Mesoporous SBA-15 materials modified with oxodiperoxo tungsten complexes as efficient catalysts for the epoxidation of olefins with hydrogen peroxide

A hybrid mesoporous SBA-15 material (2a) containing an oxodiperoxo tungsten complex of the type [WO(O2)2L] (L = pyrazolylpyridine) was synthesized by a post-grafting route. The organic–inorganic hybrid catalyst was characterized by means of XRD, N2 adsorption–desorption and FT-IR. The catalytic property of 2a in the epoxidation of cyclooctene with H2O2 as the oxidant was investigated in comparison with other three kinds of hybrid tungsten containing SBA-15 materials bearing ethylenediamine, imidazole or 4,4′-bipyridine ligands. It was found that all oxodiperoxo tungsten catalysts were active at the reaction temperature of 55 °C with CH3CN as solvent. However, only the catalyst with the pyrazolylpyridine ligand showed good recoverability and relatively high stability against leaching of active tungsten species. Moreover, this catalyst showed very high efficiency for H2O2 utilization, and its catalytic activity could be further improved by using solvent mixtures of CH3CN and CH3COOH.

Graphical abstractAn oxodiperoxo tungsten complex modified SBA-15 material is active catalyst for the epoxidation of cyclooctene with H2O2 as the oxidant, and it exhibits relatively high stability against leaching of active tungsten species. Moreover, this catalyst showed very high efficiency for H2O2 utilization, and its catalytic activity could be further improved by using solvent mixtures of CH3CN and CH3COOH.Figure optionsDownload full-size imageDownload as PowerPoint slide