催化学报

• 研究论文 • 上一篇    下一篇

多级孔ZSM-5分子筛: 丰富的外表面酸中心和良好的二甲苯异构化催化性能

周健a,b, 刘志成a, 李丽媛a, 王仰东a, 高焕新a, 杨为民a, 谢在库a, 唐颐b   

  1. a 中国石油化工股份有限公司上海石油化工研究院, 上海 201208;
    b 复旦大学化学系, 上海 200433
  • 收稿日期:2013-02-24 修回日期:2013-04-10 出版日期:2013-07-16 发布日期:2013-07-16
  • 通讯作者: 刘志成, 谢在库
  • 基金资助:

    国家重点基础研究发展计划(973计划, 2009CB623506);中国博士后科学基金(2012M510101); 高性能陶瓷和超微结构国家重点实验室开放课题基金(SKL201208SIC);上海市博士后科研资助计划(12R21422000).

Hierarchical mesoporous ZSM-5 zeolite with increased external surface acid sites and high catalytic performance in o-xylene isomerization

ZHOU Jiana,b, LIU Zhichenga, LI Liyuana, WANG Yangdonga, GAO Huanxina, YANG Weimina, XIE Zaikua, TANG Yib   

  1. a Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, China;
    b Department of Chemistry, Fudan University, Shanghai 200433, China
  • Received:2013-02-24 Revised:2013-04-10 Online:2013-07-16 Published:2013-07-16
  • Supported by:

    This work was supported by the National Basic Research Program of China (973 Program, 2009CB623506), the China Postdoctoral Science Foundation Project (2012M510101), the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure (SKL201208SIC), and the Shanghai Postdoctoral Scientific Program (12R21422000).

摘要: 多级孔沸石分子筛的结构性质及其催化性能是近年来分子筛研究的热点.本文采用蒸汽辅助晶化的方法制备了多级孔ZSM-5沸石分子筛,采用NH3程序升温脱附和原位吸附红外光谱等方法研究了其表面酸性质,用邻二甲苯异构化反应考察了其催化性能.结果表明,多级孔结构分子筛的结晶度和总酸量有所下降,但Lewis酸中心却有所增加.进一步研究发现,多级孔结构分子筛的外表面酸中心数量远高于常规分子筛,从而证实了多级孔结构可以将更多的酸中心暴露到外表面;而外表面酸中心数量的增多和扩散传质的改善是多级孔ZSM-5分子筛在邻二甲苯异构化反应中具有更高催化活性和对二甲苯产率的重要原因.

关键词: 多级孔结构, ZSM-5分子筛, 表面酸中心, 催化, 二甲苯异构化

Abstract: Surface acid sites of hierarchical mesoporous ZSM-5 zeolite synthesized by steam-assisted crystallization were characterized by NH3 temperature-programmed desorption and in-situ infrared spectroscopy. Compared with the conventional ZSM-5 zeolite, the hierarchical ZSM-5 zeolite had a lower concentration of surface acid sites. However, the hierarchical structure had more Lewis acid sites and, more importantly, much more external active sites as confirmed by 2,6-di-tert-butylpyridine infrared spectroscopy. Such hierarchical structure exposed more acid sites on the external surface, which subsequently lead to higher catalytic activity in reactions involving bulky molecules, such as o-xylene isomerization.

Key words: Hierarchical structure, ZSM-5 zeolite, Surface acid site, Catalysis, Xylene isomerization