Abstract: A process for activating fluid bed catalysts useful for producing maleic anhydride from 4 carbon atom hydrocarbons is provided including contacting the fluidized catalyst containing the mixed oxides of vanadium and phosphorus with oxygen and a reducing gas at least partially combustible with oxygen at elevated temperatures sufficient to cause such combustion, wherein the molar ratio of reducing gas to oxygen is greater than the stoichiometric ratio required for complete combustion of the reducing gas. Also provided are catalysts activated by the process of the invention, as well as a process for producing maleic anhydride utilizing the catalysts thus activated.

Abstract: A process is provided for the preparation of attrition resistant, microspheroidal fluid bed catalysts comprising the mixed oxides of vanadium and phosphorus in which a vanadium phosphorus mixed oxided catalyst precursor is densified, comminuted, formed into fluidizable particles and calcined under fluidization-type conditions. The present invention further provides the attrition resistant fluidizable catalysts prepared by the inventive process, and further provides a process for utilizing such attrition resistant catalysts in the production of maleic anhydride in the vapor phase by the oxidation of 4 carbon atom hydrocarbons.

Abstract: A process is provided for the preparation of attrition resistant, microspheroidal fluid bed catalysts comprising the mixed oxides of vanadium and phosphorus in which a vanadium phosphorus mixed oxided catalyst precursor is densified, comminuted, formed into fluidizable particles and calcined under fluidization-type conditions. The present invention further provides the attrition resistant fluidizable catalysts prepared by the inventive process, and further provides a process for utilizing such attrition resistant catalysts in the production of maleic anhydride in the vapor phase by the oxidation of 4 carbon atom hydrocarbons.

Abstract: A process is provided for activating fluidizable catalysts containing the mixed oxides of vanadium and phosphorus useful for the production of maleic anhydride from 4-carbon atom hydrocarbons and oxygen by subjecting the catalyst to fluidization conditions and contacting the fluidized catalyst with oxygen at a temperature at least 20.degree. C. greater than the temperature required to produce about 85 percent conversion of hydrocarbon. A process is also provided for adding make-up fluid bed catalyst to an equilibrated catalyst by introducing a calcined and unequilibrated make-up catalyst into the fluid bed vessel containing equilibrated catalyst, subjecting the mixture to fluidization conditions and contacting the fluidized catalyst mixture with oxygen at a temperature at least 20.degree. C. greater than the temperature required to produce about 85 percent conversion of the hydrocarbon. The catalysts so activated and a process for producing maleic anhydride from 4-carbon atom hydrocarbons is also provided.

Abstract: A process is provided for preparing fluid bed catalysts containing the mixed oxides of vanadium and phosphorus prepared from a mixed phosphoric acid source. A pentavalent vanadium compound is introduced into an organic liquid capable of reducing the vanadium, the vanadium is contacted with the mixed phosphoric acid source, the resulting catalyst precursor is comminuted, introduced into water to form an aqueous slurry and spray dried to form microspheroidal, fluidizable particles.

Abstract: A process is provided for preparing fluid bed catalysts containing the mixed oxides of vanadium and phosphorus prepared from a mixed phosphoric acid source. A pentavalent vanadium compound is introduced into an organic liquid capable of reducing the vanadium, the vanadium is contacted with the mixed phosphoric acid source, the resulting catalyst precursor is comminuted, introduced into water to form an aqueous slurry and spray dried to form microspheroidal, fluidizable particles.