Abstract To get a better understanding of the effect of physicochemical properties and microstructure on SO2 absorption behavior of DESs with different molar ratios of EmimCl and EG (from 2:1 to 1:2), densities (ρ), viscosities (η), speeds of sound (u), refractive indices (nD), and thermal decomposition temperatures (Td) of EmimCl-EG DESs were measured and used to obtain the other derived properties, such as thermal expansion coefficient (αp) and activation energy for viscous flow (Eη). Moreover, FT-IR spectra and in situ variable-temperature NMR spectroscopy were employed to study the microstructures of DESs. Based on physicochemical and spectroscopic properties, the influence of the concentrations of EmimCl on the interactions in DESs was explored to be associated with their SO2 absorption behavior. The results show that the interactions between Emim+ and Cl− of EmimCl is gradually weakening with increasing the concentration of EG in DESs by forming of hydrogen bond interaction of O H⋯Cl−, resulting in a decrease of ρ, η, u, nD, and Td of DESs, and hindering the charge–transfer interaction of SO2 with Cl− and deceasing SO2 capture capacity. Moreover, the SO2 absorption capacity of DESs is proportional to their ρ and Eη, respectively.

中文翻译：

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EmimCl-EG 低共熔溶剂的理化性质和微观结构的详细研究：它们对 SO 2 吸收行为的影响

摘要 为了更好地了解不同 EmimCl 和 EG 摩尔比（从 2:1 到 1:2）、密度（ρ）、粘度（η）、速度的 DESs 的理化性质和微观结构对 SO2 吸收行为的影响。测量了 EmimCl-EG DESs 的声音 (u)、折射率 (nD) 和热分解温度 (Td)，并用于获得其他衍生属性，例如热膨胀系数 (αp) 和粘性流动的活化能（ Ｅ）。此外，FT-IR 光谱和原位变温 NMR 光谱被用来研究 DESs 的微观结构。基于物理化学和光谱特性，探索了 EmimCl 浓度对 DES 中相互作用的影响与其 SO2 吸收行为有关。结果表明，随着 DESs 中 EG 浓度的增加，通过形成 OH⋯Cl− 的氢键相互作用，EmimCl 的 Emim+ 和 Cl− 之间的相互作用逐渐减弱，导致 ρ、η、u、nD 和DESs 的 Td，阻碍 SO2 与 Cl− 的电荷转移相互作用并降低 SO2 的捕获能力。此外，DES 的 SO2 吸收能力分别与其 ρ 和 Eη 成正比。