Activity Coefficients of [Cnmim]Br (n = 3 to 8) Ionic Liquids in Aqueous Fructose Solution at T = 298.15 K

Activity coefficients of the 1-alkyl-3-methylimidazolium bromide [Cnmim]Br (n = 3 to 8) ionic liquids (ILs) in fructose + water mixed solvents at 298.15 K were determined by cell potential measurements. The molalities of [Cnmim]Br ranged from (0.005 to 0.1) mol·kg–1 and those of fructose from (0.2 to 0.8) mol·kg–1. Gibbs free energy interaction parameters were also obtained together with salt constants. The interactions between [Cnmim]Br and fructose are mainly controlled by electrostatic interactions. Gibbs free energy interaction parameters (gES) and salting constants (kS) are negative for the ILs (n = 3 to 6), indicating fructose are salted-in by the ILs in water, whereas fructose are salted-out by the ILs (n = 7 and 8).