PREPARATION OF FLUIDIZABLE VANADIUM PHOSPHORUS OXIDE CATALYSTS USING A MIXED PHOSPHORUS SOURCE

摘要

Maleic anhydride (I) is prepd. by the oxidn. of 4C hydrocarbons (II) with an O2-contg. gas in a fluid bed reactor at 250-600 deg.C in the presence of a microspheroidal, fluidisable catalyst contg. mixed oxides of V and P. The catalyst is prepd. as follows; (a) a V (5+) cpd. is added to a reducing organic liq. (III) to reduce at least some of it to V (4+); (b) before or after the redn. the V (5+) or V (4+) cpd. is treated with a mixt. contg. 75-90 wt.% H3PO4 and 10-25 wt.% H4P2O7; (c) the prod. of steps (a) and (b) comminuted before or after its addn. to H2O; and (d) the slurry is spray-dried.