使用基于Ab Initio的动力学识别MTO启动机制的反应序列
Philipp N Plessow1, Ashley Smith1, Steffen Tischer1,2
1Institute of Catalysis Research and Technology , Karlsruhe Institute of Technology , Hermann-von-Helmholtz-Platz 1 , D-76344 Eggenstein-Leopoldshafen , Germany.
Journal of the American Chemical Society
|March 29, 2019
概括
在H-SSZ-13上模拟了甲醇转烯 (MTO) 过程的启动. 甲醇的脱和CO-甲基化形成甲基乙酸,自催化在早期起着关键作用.
科学领域:
- 化学工程
- 催化科学
- 计算化学
背景情况:
- 甲醇转烯 (MTO) 过程对于将甲醇转化为轻烯至关重要.
- 了解H-SSZ-13等热石的MTO启动机制对于过程优化至关重要.
- 现有的模型通常简化复杂的反应网络和自催化效应.
研究的目的:
- 使用多尺度建模方法研究H-SSZ-13的MTO过程的启动机制.
- 阐明主导反应途径和自催化在原子尺度上的作用.
- 为解释MTO实验结果提供一个框架.
主要方法:
- 结合ab initio计算 (MP2:DFT) 与批量反应器模型的多尺度建模.
- 包括H-SSZ-13的100多个计算速率常数.
- 详细的反应网络包括启动 (42个步骤) 和自催化循环 (63个步骤).
主要成果:
- 确定甲醇脱为CO,其次是CO甲基化,作为主要的启动途径.
- 甲基乙酸作为初始C-C键产物的形成,尽管能量障碍很高.
- 证明了烯的自催化变得比以前假设的更早.
结论:
- 要了解原子层面的MTO启动,需要一个全面的多尺度模型.
- 自催化是MTO过程中的关键因素,即使在低度的olefin中也会影响启动.
- 这些发现为MTO反应动力学提供了新的见解,并指导了实验设计.
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