Method of reactivating catalyst

摘要

A method of reactivating a catalyst having reduced activity as a result of having been used in producing an unsaturated aldehyde as a main product by catalytic vapor-phase oxidation reaction of propylene, isobutylene or tertiary butanol, said catalyst being a catalytic oxide comprising molybdenum, bismuth and iron with a Mo:Fe atomic ratio of 12:at least 0.1. The method comprises heat-treating the used catalyst at a temperature of 300 to 500 DEG C in the presence of a flowing oxidizing gas containing at least 5 % by volume of molecular oxygen and at least 0.1 % by volume of steam.