GB794473A - Improvements in the production of monoazo dyestuffs containing chromium - Google Patents

Abstract

Chromed azo dyestuffs are made by coupling a diazo-compound of a 2-alkoxyaniline with a halogen-containing phenol which couples in o-position to the OH group and chroming the product to give a 1 : 1 complex. Chroming is performed in conventional fashion. The alkoxyanilines may contain substituents such as halogen atoms or nitro, alkyl, alkoxy, sulphonic acid, sulphonamido and carboxylic acid groups. 4 - Chloro -, 2,4 - dichloro -, 2,4,5 - trichloro- and 3 - methyl - 4 - chloro - phenols are specified coupling components. The dyestuffs dye and print wool, silk, leather, casein wool and polyamide fibres and colour organic solutions and synthetic resins such as cellulose ester varnish, varnishes and articles made from cellulose esters and ethers. The dyestuffs may be reacted with colourless complex-forming compounds as in Specification 692,073. In examples illustrative of the preparation of the dyestuffs and their use in dyeing wool or colouring cellulose ester varnishes in red shades the coupling components used are chosen from those specified above the diazo components being 2-methoxyaniline - 5 - sulphonic acid and its diethylamide, 2 - methoxy - 4 - and 5 - nitro - and 2,5-diethoxy-anilines and 2-methoxy-5-methylaniline-4-sulphonic acid dimethylamide, certain of the products being after-treated with 2-hydroxybenzoic acid-5-sulphonic acid phenylamide by the process of Specification 692,073 to yield red dyestuffs for wool. Specification 272,908, [Class 2 (iii)], also is referred to.