The solubilities of carbon dioxide (CO₂) in three low-viscous ionic liquids (ILs)—1-ethyl-3-methylimidazolium thiocyanate ([emim][SCN]), 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), and 1-ethyl-3-methylimidazolium tricyanomethanide ([emim][TCM])—were determined by volumetric method at the temperature range of (298.0 to 373.2) K and pressure range of (0 to 300.0) kPa, which are relevant to the capture of CO₂ from flue gas and natural gas. The Henry’s law constants and partial molar volume at infinite dilution of CO₂ in the three ILs were calculated by fitting the solubility data with the Krichevsky–Kasarnovsky (K-K) model. The absorption enthalpies, Gibbs free energy changes, and absorption entropies of CO₂ in the three ILs were also calculated based on the dependence of Henry’s constants on temperature. DFT calculations were further performed to better understand the interaction of ILs with CO₂ on the molecular level and provide theoretical basis for the different CO₂ solubilities in the three ILs.

中文翻译：

---

二氧化碳在（298.2至373.2）K和（0至300.0）kPa下的溶解度

二氧化碳（CO ₂）在三种低粘度离子液体（ILs）中的溶解度：1-乙基-3-甲基咪唑硫氰酸盐（[emim] [SCN]），1-乙基-3-甲基咪唑鎓二氰胺（[emim] [ DCA]）和1-乙基-3-甲基咪唑鎓三氰胺（[emim] [TCM]）—是通过体积法在（298.0至373.2）K的温度范围和（0至300.0）kPa的压力范围内测定的。与从烟道气和天然气中捕获CO ₂有关。通过用Krichevsky-Kasarnovsky（KK）模型拟合溶解度数据，计算出三个IL中无限稀释的CO ₂的亨利定律常数和部分摩尔体积。吸收焓，吉布斯自由能变化和CO _2的吸收熵还根据亨利常数对温度的依赖性来计算三个IL中的。进一步进行了DFT计算，以更好地理解IL与CO ₂在分子水平上的相互作用，并为三种IL中不同的CO ₂溶解度提供了理论基础。