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Elucidating the Cooperative Roles of Water and Lewis Acid–Base Pairs in Cascade C–C Coupling and Self-Deoxygenation Reactions
JACS Au ( IF 8.5 ) Pub Date : 2021-08-17 , DOI: 10.1021/jacsau.1c00218 Houqian Li 1 , Dezhou Guo 1 , Nisa Ulumuddin 1 , Nicholas R Jaegers 1, 2 , Junming Sun 1 , Bo Peng 2 , Jean-Sabin McEwen 1, 2, 3, 4, 5 , Jianzhi Hu 1, 2 , Yong Wang 1
JACS Au ( IF 8.5 ) Pub Date : 2021-08-17 , DOI: 10.1021/jacsau.1c00218 Houqian Li 1 , Dezhou Guo 1 , Nisa Ulumuddin 1 , Nicholas R Jaegers 1, 2 , Junming Sun 1 , Bo Peng 2 , Jean-Sabin McEwen 1, 2, 3, 4, 5 , Jianzhi Hu 1, 2 , Yong Wang 1
Affiliation
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Water plays pivotal roles in tailoring reaction pathways in many important reactions, including cascade C–C bond formation and oxygen elimination. Herein, a kinetic study combined with complementary analyses (DRIFTS, isotopic study, 1H solid-state magic angle spinning nuclear magnetic resonance) and density functional theory (DFT) calculations are performed to elucidate the roles of water in cascade acetone-to-isobutene reactions on a ZnxZryOz mixed metal oxide with balanced Lewis acid–base pairs. Our results reveal that the reaction follows the acetone–diacetone alcohol–isobutene pathway. Isobutene is produced through an intramolecular rearrangement of the eight-membered ring intermediate formed via the adsorption of diacetone alcohol on the Lewis acid–base pairs in the presence of cofed water. OH adspecies, formed by the dissociative adsorption of water on the catalyst surface, were found to distort diacetone alcohol’s hydroxyl functional group toward its carbonyl functional group and facilitate the intramolecular rearrangement of diacetone alcohol to form isobutene. In the absence of water, diacetone alcohol binds strongly to the Lewis acid site, e.g., at a Zr4+ site, via its carbonyl functional group, leading to its dramatic structural distortion and further dehydration reaction to form mesityl oxide as well as subsequent polymerization reactions and the formation of coke. The present results provide insights into the cooperative roles of water and Lewis acid–base pairs in catalytic upgrading of biomass to fuels and chemicals.
中文翻译：
阐明水和路易斯酸碱对在级联 C-C 偶联和自脱氧反应中的协同作用
水在许多重要反应（包括级联 C-C 键形成和氧消除）中的反应途径中起着关键作用。在此，动力学研究结合互补分析（漂移、同位素研究、1 H 固态魔角自旋核磁共振）和密度泛函理论 (DFT) 计算来阐明水在级联丙酮到异丁烯中的作用Zn x Zr y O z上的反应具有平衡路易斯酸碱对的混合金属氧化物。我们的结果表明，该反应遵循丙酮-双丙酮醇-异丁烯途径。异丁烯是通过八元环中间体的分子内重排产生的，该中间体是在共进水存在下通过双丙酮醇吸附在路易斯酸碱对上形成的。发现由水在催化剂表面解离吸附形成的 OH 物质使双丙酮醇的羟基官能团向其羰基官能团扭曲，并促进双丙酮醇的分子内重排形成异丁烯。在不存在水的情况下，双丙酮醇与路易斯酸位点紧密结合，例如在 Zr 4+ 处位点，通过其羰基官能团，导致其剧烈的结构扭曲和进一步脱水反应以形成异亚甲基氧以及随后的聚合反应和焦炭的形成。目前的结果提供了对水和路易斯酸碱对在生物质催化升级为燃料和化学品中的协同作用的见解。
更新日期：2021-09-27
中文翻译：
阐明水和路易斯酸碱对在级联 C-C 偶联和自脱氧反应中的协同作用
水在许多重要反应（包括级联 C-C 键形成和氧消除）中的反应途径中起着关键作用。在此，动力学研究结合互补分析（漂移、同位素研究、1 H 固态魔角自旋核磁共振）和密度泛函理论 (DFT) 计算来阐明水在级联丙酮到异丁烯中的作用Zn x Zr y O z上的反应具有平衡路易斯酸碱对的混合金属氧化物。我们的结果表明，该反应遵循丙酮-双丙酮醇-异丁烯途径。异丁烯是通过八元环中间体的分子内重排产生的，该中间体是在共进水存在下通过双丙酮醇吸附在路易斯酸碱对上形成的。发现由水在催化剂表面解离吸附形成的 OH 物质使双丙酮醇的羟基官能团向其羰基官能团扭曲，并促进双丙酮醇的分子内重排形成异丁烯。在不存在水的情况下，双丙酮醇与路易斯酸位点紧密结合，例如在 Zr 4+ 处位点，通过其羰基官能团，导致其剧烈的结构扭曲和进一步脱水反应以形成异亚甲基氧以及随后的聚合反应和焦炭的形成。目前的结果提供了对水和路易斯酸碱对在生物质催化升级为燃料和化学品中的协同作用的见解。
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