Binary diffusion coefficients for mixtures of ionic liquids [EMIM][N(CN)2], [EMIM][NTf2], and [HMIM][NTf2] with acetone and ethanol by dynamic light scattering (DLS).
Binary diffusion coefficients for mixtures of ionic liquids [EMIM][N(CN)2], [EMIM][NTf2], and [HMIM][NTf2] with acetone and ethanol by dynamic light scattering (DLS).
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通过动态光散射 (DLS) 计算离子液体 [EMIM][N(CN)2]、[EMIM][NTf2] 和 [HMIM][NTf2] 与丙酮和乙醇的混合物的二元扩散系数。
DOI：
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发表时间：
2013
影响因子：
3.3
通讯作者：
A. Fröba
中科院分区：
文献类型：
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作者：
M. Rausch;L. Hopf;A. Heller;A. Leipertz;A. Fröba
离子液体[EMIM][N（CN）2]二元混合物的互扩散系数（1-乙基-3-甲基咪唑鎓二氰基亚胺），[EMM][NTf 2]（1-乙基-3-甲基咪唑鎓双（三氟甲基磺酰基）酰亚胺），和[HMIM][NTf 2]（1-己基-3-甲基咪唑鎓双（三氟甲基磺酰基）酰亚胺）与丙酮和乙醇进行了研究，在依赖于组成的温度范围从283.15至323.15 K，应用动态光散射（DLS）。分析了实验参数对可达不确定度的影响，以确保在足够的测量时间内获得准确的数据。对于所有探测系统，增加二元扩散系数，发现温度升高。阴离子和阳离子的系统变化的研究离子液体，以及与文献数据的比较表明，不同的离子对所得的二元扩散系数的相当大的影响。相互扩散系数被发现是较低的混合物与乙醇比与丙酮，这可能与乙醇和离子之间形成氢键。大多数研究的IL溶剂混合物显示出随着溶剂浓度的增加而增加的二元扩散系数。然而，对于[EMIM][NTf 2]与乙醇的混合物，发现在乙醇摩尔分数范围从0.7至0.8，这可能暗示在临界分层点附近的相互扩散系数的最小值。纯离子液体的粘度被证明是没有可靠的指标，在具有相同溶剂的混合物中的相互扩散。
Mutual diffusivities for binary mixtures of the ionic liquids (ILs) [EMIM][N(CN)2] (1-ethyl-3-methylimidazolium dicyanimide), [EMIM][NTf2] (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), and [HMIM][NTf2] (1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) with acetone and ethanol were studied in dependence on composition in the temperature range from 283.15 to 323.15 K, applying dynamic light scattering (DLS). The influence of experimental parameters on the achievable uncertainties was analyzed to ensure the acquisition of accurate data in adequate measurement times. For all probed systems, increasing binary diffusion coefficients were found for increasing temperatures. The systematic variation of anion and cation of the investigated ILs as well as a comparison with the literature data demonstrates the considerable influence of different ions on the resulting binary diffusion coefficients. Mutual diffusivities were found to be lower for the mixtures with ethanol than for those with acetone, which could be related to the formation of hydrogen bonds between ethanol and the ions. Most of the investigated IL solvent mixtures show increasing binary diffusion coefficients with increasing solvent concentration. For the mixtures of [EMIM][NTf2] with ethanol, however, a minimum of the mutual diffusivities was found in the ethanol mole fraction range from 0.7 to 0.8, which may hint at the vicinity of a critical demixing point. The viscosity of the pure ILs turned out to be no reliable indicator for the mutual diffusivity in mixtures with the same solvent.