催化学报

催化学报 ›› 2009, Vol. 30 ›› Issue (4): 305-311.

• 研究论文 • 上一篇    下一篇

ZSM-5 分子筛中相邻酸性位的酸性强度及其对乙烯质子化反应影响的理论计算

王善鹏, 王伊蕾, 曹亮, 邢双英, 周丹红   

  1. 辽宁师范大学化学化工学院功能材料化学研究所, 辽宁大连 116029
  • 收稿日期:2009-04-25 出版日期:2009-04-25 发布日期:2013-01-21

Theoretical Study on the Acidity of Neighboring Acid Sites in ZSM-5 Zeolite and Its Effect on Ethylene Protonation

WANG Shanpeng, WANG Yilei, CAO Liang, XING Shuangying, ZHOU Danhong*   

  1. Institute of Chemistry for Functionalized Materials, College of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, Liaoning , China
  • Received:2009-04-25 Online:2009-04-25 Published:2013-01-21

PDF

1395

被引次数

11

摘要： 应用量子力学与分子力学联合的 ONIOM2(B3LYP/6-31G(d,p):UFF)方法, 对 ZSM-5 分子筛中与 T6, T9 和 T12 位相邻的骨架铝的落位稳定性以及酸性强度进行了理论计算. 根据 Si/Al 替代能确定了最稳定的相邻酸性位在 Al6-Al6 位, 其次是 Al6-Al9 位, 通过 (Si/Al,H) 替代能计算确定了氢质子的落位. 计算结果证明了相邻骨架铝会导致酸性强度降低, 而且 Al6-Al9 位的酸性低于 Al6-Al6 位. 应用密度泛函理论方法进一步考察了相邻酸性位对乙烯分子吸附和质子化反应历程的影响. 结果表明, -Al-O-Si-O-Al-结构的相邻酸性位对乙烯分子的吸附以及质子化反应历程有明显影响, 尤其是使乙醇盐产物更不稳定.

关键词: ZSM-5 分子筛, 相邻酸性位, 乙烯质子化, ONIOM 方法

Abstract: The acidity of the neighboring acid sites in HZSM-5 zeolite was theoretically studied. The stability and the acid strength of the acid site pair are in the order of Al6-Al6 > Al6-Al9. It is also found that the -Al-O-Si-O-Al- structure neighboring acid sites have strong effect on the adsorption and the protonation of ethylene and especially lead to very low stability of ethoxide product.

Key words: ZSM-5 zeolite, next-nearest-neighber acid site, ethylene protonation, ONIOM method