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High-Accuracy Vapor Pressure Data of the Extended [C n C1im][Ntf2] Ionic Liquid Series: Trend Changes and Structural Shifts
For the first time, two distinct trends are clearly evidenced for the enthalpies and entropies of vaporization along the [C n mim][Ntf2] ILs series. The trend shifts observed for Δl g H m o and Δl g S m o, which occur at [C6mim][Ntf2], are related to structural modifications. The thermodynamic resul...
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Published in: | The journal of physical chemistry. B 2011-09, Vol.115 (37), p.10919-10926 |
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Main Authors: | , , , , , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | For the first time, two distinct trends are clearly evidenced for the enthalpies and entropies of vaporization along the [C n mim][Ntf2] ILs series. The trend shifts observed for Δl g H m o and Δl g S m o, which occur at [C6mim][Ntf2], are related to structural modifications. The thermodynamic results reported in the present article constitute the first quantitative experimental evidence of the structural percolation phenomenon and make a significant contribution to better understanding of the relationship among cohesive energies, volatilities, and liquid structures of ionic liquids. A new Knudsen effusion apparatus, combined with a quartz crystal microbalance, was used for the high-accuracy volatility study of the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide series ([C n mim][Ntf2], where n = 2, 3, 4, 5, 6, 7, 8, 10, 12). Vapor pressures in the (450–500) K temperature range were measured, and the molar standard enthalpies, entropies, and Gibbs energies of vaporization were derived. The thermodynamic parameters of vaporization were reported, along with molecular dynamic simulations of the liquid phase structure, allowing the establishment of a link between the thermodynamic properties and the percolation phenomenon in ILs. |
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ISSN: | 1520-6106 1520-5207 |
DOI: | 10.1021/jp2049316 |