PRODUCTION OF IMPROVED MIXED VANADIUM PHOSPHORUS OXIDE CATALYSTS

摘要

A process for the production of a vanadium phosphorus mixed oxide containing catalyst characterised in that it comprises: (a) introducing a pentavalent vanadium compound into an organic liquid reaction medium selected from alcohols and glycols capable of reducing at least a portion of the vanadium to a valence state of about + 4 in the absence of corrosive reducing agents; (b) introducing at least one pentavalent phosphorus compound into the reaction medium; (c) effecting reduction of the vanadium prior or subsequent to the addition of the phosphorus compound and reacting the vanadium with the phosphorus compound to form a catalyst precursor; (d) removing from the reaction medium at least 1.5 moles of the organic liquid per mole of vanadium reduced or reacted during the reduction or reaction; (e) recovering the catalyst precursor from the reaction medium; (f) drying the catalyst precursor; and (g) calcining the catalyst precursor is disclosed. The resulting catalysts exhibit a number of advantages particularly when used in the production of maleic anhydride from 4 carbon hydrocarbons.