Jun Li

Publications (3)5.15 Total impact

• Article: Transition metal substituted polyoxometalates and their application in the direct hydroxylation of benzene to phenol with hydrogen peroxide

  Jiaqi Chen, Jun Li, Yi Zhang, Shuang Gao
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  ABSTRACT: A series of transition metal substituted polyoxometalates with a Keggin structure were prepared and utilized for the hydroxylation of benzene to phenol. Among the compounds tested, [(CH3)4N]4PMo11VO40 exhibits the highest phenol yield (13.0%) and selectivity (90.6%) in acetic acid/acetonitrile. Vanadium peroxo is the active site of the reaction, and ammonium also plays an important role. The influence of various reaction parameters, such as solvent, reaction time, reaction temperature, and amount of hydrogen peroxide used were investigated to obtain the optimal reaction conditions. KeywordsHydroxylation-Benzene-Phenol-Transition metal substituted polyoxometalates
  Research on Chemical Intermediates 04/2012; 36(8):959-968. · 0.70 Impact Factor
• Article: Selective oxidation of unsaturated alcohols catalyzed by sodium nitrite and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone with molecular oxygen under mild conditions.

  Lianyue Wang, Jun Li, Hua Yang, Ying Lv, Shuang Gao
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  ABSTRACT: We have developed a simple and practical process for the oxidation of alcohols to the corresponding carbonyl compounds by using a low catalytic amount of DDQ, NaNO(2) as a cocatalyst, and molecular oxygen as terminal oxidant. Nitric oxide generated in situ by NaNO(2) in the presence of AcOH is essential for the realization of the catalytic cycle at room temperature. The practical utility of this catalytic process has been demonstrated in the gram-scale oxidation of cinnamyl alcohol.
  The Journal of Organic Chemistry 12/2011; 77(1):790-4. · 4.45 Impact Factor
• Article: Epoxidation of Allyl Chloride to Epichlorohydrin by a Reversible Supported Catalyst with H2O2 under Solvent-Free Conditions

  Jun Li, Gongda Zhao, Shuang Gao, Ying Lv, Jian Li, Zuwei Xi
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  ABSTRACT: Allyl chloride was epoxidized to epichlorohydrin with H2O2 under solvent-free conditions in 94% selectivity using a new reversible supported catalyst, heteropolyphosphatotungstate/silanized silica gel. By the action of H2O2 the heteropolyphosphatotungstate dissolves from the carrier surface and forms an active homogeneous reagent. When all H2O2 is consumed, the reduced catalyst redeposits on the support carrier. The supported catalyst retains the character of a homogeneous catalyst during reaction but exhibits heterogeneous properties upon work-up. The solid-supported catalyst is easily isolated and can be reused. The reaction system for synthesis of epichlorohydrin therefore avoids the serious pollution issues known from the commercialized chlorohydrin methods. Some other olefins can also be epoxidized by this catalytic system under neat conditions.
  07/2006;