Abstract
Olefins and allylic alcohols have been epoxidized with commercially available hydrogen peroxide (30% H2O2) using a phase transfer catalyst, composed of cetyltrimethylammonium cations and a lacunary-type phosphotungstate anion [PW11O39]7− or the complete Keggin-type heteropolyanion [PW12O40]3−, under two-phase conditions using ethyl acetate as the solvent. It was found that the lacunary-type catalyst showed higher activity and better recyclability than the complete Keggin-type catalyst under the same reaction conditions. 31P NMR spectroscopy and solubility measurements for the two catalysts revealed that the [PW11O39]7− anion had a much faster degradation rate than the [PW12O40]3− anion in an excess of H2O2, which resulted in the formation of more catalytically active species. As a result, the lacunary-type phosphotungstate anion-based catalyst gave a better catalytic performance than the complete Keggin-type anion in ethyl acetate.
Published Version
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