Venturello anion immobilized on the surface of porous activated carbon as heterogeneous catalyst for the epoxidation of olefins

Abstract

An efficient epoxidation catalyst was prepared through the immobilization of Venturello anion, {PO4[W(O)(O2)2]4}3−, onto aminopropyl-modified porous activated carbon (AC). First, the aminopropyl groups were anchored on the surface of AC by silylation with 3-aminopropyltriethoxysilane. Afterwards, electrostatic interaction between Venturello anions and ammonium groups located on the surface of AC produced the final catalyst. FT–IR spectroscopy, CHN elemental analysis, inductively coupled plasma optical emission spectroscopy, energy dispersive X-ray spectroscopy, and nitrogen adsorption–desorption analysis followed with BJH and BET calculations were used to characterize the prepared catalyst. Catalytic activity of the prepared catalyst was explored in epoxidation of different cyclic and terminal olefins with 30% H2O2 as green oxidant. The highest conversions were achieved for cyclooctene and cyclohexene due to the localization of higher electron density on their double bonds. The results revealed proper performance of the catalyst in epoxidation reaction with catalyst reusability for at least four times with no decrease in its activity.