Surface Tension of Binary Mixtures of 1-Alkyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquids: Experimental Measurements and Soft-SAFT Modeling
authors Oliveira, MB; Dominguez-Perez, M; Freire, MG; Llovell, F; Cabeza, O; Lopes-da-Silva, JA; Vega, LF; Coutinho, JAP
nationality International
journal JOURNAL OF PHYSICAL CHEMISTRY B
keywords EQUATION-OF-STATE; DIRECTIONAL ATTRACTIVE FORCES; LENNARD-JONES CHAINS; PHASE-EQUILIBRIA; COMMON ION; TEMPERATURE; SIMULATION; BEHAVIOR; ANION; INTERFACES
abstract Ionic liquids have attracted a large amount of interest in the past few years. One approach to better understand their peculiar nature and characteristics is through the analysis of their surface properties. Some research has provided novel information on the organization of pure ionic liquids at the vapor-liquid interface; yet, a systematic study on the surface properties of mixtures of ionic liquids and their organization at the surface has not previously been carried out in the literature. This work reports, for the first time, a comprehensive analysis of the surface organization of mixtures of ionic liquids constituted by 1-alkyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ionic liquids, [C(n)mim]-[NTf2]. The surface tension of mixtures composed of [C(4)mim][NTf2] + [C(n)mim][NTf2] (n = 1, 2, 5, 6, 8, and 10) was experimentally determined, at 298.2 K and atmospheric pressure, in the whole composition range. From the experimental data, the surface tension deviations and the relative Gibbs adsorption isotherms were estimated showing how the surface composition of an ionic liquid mixture differs from that of the liquid bulk and that the surface is enriched by the ionic liquid with the longest alkyl chain length. Finally, the soft-SAFT equation of state coupled with the density gradient theory (DGT) was used, for the first time, to successfully reproduce the surface tension experimental data of binary mixtures of ionic liquids using a molecular-based approach. In addition, the DGT was used to compute the density profiles of the two components across the interface, confirming the experimental results for the components distribution at the bulk and at the vapor liquid interface.
publisher AMER CHEMICAL SOC
issn 1520-6106
year published 2012
volume 116
issue 40
beginning page 12133
ending page 12141
digital object identifier (doi) 10.1021/jp3059905
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000309648900008
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journal analysis (jcr 2017):
journal impact factor 3.146
5 year journal impact factor 3.101
category normalized journal impact factor percentile 60.204
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