Preparation of maleic anhydride using fluidized catalysts

Claim 1

A process for the production of maleic anhydride by the oxidation of 4-carbon hydrocarbons with molecular oxygen or an oxygen containing gas in a fluid bed reactor at a reaction temperature of about 250° C. to 600° C. in the presence of a microspheroidal, fluidizable catalyst containing the mixed oxides of vanadium and phosphorus, wherein said catalyst is prepared by (a) introducing at least one pentavalent vanadium compound into an organic liquid capable of reducing at least a portion of the vanadium to a valence state of +4; (b) effecting reduction of at least a portion of the vanadium to a valence state of +4; (c) contacting the vanadium with a mixed phosphorus component prior or subsequent to effecting said reduction, wherein said mixed phosphorus component comprises about 75-90 weight percent orthophosphoric acid and about 10-25 weight percent pyrophosphoric acid; (d) comminuting the catalyst precursor resulting from steps (a) through (c); (e) introducing the catalyst precursor into water prior or subsequent to said comminuting to form an aqueous slurry; and (f) spray drying said slurry to form microspheroidal catalyst particles.