Patent GB-454470-A (GB)
Title: A process for the manufacture of azodyestuffs
IPC: C09B35/20
Filed: 1935-11-18
Abstract: Polyazo dyestuffs containing at least three sulphonic groups in the molecule are manufactured by coupling tetrazotized diaminodiaryldisulphonic acids on one side with a sulphonated 1-aryl-3-methylpyrazolone or a naphtholsulphonic or an N-arylamino- or N-acylaminonaphtholsulphonic acid (other than a 1-N-acylamino-8-naphthol- or 2-N-acylamino-5-naphtholsulphonic acid), and on the other side with phenol, its homologues or substitution products.  Alternatively, a monodiazotized diaminodiaryldisulphonic acid or its monoacyl derivative is first coupled with one of the coupling components, and the monoazo dyestuff obtained is further diazotized, after saponification if necessary, and coupled with the second coupling component.  The products may be acylated by means of an arylsulphohalide in the presence of acid binding agents.  They dye animal fibres, e.g. wool and hair, yellow, orange, red and brown shades.  Examples describe the preparation of the following dyestuffs: (1) phenol \sM 3 : 3<1>-dimethyl-benzidine-6 : 6<1>-disulphonic acid --> -1-(4<1>-sulpho - 2<1> : 5<1> - dichlorophenyl) - 3 - methyl-pyrazolone; the product is treated with p-toluenesulphochloride in the presence of sodium carbonate; (2) phenol \sM 3 : 3<1>-dimethylbenzidine-6 : 6<1>-disulphonic acid --> 2 - phenylamino - 8 - hydroxynaphthalene - 6 - sulphonic acid; (3) 2-hydroxynaphthalene-6 : 8-disulphonic acid \sM 4 : 4<1>-diamino-5 : 5<1>-dicarboxydiphenyl-2:2<1>-disulphonic acid --> phenol; the product is treated with p-toluenesulphochloride in the presence of sodium carbonate; it yields brown after-chromed dyeings; (4) 2-hydroxynaphthalene-6 : 8-disulphonic acid \sM 3 : 3<1>-dimethylbenzidine-6 : 6<1>-disulphonic acid --> phenol; the product is esterified as in (3); (5) 1 - hydroxynaphthalene - 4 - sulphonic acid \sM 3 : 3<1>-dimethylbenzidine-6 : 6<1>-disulphonic acid --> phenol; (6) the product of (5) is esterified on one or both hydroxyl groups by the action of p-toluenesulphochloride in the presence of sodium carbonate; by boiling the diacylated dyestuff with caustic soda solution the acyl group in the naphthalene residue is saponified.  Other components specified are: tetrazocomponents: benzidine-2.2<1>- and 3 : 3<1>-disulphonic acids, dichlorobenzidinedisulphonic acids and dianisidinedisulphonic acids; first coupling components: 1 - (4<1>-sulphophenyl) - 3 - methylpyrazolone, 1 - (3<1>-sulpho-4<1>-chlorophenyl) - 3 - methylpyrazolone, 1 - hydroxynaphthalene - 3 - and -5-sulphonic acids, -4-chloro-8-sulphonic acid and -3 : 6- and -3 : 8-disulphonic acids, 2-hydroxynaphthalene-6-, -7- and -8-sulphonic and -3 : 6-disulphonic acids and 2-acetylamino-8-naphthol-6-sulphonic acid; second coupling components: o-, m- and p-cresol, salicylic acid and o-cresotinic acid.  Specifications 3495/93, 3375/02, [both in Class 2], 20649/09 and 7303/13, [both in Class 2 (iii)], are referred to. 4 : 4<1>-Diamino-5 : 5<1>-dicarboxydiphenyl-2 : 2<1>-disulphonic acid is obtained by oxidizing diacylated 3 : 3<1>-dimethylbenzidine-6 : 6<1>-disulphonic acid by means of permanganate and saponifying the product.  1 - (3<1> - Sulpho - 4<1> - chlorophenyl) - 3 - methylpyrazolone is obtainable by condensing 4-chlorophenylhydrazine-3-sulphonic acid with acetoacetic ester.