Diffusion Dependence of the Dual-Cycle Mechanism for MTO Reaction Inside ZSM-12 and ZSM-22 Zeolites

doi:10.1021/acs.jpcc.7b07374

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	Diffusion Dependence of the Dual-Cycle Mechanism for MTO Reaction Inside ZSM-12 and ZSM-22 Zeolites
	Huang, Ling 1; Li, Guangchao 1,2; Chu, Yueying 1; Liu, Zhigiang 1,2; Yi, Xianfeng 1,2; Zheng, Anmin 1; Tang, Xiaomin 1,2
刊名	JOURNAL OF PHYSICAL CHEMISTRY C
	2017-10-19
卷号	121 期号:41 页码:22872-22882
DOI	10.1021/acs.jpcc.7b07374
文献子类	Article
英文摘要	The "dual-cycle" pathway (i.e., olefin-based cycle and aromatic-based cycle) of methanol-to-olefin (MTO) has been generally accepted as hydrocarbon pool mechanism. Understanding the role of diffusion of reactant, intermediate, and product in the MTO process is essential in revealing its reaction mechanism. By using molecular dynamics (MD) simulations for two one-dimensional zeolites (ZSM-12 and ZSM-22) with a channel difference being only 0.3 angstrom in pore size, the diffusion behaviors of some representative species following "dual-cycle" mechanism (e.g., methanol, polymethylbenzenes, and olefins molecules) have been theoretically investigated in this work. It was found that the diffusion coefficients of methanol and olefins along ZSM-12 were ca. 2-3 times faster than that along ZSM-22 at 673 K. In the aromatic-based cycle, the polymethylbenzenes are crucial intermediates during the MTO reaction. 1,2,3,5-Tetramethylbenzene is almost imprisoned inside ZSM-12; such slower diffusion of tetramethylbenzene offers more opportunities for the geminal methylation reaction to form MTO activated pentamethylbenzenium cation, which would split into olefins through "paring" or "side-chain" pathways. However, in the ZSM-22 zeolite, since 1,2,4-trimethylbenzene is stacked, the following methylation reaction solely results in the formation of tetramethylbenzene, which is not an MTO activated species in ZSM-22 and more bulky polymethylbenzene further blocks the channel more seriously. When it comes to the olefin-based cycle, olefins can diffuse freely inside these two zeolites with methoxide intermediates bound to the zeolite frameworks, which thus facilitates formation of longer-chain olefin through olefin methylation reaction in these two zeolite catalysts. The combination of the higher reaction activity (from DFT calculation) and the longer contact time (from MD simulation) between the olefin and methoxide is apparently illustrated as the olefin-based cycle does more preferentially occur inside ZSM-22 than inside ZSM-12. Apparently, the MTO reaction mechanism is strongly determined by the diffusion behaviors of reaction species inside the zeolite confined pores.
WOS关键词	METHANOL-TO-HYDROCARBONS ; MOLECULAR-DYNAMICS SIMULATIONS ; SHAPE SELECTIVITY ; CATALYTIC PERFORMANCE ; PRODUCT SELECTIVITY ; RESONANT DIFFUSION ; OLEFIN CONVERSION ; ACIDIC H-ZSM-22 ; CO-REACTION ; PORE
WOS研究方向	Chemistry ; Science & Technology - Other Topics ; Materials Science
语种	英语
WOS记录号	WOS:000413617900030
资助机构	National Natural Science Foundation of China(91645112 ; National Natural Science Foundation of China(91645112 ; Natural Science Foundation of Hubei Province of China(2014CFA043) ; Natural Science Foundation of Hubei Province of China(2014CFA043) ; CAS(QYZDB-SSW-SLH026) ; CAS(QYZDB-SSW-SLH026) ; 21522310 ; 21522310 ; 21473244) ; 21473244) ; National Natural Science Foundation of China(91645112 ; National Natural Science Foundation of China(91645112 ; Natural Science Foundation of Hubei Province of China(2014CFA043) ; Natural Science Foundation of Hubei Province of China(2014CFA043) ; CAS(QYZDB-SSW-SLH026) ; CAS(QYZDB-SSW-SLH026) ; 21522310 ; 21522310 ; 21473244) ; 21473244)
内容类型	期刊论文
源URL	[http://ir.wipm.ac.cn/handle/112942/11529]
专题	武汉物理与数学研究所_磁共振应用研究部
作者单位	1.Chinese Acad Sci, Wuhan Inst Phys & Math, Natl Ctr Magnet Resonance Wuhan, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Hubei, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Huang, Ling,Li, Guangchao,Chu, Yueying,et al. Diffusion Dependence of the Dual-Cycle Mechanism for MTO Reaction Inside ZSM-12 and ZSM-22 Zeolites[J]. JOURNAL OF PHYSICAL CHEMISTRY C,2017,121(41):22872-22882.
APA	Huang, Ling.,Li, Guangchao.,Chu, Yueying.,Liu, Zhigiang.,Yi, Xianfeng.,...&Tang, Xiaomin.(2017).Diffusion Dependence of the Dual-Cycle Mechanism for MTO Reaction Inside ZSM-12 and ZSM-22 Zeolites.JOURNAL OF PHYSICAL CHEMISTRY C,121(41),22872-22882.
MLA	Huang, Ling,et al."Diffusion Dependence of the Dual-Cycle Mechanism for MTO Reaction Inside ZSM-12 and ZSM-22 Zeolites".JOURNAL OF PHYSICAL CHEMISTRY C 121.41(2017):22872-22882.