Ionic liquids with anions based on fluorosulfonyl derivatives: from asymmetrical substitutions to a consistent force field model
Authors
A. S. L. Gouveia, C. E. S. Bernardes, L. C. Tome, E. Lozinskaya, Y. Vygodskii, A. S. Shaplov, J. N. Canongia Lopes, and I. M. Marrucho
Reference
Physical Chemistry Chemical Physics, vol. 19, no. 43, pp. 29617-29624, 2017
Description
Seven anions including four imide-based, namely bis[(trifluoromethyl)sulfonyl]imide (TFSI), bis(fluorosulfonyl)imide (FSI), bis[(pentafluoroethyl)sulfonyl]imide (BETI), 2,2,2-trifluoromethylsulfonyl-N-cyanoamide (TFSAM) and 2,2,2-trifluoro-N-(trifluoromethylsulfonyl) acetamide (TSAC), and two sulfonate anions, trifluoromethanesulfonate (triflate, TF) and nonafluorobutanesulfonate (NF), have been considered and compared in this work. The volumetric mass density and dynamic viscosity of five ionic liquids containing those anions combined with the commonly used 1-ethyl-3-methylimidazolium cation (C2C1im) —[C2C1im][FSI], [C2C1im][BETI], [C2C1im][TFSAM], [C2C1im][TSAC] and [C2C1im][NF]— were measured in the temperature range 293.15 ≤ T/K ≤ 353.15 and at atmospheric pressure. The results show that [C2mim][FSI] and [C2mim][TFSAM] exhibit the lowest densities and viscosities among all studied ionic liquids. The experimental volumetric data was used to validate a more consistent re-parameterization of the CL&P force field, to be used in MD simulations of ionic liquids containing ubiquitous bis[(trifluoromethyl)sulfonyl]imide and trifluoromethanesulfonate anions and to extend the application of the model to other molten salts with similar ions.
