Details

Autor(en) / Beteiligte

• Williams, Federico J
• Bird, Daniel P. C
• Palermo, Alejandra
• Santra, Ashok K
• Lambert, Richard M

Titel

Mechanism, Selectivity Promotion, and New Ultraselective Pathways in Ag-Catalyzed Heterogeneous Epoxidation

Ist Teil von

• Journal of the American Chemical Society, 2004-07, Vol.126 (27), p.8509-8514

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2004

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The selective oxidation of styrene on clean and modified Ag(100) surfaces has been studied by synchrotron fast XPS and temperature-programmed reaction spectroscopy. By following the time dependence of surface species, it is unequivocally demonstrated that the necessary and sufficient conditions for epoxide formation are oxygen adatoms and π-adsorbed alkene molecules. Increased oxygen coverage and coadsorbed Cs have pronounced and opposite effects on epoxidation selectivity, consistent with the view that the valence charge density on Oa is pivotal in determining this property. Submonolayer quantities of Cs nitrate generated in situ open a new, low-temperature ultraselective, epoxidation pathway thought to involve direct oxygen transfer from the oxyanion to the alkene.