Cobalt(II) acetylacetonate covalently anchored onto magnetic mesoporous silica nanospheres as a catalyst for epoxidation of olefins

A heterogeneous catalyst based on Cobalt as active sites and amine functionalized magnetic mesoporous silica nanospheres as support was successfully prepared by the complexation of Cobalt(II) acetylacetonate [Co(acac)₂] with (3-aminopropyl)triethoxysilane (3-APTES) functionalized magnetic nanoparticles. The catalyst was characterized by transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), N₂ adsorption–desorption and a vibrating sample magnetometer (VSM). The obtained catalyst exhibited excellent activity and selectivity for epoxidation of olefins by using molecular oxygen as an oxidant, especially for the epoxidation of a-methylstyrene (conversion: up to 98%; selectivity: exceed 98%). Meanwhile, the novel catalyst could be recovered by magnetic separation from the reaction mixture and recycled five times without any significant loss in activity. - Highlights: • A facile method was put forward to prepare magnetic mesoporous nanoparticles. • The catalyst showed high activity in epoxidation of olefins by oxygen. • The catalyst was easily recovered with external magnetic field. • The catalytic could be reused without any obvious loss of activity