| abstract |
An object of the present invention is to provide a process for producing a catalyst for gas-phase contact oxidation of methacrolein, isobutyraldehyde or isobutyric acid to produce methacrylic acid in a high yield and a high selectivity. A catalyst wherein an alkali metal element, particularly cesium among alkali metal elements, is added by a specific method in a partially neutralized salt of a hetero polyacid which contains Mo, V, P, an alkali metal element and NH 4 as essential active ingredients, the catalyst being characterized by having extremely high catalytic performance. |