GB290733A - The manufacture of new and improved azo dyestuffs which are insoluble in water - Google Patents

Abstract

290,733. Carpmael, W., (,[. G. Farbenindustrie Akt.-Ges.). Feb. 18, 1927. Disazo dyes ; lakes.-Insoluble disazo dyes are made by coupling the tetrazo compound of 2 : 7- diaminocarbazol or an unsulphonated derivative thereof with a suitable component, other than a naphthol, e.g. with a 2 : 3-oxynaphthoic arylide, an oxynaphthocarbazol, or with a diacetoacetic arylide. The dyes may also be formed on a substratum or on the fibre. In examples, cotton yarn is impregnated (1) with the anilide of 2 : 3- oxynaphthoic acid and developed with tetrazotized 2 : 7-diaminocarbazol to give a marine blue shade, (2) with the a-naphthalide of 2 : 3-oxynaphthoic acid and developed with tetrazotized 3 : 6-dimethyl-2: 7-diaminocarbazol to give a deep bluish-black shade, (3) with the anilide of 2 : 3-oxynaphthoic acid and developed with tetrazotized 3 : 6-dichlor-2 : 7-diaminocarbazol to give a violet shade, and (4) with 7- oxynaphthocarbazol or diacetoacetic tolidide and developed with tetrazotized 2 : 7-diaminocarbazol to give a black or yellowish-brown shade. Specifications 7676/13, [Class 15 (ii). Dyeing, Processes &c. for] ; 210,217, and 275,326 are referred to. 3 : 6-Dichlor-2 : 7-diaminocarbazol is made by heating 2 : 2<1>-diamino-3 : 3<1>-dichlorbenzidine (by nitrating 3 : 3<1>-dichlorbenzidine and reducing) with dilute hydrochloric or sulphuric acid in an autoclave.