Process for producing trimellitic anhydride

摘要

A process for producing trimellitic anhydride which comprises performing liquid phase oxidation of pseudocumene containing 5% by weight or above of dimethyl bezaldehyde as a raw material for oxidation with air in aliphatic monocarboxylic acid having 1 to 5 carbon atoms as a solvent in the presence of a catalyst comprising both each metal of cobalt, manganese and zirconium and bromine to obtain trimellitic acid and then heat dehydrating trimellitic acid thus obtained or heat treating trimellitic acid thus obtained in the presence of a catalyst comprising 10 ppm or above of Ni thereby producing trimellitic anhydride.