Solvation of the Ionic Liquid [C4mim][PF6] in Aqueous Ethanol Solutions from Molar Volume, Viscosity and Conductivity Measurements

Abstract Standard partial molar volumes V 2,Φ 0 , viscosity B -coefficients and molar conductivities λ m for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [C 4 mim][PF 6 ] in aqueous ethanol solutions ( x ethanol = 0.5∼0.9) have been determined from density, viscosity and conductivity measurements at 298.15 K. It is shown that values of V 2,Φ 0 decrease, while those of viscosity B -coefficients increase with increasing mole fraction of ethanol in the solvents. The molar conductivities of the ionic liquid are found to be decreased with increase of both the ionic liquid concentration and the ethanol content in the systems. Experimental results have been discussed in terms of the ionic liquid–solvent interactions and the ion associations of the ionic liquid in aqueous ethanol solutions.