Understanding the selectivity of propylene oxidation with silver catalysts
Conference Paper
Overview
Overview
abstract
Selectivities for direct propylene epoxidation with silver catalysts are much lower than those for the corresponding reactions of ethylene. The vulnerability of the allylic hydrogen to abstraction by oxygen is often cited as the crucial difference. Relatively little attention has been paid to the network of reactions that may follow oxygen addition to propylene on silver. This work has explored that network via studies of propylene oxide reactions on unpromoted and cesium-promoted silver in the presence and absence of oxygen. A clear picture of the mechanism for propylene epoxidation on silver and effects of Cs promotion on mechanism has emerged. Like the analogous chemistry of ethylene, the reaction network that connects propylene with propylene oxide and other C3 oxygenate products can be explained in terms of surface oxametallacycle intermediates. DFT calculations provide energetics that shed light on product selectivities from this complex network.
