Patent ID: 7985875

Claim:
A process for preparing an aromatic polycarboxylic acid by liquid phase oxidation comprising contacting a benzene or naphthalene compound having two or three C1-C4 alkyl, hydroxyalkyl or formyl groups with an oxygen-containing gas in the presence of a carboxylic acid solvent, a catalyst comprising at least one metal selected from the group consisting of cobalt, magnesium, chromium, copper, nickel, vanadium, iron, molybdenum, tin, cerium and zirconium, and a promoter in a reaction zone, the promoter is an ionic liquid comprising an organic cation selected from the group consisting of 1-alkylpyridinium and 1,3-dialkylimidazolium and an anion consisting essentially of bromide or iodide and said ionic liquid having a melting point of below 200° C.