Direct epoxidation of propene over gold-titanium catalysts : catalyst development and reaction mechanism

Gold-titania catalysts are attractive to produce propene oxide directly. Very low gold-loaded catalysts have a remarkably high epoxidation activity, not only per amount of gold, but also per total catalyst mass. The small gold nanoparticles, however, have a significant propene hydrogenation activity as an undesirable side reaction. In this work, we are presenting an effective way to prevent the propene hydrogenation: co-feeding a small amount of CO. Even though CO is not significantly converted, this completely blocks the propene hydrogenation reaction while it does not affect the epoxidation. An added advantage is that also the direct water formation is reduced. We will be presenting the latest results on the development of highly active low gold loaded catalysts, reaction kinetics, including operation with explosive mixtures, and improvements that can be obtained by co-feeding CO.