Ammoxidation of Propene over Antimony-Vanadium-Oxide Catalysts

Antimony-vanadium-oxide catalysts were prepared with various Sb/V ratios and were used for propene ammoxidation. It was observed that antimony in excess of the amount required for forming SbVO4 was required to have a catalyst that is selective to acrylonitrile formation. Characterisation of catalysts with FTIR revealed partial reduction of the oxidised phase Sb0.92V0.92O4 upon use to form Sb0.95V1.05O4. XPS data showed the surfaces of most selective catalysts to be further enriched with antimony in course of the catalytic reaction, thereby creating a surface structure that is selective. For acrylonitrile formation a yield of 55% was obtained at 90% of conversion. In propene oxidation, on the other hand, the yield for acrolein formation was limited to 20% due to consecutive combustion of the aldehyde.