GB251637A - The manufacture of new disazo dyestuffs - Google Patents

Abstract

251,637. I. G. Farbenindustrie Akt.- Ges., (Assignees of Farbenfabriken vorm. F. Bayer & Co.). April 28, 1925, [Convention date]. Disazo dyes are made by diazotizing an aromatic amino-dicarboxylic acid, or a derivative thereof, an amino-sulpho-carboxylic acid, or an amino-sulpho-oxycarboxylic acid or a derivative thereof, coupling with a-naphthylamine-6-or-7- sulphonic acid, re-diazotizing the aminoazo-dyestuff thus produced, and coupling with an aromatic o-oxycarboxylic acid. In examples, (1) 4-amino-phthalic acid is diazotized, coupled with a-naphthylamine-6-sulphonic acid, re-diazotized, and coupled with m-cresotinic acid; the product, when used for chrome printing on cotton, gives a beautiful brown shade of outstanding fastness to chlorine, soaping and light, and dyes wool, with after chroming, a reddish-brown shade, and (2) 3-amino-5-sulpho-2-oxybenzoic acid is diazotized, coupled with a-naphthylamine-6-sulphonic acid, re-diazotized, and coupled with salicyclic acid; the, product dyes wool direct in orangebrown shades which become reddish-brown on after chroming, and gives reddish-brown shades in chrome printing on cotton. Specifications 22641/91 and 5112/92, [both in Class 2, Acids and salts, Organic &c.], are referred to. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the use of aromatic amino-monocarboxylic acids or their derivatives in general as first components. This subject-matter does not appear in the Specification as accepted.