Patent GB-541362-A (GB)
Title: Manufacture of azo dyestuffs
IPC: C09B35/50
Filed: 1940-03-29
Abstract: 541,362. Dyes. DU PONT DE NEMOURS & CO., E. I. March 29, 1940, No. 5672. Convention date, March 29, 1939. [Classes 2 (iii) and 15 (ii)] Tetrakisazo dyes of the type A #X# Y# Z# W: wherein A represents 1:3-dihydroxybenzene, X represents 1:3-diaminobenzene, or 1:4 diaminobetizene which may be substituted in the 2- and 5-positions by alkyl or alkoxy groups, Y and Z each represent 1-aminonaphthalene, which may be substituted by an alkoxy group in the 2-position and/or by a sulphonic group in the 6- or 7-position, and W represents a 1- or 2-hydroxynaphthalene-mono-, di- or trisulphonic acid, are made by diazotization and coupling in accordance with the arrow indications, one of the amino groups of the diamine X being rendered non-diazotizable, e.g., by oxalylation or other acylation, until the successive diazotizations and couplings with the successive components Y, Z and W have been effected. Detailed examples relate to the production of the dyestuffs, (1) 1:3-dihydroxybenzene#1:4- diamino benzene- 1:6-aminonaphthalenesulphonic acid# 1:6-aminonaphthalenesulphonic acid # 1:5-hydroxynaphthalenesulphonic acid ; (2) and (3) the same with replacement of the last component by 2:7-hydroxynaphthalenesulphonic acid and 1:4-hydroxynaphthalenesulphonic acid respectively, and the process of dyeing rayon with these dyestuffs and aftertreating the dyeings with formaldehyde in the dyebath or in a fresh bath to improve the fastness to washing is described in detail. Such after-treatment may be substituted or supplemented by an after-treatment with a solution of a metal salt, such as copper or nickel sulphate, chromium chloride, copper formate or acetate or a cobalt or iron salt to improve the fastness to light. A table is also given showing the shades obtainable on after-treatment with formaldehyde of dyeings with the dyestuffs from various combinations of components, additional components X being 1:3-diaminobenzene and the 2-methyl-5-methoxy-derivavative of 1:4-diaminobenzene, additional components Y or Z being 1-aminonaphthalene and 1:7-aminonaphthalenesulphonic acid and additional components W being 2:6- and 1:3- hydroxynaphthalenesulphonic acids and 2:3:6- hydroxynaphthalenedisulphonic acid. There are also specified as components Y and Z, 1- amino-2-methoxynaphthalene-6-sulphonic acid, and as component W, 1:3:7- and 1:4:7-hydroxynaphthalenedisulphonic acids, and 1:3:6:8- hydroxynaphthalenetrisulphonic acid. Specification 19743/92, [Class 2], is referred to. The Specification, as open to inspection under Sect. 91, comprises also the manufacture of the corresponding dyes in which A may be additionally a 1:3-dihydroxybenzene substituted in 5- position by alkyl, alkoxy, hydroxy, amino, halogen, cyano, carboxy or sulpho, X may be additionally any 1:3- or 1:4-diaminobenzene substituted once by alkyl, alkoxy, nitro, cyano, carboxy, or sulpho, Y and Z may oe additionally any 1-aminonaphthalene with free 4- position substituted in 2- and/or 3- position by alkyl or alkoxy and/or in not more than two positions 5-, 6-, 7- and 8- by alkyl, alkoxy, carboxy or sulpho and W may be additionally any 1:8-dihydroxynaphthalenesulphonic acid, any 1-hydroxynaphthalene substituted in 3- or 4-position by sulpho and, if desired, in not more than two of the positions 5-, 6-, 7- and 8- by alkyl, alkoxy, carboxy or sulpho, any 2- hydroxynaphthalene substituted in 3- and/or not more than two of the positions 5-, 6-, 7- and 8 by alkyl, alkoxy, carboxy or sulpho, or any 1- or 2-hydroxynaphthalene substituted in 2- or 1- or 3- or 4- position by alkyl or alkoxy and/or in not more than two of the positions 5-, 6-, 7- and 8- by alkyl, alkoxy, carboxy or sulpho. Numerous additional examples are given of various combinations of these components. This subject-matter does not appear in the Specification as accepted.