The density and dynamic viscosity for dilute solutions of [Emim][NTf2] [Bmim][NTf2], and [Bmmim][NTf2] in ethylene glycol

Abstract

In this paper, three dilute solutions were prepared and studied for density and dynamic viscosity measurement at different temperature ranges and molality ranges. The three dilute solutions are imidazolium cation ionic liquids (ILs) and ethylene glycol (EG). The measured temperature ranges are (293.15–328.15) K for density and (298.15–328.15) K for dynamic viscosity, respectively. The molality ranges of IL in EG are (0.0100–0.5001) mol∙kg−1. The ILs cations are 1-ethyl-3-methylimidazolium, 1-buty-3-methylimidazolium, and 1-butyl-2,3-dimethylimidazolium and anion is bis[(trifluoromethyl)sulfonyl]imide. The molality concentration dependence on apparent molar volume was fitted according to the Redlich-Rosenfeld-Meyer (RRM) equation. The obtained fitted values of apparent molar volumes of infinite dilution (VΦ0/m3∙mol-1), Sv/m3∙mol-3/2∙kg1/2, and Bv/m3∙mol-2∙kg were used for analysis of ion-solvent interaction and ion-ion interaction in solution. The relative viscosities have also been calculated from the dynamic viscosities at different temperatures and substance concentrations. The relationship between the relative viscosity and substance concentration of diluted solution has been characterized by the Jones–Dole equation. The fitted parameters of D and F from the Jones-Dole equation were used for the analysis of interaction changing of solute-solute and solute-solvent. The group introduction of –CH2- (methylene) on position 1 and –CH3 (methyl) on position 2 of imidazolium cation have also been discussed for interaction changing in IL and EG solvent solution. Through the analysis of IL microstructure change, the interaction forces were also described and discussed for the studied solutions.