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Abstract

The tribomechanical treatment of vanadyl hydrogenphosphate hemihydrate (VHP) has been proven to be a valuable tool to enhance the catalytic performance of vanadyl pyrophosphate (VPP) catalysts for the oxidation of n butane to maleic anhydride. It was demonstrated that tribomechanically improved catalytic properties are mainly caused by decreased particle sizes and increased internal micro strain in the VHP precursor. This altered VHP microstructure is transferred to the VPP catalyst in a topotactic reaction, which is described as 2 VOHPO4 • 0.5H2O  (VO)2P2O7 + 2 H2O (1) Untreated and tribomechanically treated VHP’s, milled in different laboratory mills, were investigated by thermo analysis (TG/DSC/MS) to gain more information on the thermal decomposition of VHP concerning the dynamic release of water from the crystal lattice. The VHP precursors studied were prepared by the alcoholic route (VHPROH) and by the aqueous route (VHPH2O).