic acid is diazotized and coupled with m-toluidine, the product is further diazotized and coupled with phenol, and the product is alkylated with methyl chloride ; the product may be saponified with caustic soda solution, and the saponified dyestuff may be diazotized on the fibre and developed, e.g., with #-naphthol or pyrazolone; (2) the saponified dyestuff of (1) is diazotized and coupled with 1- phenyl- or 1-(3<1>-aminophenyl)-5-pyrazolone-3- carboxylic acid ; when the latter coupling component is used, the product may be further diazotized on the fibre and developed with #- naphthol or pyrazolone, or may be after-treated on the fibre with diazotized p-nitraniline ; the pyrazolone component may be replaced by 2- amino-8-naphthol-6-sulphonic acid (in which case the product may be diazotized and coupled with m-phenylenediaminein substance or on the fibre), or by the copper compound of oaminophenolsulphonic and -azo-resorcinol ; (3) 4-nitro-4<1>-aminostilbene-2:2<1>-disulphonic acid is diazotized and coupled with m-toluidine, the product is diazotized and coupled with phenol, and the product is alkylated with methyl chloride ; the nitro group may be reduced by means of sodium sulphide, and the product may be diazotized on the fibre and developed ; the reduced, dyestuff may be acylated by treatment with acetic anhydride or benzoyl chloride, or with p-nitrobenzoyl chloride followed by reduction with sodium sulphide, in which case the product may be diazotized on the fibre and developed, e.g., with #-naphthol ; (4) the reduced dyestuff of (3) is.diazotized and-coupled as in (2), or with 2:5:7-acid. In the foregoing examples, the m-toluidine may be replaced by aniline- or o-toluidinew-methanesulphonic acid, the methanesulphonic acid residue being subsequently eliminated by saponofication. A sample has been, furnished under Sect. 2 (5) of the product obtained by diazotizing 4- aminodiphenyldisulphonic acid (obtained by sulphonating 4-aminodiphenyl-3-sulphonic acid) coupling with m-toluidine, rediazotizing, coupling with phenol and alkylating with ethyl chloride. Monoacetylbenzidine - - 3 :3<1>- disulphonic acid is obtainable by partial acetylation of benzidine- 3:31-disulphonic acid by means of an equimolecular proportion of acetic anhydride in aqueous solution.