Process for producing a high purity aromatic polycarboxylic acid

摘要

A process for producing a high purity aromatic polycarboxylic acid by purifying a crude aromatic polycarboxylic acid in accordance with the steps of (I) forming an amine salt of an aromatic polycarboxylic acid from the crude polycarboxylic acid and an amine, (II) continuously decomposing the salt in a salt decomposition reactor in operations of (i) supplying an aqueous solution of the amine salt of an organic polycarboxylic acid formed in the step of forming a salt, (ii) removing the amine and water by distillation under heating and (iii) taking out a slurry containing crystallized aromatic polycarboxylic acid, and (III) separating and recovering crystals of the aromatic polycarboxylic acid from the slurry which is taken out in the step of decomposing the salt. A high purity aromatic polycarboxylic acid having excellent hue and large particle diameters can be produced from a crude aromatic polycarboxylic acid industrially with stability at a low cost of production in accordance with a process having a simple construction.