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Peroxometalates Immobilized on Magnetically Recoverable Catalysts for Epoxidation

Authors

  • Yunxiang Qiao,

    1. Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
    2. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
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  • Dr. Huan Li,

    1. Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
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  • Li Hua,

    1. Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
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  • Dr. Lars Orzechowski,

    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
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  • Dr. Kai Yan,

    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
    2. Institut für Technische und Makromolekulare Chemie, Lehrstuhl für Technische Chemie und Petrolchemie, RWTH Aachen, Worringerweg 1, 52064 Aachen (Germany)
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  • Dr. Bo Feng,

    1. Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
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  • Zhenyan Pan,

    1. Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
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  • Dr. Nils Theyssen,

    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
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  • Prof. Walter Leitner,

    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr (Germany)
    2. Institut für Technische und Makromolekulare Chemie, Lehrstuhl für Technische Chemie und Petrolchemie, RWTH Aachen, Worringerweg 1, 52064 Aachen (Germany)
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  • Prof. Zhenshan Hou

    Corresponding author
    1. Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
    • Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (P. R. China), Fax: (+86) 21-64253372
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Abstract

Magnetically separable catalysts were prepared and employed for the epoxidation of olefins with hydrogen peroxide. In all cases the magnetic core was firstly covered with a silica layer to prevent iron ion-initiated decomposition of hydrogen peroxide. The catalytic active species, an ionic liquid-type peroxotungstate, was then immobilized either by hydrogen bonding (catalyst 1) or by covalent Si[BOND]O linkage (catalyst 2). In addition to a thorough characterization by FT-IR, XRD, NMR, DRIFT, XPS, and TEM, the catalytic potential was evaluated in the epoxidation of a variety of olefins as well as allylic alcohols. Both catalysts showed essentially a constant activity after at least ten consecutive cycles. On the basis of the research above, a new type of magnetically separable catalyst was constructed by immobilization of lacunary-type phosphotungstate by hydrogen bonding between the sulfonate anion and silanol group on the surface of the core–shell magnetic nanoparticles. After the detailed characterization, the catalyst was used in the epoxidation of a variety of olefins and allylic alcohols and was found to possess high activity, selectivity towards epoxides, and a constant activity after at least ten catalytic recycles without solvent.

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