Patent GB-700211-A (GB)
Title: Manufacture of azo dyestuffs
IPC: C09B31/153
Filed: 1951-07-19
Abstract: The invention comprises dyestuffs of the formula <FORM:0700211/IV (c)/1> where R is a naphthalene residue, Z is azo or azoxy and Py is the residue of a 5-pyrazolone attached in the 4-position; also complex metal compounds of the dyestuffs.  Preferably Py is the residue of a 1-aryl-3-methyl-5-pyrazolone where the aryl group is of the benzene or diphenyl series, and both R and Py are free from solubilizing groups.  These are made by (1) coupling diazotized amines of the formula <FORM:0700211/IV (c)/2> with the appropriate pyrazolone, or (2) oxidizing aminoazo compounds of the formula <FORM:0700211/IV (c)/3> Oxidation may be effected with alkali hypochlorite or a copper salt; in the latter case the copper complex is formed, which may be demetallized with hydrochloric acid or an alkali sulphide. Alternatively the metal-free dyestuffs may be converted into their copper, chromium, iron, nickel or cobalt derivatives in substance, in the dyebath or on the fibre, e.g. by the processes of Specifications 455,274 and 619,969.  The metal-free dyestuffs may be used for dyeing or printing wool, silk, leather, cotton, linen and regenerated cellulose.  The starting materials for method (1) are made from 4-nitro-4\sv-aminostilbene-2 : 2\sv-disulphonic acid by (a) diazotizing and coupling with anthranilic acid or condensing with 2 : 5-diaminobenzoic acid to give the azo compound <FORM:0700211/IV (c)/4> or the corresponding azoxy compound, acylating, reducing the nitro group to amino, diazotizing, coupling with a naphthylamine, oxidizing to the triazole and finally hydrolysing the acylamino group; or (b) diazotizing, coupling with a naphthylamine, oxidizing to the triazole and then either condensing with 2 : 5-diaminobenzoic acid or reducing the nitro group to amino, diazotizing and coupling with anthranilic acid.  The starting materials for method (2) are made from the azo-nitro-stilbene (formula in preceding sentence) or the corresponding azoxy-nitro-stilbene by diazotizing, coupling with a pyrazolone, reducing the nitro group to amino, diazotizing and coupling with a naphthyl-amine.  The anthranilic acid is preferably coupled as its o -methanesulphonic acid and then hydrolysed.  In the examples, (1) the compound of the formula <FORM:0700211/IV (c)/5> (sodium salt) is condensed with 2 : 5-diaminobenzoic acid and caustic soda; the product is diazotized and coupled with 1-phenyl-3-methyl-5-pyrazolone.  Similar dyestuffs are obtained by diazotizing the corresponding amino compound, coupling with anthranilic acid o -methane-sulphonic acid, hydrolysing, diazotizing and coupling with the pyrazolone or by performing these operations before coupling with the naphthylamine and oxidizing to the triazole; (2) 4 : 4\sv-dinitrostilbene-2 : 2\sv-disulphonic acid is condensed with 2 : 5-diaminobenzoic acid and the product diazotized and coupled with 1-phenyl-3-methyl-5-pyrazolone; the resulting dyestuff (as trisodium salt) is reduced to the amino compound, diazotized, coupled with 1-naphthylamine-4 : 8-disulphonic acid and oxidized with ammoniacal copper sulphate; (3) as in (2) using 2-naphthylamine and oxidizing with ammoniacal copper sulphate or sodium hypochlorite; (4) cotton is dyed orange with the product of example (1) and after-coppered.  Other specified naphthylamines are the 1-amino-4-and-5-sulphonic acids, 2-amino-6- and -7- sulphonic acids and the 2-amino-3 : 6-disulphonic acids. Other specified pyrazolones are the 1-aryl-3-methyl-5-pyrazolones where the aryl group is 4\sv-phenylphenyl, 4\sv-(p-aminophenyl)-phenyl, 4\sv-(p-acetylamino-phenyl)-phenyl, 4\sv-(p-benzoylaminophenyl)-phenyl, 3\sv- or 4\sv-benzoylaminophenyl, 3\sv-carbanilidophenyl, b -naphthyl, and 3\sv or 4\sv-sulphophenyl.