Effect of surface modification on silica supported Ti catalysts for cyclohexene oxidation with vapor-phase hydrogen peroxide

Abstract

Surface modification via grafting of organic moieties on a Lewis acid catalyst (silica supported Ti catalyst, Ti-SiO₂) alters the activation of H₂O₂ in vapor-phase cyclohexene epoxidation. Grafting a fluorous group (1H,1H-perfluoro-octyl) suppresses activity of Ti-SiO₂. Conversely, grafting either a nonpolar group (octyl) or a polar aprotic group (triethylene glycol monomethyl ether) enhances rates and shifts selectivity toward trans-1,2-cyclohexanediol.