| 摘要 |
PROBLEM TO BE SOLVED: To provide a catalyst for producing methacrylic acid capable of producing methacrylic acid at a high yield.SOLUTION: The catalyst for producing methacrylic acid is used when producing methacrylic acid by performing gas-phase contact oxidation of methacrolein by molecular oxygen and includes molybdenum element, phosphorus element, copper element, and Z-element that is at least one kind of elements selected from a group consisting of potassium, rubidium, and caesium. In a pattern obtained by applying first order derivative to a copper K absorption edge X-ray absorption fine structure spectrum when the catalyst is in contact with an atmosphere containing methacrolein at 300°C and then in contact with an air atmosphere while maintaining the 300°C, a value of m/n is 1.8≤m/n≤4.4 where m is the maximum value of a first peak intensity exhibiting a local maximum in a range of 8,982 to 8,985 eV and n is the maximum value of a second peak intensity exhibiting a local maximum in a range of 8,990 to 8,993 eV. |
