KATALYSATOR FUER OXIDATIONSREAKTIONEN UND VERFAHREN ZU DESSEN HERSTELLUNG

Catalyst containing a vanadium/phosphorus complex oxide, for the oxidation of hydrocarbons to maleic anhydride. The catalyst contains 1 to 1.3 atoms of phosphorus per atom of vanadium. The pore volume of those pores which have a radius of 100 to 1,000 ANGSTROM is at least 30 percent of the total pore volume of the pores which have a radius of less than 10,000 ANGSTROM . The method for preparing the catalyst involves introducing a phosphorus-containing compound into an organic solvent, and continuously adding a vanadium-containing compound over the course of 0.5 to 4 hours. 1 to 1.3 atoms of phosphous is employed per atom of vanadium. The water formed during the reaction is removed continuously and directly from the reaction mixture. Thereafter the reaction mixture is separated. The V-P-O complex oxide is isolated as a solid, dried at a temperature of 90 DEG to 150 DEG C. and activated at a temperature of 200 DEG to 300 DEG C. to provide the catalyst.