Catalyst for prepn of phthalic anhydride by oxidn of ortho-xylene - contg large amt. of vanadium pent:oxide on amorphous aluminosilicate as micro-carrier

In a catalyst for the prepn of phthalic anhydride from o-xylene and atmos O2, an amorphous aluminosilicate is used as micro-carrier for V2O5 as active component. ADVANTAGE - The amt of V2O5 in the catalyst is 70-05% (claimed), giving a cheaper catalyst with high activity and selectivity, similar to that of V2O5/anatase catalysts contg 2-20% of V2O5. In industrial prodn the wt of catalyst is less, and the prepn and processing of the catalyst for the recovery of V2O5 is more economical and ecologically acceptable. In an example, (A) a suspension of aluminosilicate in a soln of vanadyl oxalate was evaporated, dried at 100 degC, ground and calcined at 450 degC to give a catalyst with 89 wt% of V2O5. (B) for comparison a catalyst with 18 wt% of V2O5 on anatase was used, and each catalyst was used in oxidn of o-xylene. Selectivity to phthalic anhydride was 109% in both cases. The relative pre-exponential coefft of the velocity constant was: (A) 1.01, (B) 1.00; the catalytically active mass, g, wrt 1g of V2O5 was: (A) 1.12, (B) 5.55.