Patent GB-536159-A (GB)
Title: Manufacture of brown polyazo dyestuffs, especially suitable for dyeing leather
IPC: C09B33/22
Filed: 1940-02-14
Abstract: 536,159. Dyes. GEIGY AKT.-GES., J. R. Feb. 14, 1940, No. 2824. Convention date, Feb. 15, 1939. [Class 2 (iii)] Polyazo dyes, giving full level brown dyeings, specially fast to polishing, on leather and of the general formula wherein A represents the residue of 3-hydroxydiphenylamine or a derivative thereof capable of coupling twice in alkaline  medium, B represents the residue of a 1: 8 - aminonaphtholmono-or-di-sulphonic acid coupled in alkaline medium, C and D represent the residues of the same or different diazo or diazoazo compounds, preferably substituted by nitro groups, the finished dyestuff containing at least 2 sulphonic groups, are obtained by (a) coupling in alkaline medium the diazotized 1 : 8- aminonaphtholsulphonic acid (1 mol.) with 3 - hydroxydiphenylamine or its derivative (1 mol.) and coupling the product in alkaline medium successively with the 2 mols. of the diazotized amine (or amines) and/or aminoazo compound (or compounds), (b) coupling in alkaline medium a diazotized amine or aminoazo compound ( 1 mol. ) with the 1: 8 - aminonaphtholsulphonic acid (1mol.), diazotizing and coupling in alkaline medium with the 3 - hydroxydiphenylamine or its derivative (1 mol.) and coupling the product in alkaline medium with a diazotized amine or aminoazo compound (1 mol.). Examples relate to the production of the dyestuffs, (1) sulphanilic acid - (alkaline) 1 : 8-aminonaphthol-3: 6-disulphonic acid # (alkaline) 3-hydroxydiphenylamine or its 2<SP>1</SP>-, 3<SP>1</SP>- or 4'-methyl derivative (alkaline) # 4-nitroaniline by method (a); (2) 4-nitroaniline, or its 2-sulphonic acid # (alkaline) 1 : 8 - aminonaphthol-3: 6 - disulphonic acid # (alkaline) 3-hydroxy-2<SP>1</SP>-methyldiphenylamine (alkaline) # 4<SP>1</SP>-amino-4-nitrodiphenylamine-2-sulphonic acid or 4 - nitroaniline (# Cleve's acid, if desired) by method (a); (3) sulphanilic acid # (alkaline) 1 : 8 - amiinonaphthol- 3 : 6-disulphonic acid # (alkaline) 3-hydroxy-2<SP>1</SP>-methyldiphenylamine #naphthionic acid by method (a), the naphthionic acid may be replaced by one of the aminoazo compounds naphthionic or sulphanilic acid or 4-nitroaniline # Cleve's acid ; (4) 4- nitroaniline or sulphanilic acid or 4<SP>1</SP> - amino- 4-nitrodiphenylamine- 2 - sulphonic # (alkaline) 1: 8 aminonaphthol - 3 : 6 - disulphonic acid - (alkaline) 3-hydroxy-2'-methyldiphenylamine (alkaline) #(Cleve's acid, if desired #) 4<SP>1</SP>-amino - 4 - nitrodiphenylamine - 2 - sulphonic acid, by method (b). Other specified derivatives of 3 - hydroxydiphenylamine are the 2<SP>1</SP>-and 4<SP>1</SP>-chloro- and the 2<SP>1</SP>- and 4<SP>1</SP>-methoxy- and ethoxyderivatives. The use of the 1:8:4-acid as the 1:8- aminonaphtholsulphonic acid is also specified. Specification 251,140, [Class 2 (iii)], is referred to. 2 1 and 4 <SP>1</SP>- chloro-, methoxy- and, ethoxy derivatives of 3 - hydroxydiphenylamine are obtained by heating the 2<SP>1</SP>- and 4<SP>1</SP>-chloranilines, anisidines and phenetidines respectively with resorcinol in presence of boric acids. The Specification as open to inspection under Sect. 91 comprises also the manufacture of the dyestuffs by (c) coupling a diazotized amine or aminoazo compound (1 mol.) with the 3- hydroxydiphenylamine or its derivative (1 mol.) coupling with the diazotized 1 :8 - aminonaphtholsulphonic acid (1 mol.) and coupling the product with a diazotized amine or aminoazo compound (1 mol.), and (d) coupling in alkaline medium a diazotized amine or aminoazo compound (1 mol.) with the 1 : 8-aminonaphtholsulphonic acid (1 mol.), diazotizing the product and coupling with the mono-or dis-azo dyestuff obtained by coupling a diazotized amine or aminoazo compound (1 mol.) with the 3- hydroxydiphenylamine or its derivative (1 mol.). Additional examples (5) and (6) illustrating process (c) and (d) respectively relate to the production of the dyestuffs, 4-nitroaniline or 4<SP>1</SP>- amino - 4 - nitrodiphenylamine - 2 - sulphonic acid - (alkaline) 1 : 8 - aminonaphthol-3: 6- or (in (5)) 4 : 6- or 2 : 4-disulphonic acid # 3- hydroxy-2<SP>1</SP>-methyldiphenylamine # sulphanilic or (in (6)) naphthionic acid. This subjectmatter does not appear in the Specification as accepted.