GB274128A - Manufacture of azo dyestuffs - Google Patents

Abstract

274,128. I. G. Farbenindustrie Akt.- Ges. July 9, 1926, [Convention date]. Azo dyes; lakes.-Azo dyes are produced in substance, on a substratum, or on the fibre by coupling diazotized 1 : 3-dimethyl-4-amino-6-halogen (or 2 : 6-dihalogen) benzenes with arylides of 2: 3-oxynaphthoic acid, the combination of diazotized 1 : 3 - dimethyl-4-amino-6-halogenbenzenes with arylides in which the aryl group is an asymmetrical m-xylidine residue being excluded. Various shades of yellow and red are obtained, the dyeings produced on the fibre being fast to light, chlorine, and kier-boiling. In an example, cotton is dyed red by padding with the 4-chlor-2-toluidide and developing with the diazotized 6-chlor derivative. The 6-brom- and 2 : 6- dichlorderivatives are also specified as diazo components, and the 2-toluidide, 5-chlor-2-anisidide, 4-chlor-2-toluidide, and #-naphthylamide as coupling components. Specifications 6379/12; 17279/13, [Class 15 (ii), Dyeing, Processes &c. for] ; 199,771, and 254,578 are referred to. The Specification as open to inspection under Sect. 91 (3) (a) comprises also an example in which cotton is dyed bluish red by padding with the alpha-naphthylamide and developing with the diazotized 2 : 6-dichlor-derivative. This subjectmatter does not appear in the Specification as accepted. 1 : 3 - Dimethyl-4-amino-6-halogen (or 2 : 6-dihalogen) benzenes are obtained by halogenating' asymmetrical m-xylidine in sulphuric' acid or the like as described for the chlorine derivatives in Specification 278,729.