Journal of Petrochemical Universities

Journal of Petrochemical Universities ›› 2011, Vol. 24 ›› Issue (2): 10-13.DOI: 10.3696/j.issn.1006-396X.2011.02.003

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The Acidity of RTH Structure by the Density Functional Theory

  

  1. School of Chemistry and Materials Science, Liaoning Shihua University, Fushun Liaoning 113001, P.R.China
  • Received:2010-11-22 Revised:2010-12-17 Published:2011-04-25 Online:2011-04-25

RTH 结构分子筛的酸性的密度泛函理论研究

彭西来,桂建舟,刘丹* ,江海英,杨爽,高玉环   

  1. 辽宁石油化工大学化学与材料科学学院,辽宁抚顺113001
  • 作者简介:彭西来(1986 -), 男, 江西吉安市, 在读硕士
  • 基金资助:
    :国家自然科学基金项目(20706027);教育部重点项目(209031);辽宁省高等学校优秀人才支持计划项目(LR201024);辽宁省自然科学基金项目20102131);辽宁省教育厅项目(2009A430 ,L2010243)

Abstract: The acidity of zeolite with RTH structure had been studied using the density functional theory generalized gradient approximation(GGA) method for the first time. The Al substitution energy of four different T sites and the deprotonation energies of sixteen different Brnsted acid sites were calculated to found the preferred Al substitution energy and acidic strength of different B acid sites. The results show that T4, locating in the opening (0.56 nm×0.25 nm) of 8-membered ring, is the most favorable T site for Al substitution in the RTH structure. With considerations on both structure and acidity, Al4-O9(H)-Si2 and Al4-O16(H)-Si4, locating in the intersection part of the two 8-membered ring channel, show stronger Brnsted acidity and are the most possible active sites for acid catalytic reaction.

Key words:

摘要: 采用密度泛函理论中的广义梯度近似方法(GGA)对RTH 结构分子筛的酸性进行了研究。考察了4 个不同T 位的Al 的替代能以及16 个不同Brö nsted 酸位的脱质子能, 从而推断可能的Al 的取代位以及不同酸位的酸性强弱。结果表明, RTH 结构分子筛上最有可能的Al 的取代位为T4 , 位于八元环的孔口(0 .56 nm ×0.25 nm); 从结构和酸性考虑, 易与反应物接触且酸性较强的Brö nsted 酸位点在Al4 -O9(H)-Si2 和Al4 -O16(H)-Si4 上, 并且这两个酸位点都指向两个八元环孔口。

关键词: RTH , 酸性 , 分子筛 , 密度泛函理论

Cite this article

PENG Xi-lai, GUI Jian-zhou, LIU Dan,et al. The Acidity of RTH Structure by the Density Functional Theory[J]. Journal of Petrochemical Universities, 2011, 24(2): 10-13.

彭西来,桂建舟,刘丹. RTH 结构分子筛的酸性的密度泛函理论研究[J]. 石油化工高等学校学报, 2011, 24(2): 10-13.