PRODUCTION OF 5-AMINO-2,4,6-TRIIDOISOPHTHALIC ACID

摘要

PROBLEM TO BE SOLVED: To provide a method for obtaining a high-purity objective substance without requiring a high-pressure condition while preventing the formation of by-product in producing 5-amino-2,4,6triiodoisophthalic acid by using 5- nitroisophthalic acid as a raw material. SOLUTION: 5-Nitroisophthalic acid is reduced with hydrogen in the presence of an alkali metal hydroxide in an atmosphere having an isoelectric point of 5-nitroisophthalic acid especially in the range of pH 4-7 to form an alkali metal salt of 5-aminoisophthalic acid, which is made into liberated 5-aminoisophthalic acid with sulfuric acid or phosphoric acid. The liberated 5-aminoisophthalic acid is triiodated by treatment with a hydrochloric acid solution of iodine monochloride.