物理化学学报 >> 2013, Vol. 29 >> Issue (06): 1273-1280.doi: 10.3866/PKU.WHXB201303183

催化和表面科学 上一篇    下一篇

原位傅里叶变换红外光谱研究Y型分子筛表面酸性对吸附有机分子的影响

张晓彤1, 于文广1, 秦玉才2, 董世伟1, 裴婷婷1, 王琳1, 宋丽娟1,2   

  1. 1 辽宁石油化工大学, 辽宁省石油化工催化科学与技术重点实验室, 辽宁 抚顺 113001;
    2 中国石油大学(华东)化学化工学院, 山东 青岛 266426
  • 收稿日期:2013-01-02 修回日期:2013-03-18 发布日期:2013-05-17
  • 通讯作者: 宋丽娟 E-mail:lsong56@263.net
  • 基金资助:

    国家自然科学基金(20976077, 21076100); 中国石油天然气股份有限公司炼油催化剂重大专项(10-01A-01-01-01); 辽宁省高校创新团队项目(200T110)及辽宁省高端人才队伍建设项目资助

Influence of Surface Acidity of Y Zeolites on the Adsorption of Organic Molecules by In situ Fourier Transform Infrared Spectroscopy

ZHANG Xiao-Tong1, YU Wen-Guang1, QIN Yu-Cai2, DONG Shi-Wei1, PEI Ting-Ting1, WANG Lin1, SONG Li-Juan1,2   

  1. 1 Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Province, Liaoning ShiHua University, Fushun 113001, Liaoning Province, P. R. China;
    2 College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266426, Shandong Province, P. R. China
  • Received:2013-01-02 Revised:2013-03-18 Published:2013-05-17
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20976077, 21076100), Major Program of Petroleum Refining of Catalyst of Petro China Company Limited (10-01A-01-01-01), Innovation Team of Liaoning Province Colleges, China (200T110), and Construction Project of Liaoning Province High-end Talent Team.

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摘要：

采用吡啶原位吸附傅里叶变换红外(Py-FTIR)光谱对液相离子交换(LPIE)和固相离子交换(SSIE)法制备的CeY分子筛以及HY和NaY的酸性进行了测定. 在原位条件下采用单探针分子噻吩、环己烯和苯对其在分子筛上的吸附过程进行了研究; 以噻吩和环己烯、噻吩和苯组成的双探针分子对吸附过程中存在的竞争吸附、催化反应以及吸附机理进行了系统研究. 结果表明, HY和L-CeY 分子筛表面强Brönsted (B)酸性位可导致吸附在其表面的噻吩发生低聚反应以及吸附的环己烯产生二聚环己烯碳正离子. 低聚的噻吩和吸附的环己烯在分子筛上发生强的化学吸附, 进一步抑制和阻碍噻吩硫化物与分子筛吸附活性中心发生作用, 从而降低了吸附剂的选择性以及吸附硫化物的能力. 吸附剂表面Lewis (L)酸中心是吸附的主要活性中心, 大量弱的L 酸, 有利于噻吩吸附. 并且, S-CeY分子筛表面弱的L酸对吸附噻吩具有一定的选择性, 它受到环己烯的影响较小, NaY吸附剂对噻吩、环己烯和苯选择性较差, 它只与吸附质作用的先后有关.

关键词: 原位傅里叶变换红外光谱, 改性Y分子筛, 表面酸性, 竞争吸附, 催化反应

Abstract:

The surface acidity of Y-type zeolites (HY and NaY) modified by solid state ion exchange (SSIE) and liquid phase ion exchange were characterized by in situ Fourier transform infrared (FTIR) spectroscopy using pyridine as the probe molecule (Py-FTIR). The adsorption of single probe molecules (thiophene, cyclohexene and benzene) and double probe molecules (thiophene and cyclohexene, thiophene and benzene) compared with sorbents were studied using in situ FTIR spectroscopy. The results indicated that the Brönsted acid (B acid) of HY (L-CeY) is the catalytic center of cyclohexene dimerized alkenyl carbenium ions and thiophene oligomerization, while the Lewis acid (L acid) is the major center of adsorption of thiophene, cyclohexene, and benzene. In addition, there is strong chemisorption and competitive adsorption of cyclohexene and thiophene, which provides evidence for the poor performance of removing sulfur. The S-CeY zeolite has abundant of weak Lewis acid sites. The sorbent is good at absorbing thiophene, while the influence of the competition adsorption of cyclohexene was not predominately. As to NaY zeolite, there is no preference for adsorption of thiophene, cyclohexene and benzene.

Key words: In situ Fourier tansform infrared spectroscopy, Modified Y zeolite, Surface acidity, Competitive adsorption, Catalytic reaction