Densities, viscosities and derived thermophysical properties of water-saturated imidazolium-based ionic liquids
authors Martins, MAR; Neves, CMSS; Kurnia, KA; Carvalho, PJ; Rocha, MAA; Santos, LMNBF; Pinho, SP; Freire, MG
nationality International
journal FLUID PHASE EQUILIBRIA
author keywords Ionic liquids; Water; Imidazolium; Bis(trifluoromethylsulfonyl)imide; Density; Viscosity
keywords MUTUAL SOLUBILITIES; CATION SYMMETRY; AQUEOUS-SOLUTIONS; SURFACE-TENSION; MIXTURES; TEMPERATURE; IMPACT; PURE; DEPENDENCE; SALTS
abstract In order to evaluate the impact of the alkyl side chain length and symmetry of the cation on the thermophysical properties of water-saturated ionic liquids (ILs), densities and viscosities as a function of temperature were measured at atmospheric pressure and in the (298.15-363.15) K temperature range, for systems containing two series of bis(trifluoromethylsulfonyl)imide-based compounds: the symmetric [C(n)C(n)im][NTf2] (with n = 1-8 and 10) and asymmetric [C(n)C(1)im][NTf2] (with n= 2-5, 7, 9 and 11) ILs. For water-saturated ILs, the density decreases with the increase of the alkyl side chain length while the viscosity increases with the size of the aliphatic tails. The saturation water solubility in each IL was further estimated with a reasonable agreement based on the densities of water-saturated ILs, further confirming that, for the ILs investigated, the volumetric mixing properties of ILs and water follow a near ideal behavior. The water-saturated symmetric ILs generally present lower densities and viscosities than their asymmetric counterparts. From the experimental data, the isobaric thermal expansion coefficient and energy barrier were also estimated. A close correlation between the difference in the energy barrier values between the water-saturated and pure ILs and the water content in each IL was found, supporting that the decrease in the viscosity of ILs in presence of water is directly related with the decrease of the energy barrier. (C) 2015 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 0378-3812
year published 2016
volume 407
beginning page 188
ending page 196
digital object identifier (doi) 10.1016/j.fluid.2015.05.023
web of science category Thermodynamics; Chemistry, Physical; Engineering, Chemical
subject category Thermodynamics; Chemistry; Engineering
unique article identifier WOS:000364894600017
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journal impact factor (jcr 2016): 2.473
5 year journal impact factor (jcr 2016): 2.499
category normalized journal impact factor percentile (jcr 2016): 64.949
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