STRUCTURE-SENSITIVITY STUDY OF PARTIAL PROPENE OXIDATION OVER AV(2)P(2)O(10) VANADIUM PHOSPHATE-COMPOUNDS

The activity and selectivity of five AV(2)P(2)O(10) compounds have bee n examined with respect to the mild oxidation of propene at different temperatures. These materials with orthorhombic symmetry (A=Ca, Cd) or monoclinic symmetry (A=Ba, Pb, Cd) have been prepared as well crystal lized samples in an evacuated silica tube. Their crystalline structure , followed by X-ray diffraction (XRD), was unchanged after the catalyt ic reaction and their structural properties made them ideal model cata lysts to study structure-sensitivity effects. Orthorhombic compounds w ere more active than monoclinic ones. Catalytic results were discussed , taking into account the nature of the inserted cations, the distorti on of the framework and the organization of the lattice polyhedra.