| 摘要 |
PROBLEM TO BE SOLVED: To provide a catalyst capable of producing methacrylic acid in a high yield by setting the pore radius of a methacrylic acid producing catalyst of a specific element to a specific range and providing two peaks within this range. SOLUTION: The pore radius of a methacrylic acid producing catalyst represented by the formula: PaMobVcCudXeYfZgOh used in the gaseous catalytic oxidation of methacrolein by molecular oxygen is set to a range of 0.5-10 μm and two peaks are provided in this range. In the formula, P, Mo, V, Cu and O are phosphorus, molybdenum, vanadium, copper and oxygen, X is one element selected from potassium, rubidium, cesium and thallium, Y is one element selected from bismuth, zirconium, silver and iron, Z is one element selected from antimony, arsenic, germanium or the like and a to h are atomic ratios of respective elements. |
