Influence of Hydration on the Structure of Reline Deep Eutectic Solvent: A Molecular Dynamics Study
Influence of Hydration on the Structure of Reline Deep Eutectic Solvent: A Molecular Dynamics Study
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DOI：
10.1021/acsomega.8b02447
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发表时间：
2018-11-01
期刊：
影响因子：
4.1
通讯作者：
Kashyap, Hemant K.
中科院分区：
文献类型：
--
作者：
Kumari, Pratibha;Shobhna;Kashyap, Hemant K.
本文采用全原子分子动力学模拟方法，研究了水的质量分数从3.4%到58.1wt%不同水化程度时，水对RELINE深共晶溶剂分子能级排列的影响，并补充了最近测量的中子散射实验数据。这项研究特别重要，因为水是作为第二个氢键供体/受体引入RELINE中的，其中结构主要由氢键和静电相互作用决定。我们分析了模拟的X射线散射结构函数、它们的部分成分和氢键相互作用，以了解水对重水-水混合物中各种分子间相互作用的影响。观察到，在较低的水化水平下，重线结构被定性地保留下来。在较高的水合水平下，大多数水分子优先溶剂化氯离子和胆碱阳离子的氨基，主要影响胆碱-胆碱、胆碱-氯和氯-氯的相互作用。研究表明，当水含量大于或等于41wt%时，随着水化程度的进一步提高，水化产物的分子排列发生了很大的变化，并开始从水化产物向水溶液转变。氢键分析表明，存在较强的氯离子-水氢键相互作用，随着混合物水化程度的增加，氢键逐渐取代氯化胆碱和氯化尿素的氢键。
In this article, we have performed an all-atom molecular dynamics simulation study to investigate the influence of water on the molecular level arrangement of reline deep eutectic solvent for different hydration levels ranging from 3.4 to 58.1 wt % of water and complemented the observations of recently measured neutron scattering experimental data. This study is particularly important because water is being introduced as a second hydrogen bond donor/acceptor in reline, wherein the structure is primarily governed by hydrogen bonding and electrostatic interactions. We have analyzed the simulated X-ray scattering structure functions, their partial components, and hydrogen bonding interactions to understand the effects of water on various intermolecular interactions in reline-water mixtures. It is observed that at lower hydration level, reline structure is qualitatively retained. At higher hydration level, most water molecules preferentially solvate chloride anions and ammonium group of choline cations mostly impacting choline-choline, choline-chloride, and chloride-chloride interactions. The present study reveals that at and above 41 wt % of water, the molecular arrangement of reline drastically changes and set to transition from reline to an aqueous solution of reline components with further increase in the hydration level. Hydrogen bond analysis reveals the presence of strong chloride-water H-bonding interaction, which gradually replaces choline-chloride and urea-chloride hydrogen bondings as the hydration level in the mixture increases.