EFFECT OF THE METHOD OF SYNTHESIS, FORMING, AND ACTIVATION ON THE CATALYTIC ACTIVITY OF VANADIUM PHOSPHORUS CATALYSTS

Methods where vanadium in the precursor is reduced to V4+ in solution are well suited to the synthesis of vanadium-phosphorus catalysis beca use the high temperatures (500 to 800-degrees-C) requited lo transform the precursor to the active catalyst are thus avoided. which is desir able from the chemical as well as structuro-physical aspects. The way of forming and activating the catalyst. i.e. the temperature regime of the treatment and the kind of the gas atmosphere, were found to affec t appreciably the catalyst activity in the partial oxidation of butane lo maleic anhydride. Forming procedures resulting in sufficiently fin e crystals and optimized lattice defects are suitable. The application of synthesis, forming and activation procedures exhibiting a low tend ency lo form. in the catalyst phase composition. condensed phosphates such as VO(PO3)2 or even V(PO3)3 is also beneficial to the catalytic a ctivity. 'The catalytic properties of the vanadium-phosphorus catalyst which was prepared in concentrated HCl were improved considerably by doping the lattice with modifying metal cations.