Farringtonite as an efficient catalyst for linear-chain α-olefin epoxidation with aqueous hydrogen peroxide

Abstract

The epoxidation of linear-chain α-olefins over heterogeneous catalysts is still challenging, while epoxides as versatile raw intermediates are highly desirable. Here, we describe the facile preparation of farringtonite, obtained via the calcination of commercial anhydrous trimagnesium phosphate, and its novel application in the epoxidation of olefins. Farringtonite was characterized via XRD, FT-IR, SEM-EDS, and CO₂-TPD studies. The CO₂-TPD data exhibited that farringtonite mainly possesses medium-base sites. The catalytic activity of farringtonite was optimized via adjusting different parameters, including the solvent, temperature, amount of H₂O₂, farringtonite loading, stirring rate, and so on, using 1-octene epoxidation as the model reaction and 30% H₂O₂ as the oxidant. The results from 1-octene epoxidation indicated that the farringtonite catalyst exhibited efficient catalytic activity, with high conversion of up to 85.2% and epoxide selectivity of 87.6% under the optimal conditions. In addition to 1-octene, 1-decene and 1-heptene were also used, achieving good-to-excellent conversions with high selectivities. In addition, farringtonite could be recycled four times with the preservation of its high catalytic activity. From a mechanistic standpoint, the in situ generation and consumption of Payne's reagent is responsible for the epoxidation reaction. Therefore, farringtonite serves as an excellent catalyst for the epoxidation of α-olefins.