Process for oxidizing impurities in crude terephthalic acid
||US 9079846 B2
||Oct 12, 2012
||Jul 14, 2015
A process for oxidizing solid crude terephthalic acid is described. The process includes contacting solid crude terephthalic acid with a solvent comprising a carboxylic acid and one or more of an ionic liquid or ammonium acetate; a bromine source; a catalyst; and an oxidizing agent to produce solid purified terephthalic acid at a temperature of about 100 to about 210 DEG C., and a pressure of about 2 to about 4.5 MPa, for a time of about 5 to about 60 min, and recovering the solid purified terephthalic acid.