PROCESS FOR PURIFICATION OF AROMATIC CARBOXYLIC ACIDS.

摘要

Impure aromatic carboxylic acids such as are obtained by liquid phase oxidation of feed materials comprising aromatic compounds with substituent groups oxidizable to carboxylic acid groups, or comprising aromatic carboxylic acid and one or more aromatic carbonyl impurities that form hydrogenated species more soluble in aqueous solvents or with less color or color-forming tendencies than the aromatic carbonyl impurity, are purified to an aromatic carboxylic acid product with lower levels of impurities by a process comprising contacting an aqueous solution comprising the impure aromatic carboxylic acid with hydrogen at elevated temperature and pressure with an attrition iresistant, acid stable catalyst composition comprising at least one hydrogenation catalyst metal and a support comprising relatively high surface area silicon carbide.