Methylcyclopentenyl cation mediated reaction route in methanol-to-olefins reaction over H-RUB-50 with small cavity  

作　　者：Wenna Zhang Shutao Xu Yuchun Zhi Yingxu Wei Zhongmin Liu 

机构地区：[1]National Engineering Laboratory for Methanol to Olefins,State Energy Low Carbon Catalysis and Engineering R&D Center,Dalian National Laboratory for Clean Energy,iChEM(Collaborative Innovation Center of Chemistry for Energy Materials),Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,Liaoning,China [2]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Journal of Energy Chemistry》2020年第6期25-30,I0002,共7页能源化学（英文版）

基　　金：the financial support from the National Natural Science Foundation of China(Nos.91745109,21703239 and 21972142);the Key Research Program of Frontier Sciences,CAS,Grant No.QYZDY-SSW-JSC024;the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2014165);the International Partnership Program of Chinese Academy of Sciences,Grant No.121421KYSB20180007;Liaoning Revitalization Talents Program(XLYC1807227)。

摘　　要：Methylcyclopentenyl cations(MCP+)have been regarded as active intermediates during methanol conversion,however,their function mode in the reaction are still uncertain.In our recent report,trimethylcyclopentenyl cation(triMCP+)and its deprotonated counterpart(trimethylcyclopentadiene,tri MCP)were directly captured on H-RUB-50 catalyst with small cavity by the aid of in situ 13C MAS NMR spectroscopy,and their higher catalytic reactivity were clarified by 12C/13C-CH3OH isotopic switch experiment.In this contribution,an alternative route-cyclopentadienes-based cycle was applied on methanol conversion catalyzed on the H-RUB-50,in which ethene was produced with the participation of tri MCP+as critical intermediate.Then the cyclopentadienes-based cycle was predicted to be energetically favorable for ethene formation by density functional theory(DFT)calculations.The energetic comparison of paring mechanism in the aromatics-based cycle and cyclopentadienes-based cycle with the involvements of trimethylcyclopentadienyl(tri MCPdi+)and tri MCP+as the corresponding active intermediates suggests that cyclopentadienes-based cycle is a feasible route for ethene formation.Furthermore,this work highlights the importance of the steric constraint and the host-guest interaction induced by the zeolite with cavity structure in the formation of intermediates and reaction pathway.

关 键 词：Methanol to OLEFINS H-RUB-50 Methylcyclopentenyl CATION Cyclopentadienes-based cycle 

分 类 号：TQ221.2[化学工程—有机化工]