• Wenxiang Zhang

      Articles written in Journal of Chemical Sciences

    • Selective hydrogenation of maleic anhydride over Pd/Al2O3 catalysts prepared via colloid deposition

      Hongjing Yuan Chunlei Zhang Weitao Huo Chunli Ning Yong Tang Yi Zhang Dequan Cong Wenxiang Zhang Jiahuan Luo Su Li Zhenlu Wang

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      Pd/Al2O3 catalysts were prepared via colloid deposition and the performance of the catalysts was examined in the selective hydrogenation of maleic anhydride to succinic anhydride. When the reaction was carried on in a batch system with 1,4-dioxane as the solvent (353K and 1.0MPa), high conversion of maleic anhydride (>98%) and high selectivity (>99%) for succinic anhydride were observed after 5 h. The as-prepared Pd/Al2O3 catalyst also showed excellent performance in solvent-free system and fixed-bed systems. The maleic anhydride (MA) conversion was greater than 98%, and high selectivity (>99%) for succinic anhydride was obtained after 1600 h in a fixed bed reacter. The results showed that the activity of the Pd/Al2O3 catalysts was excellent due to its high active surface area.

    • The direct transformation of ethanol to ethyl acetate over Cu/SiO2 catalysts that contain copper phyllosilicate

      Xue Yu Shubo Zhai Wanchun Zhu Shuang Gao Jianbiao Yan Hongjing Yuan Lili Chen Jiahuan Luo Wenxiang Zhang Zhenlu Wang

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      Cu/SiO2 catalysts that contain copper phyllosilicate, were successfully prepared using the ammonia-evaporation method. The catalysts were characterized via XRD, ICP, BET, FTIR, TPR, XPS, NH3-TPD and FTIR of Pyridine Adsorption techniques. The results demonstrated that the formation of the copper phyllosilicate species significantly affected the structural properties and caused the CuO nanoparticles to become highly dispersed, and the copper phyllosilicate would provide access to the Lewis acidic Cu+ species. It was found that the catalyst with a 23.7 wt% copper loading exhibited the best ethanol conversion and ethyl acetate selectivity. When compared to a catalyst with the same copper loading which was prepared with the impregnation method, the higher activity and selectivity of catalysts might be ascribed to the homogenous distribution of copper nanoparticles, which was the active site for the dehydrogenation, and the amount of Lewis acidic Cu+ sites active for esterification. The synergetic effect between the Cu0 and Lewis acidic sites was the key factor to achieve direct transformation of ethanol to ethyl acetate.

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