Chinese Journal of Applied Chemistry ›› 2016, Vol. 33 ›› Issue (9): 1017-1025.DOI: 10.11944/j.issn.1000-0518.2016.09.150452

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Catalytic Oxidation Property and Mechanism of 2,2,6,6-Tetramethylpiperidine-1-oxyl Immobilized on Crosslinked Polystyrene Microspheres

DONG Tingting,BI Congcong,GAO Baojiao()   

  1. Department of Chemical Engineering,North University of China,Taiyuan 030051,China
  • Received:2015-12-17 Accepted:2016-03-28 Published:2016-08-23 Online:2016-08-23
  • Contact: GAO Baojiao
  • Supported by:
    Supported by the Young Science Fund of Shanxi Province(No.2014021015-1)

Abstract:

2,2,6,6-Tetramethylpiperidine-1-oxyl(TEMPO) was immobilized on crosslinked polystyrene(CPS) microspheres to give a heterogeneous microspheres TEMPO/CPS catalyst. A combined catalysts of TEMPO/CPS microspheres and metal salts were used in the oxidation of cinnamyl alcohol with molecular oxygen as the oxidant. The catalytic properties and catalytic mechanisms of these combinational catalysts were investigated. Some combined catalysts can effectively catalyze the oxidation reaction of cinnamyl alcohol to cinnamyl aldehyde as sole product. For nitrate co-catalysts, if the corresponding metal ion has weaker oxidizing ability than NO3- ion, for example, Fe(NO3)3 and Cu(NO3)2, the cations and anions will work together in the catalytic process. If the oxidizability of metal ion is stronger than NO3- ion, for example, Co(NO3)2 and Mn(NO3)2, the metal ion will alone play a role in the oxidation. Among several transition metal salts, Fe(NO3)3 is the best co-catalyst, and leads to the oxidation of cinnamyl alcohol to cinnamyl aldehyde in 92% conversion under mild conditions(at 55 ℃ and with O2 at ordinary pressure).

Key words: tetramethylpiperidine-1-oxyl, heterogeneous catalyst, cinnamyl alcohol, molecular oxygen, catalytic oxidation