Patent GB-555971-A (GB)
Abstract: 555,971. Dyes and intermediates. GEIGY AKT.-GES., J. R. Nov. 25, 1941, No. 15160. Convention date, Nov. 26, 1940. [Class 2 (iii)] 2-Aryl-1:3-arylenetriazoles are obtained by treating with an oxidizing agent an o-amino azo dyestuff, containing one or more sulphonic acid groups, of the general formula wherein R 1  and R 2  represent radicles of the benzene or naphthalene series, at least one being of the naphthalene series, X 1  and X 2  represent metallisable substituents, e.g. hydroxy or carboxy groups, or substituents e.g. halogen atoms or alkoxy groups, convertible into such metallisable substituents under the conditions of the metallisation, the substituents X 1  and X 2  being each in o- or peri-position to one of the linkages of the final triazole ring. Specified oxidizing agents are hydrogen peroxide, perborates, percarbonates, persulphates, hypochlorites, permanganates, compounds of hexavalent chromium and cupric tetrammine sulphate. The oxidation may be effected in presence of an oxidation accelerator, e.g. copper powder, copper ions, iodine, iron salts or haemoglobin. Specified nitro-substituted derivatives, and specified sulphonated diazo components for the azo dyestuffs ' are 2- aminophenol-4-sulphonic acid and its 5- or 6- halogen- or nitro-substituted derivatives, 4- halogen- or nitro-substituted derivatives of 2- aminophenol-6-sulphonic acid and 2:1-aminonaphthol-4-sulphonic acid and its derivatives nitro-substituted in the nucleus not carrying the amino group, and specified coupling com- , ponents are 2:3-aminonaphthoic acid and its derivatives substituted by nitro or sulphonic acid groups in the nucleus not carrying the amino group, and 1:8:4- or 1:8:5-aminonaphtholsulphonic acids (coupled acid). The triazole products are taken up by animal fibres from an acid bath and are convertible into dyestuffs of good fastness to light by treatment in substance or on the fibre with agents yielding metal, e.g. chromium or copper. When compounds of hexavalent chromium are used as oxidizing agents, conversion into the chromium complex dyestuff is effected simultaneously with oxidation. When ammoniacal solutions of copper salts are used as oxidizing agents, conversion into copper complex pigments is effected simultaneously with oxidation and the copper may be removed by treatment with sodium sulphide or strong mineral acids. In examples, (1) the azo dyestuff, 4-chloro-2-aminophenol-6- sulphonic acid# 2:3-aminonaphthoic acid is treated with sodium hypochlorite in aqueous solution at 45‹C. and the triazole produced is salted out ; the product, if desired after nitration, may be applied to wool and afterchromed to obtain fast yellow dyeings ; (2) the same azo dyestuff is treated with copper tetrammine sulphate or copper acetate in aqueous solution at 90-100‹C. while passing air through the solution, and with or without an addition of hydrogen peroxide or sodium hypochlorite, and the precipitated triazole pigment containing copper is filtered off, washed and dried ; the product may be freed from copper by treatment in aqueous suspension at 90‹C. with sodium sulphide ; (3) the same azo dyestuff is treated with sodium bichromate and hydrochloric acid in aqueous solution at 95-100‹C., the solution being then neutralized with sodium carbonate and the chromium-containing triazole produced salted out; the product dyes wool, from a bath containing formic acid, a level greenish yellow, fast to light ; (4) the ammonium salt of the azo dyestuff, 4 - chloro - 2 - aminophenol - 6 - sulphonic acid# (acid) 1:8:4 - aminonaphtholsulphonic acid, is treated in aqueous solution at 80-90‹C. with copper tetrammine sulphate while passing air through the solution, and the precipitated triazole pigment containing copper is filtered off and treated in aqueous suspension at 90‹C. with sodium sulphide, the resulting sodium salt being precipitated by addition of acetic acid and sodium chloride; the product gives brown-yellow dyeings, fast to light, when after-chromed on wool. A table is also given showing the shades obtained on wool directly and with after-chroming with the use of the products of oxidation with sodium hypochlorite of the dyestuffs, nitro-2-aminophenol-4-sulphonic acid or 4-nitro-2-aminophenol-6-sulphonic acid# 2:3-aminonaphthoic acid and 5-nitro-2-aminophenol or its 4-chloro- or 4- methyl - derivative # 2:3 - aminonaphthoic - 6 - sulphonic acid and the product of the oxidation with copper tetrammine sulphate and air of the dyestuff, 4 - chloro - 2 - aminophenol # (acid) 1:8:4-aminonaphtholsulphonic acid. 2:3 - Aminonaphthoic - 6 - sulphonic acid is obtained from 2:3-hydroxynaphthoic-6-sulphonic acid by the Bucherer reaction. The Specification as open to inspection under Sect. 91 comprises also the subject-matter of Specification 556,143, viz. the production of the same 2-aryl-1:3-arylenetriazoles by reduction of the corresponding azo dyestuffs having an o-nitro group in place of the o-amino group. This subject-matter does not appear in the Specification as accepted.