A Three-Dimensional Mesoporous Titanosilicate Support for Gold Nanoparticles: Vapor-Phase Epoxidation of Propene with High Conversion

摘要

Gold nanoparticles deposited on TiO_2 provide a new route for the direct epoxidation of propene using molecular oxygen. Such an alternative direct gas-phase epoxidation process is of tremendous industrial significance and is more environmentally friendly than the multistep chlorohydrin and hydro-peroxide processes that are currently employed. We have established the viability of the vapor-phase epoxidation of propene over nanosize Au catalysts supported on Ti-contain-ing supports such as TiO_2, TiO_2/SiO_2, TS-1, Ti-MCM-41, Ti-MCM-48, and Ti-containing hydrophobic silsequioxanes. However, low conversion of propene, rapid catalyst deacti-vation, and regeneration problems have all been major hurdles in making the process commercially viable, even though propene oxide (PO) selectivity is greater than 90 %.