The activity and selectivity in the oxidation of buta-1,3-diene, and oxidation and isomerization of but-1-ene on unsupported and supported V2O5 catalysts have been investigated in terms of the catalyst structure. The rate of oxidation is mainly determined by the number of surface V=O species on the catalyst for both buta-1,3-diene and but-1-ene. The roughness of the V2O5 surface affected the activity for buta-1,3-diene, but not for but-1-ene oxidation. It was also found that TiO2 support increases the activity of the surface V=O for but-1-ene oxidation. The selectivity to maleic anhydride was determined by the number of V2O5 layers on the support for both reactions. When the number of V2O5 layers was 1 or 2, the selectivity was low, while it increased markedly with an increase in the number of V2O5 layers to 5, and attained a constant value above 5 layers. Both V2O5 and support were active for the isomerization of but-1-ene to cis- and trans-but-2-ene. On V2O5, the cis/trans ratio was low, while it was as high as 3 for the Al2O3 support. The rate and selectivity of the isomerization on supported catalysts were explained in terms of the structure of V2O5 on the support. Difference in the structure-activity/selectivity correlation between oxidation and isomerization and that between but-1-ene oxidation and buta-1,3-diene oxidation were also discussed.
|Number of pages||22|
|Journal||Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases|
|Publication status||Published - 1986 Jan 1|
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