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

A novel Se-doped silica material was fabricated, and this easily prepared material could be used as an efficient recyclable catalyst for beta-ionone oxidation. Interestingly, by doping with fluorine in the catalyst, the reaction selectivity was significantly enhanced to produce the important pharmaceutical intermediate beta-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 beta-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 beta-ionone substrate and for the contact of the electron-enriched endocyclic C=C with the catalyst.

Automated summary

A novel Se-doped silica material was prepared as an efficient recyclable catalyst for beta-ionone oxidation. By doping with fluorine, the reaction selectivity was significantly enhanced, leading to selective production of beta-ionone epoxide as an important pharmaceutical intermediate. The enhanced electropositivity of the catalytic Se species, along with the reinforced electropositivity of Si sites in the silica support, played a key role in controlling the reaction selectivity in the beta-ionone epoxidation reaction.