PROCESS FOR THE PREPARATION OF 4-BROMONAPTHALIC ACID ANHYDRIDE

摘要

A process for the preparation of 4-bromo-naphthalic acid anhydride by bromination of an alkali metal salt of naphthalic acid in an aqueous medium at a pH of 6.8 to 9 by dropwise adding 0.55 to 0.65 mol of bromine per mol of naphthalic acid and oxidizing the bromine at the same pH-value with chlorine. By this process 4-bromo-naphthalic acid anhydride can be obtained in a quantitative yield whereby the formation of 4-chloro-naphthalic acid is avoided.