Mechanism of 2-Ethylhexenal Hydrogenation on Pd(111): A Density Functional Study

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• 作者：Jingjing Ji ; Liang Zhao ; Dan Wang ; Jinsen Gao ; Chunming Xu ; Huangfan Ye
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 29, 2015
• 年：2015
• 卷：119
• 期：4
• 页码：1809-1817
• 全文大小：588K
• ISSN：1932-7455

文摘

The detailed hydrogenation processes of 2-ethylhexenal on Pd(111) toward 2-ethylhexanol were investigated by density functional theory (DFT) calculations to understand the hydrogenation mechanism of 2-ethylhexenal. Several adsorption modes of 2-ethylhexenal on Pd(111) were studied. The adsorption of cis-conformers on the Pd(111) surface was found to be more stable than the trans-conformers; however, cis-isomers are less stable in the gas phase. Both E-畏₃-trans and E-畏₄-trans modes were used to probe the hydrogenation of 2-ethylhexenal, although the former plays a primary role in hydrogenation reactions. Several plausible reaction pathways were calculated. For E-畏₃-trans mode, C3 鈫?C2 鈫?O 鈫?C1, C3 鈫?C2 鈫?C1 鈫?O, C2 鈫?C3 鈫?O 鈫?C1, and C2 鈫?C3 鈫?C1 鈫?O routes are feasible to produce saturated alcohol. However, for the E-畏₄-trans mode, the formation of the 2-ethylhexanal intermediate, which is a saturated aldehyde, appeared to be easy through both C2 鈫?C3 and C3 鈫?C2 pathways because of low active barriers. Only 2-ethylhexanal generated via the C3 鈫?C2 route was presumed to be available to generate 2-ethylhexanol on E-畏₄-trans mode. In general, the consecutive hydrogenation reaction of 2-ethylhexenal to 2-ethylhexanal and then to 2-ethylhexanol on the Pd(111) surface determines the whole reaction process and even becomes the rate-limiting step.