Influence of 1-alkyl-3-methylimidazolium based ionic liquids on the thermodynamic and transport properties of L(+)-lactic acid in aqueous solutions of polyethylene glycol

In this study, effect of some ionic liquids on the thermodynamic and transport properties of L(+)-lactic acid in aqueous polyethylene glycol solutions have been investigated. Density, speed of sound and viscosity of L(+)-lactic acid in the aqueous solutions of polyethylene glycol, (polyethylene glycol + 1-hexyl-3-methylimidazolium bromide) and (polyethylene glycol + 1-octyl-3-methylimidazolium bromide) were measured at temperatures 288.15-318.15 K. Apparent molar volumes, transfer apparent molar volume, apparent molar isentropic compressibility and viscosity B-coefficient of L(+)-lactic acid were calculated by using experimental data and were discussed in terms of solute-solute and solute-solvent interactions. The results reveal that solute-solvent interactions were decreased by increasing concentration of ionic liquid, length of alkyl group of ionic liquid and temperature.