METAKURIRUSANGOSEISHOKUBAINOSAISEIHOHO

摘要

PURPOSE:To restore the activity of the titled catalyst, by subjecting a methacrylic acid synthesizing catalyst with reduced activity to heating treatment in the presence of steam to carry out regeneration treatment thereof without taking out the same from a reaction apparatus. CONSTITUTION:When the activity of a catalyst based on free phosphomolybdic acid and/or phosphovanadomolybdic acid used in preparing methacrylic acid by gas phase catalytic oxidation of methacrolein is lowered, it is treated at 70- 240 deg.C in a gas stream with steam partial pressure of 10vol%. By this method, regeneration can be carried out in a reaction apparatus and the catalyst becomes economical and is extended in the life thereof.