Thermodynamic and transport properties of ionic liquids, 1-alkyl-3-methylimidazolium thiocyanate in the aqueous lithium halides solutions

Abstract

Thiocyanate based ionic liquids, [RMIM][SCN], as fluorine free and low toxic were used effectively in different areas of resaerch. In this work, the thermodynamic and transport properties of aqueous solutions of the synthesized ionic liquids based on thiocyanate anion, [RMIM][SCN] (R = butyl, hexyl and octyl) have been investigated at T = (288.15–318.15) K. Also, effect of LiX (X = Cl−, Br−) salts on the investigated properties have been studied at T = 298.15 K. In this respect, density, speed of sound and viscosity of the solutions have been measured and these properties were used to calculate the apparent molar volume, Vφ, and apparent molar isentropic compressibility κφ. The properties were correlated with corresponding empirical relations to achieve standard partial molar volume, Vφ0, partial molar isentropic compressibility, κφ0, and viscosity B-coefficient. These parameters were used to analysis of the interactions between components. In order to separate Vφ0 contributions of the ILs in binary solutions, the scaled particle theory was used at T = (288.15–318.15) K. The results show that the hydrophobic hydration interactions are dominant interactions.