ABSTRACT
Ammoxidation must usually be carried out at temperatures higher than oxidation. At 320°C the oxidation of propene to acrolein proceeds with high conversion and selectivity of almost 100%. The addition of ammonia at this temperature causes a dramatic decrease in conversion, indicating that the surface becomes poisoned. The poisoning effect disappears at higher temperatures, so that at 430°C conversion remains high independent of the increasing ammonia propene ratio, and selectivity to acrylonitrile increases slightly with this ratio.
