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Insight into Three‐Coordinate Aluminum Species on Ethanol‐to‐Olefin Conversion over ZSM‐5 Zeolites
Author(s) -
Wang Zichun,
O'Dell Luke A.,
Zeng Xin,
Liu Can,
Zhao Shufang,
Zhang Wenwen,
Gaborieau Marianne,
Jiang Yijiao,
Huang Jun
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201910987
Subject(s) - dehydration , chemistry , ethylene , brønsted–lowry acid–base theory , lewis acids and bases , catalysis , olefin fiber , ethanol , zeolite , zsm 5 , organic chemistry , biochemistry
Commercial bioethanol can be readily converted into ethylene by a dehydration process using solid acids, such as Brønsted acidic H‐ZSM‐5 zeolites, and thus, it is an ideal candidate to replace petroleum and coal for the sustainable production of ethylene. Now, strong Lewis acidic extra‐framework three‐coordinate Al 3+ species were introduced into H‐ZSM‐5 zeolites to improve their catalytic activity. Remarkably, Al 3+ species working with Brønsted acid sites can accelerate ethanol dehydration at a much lower reaction temperature and shorten the unsteady‐state period within 1–2 h, compared to >9 h for those without Al 3+ species, which can significantly enhance the ethanol dehydration efficiency and reduce the cost. The reaction mechanism, studied by solid‐state NMR, shows that strong Lewis acidic EFAl‐Al 3+ species can collaborate with Brønsted acid sites and promote ethanol dehydration either directly or indirectly via an aromatics‐based cycle to produce ethylene.