Journal of the American Chemical Society p. 507 - 517 (2016)
Update date:2022-08-11
Topics:
Sun, Junming
Baylon, Rebecca A. L.
Liu, Changjun
Mei, Donghai
Martin, Kevin J.
Venkitasubramanian, Padmesh
Wang, Yong
The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Br?nsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Br?nsted acidity is also detrimental. First, secondary isobutene isomerization is favored, producing a mixture of butene isomers. Second, undesired polymerization and coke formation prevail, leading to rapid catalyst deactivation. Most importantly, both steady-state and kinetic reaction studies as well as FTIR analysis of adsorbed acetone-d6 and D2O unambiguously showed that a highly active and selective nature of balanced Lewis acid-base pairs was masked by the coexisting Br?nsted acidity in the aldolization and self-deoxygenation of acetone to isobutene. As a result, ZnxZryOz catalysts with only Lewis acid-base pairs were discovered, on which nearly a theoretical selectivity to isobutene (~88.9%) was successfully achieved, which has never been reported before. Moreover, the absence of Br?nsted acidity in such ZnxZryOz catalysts also eliminates the side isobutene isomerization and undesired polymerization/coke reactions, resulting in the production of high purity isobutene with significantly improved catalyst stability (<2% activity loss after 200 h time-on-stream). This work not only demonstrates a balanced Lewis acid-base pair for the highly active and selective cascade ethanol-to-isobutene reaction but also sheds light on the rational design of selective and robust acid-base catalyst for C-C coupling via aldolization reaction.
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Doi:10.1021/ml300192k
(2012)Doi:10.1021/jo01344a537
(1966)Doi:10.1016/S0957-4166(02)00221-5
(2002)Doi:10.1021/ja00193a033
(1989)Doi:10.1021/jo00333a048
(1981)Doi:10.1021/ac980757x
(1999)