| 摘要 |
<p>Preparing a catalyst comprises first calcination of a catalyst precursor comprising a heteropolyacid compound containing phosphorus and molybdenum at 360-410[deg] C in an atmosphere containing gas and 0.1 vol.% to less than 2 vol.% of a water component; a second calcination of the calcined product from the first calcination step at 420-500[deg] C in an atmosphere of a non-oxidizing gas; and cooling the calcined product from the second calcination step in an atmosphere of a non-oxidizing gas at = 280[deg] C. An independent claim is included for producing methacrylic acid comprising catalytic oxidation of at least one compound consisting of methacrolein, isobutyraldehyde, isobutane or isobutyric acid in the gas phase in the presence of the catalyst.</p> |
