Process for the manufacture of 4, 5-dichloro- and 4, 5-dibromo-naphthalene-1, 8-dicarboxylic acids and their anhydrides

摘要

4,5-Dichloro- and 4,5-dibromo-naphthalene-1,8-dicarboxylic acids and anhydrides are made by dissolving 1,4,5,8-naphthalene-tetracarboxylic acid or the anhydride thereof in water with the addition of an alkali metal hydroxide, carbonate, acetate or phosphate and the solution obtained is reacted within a pH-range from 4 to 6.5 at a temperature within the range from 10 DEG C. to 70 DEG C. with chlorine or bromine or an agent which releases chlorine or bromine under such conditions, e.g. a sodium hypochlorite liquor or N-bromosuccinimide. Detailed examples are given.