Epoxides are an important class of industrial chemicals that have been used as chemical intermediates. Catalytic epoxidation of olefins affords an interesting production technology. We found a widely usable green route to the production of epoxides: A silicotungstate compound, [gamma-SiW10O34(H2O)2]4-, is synthesized by protonation of a divacant, lacunary, Keggin-type polyoxometalate of [gamma-SiW10O36]8- and exhibits high catalytic performance for the epoxidation of various olefins, including propylene, with a hydrogen peroxide (H2O2) oxidant at 305 kelvin. The effectiveness of this catalyst is evidenced by >/=99% selectivity to epoxide, >/=99% efficiency of H2O2 utilization, high stereospecificity, and easy recovery of the catalyst from the homogeneous reaction mixture.

EpoxidationEpoxidation O 0218 Efficient Epoxidation of Olefins with ≥ 99% Selectivity and Use of Hydrogen Peroxide. -A green route for the efficient and selective epoxidation of a wide variety of olefins using H2O2 as oxidant and a lacunary Keggin-type silicodecatungstate as catalyst is developed. The catalytic epoxidation proceeds with ≥99% selectivity to epoxide, ≥99% efficiency of H2O2 utilization, high stereospecificity and easy recovery of catalyst. -(KAMATA, K.; YONEHARA, K.; SUMIDA, Y.; YAMAGUCHI, K.; HIKICHI, S.; MIZUNO*, N.; Science (Washington, D. C.) 300 (2003) 5621, 964-966; Dep. Appl. Chem., Grad. Sch. Eng., Univ. Tokyo, Bunkyo, Tokyo 113, Japan; Eng.) -Koehler 34-036

We propose a new sealed battery operating on a redox reaction between an oxide (O2−) and a peroxide (O22−) with its theoretical specific energy of 2570 Wh kg−1 (897 mAh g−1, 2.87 V) and demonstrate that a Co-doped Li2O cathode exhibits a reversible capacity over 190 mAh g−1, a high rate capability, and a good cyclability with a superconcentrated lithium bis(fluorosulfonyl)amide electrolyte in acetonitrile. The reversible capacity is largely dominated by the O2−/O22− redox reaction between oxide and peroxide with some contribution of the Co2+/Co3+ redox reaction.

Oxidation optimization: A combination of tungsten and zinc oxides on a SnO2 support (W–Zn/SnO2) is a heterogeneous and reusable solid catalyst for selective oxidation with aqueous H2O2. With it, various substrates, such as alkenes, amines, silanes, and sulfides, were oxidized into the corresponding products in high yields (see scheme). The catalyst can be reused several times without an appreciable loss in catalytic performance.