期刊
CATALYSIS SCIENCE & TECHNOLOGY
卷 12, 期 7, 页码 2289-2305出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/d1cy02361f
关键词
-
资金
- EPSRC [EP/I038748/1, EP/I019693/1, EP/K014706/1, EP/K014668/1, EP/K014854/1, EP/K014714/1, EP/M013219/1]
- CRITICAT Centre for Doctoral Training [EP/I017008/1, EP/L016419/1]
- UK Catalysis Hub
- EPSRC
- Diamond Light Source [SM18680-1, SM 20906-1, SM 22347-1, SM23081-1]
Synchrotron FTIR microspectroscopy coupled with mass spectrometric analysis was used to investigate the initial stages of the methanol to olefins (MTO) reaction. Surface methoxy groups were found to be key in the formation of olefinic hydrocarbon pool through insertion of carbene-like species.
Synchrotron FTIR microspectroscopy coupled with mass spectrometric analysis of desorbed products has been used to investigate the initial stages of the methanol to olefins (MTO) reaction in single crystals of SAPO-34. Surface methoxy groups (SMS) are key to initial dimethylether (DME) and subsequent carbon-carbon bond formation. Deprotonation of SMS is the critical first step in direct olefin formation at low temperatures and DME is not involved in the carbon-carbon forming step. Experiments with CD3OH confirm the deprotonation step and show an inverse kinetic isotope effect consistent with irreversible deprotonation. The subsequent formation of alkoxide species, which are the precursors of the olefinic hydrocarbon pool present in working MTO catalysts, is initiated via insertion of surface carbene-like species into adjacent SMS. The observed induction period for this process is determined by the limited mobility of SMS and/or carbene species. Olefins formed from cracking of the alkoxide species then transmit carbon-carbon bond formation through the SAPO-34 by rapid diffusion and reaction with further SMS. Acetyl species seen with methanol at higher temperatures support the insertion of CO into SMS suggested in the literature, but these species do not play a role in direct olefin formation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据