Activity of supported tungsten oxide catalysts for the metathesis of propene

Abstract

The activity of several supported tungsten oxide catalysts for the metathesis of propene has been studied under temperature-programmed conditions. WO₃/TiO₂ was found to be active at moderate temperatures; its activity passes through a maximum when the reaction temperature is decreased from 670 to 450 K. WO₃/ZnO is less active and its activity as a function of the reaction temperature goes through a maximum under certain conditions. In contrast to these catalysts and to the earlier reported behaviour of the well known WO₃/Al₂O₃ catalyst, the activity of the WO₃/SiO₂ catalyst steadily increases for reaction temperatures up to 860 K. In this respect the WO₃/SiO₂–Al₂O₃ catalyst behaves like the WO₃/SiO₂ catalyst and not like the WO₃/Al₂O₃ catalyst.

The acidity of the supports has been determined by means of a temperature-programmed desorption technique, using t-butylamine as the adsorbed species. The results of this work do not suggest a relationship between the acidity of the supports and the activity for metathesis.