Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi110016, India.
J Phys Chem B. 2022 Sep 1;126(34):6472-6482. doi: 10.1021/acs.jpcb.2c02406. Epub 2022 Aug 17.
Because of the rising concentration of harmful greenhouse gases like methane in the atmosphere, researchers are striving for developing novel techniques for capturing these gases. Recently, neoteric liquids such as deep eutectic solvents (DESs) have emerged as an efficient means of sequestration of methane. Herein, we have performed molecular dynamics (AIMD) simulations to elucidate the solvation structure around a methane molecule dissolved in reline and ethaline DESs. We aim to elicit the structural organization of different constituents of the DESs in the vicinity of methane, particularly highlighting the key interactions that stabilize such gases in DESs. We observe quite different solvation structures of methane in the two DESs. In ethaline, chloride ions play an active role in solvating methane. Instead, in reline, chloride ions do not interact much with the methane molecule in the first solvation shell. In reline, choline cations approach the methane molecule from their hydroxyl group side, whereas urea molecules approach methane from their carbonyl oxygen as well as amide group sides. In ethaline, ethylene glycol and Cl dominate the nearest neighbor solvation structure around the methane molecule. In both the DESs, we do not observe any significant methane-DES charge transfer interactions, apart from what is present between choline cation and Cl anion.
由于大气中甲烷等有害温室气体浓度不断上升，研究人员正在努力开发新型技术来捕获这些气体。最近，新型液体如深共晶溶剂（DESs）已成为捕获甲烷的有效手段。在此，我们进行了分子动力学（AIMD）模拟，以阐明溶解在 reline 和 ethaline DESs 中的甲烷分子周围的溶剂化结构。我们旨在揭示 DESs 中甲烷附近不同成分的结构组织，特别是强调稳定 DESs 中这些气体的关键相互作用。我们观察到甲烷在这两种 DESs 中的溶剂化结构非常不同。在 ethaline 中，氯离子在溶解甲烷中起着积极的作用。相反，在 reline 中，氯离子在第一溶剂化壳层中与甲烷分子的相互作用不大。在 reline 中，胆碱阳离子从其羟基侧接近甲烷分子，而脲分子从其羰基氧和酰胺基团侧接近甲烷分子。在 ethaline 中，乙二醇和 Cl 主导着甲烷分子周围最近邻的溶剂化结构。在这两种 DESs 中，除了胆碱阳离子和 Cl 阴离子之间存在的相互作用外，我们没有观察到任何显著的甲烷-DES 电荷转移相互作用。
