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Abstract: Polyoxometalates (abbreviated as POMs) are useful acids and oxidation catalysts in various reactions since its catalytic features can be controlled at a molecular level. This review summarizes some recent research progress in catalytic application of Keggin and Wells–Dawson type polyoxometalates. Particular attention is given to most developments of our recent studies on the use of POMs as heterogeneous and homogeneous catalysts for the selective oxidation and acid-catalyzed reactions. [Copyright &y& Elsevier]

Abstract: Wells–Dawson type Heteropolyacids (H6+n P2Mo18−n V n O62) (n =0–2, 4) have proved to be efficient heterogeneous catalysts for the reaction of epoxides with carbonyl compounds to form 1,3-dioxolane derivatives. Especially, when H7P2Mo17VO62 was used to catalyze the reaction between acetone and epoxypropane, the selectivity to 1,3-dioxolane reached to 93.3% with nearly complete conversion of epoxide and 1.1×104 h−1 of TOF. [Copyright &y& Elsevier]

Abstract: The epoxidation of cyclopentene with hydrogen peroxide catalyzed by 12-heteropolyacids of molybdenum and tungsten (H3PMo12−n W n O40, n =1–11), 12-tungstophosphoric acid and 12-molybdophosphoric acid combined with cetylpyridinium bromide as a phase transfer reagent was carried out in acetonitrile. Among 13 heteropolyacids investigated, catalyst of H3PMo6W6O40 showed the highest activity, giving a conversion of 60% and a selectivity of 95% in the epoxidation of cyclopentene. The fresh catalysts and the catalysts under reaction condition were characterized by UV–vis, FT-IR and 31P NMR spectroscopy, which has revealed that all of the molybdotungstophosphoric acids were degraded in the presence of hydrogen peroxide to form a considerable amount of phosphorus-containing species. The active species resulted from H3PMo6W6O40 are new kinds of phosphorus-containing species, which is different from {PO4[WO(O2)2]4}3−. [Copyright &y& Elsevier]