| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a process for producing a methacrylic acid producing catalyst having an excellent catalyst life, and a process for producing methacrylic acid with high productivity over a long period using the catalyst. <P>SOLUTION: The catalyst composed of a heterpoly acid compound including phosphorus and molybdenum is produced by carrying out the first-stage burning of a catalyst precursor under circumstances of an oxidative gas containing a water content of 10 volume % or less at 300 to 400°C, then the second-stage burning under circumstances of a non-oxidative gas at 400 to 500°C, and the third-stage burning under circumstances of the oxidative gas containing a water content of 30 volume % or less at 300 to 400°C. Under the presence of the catalyst, a compound selected from the group consisting of methacrolein, isobutyl aldehyde, isobutane and isobutyric acid is subjected to a gas phase catalytic oxidation reaction. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
