Au catalysts-assisted selective hydrocarbon oxidation

Supported Au catalysts have been shown to effect selective oxidation of hydrocarbons. Selective epoxidation of olefins can be achieved either using hydrogen peroxide, or, in the liquid phase, by coupling the reaction with CO oxidation. In the latter case, a combination of two catalysts, Au/TiO ₂ and TS-1 was found to catalyze epoxidation of olefins that possess an alpha hydrogen, including propene and butene. Interestingly, results from ¹⁸O isotope labelling of either O ₂ or H ₂O led to the conclusion that in a water-methanol solvent, the O in the epoxide was derived exclusively from O ₂ and not H ₂O or methanol. Selective oxidation of saturated hydrocarbon, on the other hand, can be accomplished using a mixture of H ₂ and O ₂. For example, propane can be oxidized to acetone. This reaction, however, appears to require a Au particle in the proximity of a titanyl moiety. The implications of this to the reaction mechanism will be discussed.