MECHANISM OF AMMOXIDATION OF PROPANE ON A SB V/O SYSTEM/

The mechanism of the direct ammoxidation of propane is investigated on a Sb/V mixed oxide catalyst (atomic ratio 5/1) in order to understand the sequence of the intermediates and the role of ammonia in the form ation of acrylonitrile. The sample was characterized by different tech niques (BET, FTIR, XRD and XPS) and tested in different conditions (ox idation and ammoxidation of propane and propene). It is proposed that propane is first converted to propene and hence to ''oxidation product s'' (which could be acrolein or an intermediate absorbed an the cataly st surface, as allyl radical). In the absence of ammonia these ''oxida tion products'' are converted to carbon oxide. But in its presence the y are converted into acrylonitrile, which is appreciably more stable a nd undergoes minor degrees of oxidative degradation.