| 摘要 |
PURPOSE:To obtain an oxidizing catalyst having high selectivity and excellent in a yield ratio and strength by adding Be or the like to heteropoly-acid comprising P, Mo, V and O prepared in the presence of a nitrogen containing heterocyclic compound. CONSTITUTION:As a catalyst in preparing methacrylic acid or the like by subjecting 4C unsaturated hydrocarbon or the like, heteroploy-acid is molybdophosphoric acid or a partial substitution product thereof and has an almost salt crystal structure of which 2theta is about 26.2 deg., 10.5 deg., 21.3 deg. and 30.3 deg. in X-ray pattern and the general formula thereof is PaMobVcXdOe(wherein X is Be, Ca or the like, when b is 12, a is 0.1-3, c is 0-6, d is 0.05-5, e is determined by each valency and each atomic ratio). This catalyst is excellent is selectivity and a yield in preparing methacrylic acid and has strength and long life. |
