PROCESS FOR THE MANUFACTURE OF BLUE DISPERSION DYESTUFFS

摘要

Brominated 1,5-dihydroxy-4,8-diamino- or 1,8 - dihydroxy - 4,5 - diamino - anthraquinones are prepared by heating the corresponding 1,5- dibromo - 4,8 - diacylamino- or 1,8 - dihydroxy - 4,5 - diacylamino - anthraquinone with sulphuric acid, optionally containing SO 3 , in presence of boric acid. The products may be further reacted with an alkylating agent. The reaction preferably takes place at 40-200 C. using at least 5 parts sulphuric acid and at least 0À1 part of boric acid per part dibromodiacylaminoanthraquinone. The sulphuric acid preferably contains not more than 40% SO 3 . Alkylation takes place at 100-150 C. by heating with formaldehyde, or formaldehyde releasing agent or an aliphatic alcohol in sulphuric acid. The dyes give blue shades on cellulose acetate, polyamides and polyesters.