催化学报

催化学报 ›› 2010, Vol. 31 ›› Issue (1): 33-37.

• 研究论文 • 上一篇    下一篇

HSAPO-34 分子筛上氧鎓叶立德机理的第一性原理研究

王仰东, 王传明, 刘红星, 谢在库   

  1. 中国石油化工股份有限公司上海石油化工研究院, 上海 201208
  • 收稿日期:2010-01-25 出版日期:2010-01-25 发布日期:2010-01-25

A First-Principle Study of Oxonium Ylide Mechanism over HSAPO-34 Zeolite

WANG Yangdong, WANG Chuanming, LIU Hongxing, XIE Zaiku*   

  1. Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, China
  • Received:2010-01-25 Online:2010-01-25 Published:2010-01-25

PDF

1276

被引次数

30

摘要： 采用基于周期性边界条件的密度泛函理论研究了 HSAPO-34 分子筛上甲醇通过氧鎓叶立德机理直接耦合生成乙烯的可能性. 结果表明, 二甲醚和三甲基氧鎓离子在 HSAPO-34 分子筛上的生成能垒分别为 1.68 和 0.93 eV, 中间体氧鎓叶立德不能稳定存在, 同时表明 C–C 键通过协同反应形成的能垒均超过 3.0 eV. 因此, 甲醇制烯烃催化过程不可能遵循氧鎓叶立德机理.

关键词: HSAPO-34 分子筛, 甲醇制烯烃, 氧鎓叶立德机理, 密度泛函理论, 三甲基氧鎓离子

Abstract:  Based on density functional theory calculation with periodic boundary conditions, the possibility of the direct coupling of methanol into ethene by oxonium ylide mechanism was investigated. The calculated results indicate that the energy barriers for the formation of dimethyl ether and trimethyl oxonium ion inside HSAPO-34 zeolite are 1.68 and 0.93 eV, respectively. The suggested intermediate oxonium ylide is very unstable and the energy barriers for the formation of C–C bond are over 3.0 eV by concerted pathway. It is thus concluded that the methanol to olefin reaction cannot follow the oxonium ylide mechanism.

Key words: HSAPO-34 zeolite, methanol to olefin process, oxonium ylide mechanism, density functional theory, trimethyl oxonium ion