| 摘要 |
PROBLEM TO BE SOLVED: To enhance the activity and the selectivity of a catalyst for manufacturing methacrylic acid by bringing a gas containing oxygen within a specific temperature range into contact with the catalyst for manufacturing methacrylic acid containing the phosphate of an alkaline metal used in a method for manufacturing methacrylic acid using an amide α-hydroxyisobutylate. SOLUTION: This catalyst for manufacturing methacrylic acid contains the phosphate of an alkaline metal used in a method for manufacturing methacrylic acid using an amide α-hydroxyisobutylate in the gas phase in the non-presence of oxygen. In order to regenerate the catalyst, gas containing oxygen of 50-800 deg.C is brought into contact with the catalyst. Thus the activity and the selectivity of the catalyst are upgraded. In addition, as far as the catalyst contains at least the phosphate of an alkaline metal, the catalyst is not specified. However, the catalyst having a composition represented as XaYbPcSidOe is preferably used as it shows a high yield of the methacrylic acid. In the formula, X is an alkali metal element; Y is magnesium or another element; and a-e show the atomic ratio of each of the elements. |
