Heterogeneous epoxidation of alkenes containing allylic hydrogen on Cu-based catalysts

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Heterogeneous epoxidation of allylic alkenes represents a demanding task, since the easy abstraction of labile allylic hydrogen triggers total combustion of the alkene and prevents selective oxidation. Recently, it was shown that copper is intrinsically much more selective than widely used silver for both alkene epoxidation in general and for the difficult case of allylic alkenes in particular. The present project aims at an understanding of the microscopic mechanisms of allylic alkenes epoxidation on well-defined Cu single crystal surfaces and a connection of these mechanisms with the reactivity and selectivity of Cu-based supported catalysts operated under practical conditions. The main focus of this study will lie on investigation of the role of structural parameters such as alkene adsorption geometry, vicinity of the olefinic double bond and of the allylic hydrogen to the surface, the microscopic structure of the catalyst surface etc. in the activity and selectivity towards epoxidation. Additionally, possible alternative epoxidation pathways will be investigated, which do not include a common step of alkene oxidation with atomic oxygen. The experiments will be carried out in the group of Prof. Lambert (University of Cambridge, England).