Methanol coupling in the zeolite chabazite studied via Car-Parrinello molecular dynamics

被引：19

作者：

Lo, C ^{[1
]}

Giurumescu, CA ^{[1
]}

Radhakrishnan, R ^{[1
]}

Trout, BL ^{[1
]}

机构：

[1] MIT, Dept Chem Engn, Cambridge, MA 02139 USA

来源：

MOLECULAR PHYSICS | 2004年 / 102卷 / 03期

基金：

美国国家科学基金会;

关键词：

D O I：

10.1080/00268970410001703903

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

We have used Car-Parrinello constrained molecular dynamics to study the coupling of two molecules of methanol in the zeolite chabazite to form ethanol and water. We have chosen to study this reaction because it represents the formation of the first C-C bond, which is thought to be the rate limiting step for the MTO and MTG processes. We have elucidated a new mechanism for this reaction that does not require the prior formation of surface methoxy groups or dimethyl ether intermediates. The mechanism involves stable intermediates of methane and protonated formaldehyde. We have also calculated an upper bound of the free energy barrier for the overall reaction, and found that it compares favourably with the rough experimental measurements available. Finally, we consider what are the natural reaction coordinates for the methanol-methanol coupling process.

引用

页码：281 / 288

页数：8

共 31 条

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