Oxidation of propane to propylene oxide on gold catalysts

Propane epoxidation was carried out by sequential propane dehydrogenation–propylene epoxidation steps using a two-catalyst bed and H 2 and O 2 as the oxidant mixture. The propane dehydrogenation step used a Au/TiO 2 catalyst that was active at the low temperature (443 K) used for the propylene epoxidation step; the latter used a Au/TS-1 catalyst. In situ Au L 3-edge X-ray absorption near-edge structure and ultraviolet–visible measurements on Au/TiO 2 under propane dehydrogenation conditions showed activation of oxygen on gold nanoparticles and evidence for the formation of adsorbed oxygen intermediate species responsible for the production of propylene. Propane epoxidation with H 2 and O 2 at 443 K and 0.1 MPa with the dual Au/TiO 2 and Au/TS-1 catalysts resulted in an overall propane conversion of 2%, propylene selectivity of 57%, and propylene oxide selectivity of 8%, corresponding to a propylene oxide space-time yield of 4 g kg cat −1 h −1 . The catalysts showed little deactivation and maintained their conversion and selectivity levels for the 12 h duration of the measurements.