物理化学学报 >> 2017, Vol. 33 >> Issue (6): 1236-1241.doi: 10.3866/PKU.WHXB201703281

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环己烯对噻吩在CuY分子筛上吸附的影响机制

莫周胜1,秦玉才2,张晓彤2,段林海2,宋丽娟1,2,*()   

  1. 1 中国石油大学(华东)化学工程学院,山东青岛266555
    2 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
  • 收稿日期:2016-11-25 发布日期:2017-05-19
  • 通讯作者: 宋丽娟 E-mail:lsong56@263.net
  • 基金资助:
    国家自然科学基金(21376114);国家自然科学基金(21476101);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)

Influencing Mechanism of Cyclohexene on Thiophene Adsorption over CuY Zeolites

Zhou-Sheng MO1,Yu-Cai QIN2,Xiao-Tong ZHANG2,Lin-Hai DUAN2,Li-Juan SONG1,2,*()   

  1. 1 College of Chemistry & Chemical Engineering, China University of Petroleum(East China), Qingdao 266555, Shandong Province, P. R. China
    2 Key Laboratory of Petrochemical Catalytic Science and Technology of Liaoning Province, Liaoning Shihua University, Fushun 113001, Liaoning Province, P. R. China
  • Received:2016-11-25 Published:2017-05-19
  • Contact: Li-Juan SONG E-mail:lsong56@263.net
  • Supported by:
    National Natural Science Foundation of China(21376114);National Natural Science Foundation of China(21476101);Major Program of Petroleum Refining of Catalyst of PetroChina Company Limited(10-01A-01-01-01)

摘要:

利用液相离子交换法制备了CuY分子筛,并用X射线光电子能谱分析(XPS)对Cu元素进行了价态表征,用原位傅里叶转换红外(in-situ FTIR)和氨气程序升温脱附(NH3-TPD)技术对其进行了酸性表征。同时,以噻吩和环己烯为探针分子,CuY分子筛为吸附剂,研究了环己烯对噻吩在CuY分子筛B酸中心上吸附的影响机制。实验结果显示,CuY分子筛表层的Cu离子主要以Cu+为主,其表面酸性主要由中强B酸和L酸组成。与稀土离子不同的是,铜离子的存在抑制了噻吩或环己烯在B酸中心上的聚合反应。因此,环己烯主要通过与噻吩的竞争吸附影响噻吩在CuY分子筛B酸性位上的吸附。

关键词: 原位傅里叶转换红外光谱, 质子酸, 竞争吸附, 反协同效应

Abstract:

A CuY zeolite prepared by liquid phase ion exchange was characterized by X-ray photoelectron spectroscopy, pyridine in situ Fourier transform infrared (in situ FTIR) spectroscopy, and ammonia temperature programmed desorption. The effect of cyclohexene on the adsorption of thiophene over the prepared CuY zeolite was explored by in situ FTIR. In particular, the role of the zeolite's Br?nsted acidity was investigated in the adsorption process. The results show that the percentage of Cu+ on the surface of the CuY zeolite can reach 77%. The surface acidity of the CuY zeolite mainly comprises medium and strong Br?nsted acidity and Lewis acidity. According to the adsorption results, cyclohexene negatively influences thiophene adsorption on the Br?nsted or Lewis acid sites in CuY by competitive adsorption. Although polymerization of thiophene and cyclohexene can occur easily on the HY or REY zeolites, the presence of Br?nsted acids in the CuY zeolite was not sufficient to polymerize either thiophene or cyclohexene. This difference may be caused by an anti-synergistic effect between the Cu ions of the CuY zeolite and neighboring Br?nsted acid sites, the result of which inhibits the polymerization of adsorbed thiophene and cyclohexene.

Key words: In-situ FTIR spectroscopy, Br?nsted acidity, Competitive adsorption, Anti-synergistic effect

MSC2000: 

  • O643