GB700210A - Manufacture of azo-dyestuffs - Google Patents

Abstract

The invention comprises dyestuffs of the formula <FORM:0700210/IV (c)/1> where R1 is a benzene residue containing a p-alkoxy group, Z is azo or azoxy and R2 is a benzene residue containing a further benzene ring attached to it in the m- or p-position either directly or through a bridge member. R1 and R2 are preferably free from solubilizing groups. The dyestuffs may be made by (1) coupling diazotized 4-nitro-4\sv-aminostilbene-2 : 2\sv-disulphonic acid with a phenol, alkylating the hydroxyl group and condensing the product with 2 : 5-diaminobenzoic acid; (2) coupling and alkylating as in (1), then reducing the nitro group to amino diazotizing and coupling with anthranilic acid; or (3) coupling diazotized 4-nitro-4\sv-aminostilbene-2 : 2\sv-disulphonic acid with anthranilic acid, acylating the amino group, reducing the nitro group to amino, diazotizing, coupling with a phenol, alkylating the hydroxyl group and finally hydrolysing the acylamino group. The azoazoxy or disazo dyestuff resulting from one of these three processes is then diazotized and coupled with the appropriate pyrazolone. The anthranilic acid is preferably coupled as its w-methanesulphonic acid and then hydrolysed. The products are suitable for dyeing and printing wool, silk, leather, cotton, linen and regenerated cellulose. They be metallized in substance, in the dyebath or on the fibre, e.g. by the processes of Specifications 455,274 and 619,969; suitable metals are copper, chromium, iron, nickel and cobalt. The preparation of dyestuffs is exemplified where R1 is p-methoxyphenyl and R2 is 4-phenylphenyl, 4-(p-aminophenyl)-phenyl, 4-(p-acetylamino)-phenyl, 3- or 4-benzoylaminophenyl and 3-carbanilidophenyl. It is also stated that the two rings in R2 may be joined by oxygen and that the outer one may be substituted, e.g. by alkyl, alkoxy, halogen or methylamino. 1-(p-phenoxyphenyl)-3-methyl-5-pyrazolone is specified as coupling component. In a further example cotton is dyed red-orange with the dyestuff where R1 is p-methoxyphenyl and R2 is 4-phenylphenyl, with after-coppering.