催化学报 ›› 2013, Vol. 34 ›› Issue (3): 612-619.DOI: 10.3724/SP.J.1088.2013.20932

• 研究论文 • 上一篇    

不同硅铝比的MCM-22分子筛的气相硅烷化处理

高宁宁a,b, 谢素娟a, 刘盛林a, 刘克峰a,b, 李秀杰a, 徐龙伢a   

  1. a 中国科学院大连化学物理研究所, 辽宁大连 116023;
    b 中国科学院大学, 北京 100049
  • 收稿日期:2012-09-15 修回日期:2012-10-12 出版日期:2013-04-02 发布日期:2013-04-03
  • 通讯作者: 谢素娟
  • 基金资助:

    国家重点基础研究发展计划(973计划, 2009CB623501).

Vapor-phase silylation of MCM-22 zeolite with various SiO2/Al2O3 molar ratios

GAO Ningninga,b, XIE Sujuana, LIU Shenglina, LIU Kefenga,b, LI Xiujiea, XU Longyaa   

  1. a Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    b University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2012-09-15 Revised:2012-10-12 Online:2013-04-02 Published:2013-04-03
  • Supported by:

    This work was supported by the National Basic Research Program of China (973 Program, 2009CB623501).

摘要:

对不同硅铝比的MCM-22分子筛进行气相硅烷化处理,并采用X射线衍射、固体核磁、N2吸附-脱附和甲苯吸附等技术对样品进行了表征. 结果显示,原料硅铝比为50~100的MCM-22分子筛均可以利用气相硅烷化,在不脱除骨架铝的基础上,将Si(OH)2柱撑结构引入其层间超笼系统,从而使层间距增大,孔体积增加; 将密度泛函理论用于计算硅烷化前后的MCM-22分子筛的N2吸附等温线,成功得到十元环孔道和超笼体系的比表面积和孔体积,发现气相硅烷化使MCM-22分子筛超笼体系的比表面积和孔体积增大,而十元环孔道减小.另外,气相硅烷化可有效提高不同硅铝比MCM-22分子筛的甲苯平衡吸附量.

关键词: MWW结构, MCM-22分子筛, 硅烷化, 层间扩孔, 密度泛函理论

Abstract:

MCM-22 precursor with various SiO2/Al2O3 molarratios was treated by vapor-phase silylation. MCM-22 zeolite and its products of vapor-phase silylation were characterized by X-ray diffraction, solid state nuclear magnetic resonance, N2 adsorption-desorption, and toluene adsorption techniques. The results showed that Si(OH)2 pillaring structure was formed in the interlayer of MCM-22 with SiO2/Al2O3 molarratios of 50-100 without extraction of framework aluminum through vapor-phase silylation, resulting in the expansion of interlayer distance and the increase of micropore volume. The N2 adsorption-desorption isotherms of MCM-22 zeolite before and after silylation were analyzed by the density functional theory, and the specific surface area and pore volume of 10 member ring (10 MR) micropores and those of the supercage system were successfully obtained. As a result of vapor-phase silylation, the specific surface area and pore volume of the supercage system increased, while those of 10 MR micropores decreased. The equilibrium adsorption amount of toluene over MCM-22 zeolite with various SiO2/Al2O3 molar ratios was enhanced after vapor-phase silylation.

Key words: MWW structure, MCM-22 zeolite, silylation, interlayer expansion, density functional theory