B改性的SAPO-34对MTO选择性的影响
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- 英文论文题名：Acidity and Selectivity of MTO over Isomorphously Substituted SAPO-34 by Boron:Density Functional Investigations
- 论文作者：刘红艳 ; 武真羽 ; 王宝俊
- 英文论文作者：Hongyan Liu ; Zhenyu Wu ; Baojun Wang ; College of Chemistry and Environmental Engineering ; Shanxi Datong University ; Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province ; Taiyuan University of Technology
- 年：2016
- 作者机构：山西大同大学化学与环境工程学院;太原理工大学煤科学与技术教育部与山西省重点实验室;
- 论文关键词：密度泛函理论 ; 甲醇制烯烃 ; 侧链机理 ; H-SAPO-34 ; 硼同晶取代
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第十九分会：化学中的量子与经典动力学
- 语种：中文
- 分类号：TQ221.21;O641.1
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第十九分会 ; 化学中的量子与经典动力学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：2
- 文件大小：397k
- 原文格式：D
- 会议级别：全国
摘要
通过比较未改性的和B改性的SAPO-34分子筛,研究B改性对MTO反应活性和选择性的影响。在本章内容中,我们运用周期性密度泛函理论并且考虑了考虑了色散相互作用(DFT-D),系统的研究了未改性和B改性的SAPO-34催化MTO的六甲基苯(HMB)基于的侧链烃池机理。计算结果表明:SAPO-34分子筛中B的同晶取代略微降低了分子筛的酸性,从而降低了反应的活性。然而,对乙烯的选择性明显增大。在HMB基于的侧链循环中,丙烯形成过程中的第二个去质子化反应是速控步骤。此外,这些理论的结论使得我们明白产物的选择性也取决于分子筛的酸性。
Silicoaluminophosphate(SAPO)-34 molecular sieves modified with B were investigated for their activity, selectivity in the methanol to olefins(MTO) reaction and compared with that of unmodified SAPO-34. In this work, HMB-based cycle in the reference and boron-modified HSAPO-34 zeolites were systematically investigated using periodic density functional theory with considering dispersive interactions(DFT-D). The results demonstrated that isomorphous substitution of B in H-SAPO-34 zeolite slightly enhanced the acidity of zeolite, which resulted in the reduction of activity of the reaction. However, ethene selectivity showed a significant increase compared to that of the reference sample. The rate-determining step was identified as the second deprotonation reaction in the route toward propene in the HMB-based cycle. In addition, these theoretical insights enable us understand the dependence of reactive activity and the selectivity of product on zeolite acidity.
Silicoaluminophosphate(SAPO)-34 molecular sieves modified with B were investigated for their activity, selectivity in the methanol to olefins(MTO) reaction and compared with that of unmodified SAPO-34. In this work, HMB-based cycle in the reference and boron-modified HSAPO-34 zeolites were systematically investigated using periodic density functional theory with considering dispersive interactions(DFT-D). The results demonstrated that isomorphous substitution of B in H-SAPO-34 zeolite slightly enhanced the acidity of zeolite, which resulted in the reduction of activity of the reaction. However, ethene selectivity showed a significant increase compared to that of the reference sample. The rate-determining step was identified as the second deprotonation reaction in the route toward propene in the HMB-based cycle. In addition, these theoretical insights enable us understand the dependence of reactive activity and the selectivity of product on zeolite acidity.
引文
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