Regenerating a catalyst having a heteropoly acid compound, useful to prepare methacrylic acid, comprises heat-treating a mixture containing deactivated catalyst, an ammonium-, a nitrate- ion and water, drying and calcinating the mixture

摘要

Regeneration of a catalyst comprising a heteropoly acid compound containing phosphorus and molybdenum, for the preparation of methacrylic acid, comprises heat-treating a mixture containing deactivated catalyst, an ammonium ion, a nitrate ion and water at at least 100[deg] C, and drying and calcinating the mixture. An independent claim is included for the preparation of methacrylic acid comprising regenerating the catalyst, by the above process, and subjecting a gas phase oxidation of at least a compound methacrolein, isobutyraldehyde, isobutane or isobutyric acid in the presence of the regenerated catalyst.