PURIFICATION OF NAPHTHALENEDICARBOXYLIC ACID

摘要

PROBLEM TO BE SOLVED: To obtain highly purified naphthalenedicarboxylic acid useful as a raw material of a polyethylene naphthalate(PEN) resin having excellent performance in a high recovery ratio from to crude naphthalenedicarboxylic acid obtained by oxidizing a dialkylnaphthalene. SOLUTION: Crude naphthalenedicarboxylic acid is dissolved in a pyridine or an aqueous solution of the pyridine, formylnaphthoic acid, etc., contained in the crude naphthalenedicarboxylic acid are removed by hydrogenation treatment and pyrimidine is distilled out in the presence of water to precipitate naphthalenedicarboxylic acid having a slight solubility in water, e.g. 2, 6- naphthalenedicarboxylic acid.