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    ABSTRACT: An efficient and selective synthesis of unsymmetrical tetrahydrofurfuryl carbonate and other organic carbonates was realized in the liquid phase transesterification dimethyl carbonate (DMC) with alcohols over the K2CO3/ZrO2 catalyst. Compared with MgO, CaO, MgAl-HDT, ZrO2, and CsF/α-Al2O3, the K2CO3/ZrO2 catalyst with lower basicity displayed a significantly higher activity. The results of FT-IR, XPS and CO2-TPD suggested that the carboxylate species on the surface of the K2CO3/ZrO2 catalyst were the active sites for the DMC transesterification. Other K2CO3 supported TiO2, SiO2 and Al2O3 catalysts showed a rather low catalytic activity due to the lack of carboxylate species.
    Applied Catalysis B Environmental 06/2014; s 152–153:226–232. · 5.83 Impact Factor
  • Applied Catalysis A General 11/2012; 443–444:191-201. · 3.41 Impact Factor
  • Lungang Chen, Yulei Zhu, Hongyan Zheng, Chenghua Zhang, Bin Zhang, Yongwang Li
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    ABSTRACT: BACKGROUND: The catalytic degradation of aqueous Fischer–Tropsch (FT) effluents to fuel gas over Ru/AC has been investigated. In order to understand the catalytic performance and stability of oxide-supported Ru catalysts, several oxide supports (titania, zirconia, γ-alumina and silica) were selected for study, with a focus on the hydrothermal stability of catalysts.RESULTS: The catalytic efficiency for transforming the oxygenates in aqueous FT effluents to C1–C6 alkanes decreased in the order: Ru/ZrO2∼ Ru/TiO2 > Ru/SiO2 > Ru/Al2O3. The conversion of alcohols was greatly suppressed over Ru/γ-Al2O3. The former two catalysts (Ru/ZrO2 and Ru/TiO2) exhibited enhanced efficiency and long-term stability (400 h) relative to Ru/SiO2 and Ru/Al2O3. N2-physisorption, XRD and SEM showed that titania and zirconia exhibited high structural stability in an aqueous environment. However, the structures of γ-alumina and silica were unstable due to significant drop in surface area and adverse changes in surface morphology. Especially for the case of the Ru/γ-Al2O3 catalyst, the γ-alumina was transformed into boehmite structure after reaction, and metal leaching and carbon deposition were extensive.CONCLUSION: Ru/ZrO2 or Ru/TiO2 may be a promising alternative for degrading aqueous FT effluents due to their long-term stability. Copyright © 2012 Society of Chemical Industry
    Journal of Chemical Technology & Biotechnology 08/2012; 87(8):1089-1097. · 2.50 Impact Factor
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    Bin Zhang, Yulei Zhu, Guoqiang Ding, Hongyan Zheng, Yongwang Li
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    ABSTRACT: The aqueous-phase hydrogenolysis of furfuryl alcohol (FFA) to 1,2-pentanediol (1,2-PeD) was carried out on a series of supported Ru catalysts and MnOx supported Pt, Pd and Rh catalysts. The Ru/MnOx catalysts showed high selectivity for 1,2-PeD, while the Pd and Rh catalysts displayed high selectivity for tetrahydrofurfuryl alcohol. The function of MnOx, the effects of solvent, temperature, H2 pressure and reaction time were further investigated. The support MnOx in the Ru/MnOx catalysts not only suppressed the polymerization of the FFA, but also enhanced the 1,2-PeD selectivity. Low pressure and high temperature favoured the generation of 1,2-PeD, and water significantly enhanced the reaction rate. At 150 °C, 1.5 MPa, the yield of 1,2-PeD was up to 42.1% over the Ru/MnOx catalyst. The proposed mechanism for FFA hydrogenolysis in aqueous medium over the Ru/MnOx catalyst is suggested to occur via a partially hydrogenated intermediate.
    Green Chemistry 01/2012; 14(12):3402-3409. · 6.83 Impact Factor
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    ABSTRACT: BACKGROUND: Aqueous phase Fischer–Tropsch (FT) effluents co-produced with hydrocarbons in the FT process contain various water-soluble oxygenates, e.g. carboxylic acids, alcohols. Purification of the FT aqueous phase is important from the viewpoint of effective resource utilization and environmental stewardship. In this work, an aqueous-phase hydrodeoxygenation process was investigated for the degradation of FT aqueous phases.RESULTS: The Ru/AC catalyst was determined to be the most active catalyst. The key parameters, i.e. temperature, pressure, weight hourly space velocity and Ru loading, were comprehensively optimized. Under optimal conditions, ca 98% of the oxygenates were converted to C1∼C6 alkanes. The degraded water had no odour, a neutral pH, and as low as 1000 mg L−1 chemical oxygen demand. The Ru/AC catalyst exhibited long-term stability (1300 h) and no ruthenium leaching. A reaction pathway is proposed for this process in which the carboxylic acids are hydrogenated to alcohols via the formation of aldehydes. Alcohols and aldehydes are then converted to methane and alkanes of one carbon atom less than the substrate through CC bond cleavage.CONCLUSIONS: This process is effective for treating FT aqueous phase effluent, and holds great promise for industrial applications due to its high efficiency, simplicity and stability. Copyright © 2011 Society of Chemical Industry
    Journal of Chemical Technology & Biotechnology 01/2012; 87(1):112-122. · 2.50 Impact Factor
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    ABSTRACT: Hydrogenolysis of glycerol to 1,3-propanediol in aqueous-phase was investigated over Pt-H4SiW12O40/SiO2 bi-functional catalysts with different H4SiW12O40 (HSiW) loading. Among them, Pt-15HSiW/SiO2 showed superior performance due to the good dispersion of Pt and appropriate acidity. It is found that Brønsted acid sites facilitate to produce 1,3-PDO selectively confirmed by Py-IR. The effects of weight hourly space velocity, reaction temperature and hydrogen pressure were also examined. The optimized Pt-HSiW/SiO2 catalyst showed a 31.4% yield of 1,3-propanediol with glycerol conversion of 81.2% at 200 °C and 6 MPa. Graphical Abstract .
    Catalysis Letters 02/2011; 142(2). · 2.24 Impact Factor
  • Lungang Chen, Yulei Zhu, Hongyan Zheng, Chenghua Zhang, Bin Zhang, Yongwang Li
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    ABSTRACT: For the aqueous-phase hydrodeoxygenation (APHDO) of carboxylic acids over the Ru/C, Ru/ZrO2 and Ru/Al2O3 catalysts, the CO hydrogenation and C–C bond cleavage reactions were studied by collecting reaction kinetics data and the measures of DRIFTS. The C–C bond cleavage was improved at high temperature and with high metal loadings. The acidic supports in combination with Ru metal can favor the CO hydrogenation of carboxyl. The C–C bond cleavage derived from the decarbonylation of acyl on the catalyst was studied by the measures of DRIFTS. The APHDO and DRIFTS results demonstrated that the C–C bond cleavage was favored in the order of Ru/C > Ru/ZrO2 > Ru/Al2O3. The catalysts were characterized by multiple methods (H2-TPR, NH3-TPD, CO-FTIR and DRIFTS of propanoic acid). It is concluded that the effect of support on the reaction routes may be attributed to these factors of catalysts, i.e., surface acidity, metal–support interaction and electronic state of Ru species.
    Journal of Molecular Catalysis A Chemical 01/2011; 351:217–227. · 3.19 Impact Factor

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