GB662253A - Manufacture of new tetrakisazo-dyestuffs - Google Patents

Abstract

Tetrakisazo dyestuffs are made by coupling one mol. of 5 : 51-dihydroxy-2 : 21-dinaphthylamine-7 : 71-disulphonic acid with one mol. of the diazo compound of <FORM:0662253/IV (c)/1> and one mol. of the diazo compound of R1-N= N-R2-NH2; R and R1 are benzene residues containing a hydroxyl and a carboxyl group ortho to one another and R2 is a benzene residue in which the amino group is para to the azo group and which contains an alkoxy group ortho to the amino group; R, R1 and R2 are all free from sulphonic acid groups. R may be 4-hydroxy-3-carboxy-phenyl or the 5- or 6-methyl derivatives thereof or 2-hydroxy-3-carboxy-5-methyl-phenyl; R1 may be 4-hydroxy - 3 - carboxy - phenyl; R2 may be 4 - amino - 3 - methoxy - phenyl, 4 - amino - 2 : 5-dimethoxy - phenyl, 4 - amino - 2 - ethoxy - 5 - methoxy - phenyl, 4 - amino - 2 - methoxy - 5 - ethoxy-phenyl or 4-amino-2-methyl-5-methoxy-phenyl. The diazotization of the aminoazo compounds is preferably carried out by mixing the amine with alkali and nitrite and then adding acid. The coupling of the two diazo compounds may be carried out simultaneously or successively; in the latter case the second coupling may take place at a higher pH than the first. The dyestuffs are suitable for dyeing or printing cellulosic material, e.g. cotton, linen, artificial silk or staple fibres of regenerated cellulose. They may be coppered on the fibre or partly on the fibre and partly in the dyebath, e.g. with a complex copper tartrate (cf. Specification 455,274). Alternatively, the dyed or printed material may be treated with an aqueous solution of a copper compound (e.g. cuprammine acetate) which contains a basic condensation product of formaldehyde with a substituted guanidine (e.g. dicyandiamide) or a compound convertible thereto (e.g. cyanamide). Examples show the preparation of the dyestuffs and the dyeing of cotton therewith. Specifications 452,326 and 559,680 and French Specification 918,737 are referred to. Monoazo dyestuffs of the formula <FORM:0662253/IV (c)/2> where R is as above, are prepared by coupling diazotized 2-nitro-5-amino-benzoic acid with salicylic acid or a substituted salicylic acid and reducing the nitro group. Monoazo dyestuffs of the formula R2-N= N-R2-NH2, where R1 and R2 are as above, are made by coupling a diazotized aminophenol-o-carboxylic acid with an o-alkoxyamine of the benzene series. The latter may be coupled in the form of its o -methane-sulphonic acid.