This study explores the synthesis and characterization of deep eutectic solvents (DES) for efficient CO2 capture, focusing on the hydrogen bonding strength between hydrogen bond acceptors (HBA) and donors (HBD). Tetraethylenepentamine (TEPA) was quaternized with hydrochloric acid (HCl) to produce HBAs, which were then combined with various HBDs, including monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), ethylenediamine (EDA), triethylenetetramine (TETA), and TEPA. The DES were synthesized and their structures confirmed using FT-IR for functional group analysis and DSC for thermal behavior assessment. The molecular structure of DES was further elucidated through 2D 1H/1H NOESY, revealing significant effects of the HBA accepting site on physicochemical properties. Our results indicate that DES exhibit two distinct behaviors when water is used as an additive, creating additional voids during semicrystalline transitions and enhancing CO2 absorption efficiency. DES composed of MEA and EDA demonstrated superior absorption performance due to their lower viscosity. Polyamine-based DES showed increased CO2 capacity per mole of DES but reduced efficiency per mole of amine, attributed to increased viscosity from carboxylate formation. This research provides a detailed analysis of the hydrogen-bond network within DES and its impact on CO2 absorption. By optimizing the selection of HBA and HBD, we developed low-viscosity DES, suitable for applications in porous material impregnation, membrane impregnation, and porous liquids. This study provides new insights into the role of free volume and hydrogen bonding in enhancing gas diffusivity and reaction kinetics. The findings contribute significantly to the development of advanced DES for industrial applications, offering a promising solution for mitigating greenhouse gas emissions and promoting a sustainable, low-carbon future.

中文翻译：

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用于高性能 CO2 捕集的季铵化聚胺基低共熔溶剂的吸收特性和流变特性


本研究探索了用于有效捕获二氧化碳的低共熔溶剂 (DES) 的合成和表征，重点关注氢键受体 (HBA) 和供体 (HBD) 之间的氢键强度。四乙烯五胺（TEPA）与盐酸（HCl）季铵化生成 HBA，然后与各种 HBD 结合，包括单乙醇胺（MEA）、二乙醇胺（DEA）、N-甲基二乙醇胺（MDEA）、乙二胺（EDA）、三乙烯四胺（TETA） ）和 TEPA。合成了 DES，并使用 FT-IR 进行官能团分析和 DSC 进行热行为评估来确认其结构。通过2D 1H/1H NOESY进一步阐明了DES的分子结构，揭示了HBA接受位点对理化性质的显着影响。我们的结果表明，当使用水作为添加剂时，DES 表现出两种不同的行为，在半晶态转变过程中产生额外的空隙并提高 CO2 吸收效率。由 MEA 和 EDA 组成的 DES 由于其较低的粘度而表现出优异的吸收性能。基于聚胺的 DES 显示出每摩尔 DES 的 CO2 容量增加，但每摩尔胺的效率降低，这归因于羧酸盐形成导致的粘度增加。这项研究详细分析了 DES 内的氢键网络及其对 CO2 吸收的影响。通过优化HBA和HBD的选择，我们开发了低粘度DES，适用于多孔材料浸渍、膜浸渍和多孔液体的应用。这项研究为自由体积和氢键在增强气体扩散率和反应动力学中的作用提供了新的见解。 这些发现对工业应用的先进 DES 的开发做出了重大贡献，为减少温室气体排放和促进可持续的低碳未来提供了一种有前景的解决方案。