Oxidative dehydrogenation of isobutane over a titanium pyrophosphate catalyst

The catalytic properties of titanium pyrophosphate in the oxidative dehydrogenation of isobutane to isobutylene were investigated in the 400 - 550 degrees C temperature range. A significant change of the product distribution and of the apparent activation energy of the reaction was observed at about 490 T. This phenomenon, already observed in the oxidative dehydrognation of n-butane, has been interpreted by the existence of two reaction mechanisms depending upon the reaction temperature. Comparison with the n-butane reaction allowed different activation pathways for the activation of alkanes to be proposed. The catalytic properties of TiP2O7 in the oxidative dehydrogenation of isobutane was also compared to those obtained previously with several other pyrophosphates and TiP2O7 was found to be less active and selective for this reaction.