| 摘要 |
A method of preparing a catalyst used for producing methacrylic acids through gas phase catalytic oxidation of methacrolein with molecular oxygen. The catalyst is represented by the formula: PaMobVcGedXeYfZgOh wherein P, Mo, V, Ge and O represent phosphorous, molybdenum, vanadium, germanium and oxygen, respectively; X represents at least one element selected from the group consisting of arsenic, antimony, bismuth, zirconium, tellurium, silver and boron; Y represents at lest one element selected from the group consisting of iron, copper, zinc, chromium, magnesium, tantalum, manganese, barium, gallium, cerium and lanthanum; Z represents at least one element selected from the group consisting of potassium, rubidium, cesium and thallium, and a, b, c, d, e, f, g and h represent the atomic ratios of the respective elements, and when b=12, then a=0.5-3, c=0.01-3, d=0.01-3, e=0-3, f=0-3, g=0.01-3, and h is the number of oxygen atoms necessary for satisfying the above atomic ratios of the respective components. The method includes providing an aqueous mixture containing at least P, Mo, V, Ge, X, Y and Z and removing water from the aqueous mixture, where the improvement comprises providing at least part of the Ge for the aqueous mixture by dissolving germanium dioxide in an aqueous solution of a hydroxide of an element represented by Z in the above formula. The catalyst prepared according to the method is remarkably elevated in activity in the methacrolein oxidation reaction and allows enhancement of the yield of methacrylic acid.
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