Selective epoxidation and allylic oxidation of olefins catalyzed by BEA-Ti and porphyrin catalysts

Abstract

Selective epoxidation and allylic oxidation of cyclohexene were realized in the presence of BEA-Ti and (metallo)porphyrin catalysts. The integration of BEA-Ti and porphyrin H2MTPP afforded cyclohexene oxide with excellent selectivity (cyclohexene oxide/ 2-cyclohexen-1-one=85:15). BEA-Ti and metalloporphyrin MnMTPP yielded 2-cyclohexen-1-one with high selectivity (cyclohexene oxide/ 2-cyclohexen-1-one=12:88). Resulting active species involving of (metallo)porphyrin, TiIV sites and tert-butyl hydroperoxide (TBHP) promoted the oxidation process of cyclohexene. A possible mechanism resulting in the formation cyclohexene oxide and 2-cyclohexen-1-one was proposed. The outer-sphere effect constructed by (metallo)porphyrin, TiIV sites and TBHP on the surface of BEA-Ti framework improved the epoxidation and allylic oxidation both in the conversion and selectivity.