SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2014, Vol. 22 ›› Issue (8): 921-929.DOI: 10.1016/j.cjche.2014.06.009

• 第四届整体式结构化催剂与反应器国际会议专栏 • 上一篇    下一篇

Promoting Xylene Production in Benzene Methylation using Hierarchically Porous ZSM-5 Derived from a Modified Dry-gel Route

Wei Deng1, Xuan He1, Chao Zhang1, Yunyi Gao1, Xuedong Zhu1, Kake Zhu1, Qisheng Huo2, Zhijie Zhou3   

  1. 1. College of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
    2. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China;
    3. Key Laboratory of Coal Gasification, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
  • 收稿日期:2013-12-24 修回日期:2014-02-21 出版日期:2014-08-28 发布日期:2014-11-04
  • 通讯作者: Kake Zhu
  • 基金资助:

    Supported by the National Natural Science Foundation of China (21006024), the CNPC Innovation Foundation (2011D-5006-0507), the Shanghai Pujiang Program (11PJ1402600), the New Century Excellent Talents in University (NCET-11-0644), and the Fundamental Research Funds for the Central Universities (WB1213004-1).

Promoting Xylene Production in Benzene Methylation using Hierarchically Porous ZSM-5 Derived from a Modified Dry-gel Route

Wei Deng1, Xuan He1, Chao Zhang1, Yunyi Gao1, Xuedong Zhu1, Kake Zhu1, Qisheng Huo2, Zhijie Zhou3   

  1. 1. College of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
    2. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China;
    3. Key Laboratory of Coal Gasification, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
  • Received:2013-12-24 Revised:2014-02-21 Online:2014-08-28 Published:2014-11-04
  • Supported by:

    Supported by the National Natural Science Foundation of China (21006024), the CNPC Innovation Foundation (2011D-5006-0507), the Shanghai Pujiang Program (11PJ1402600), the New Century Excellent Talents in University (NCET-11-0644), and the Fundamental Research Funds for the Central Universities (WB1213004-1).

摘要: Methylation of benzene is an alternative low-cost route to produce xylenes, but selectivity to xylene remains low over conventional zeolitic catalysts. In this work, a combined dry-gel-conversion and steam-assistedcrystallization method is used to synthesize hierarchically porous zeolite ZSM-5 with varied Si/Al malar ratios. X-ray diffraction (XRD), N2 physisorption, NH3-temperature programmed desorption (TPD), scanning electronic microscopic (SEM) measurement and Fourier transforminfrared (FT-IR) are employed to characterize the structure and acidity of both hierarchically porous zeolites and their conventional counterparts. The method is found to be applicable to ZSM-5 with molar ratios of Si/Al from 20 to 180. The ZSM-5 zeolites are used as catalysts for benzene methylation at 460℃ to investigate the effect of additional porosity and Si/Al ratios. At low Si/Al ratios, the benzene conversions over conventional and hierarchical ZSM-5 are close, and selectivity to toluene is high over hierarchical ZSM-5. It is found that hierarchical porositymarkedly enhances the utility of zeolite and the selectivity towards xylenes via improved mass transport at higher Si/Al ratios. Under an optimized hierarchical ZSM-5 catalyst, xylene selectivity reaches 34.9% at a Si/Al ratio of 180.

关键词: Hierarchical zeolite, Benzene, Methanol, Methylation, ZSM-5, Process intensification

Abstract: Methylation of benzene is an alternative low-cost route to produce xylenes, but selectivity to xylene remains low over conventional zeolitic catalysts. In this work, a combined dry-gel-conversion and steam-assistedcrystallization method is used to synthesize hierarchically porous zeolite ZSM-5 with varied Si/Al malar ratios. X-ray diffraction (XRD), N2 physisorption, NH3-temperature programmed desorption (TPD), scanning electronic microscopic (SEM) measurement and Fourier transforminfrared (FT-IR) are employed to characterize the structure and acidity of both hierarchically porous zeolites and their conventional counterparts. The method is found to be applicable to ZSM-5 with molar ratios of Si/Al from 20 to 180. The ZSM-5 zeolites are used as catalysts for benzene methylation at 460℃ to investigate the effect of additional porosity and Si/Al ratios. At low Si/Al ratios, the benzene conversions over conventional and hierarchical ZSM-5 are close, and selectivity to toluene is high over hierarchical ZSM-5. It is found that hierarchical porositymarkedly enhances the utility of zeolite and the selectivity towards xylenes via improved mass transport at higher Si/Al ratios. Under an optimized hierarchical ZSM-5 catalyst, xylene selectivity reaches 34.9% at a Si/Al ratio of 180.

Key words: Hierarchical zeolite, Benzene, Methanol, Methylation, ZSM-5, Process intensification