Thermal Conductivity of 1-Alkyl-3-methylimidazolium [Tf2N] Ionic Liquids and Compressed 1,1,1,2-Tetrafluoroethane (R-134a),Journal of Chemical & Engineering Data

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Thermal Conductivity of 1-Alkyl-3-methylimidazolium [Tf2N] Ionic Liquids and Compressed 1,1,1,2-Tetrafluoroethane (R-134a)
Journal of Chemical & Engineering Data ( IF 2.0 ) Pub Date : 2022-07-26 , DOI: 10.1021/acs.jced.2c00054
Karim S. Al-Barghouti _{1,

2} , Aaron M. Scurto _{1,

2}

Affiliation

The thermal conductivities of mixtures of ionic liquids (ILs) and fluorocarbon gases are necessary for the design of a variety of engineering and separation applications. Here, a transient hot-wire technique was used to measure the liquid thermal conductivities of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm][Tf₂N]) and 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([HMIm][Tf₂N]) in vapor–liquid equilibrium with the hydrofluorocarbon gas, 1,1,1,2-tetrafluoroethane (R-134a), at (298.15, 323.15, 348.15) K for [HMIm][Tf₂N] and (298.15, 348.15, 398.15) K for [EMIm][Tf₂N] and pressures up to 28 bar. The thermal conductivity of the gas-saturated ionic liquid exhibits a very small and relatively linear decrease with increasing pressure (composition) of R-134a even to relatively high compositions (∼80% mol). Only at very high molar compositions of the gas (∼90+% mol) does the thermal conductivity significantly decrease toward that of the value of pure saturated liquid R-134a. However, no simple mixing rule of the pure component properties could correlate the trends in composition. As some potential applications require higher temperatures, the system of [EMIm][Tf₂N]/R-134a was measured at 398.15 K. Generally, a longer alkyl-chain length on the cation, such as [HMIm][Tf₂N], experiences a steeper decrease in thermal conductivity with increasing R-134a composition than with the [EMIm] cation.

中文翻译：

1-烷基-3-甲基咪唑 [Tf2N] 离子液体和压缩 1,1,1,2-四氟乙烷 (R-134a) 的热导率

离子液体 (IL) 和碳氟化合物气体混合物的热导率对于各种工程和分离应用的设计是必不可少的。在这里，使用瞬态热线技术测量 1-乙基-3-甲基咪唑鎓双(三氟甲基磺酰基)酰胺 ([EMIm][Tf ₂ N]) 和 1 - n-己基-3-甲基咪唑鎓双的液体热导率(三氟甲基磺酰基)酰胺 ([HMIm][Tf ₂ N]) 与氢氟烃气体 1,1,1,2-四氟乙烷 (R-134a) 处于汽液平衡状态，K 为 (298.15, 323.15, 348.15) [ [EMIm][Tf ₂的HMIm][Tf ₂ N] 和 (298.15, 348.15, 398.15) KN] 和高达 28 bar 的压力。气体饱和离子液体的热导率随着 R-134a 的压力（组成）的增加甚至相对较高的组成（~80% mol）表现出非常小的和相对线性的下降。只有在气体的摩尔组成非常高（~90+% mol）时，热导率才会显着降低，接近纯饱和液体 R-134a 的值。然而，纯成分属性的简单混合规则无法关联成分的趋势。由于一些潜在的应用需要更高的温度，[EMIm][Tf ₂ N]/R-134a 体系的测量温度为 398.15 K。通常，阳离子上的烷基链长度较长，例如 [HMIm][Tf ₂N]，与 [EMIm] 阳离子相比，随着 R-134a 组成的增加，热导率的下降幅度更大。

更新日期：2022-07-26

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