Patent GB-551436-A (GB)
Title: Manufacture and use of new dyes
IPC: C09B29/00
Filed: 1941-08-13
Abstract: 551,436. Dyes. WRIGHT J. Aug. 13, 1941. No. 10287. [Classes 2 (ii), 2 (iii) and 15 (ii)] 4- Aminoazobenzenes, free from nuclear nitro, hydroxy and sulphonic groups, carrying substituents in at least three of the positions 2, 6, 21 and 6<SP>1</SP>, and in which the 4-amino group is the sole non-acidylated amino group, are obtained by (a) reducing the corresponding 4-nitro compound, (b) hydrolyzing a corresponding 4-acidylamino compound, (c) coupling a diazotized 2:6-disubstituted aniline with a 3:5- disubstituted aniline having a free 4-position. The products may be diazotized and coupled with a coupling component in substance or on the material dyed. Specified 4-aminoazobenzene derivatives are the 2-chloro-2<SP>1</SP>:6<SP>1</SP>- dimethyl-4<SP>1</SP>-methoxy, 2:6-dichloro-2<SP>1</SP>:6<SP>1</SP>- dimethyl-41-methoxy, 2-chloro-6-bromo-2<SP>1</SP>:6<SP>1</SP>-dimethyl-41-methoxy, 2:6:2<SP>1</SP>:6<SP>1</SP>-tetramethyl, 2- acetylamino-6-methoxy 2<SP>1</SP>:4<SP>1</SP>:6<SP>1</SP>-trichloro, 2:6- dichloro-2<SP>1</SP>-methoxy-4<SP>1</SP>-methyl and 2:6-dichloro-2<SP>1</SP>-methyl-4<SP>1</SP>-methoxy derivatives. They are applicable for dyeing cellulose ester or ether materials from aqueous dispersions and the dyeings may be subjected to diazotization and coupling with components, which may be enolic compounds, e.g. phenol, cresols, 2- naphthol, m-hydroxydiphenylamine, 2:3-hydroxynaphthoic acid, arylamides of o-hydroxybenzoic, 2:3-hydroxynaphthoic, acetoacetic or benzoylacetic acid, 1 - phenyl - 3 - methyl -5- pyrazolone or diacetoacetyltolidine, or aromatic amines, e.g. N-diethylaniline, N-diethyl - m - toluidine, the N - hydroxyalkylanilines referred to in Specification 506,740, the m - aminophenol ethers referred to in Specification 533,439 the 3 - acidvlaminoanilines referred to in Specification 523,287 or N - ethyl - or N- benzyl - 1 - naphthylamine. The disazo dyes formed in substance are suitable for incorporation in cellulose ester or ether lacquers or spinning solutions (cf Specification 551,435) and are applicable for colouring fibres, foils or films of synthetic linear polyamides, e.g. by application from aqueous baths, by formation on such materials, or by incorporation in the spinning and like solutions. Examples relate to the production of (1) the dyestuff, 4-amino-2:6- dichloro - 2<SP>1</SP> : 6<SP>1</SP> - dimethyl - 4<SP>1</SP> - methoxy - azobenzene, by reducing the nitro group in the product of methylation with dimethyl sulphate of the dyestuff, 2 : 6 - dichloro - 4 - nitroaniline # 1 : 3 : 5 - xylenol ; the product dyes cellulose acetate a bright golden yellow (2) the dyestuff, 4 - amino - 2 : 6 - dichloro - 21 - methyl - 4' - methoxy - azobenzene, similarly using m - cresol as coupling component ; (3) 4 - amino - 2 : 6 : 2<SP>1</SP> : 6<SP>1</SP> - tetramethyl - azobenzene by coupling diazotized vic. m - xylidine with 1 : 3 : 5 -xylidine; (4) a cellulose acetate fabric dyed with the product of (1), the dyeing being diazotized on the fibre and, developed to a full crimson shade with 3 - acetylamino - N - diethylaniline ; (5) the dyestuff, 4 - amino - 2 : 6 - dichloro - 2<SP>1</SP> : 6<SP>1</SP> dimethyl - 4<SP>1</SP> - methoxy - azobenzene -> 3 - stearoylamino - N - diethylaniline, which may be incorporated in an acetone solution of cellulose acetate for use in dry spinning to a yarn of a full red shade very fast to scouring. Specifications 412,164 and 551,435 also are referred to. 3 - Acetylamino - 5 - methoxyaniline (for use as coupling component in preparing 2-acetylamino- 6 - methoxy - 21 : 41 : 6<SP>1</SP> - trichloro - 4 - amino - azobenzene) is obtainable by reduction of 5 - nitro - 3 - acetylamino - anisol.