Heterogeneous oxidation of alkenes: The role of silica-supported bimetallic and trimetallic catalysts

Abstract

Silica-supported bimetallic and trimetallic transition metal catalysts with different metal loadings of Cu, Ni and Co have been prepared by using the ultrasonic cavitation-impregnation method. The characterization of the prepared catalysts was done by BET, SEM-EDS, TEM and powder XRD. The catalytic activity was tested in the liquid phase oxidation of styrene, 4-chloro styrene and cyclohexene using tert-butyl hydroperoxide (TBHP) as the oxidant and acetonitrile as a solvent under mild conditions. In styrene oxidation, the trimetallic catalyst 30CuNiCoSiO showed a maximum of 95 % conversion with 74 % benzaldehyde and 25 % styrene oxide selectivity at the end of the 24 h reaction time at 40 °C. The catalysts could be recycled three times without losing their catalytic activity and no metal species leached out from the support.