高等学校化学学报 ›› 2019, Vol. 40 ›› Issue (4): 784-792.doi: 10.7503/cjcu20180670

• 物理化学 • 上一篇    下一篇

二维HZSM-5纳米片的合成及催化苯与稀乙烯烷基化制乙苯

边凯1, 候章贵2, 段欣瑞1, 李孝国2, 常洋2, 曹辉2, 张安峰1(), 郭新闻1()   

  1. 1. 大连理工大学化工学院, 精细化工国家重点实验室, 大连 116024
    2. 中海油炼油化工科学研究院, 北京 102209
  • 收稿日期:2018-10-03 出版日期:2019-04-10 发布日期:2019-01-09
  • 作者简介:联系人简介: 张安峰, 男, 博士, 副教授, 主要从事分子筛酸催化方面的研究. E-mail: zhangaf@dlut.edu.cn;郭新闻, 男, 博士, 教授, 博士生导师, 主要从事分子筛酸催化及二氧化碳加氢还原方面的研究. E-mail: Guoxw@dlut.edu.cn

Synthesis and Catalytic Performance of 2D HZSM-5 Nano-sheet for Ethylbenzene Production from Benzene with Dilute Ethylene

BIAN Kai1, HOU Zhanggui2, DUAN Xinrui1, LI Xiaoguo2, CHANG Yang2, CAO Hui2, ZHANG Anfeng1,*(), GUO Xinwen1,*()   

  1. 1. State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
    2. CNOOC Research Institute of Refining and Petrochemicals, Beijing 102209, China
  • Received:2018-10-03 Online:2019-04-10 Published:2019-01-09
  • Contact: ZHANG Anfeng,GUO Xinwen E-mail:zhangaf@dlut.edu.cn;Guoxw@dlut.edu.cn

摘要:

采用晶种导向的方法, 以四丙基溴化铵为模板剂, 乙胺为矿化剂, 硅溶胶为硅源, 氯化铝为铝源, 60 nm Silicate-1为晶种, 于水热条件下合成了具有不同b轴厚度及硅铝比的二维 HZSM-5纳米片. 采用不同碱源对分子筛进行碱处理, 其中经NaOH处理以及NaOH与四丙基氢氧化铵(TPAOH)联合处理得到了二维多级孔HZSM-5纳米片. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 Ar吸附-脱附、 氨-程序升温脱附(NH3-TPD)、 X射线荧光光谱(XRF)和X射线光电子能谱(XPS)等手段对催化剂的结构和酸性进行了表征, 考察了硅铝比和b轴厚度对催化苯与稀乙烯烷基化反应的影响. 研究结果表明, 在360 ℃, 1.4 MPa, 苯烯比为6, 乙烯体积分数为15%, 乙烯质量空速(WHSV)为1.5 h-1的反应条件下, 随着硅铝原子比从80提高至200, 苯的转化率略有下降, 乙基选择性保持在99.2%以上, 但甲苯及二甲苯选择性分别从0.11%和0.09%均下降至0.05%. 将不同b轴厚度的HZSM-5纳米片催化剂在苯烯比为1的条件下进行实验发现, 硅铝比为160的大晶粒HZSM-5催化剂失活严重, 反应50 h时苯的转化率从34.6%下降至8%, 二甲苯选择性达到0.37%; 而b轴厚度为100 nm的二维 HZSM-5纳米片作为催化剂时苯的转化率稳定在44.0%, 乙基选择性为94.8%, 二甲苯选择性下降至0.22%, 并在100 h内保持反应性能不变.

关键词: HZSM-5分子筛, 酸催化, 乙苯, 苯与乙烯烷基化

Abstract:

2D HZSM-5 nano-sheet with different b-axis thickness and Si/Al atom ratios were synthesized by seed-induced method under the hydrothermal conditions, using tetrapropylammonium bromide as the template, ethylamine as the mineralizer, silica sol as the silicon source, aluminium chloride as the aluminium source and the 60 nm silicate-1 as the crystal seed, respectively. And the 2D hierarchical HZSM-5 nano-sheet were obtained by alkaline treatment with different sources, including NaOH treatment, tetrapropylammonium hydroxide(TPAOH) treatment, and NaOH with TPAOH co-alkaline treatment. The structure and acidity of the samples were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), Ar adsorption-desorption, ammonia temperature-programmed desorption(NH3-TPD), X-ray fluorescence(XRF) and X-ray photoelectron spectroscopy(XPS). The effects of Si/Al atom ratio and the thickness of b-axis on the alkylation of benzene with dilute ethylene were investigated. The research results show that, under the reaction conditions of 360 ℃, 1.4 MPa, the molar ratio of benzene/ethylene is 6, and the concentration and weight hourly space velocity(WHSV) of ethylene were 15% and 1.5 h-1, the conversion of benzene decreased slightly with the increasing of Si/Al atom ratio, the ethyl selectivity maintained above 99.2%, while the selectivity of toluene and xylene decreased from 0.11% and 0.09% to 0.05%, respectively. The HZSM-5 catalysts with different b-axis thickness were evaluated under the condition of benzene/ethylene is 1, the microscale HZSM-5 with the high silica content deactivated seriously. The conversion of benzene declined from 34.6% to 8% during 50 h, and the ethyl selectivity was 88%. While the benzene conversion of 2D HZSM-5 nano-sheet with same Si/Al atom ratio was stable at 44.0%, the ethyl selectivity reached to 94.8%, and the xylene selectivity reduced from 0.37% to 0.22%.

Key words: HZSM-5 zeolite, Acid catalysis, Ethylbenzene, Alkylation of benzene with ethylene

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