摘要 |
A catalyst for the production of methacrylic acid comprising a heteropolyacid compound containing phosphorus and molybdenum is regenerated by a method comprising the steps of drying a mixture containing a deactivated catalyst, an ammonium ion, a nitrate ion and water, molding the dried mixture, firstly calcining the molded product in an atmosphere of an oxidizing gas at a temperature of 360 to 410° C., and then secondly calcining the product in an atmosphere of a non-oxidizing gas at a temperature of 420 to 500° C. The regenerated catalyst has substantially the same catalytic activity as a fresh catalyst in a gas phase catalytic oxidation reaction of methacrolein, isobutylaldehyde, isobutane or isobutyric acid to prepare methacrylic acid.
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