Catalytic epoxidation of β-ionone with molecular oxygen using selenium-doped silica materials

Abstract

A novel Se-doped silica material was fabricated, and this easily prepared material could be used as an efficient recyclable catalyst for β-ionone oxidation. Interestingly, by doping with fluorine in the catalyst, the reaction selectivity was significantly enhanced to produce the important pharmaceutical intermediate β-ionone epoxide selectively. Characterization of the materials indicated that by doping with F, the electropositivity of the catalytic Se species was obviously enhanced due to the strong electron-withdrawing features of F, and this was a key factor for controlling the reaction selectivity in the β-ionone epoxidation reaction. The electropositivity of a silica support might also increase and the reinforced electropositivity of Si sites might be beneficial for the adsorption of a β-ionone substrate and for the contact of the electron-enriched endocyclic CC with the catalyst.