GB526007A - Manufacture of azo-dyestuffs - Google Patents

Abstract

526,007. Dyes. SOC. OF CHEMICAL INDUSTRY IN BASLE. March 6, 1939, Nos. 7252 and 7253. Convention dates, March 5, 1938, Feb. 17, 1939. [Classes 2 (iii) and 15 (ii)] In the manufacture of azo dyes by coupling a diazo-compound of an aromatic amine which carries several negative substituents, e.g., halogen atoms, or nitro, sulphonic, carboxylic, cyanogen, carboxylic amide or sulphamide groups, with a coupling component, the coupling is effected in the presence of methyl alcohol and in the absence of water, other than that which may be formed during the operation. As diazo components are specified 2:4-dinitroaniline, 2:4-dinitro-6-halogen-, cyano- or methoxy-anilines, 2:4-dinitroaniline-6-methyl-, ethyl-, benzyl-, or phenyl-sulphones, 2:4- dinitroaniline-6-sulphamide or -dialkylsulphamides, 2:5-dinitroaniline and its substitution products, and 2:4:6:-trinitroaniline. Any coupling components may be used, particularly those which, owing to the presence of a substituted or unsubstituted amino group, lead to the production of aminoazo dyestuffs. Specified coupling components are aniline, o- or mtoluidine, p-xylidine, p-cresidine, 2:5-dioxyalkylanilines, napthtylamines, N-ethyloxyethylaniline, N-ethyloxyethyl-m-toluidine, N-dioxyethyl-m-toluidine, N-dioxyethyl-3-methyl-6- methoxyaniline, N-ethyl (or n-butyl)-oxyethyl- 3-methyl-6-methoxyaniline, N-dioxyethyl-3- acetylamino-6-methoxyaniline, 2-ethylnaphthylamine, 1-amino-5-naphthol, and alkylation products obtained by treating 1-amino-5- naphthol with epichlorhydrin. In an example, 2:4 - dinitroaniline - 6 - methylsulphone is diazotized in concentrated sulphuric acid and coupled with N-dioxyethyl-3-methyl-6-methooxyaniline in methyl alcohol solution, which may advantageously contain an acid-binding agent, e.g. magnesium carbonate or an ammonium salt. The product dyes acetate artificial silk in blue shades capable of white discharge.