Physicochemical Characterization of Ionic Liquid Binary Mixtures Containing 1-Butyl-3-methylimidazolium as the Common Cation

Abstract

Mixing ionic liquids (as well as mixing an inorganic salt in an ionic liquid) constitutes an easy, elegant methodology to obtain new ionic materials. In this study, three ionic liquids (ILs) sharing a common cation were synthesized and mixed in nine different proportions giving rise to twentyseven binary mixtures. Specifically, 1-butyl-3-methylimidazolium nitrate, [C4C1Im][NO3], 1butyl-3-methylimidazolium chloride, [C4C1Im]Cl, and 1-butyl-3-methylimidazolium methanesulfonate, [C4C1Im][CH3SO3], were synthetized and characterized. They all share 1-butyl-3-methylimidazolium as the common, archetypal cation. None of them (or any of their binary mixtures) is liquid at the room temperature (T = 298.15 K) and two of them are only in the liquid state above temperatures of 343-353 K. Despite belonging to commonly used families of ILs, their handling and the study of their liquid properties (neat and mixtures) has become particularly difficult, mainly due to their tendency to solidify and their high viscosity (caused by hydrogenbonded networks). The main goal of this work is to evaluate the thermal, dynamic, and volumetric properties of these compounds and their mixtures, as well as the solid-liquid equilibria of their binary mixtures. Thermal properties, such as melting and glass transition temperatures were determined or calculated. Therefore, both density and viscosity have been measured, which were used for the calculation of the isobaric thermal expansion coefficient, molar volumes, excess molar volumes and viscosity deviations to linearity.

New hydrophobic deep eutectic solvent for electrochemical applications

“…Most of the time, Eq.2 can be applied to describe the temperature dependence of the viscosity in a narrow temperature range. For larger temperature range, another empirical approach the so-called Vogel-Tamman-Fulcher (VTF) relationship is commonly used to describe this temperature dependence [29]. In parallel, in order to give a better understanding of the viscous flow with a thermodynamic light, many authors rely on the Eyring's transition state theory applied to the viscosity [30].…”

Breakdown of the linear physical behavior in a solid solution of a halometallate molten salt, (dimim)[Fe(Cl1−xBrx)4] 0 ≤ x ≤ 1

“…[26] For instance, double halometallate salts containing 1-butyl-3-methyl-imidazolium (bimim), which is a common cation in several binary mixtures, usually presents very small deviations in the molar volume while large deviations are detected in the viscosity. [27] In contrast, the mixture of two chlorometallate anions based on iron and gadolinium with 1-ethyl-3-methyl-imidazolium (emim) follows an ideal behavior in the magnetic and conductivity properties. [28].…”

Viscosity of a Ternary Reciprocal System Consisting of 1-Alkylpyridinium Halides

“…This is because data below the melting point of the corresponding pure components are still scarce in the current literature. We are only aware of the recent works of Vieira et al 51 and Yambou et al 7 whose viscosity data for common-cation binary mixtures cover large composition and temperature ranges. While some ternary reciprocal mixtures have been studied, 6,28,29,52,53 there are generally not enough data to derive model parameters since viscosity data are necessary for all corresponding unary and binary common-ion subsystems.…”

“…This is because data below the melting point of the corresponding pure components are still scarce in the current literature. We are only aware of the recent works of Vieira et al and Yambou et al . whose viscosity data for common-cation binary mixtures cover large composition and temperature ranges.…”