Process for producing pyromellitic anhydride

摘要

The present invention has for its object to provide a production method of pyromellitic anhydride of high purity in good yield at low cost by catalytic gas-phase oxidation of a 2,4,5-trialkylbenzaldehyde with the aid of a suitable catalyst system.The present invention relates to a production method of pyromellitic anhydride comprising a step for catalytic gas-phase oxidation of a 2,4,5-trialkylbenzaldehyde with a molecular oxygen-containing gas in which said step for catalytic gas-phase oxidation is carried out in the presence of a catalyst such that a specific surface area of the catalytic active component thereof is not greater than 50 m2/g or in the presence of a catalyst containing vanadium as well as molybdenum and/or tungsten as a catalytic active component.