GB296473A - Manufacture of azo-dyestuffs - Google Patents

Abstract

296,473. Imray, O. Y., (I. G. Farbenindustrie Akt.-Ges.). June 1, 1927. Samples furnished. Azo dyes are produced in substance, on a substratum, or on the fibre, by coupling a diazotized 2: 5-dimethyl-4-halogenaniline, in which one of the positions 3 or 6 is occupied by halogen and the other by hydrogen, with an arylide of 2 : 3- oxynaphthoic acid or of a #-ketocarboxylic acid. In examples, (1) cotton is dyed a bright red by padding with the 4-chlor-2-toluidide of 2:3- oxynaphthoic acid in caustic soda solution with addition of Turkey-red oil, and developing with diazotized 2 : 5-dimethyl-4 : 6-dichloraniline; (2) cotton is dyed a bluish-red by padding with the #-naphthalide of 2 : 3-oxynaphthoic acid and developing with diazotized 2: 5-dimethyl-3 : 4- dichloraniline. The dyeings are fast to kier-boiling and to chlorine. Specifications 6379/12, 13110/13; 17279/13, [Class 15 (ii), Dyeing, Processes &e. for], 210,217 and 210,347 are referred to. 2: 5-dimethyl-3 : 4-dichloraniline is obtained by saponifying 1-acetylamino-2 : 5-dimethyl-4 : 6- dichlorbenzene, or by chlorinating mineral salts of 2 : 5-dimethylaniline in organic solvents. 2 : 5-dimethyl-3- : 4-dichloraniline is obtained by .y chlorinating 2 : 5-dimethylaniline in sulphuric acid.