A Mechanistic Study of Methanol-to-Aromatics Reaction over Ga-Modified ZSM-5 Zeolites: Understanding the Dehydrogenation Process
A Mechanistic Study of Methanol-to-Aromatics Reaction over Ga-Modified ZSM-5 Zeolites: Understanding the Dehydrogenation Process
复制标题
Ga 改性 ZSM-5 沸石上的甲醇制芳烃反应机理研究：了解脱氢过程
DOI：
10.1021/acscatal.8b03076
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发表时间：
2018-10-01
期刊：
影响因子：
12.9
通讯作者：
Deng, Feng
中科院分区：
文献类型：
--
作者：
Gao, Pan;Xu, Jun;Deng, Feng
The methanol-to-aromatics (MTA) reaction was investigated on Ga-modified ZSM-5 zeolites (Ga/ZSM-5). As revealed by 71Ga and 1H solid-state NMR and FT-IR of pyridine adsorption measurements, cationic Ga species are formed as Lewis acid sites by substitution of Bronsted acid sites on H-ZSM-5. Further experimental studies show that C5- and C6-cycloalkenes are generated during the MTA reaction, which lead to the formation of cyclic carbocations as precursors to aromatics. Isotope exchange experiments demonstrate that the reactivity of the cyclic carbocations on Ga/ZSM-5 is much higher than that on H-ZSM-5 and they play an intermediate role in the formation of aromatics. In addition to the traditional bimolecular hydrogen transfer (HT) reaction, the dehydrogenation of alkenes with the release of H2 (DeaH2 process) was identified to significantly contribute to the formation of aromatics. The transformation of cycloalkenes to aromatics is favored by promotion of the DeaH2 process and competes with the HT route o...
