COMPOSITIONS OF THE FORMULA MO12PAVBX1CX2DX3ESBFREGSHON

摘要

Compositions of the formula I MO12PaVbX1cX2dX3eSbfRegShOn (I) where X1 is potassium, rubidium and/or cesium, X2 is copper and/or silver, X3 is cerium, boron, zirconium, manganese and/or bismuth, a is from 0.5 to 3.0, b is from 0.01 to 3.0, c is from 0.2 to 3.0, d is from 0.01 to 2.0, e is from 0 to 2.0, f is from 0.01 to 2.0, g is from 0 to 1.0, h is from 0.001 to 0.5 and n is a number determined by the valency and content of the elements different from oxygen in I, are used as catalysts for preparing methacrylic acid by gas-phase oxidation of methacrolein.