HOMOGENEOUS AND HETEROGENEOUS CONTRIBUTIONS TO THE OXIDATIVE DEHYDROGENATION OF PROPANE ON OXIDE CATALYSTS

The pyrolysis and the oxidative dehydrogenation of propane have been investigated in a quartz reactor. It has been found that by optimising the propane/air ratio it has been possible to obtain very high yields of propene and ethene. A variety of oxide-based catalysts have been prepared, characterised, and tested in the oxidative dehydrogenation reaction. It has been found that with these catalysts, the maximum selectivity to propene at a specific conversion of propane is never higher than can be obtained in the absence of a catalyst. The results also show no obvious correlation between catalytic properties and the presence of specific crystalline phases. It is suggested that lower than optimum selectivities to propene may arise because of the presence in the catalysts of small, but undetected, amounts of pure V2O5. Comparison with other published work suggests that there is an upper limit on the yield of propene which can be obtained for a purely heterogeneously catalysed reaction. A combination of homogeneous and heterogeneous contributions to the oxidative dehydrogenation reaction may provide a means of obtaining even higher yields of propene.