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Fe3O4@SiO2–TEMPO as a Magnetically Recyclable Catalyst for Highly Selective Aerobic Oxidation of 5-Hydroxymethylfurfural into 2,5-Diformylfuran under Metal- and Halogen-Free Conditions

Authors

  • Prof. Dr. Babak Karimi,

    Corresponding author
    1. Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-6731 (Iran), Fax: (+98) 241-415-3232
    • Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-6731 (Iran), Fax: (+98) 241-415-3232

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  • Hamid M. Mirzaei,

    1. Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-6731 (Iran), Fax: (+98) 241-415-3232
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  • Elham Farhangi

    1. Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-6731 (Iran), Fax: (+98) 241-415-3232
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Abstract

A highly selective aerobic oxidation of 5-hydroxymethylfurfural (5-HMF) into 2,5-diformylfuran (DFF) by employing a magnetically separable 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO) catalyst (Fe3O4@SiO2–TEMPO) under metal- and halogen-free conditions is described. Quantitative yields of DFF with excellent selectivities as high as >99 % were achieved under several versatile reaction conditions in a catalytic system consisting of Fe3O4@SiO2–TEMPO as a catalyst, tert-butyl nitrite as a co-catalyst, acetic acid as an additive, and toluene as a solvent. The results clearly demonstrate that the present catalytic system for selective conversion of 5-HMF into DFF is comparable or even superior to the many systems based on transition-metal catalysts. In addition, the catalyst can be successfully recovered and reused in five consecutive reaction runs by an external magnetic source with keeping its catalytic performance and selectivity.

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