Selective Oxidation of Alkenes by Dioxygen Using Modified Gold Nanoclusters

Selective oxidation of cyclohexene and styrene was investigated using molecular oxygen under mild conditions. Au/TiO2 and Au/Al2O3 surfaces were impregnated with three different ionic liquids. Supported ionic liquids (ILs) gold nanocatalysts are particularly versatile catalysts for oxidation reaction with exceptionally high efficiency and significant selectivity. Improved activity is attributed to the stabilization of reaction intermediates via different interaction such as hydrogen bonding and polarity/dipolarizability between ILs and intermediates. Surface coating of obtained nanoparticles with ionic liquids is found to increase the interaction energy. The estimated rate constant decreases in the following order: [EAP] > [bmim]PF6 > [emim]EtSO4. EAP/Au/Al2O3 exhibited maximum conversion compare to other IL-impregnated catalysts. Supported ionic liquids gold nanocatalysts are active catalysts for oxidation reaction with high efficiency and selectivity.