Improved para-Xylene Selectivity in meta-Xylene Isomerization Over ZSM-5 Crystals with Relatively Long b-Axis Length

Authors

  • Yan Liu,

    1. Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
    2. Department of Chemical Engineering and Technology, East China Institute of Technology, Nanchang 330013 (China)
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  • Xiaozhao Zhou,

    1. Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
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  • Dr. Xinmei Pang,

    1. Petrochemical Research Institute, PetroChina Company Limited, Beijing 100195 (China)
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  • Yinying Jin,

    1. Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
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  • Dr. Xiangju Meng,

    Corresponding author
    1. Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
    • Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
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  • Prof. Xiaoming Zheng,

    1. Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
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  • Dr. Xionghou Gao,

    1. Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina Company Limited, Lanzhou 730060 (China)
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  • Prof. Feng-Shou Xiao

    Corresponding author
    1. Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
    2. Zhejiang Provincial Engineering Research Center of Industrial, Boiler & Furnace Flue Gas Pollution Control, Hangzhou 310028 (PR China)
    • Key Lab of Applied Chemistry of Zhejiang Province, Department of Chemistry, Zhejiang University(XiXi Campus), Hangzhou 310028 (PR China)
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Abstract

ZSM-5 zeolite crystals with controllable b-axis length (sheet-like, S-ZSM-5; chain-like, C-ZSM-5) have been synthesized by using urea and starch as additives in the starting aluminosilicate gels. X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images show that these zeolite samples have good crystallinity. Transmission electron microscopy (TEM) images show that there is a strong chemical interaction between the stacked crystals in C-ZSM-5 samples. N2 sorption isotherms indicate that C-ZSM-5 crystals are mesoporous. Catalytic tests for the formation of p-xylene from m-xylene isomerization show that, compared with other zeolite catalysts, C-ZSM-5 catalysts give both high conversion and improved p-xylene selectivity, which are attributed to the combination of relatively long b-axis length and the present mesoporosity in the crystals. The improvement of p-xylene selectivity in catalytic m-xylene isomerisation is of great importance for selective industrial production of p-xylene in the future.

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