METHOD FOR PRODUCING A PURIFIED NAPHTHALENE DICARBOXYLIC ACID

摘要

A method for producing a purified naphthalenedicarboxylic acid includes steps of mixing a naphthalenedicarboxylic acid-containing material and an amine in a mixed liquid of water and an organic solvent to give a crystal of a naphthalenedicarboxylic acid amine salt; and obtaining a purified naphthalenedicarboxylic acid from the crystal of the naphthalenedicarboxylic acid amine salt, wherein (1) in the step of forming the naphthalenedicarboxylic acid amine salt by adding an amine to the slurry that contains water, an organic solvent and a naphthalenedicarboxylic acid, the amine addition rate is from 0.002 to 0.4 mol/min relative to one mol of the naphthalenedicarboxylic acid, or (2) an amine is added to the aqueous solution prepared by dissolving the naphthalenedicarboxylic acid amine salt in water, or to the liquid prepared through solid-liquid separation of the aqueous solution to insolubilize and precipitate the metal component, and the precipitated metal component is removed through solid-liquid separation.