Novel Support Effects on the Mechanism of Propene-Deuterium Addition and Exchange Reactions over Dispersed ZrO2

Article abstract of DOI:10.1006/jcat.1995.1172

The effect on the rate and mechanisms of propene-deuterium reactions of dispersing ZrO2 on various supports such as silica, alumina, and titanium dioxide has been studied by microwave spectroscopic analysis of monodeuteropropene as well as by kinetic investigation.By dispersal of ZrO2 on these supports, the rate of the C3H6-D2 reactions is increased considerably compared to that over unsupported ZrO2, with the decrease of activation energy.Hydrogen exchange in propene proceeds simultaneously with addition via the associative mechanism through n-propyl and s-propyl intermediates.Through XPS analysis of ZrO2/SiO2, it was found that a monolayer of ZrO2 is formed over the silica support.The monolayer catalyst exhibits catalytic behavior quite different from that of unsupported ZrO2.On the other hand, alumina surfaces modified by ZrO2 layers may be the main active sites in the case of ZrO2/Al2O3.The marked enhancement of the reaction rate in the lower loading region of ZrO2/TiO2 may be explained by the strong interaction of atomically dispersed zirconium ions with active centers on TiO2