Activity and osmotic coefficients of binary mixtures of NTf2- ionic liquids with a primary alcohol

Abstract

The osmotic and activity coefficients of mixtures containing the primary alcohol 1-propanol and an equimolar mixture of two ionic liquids have been determined using the vapor pressure osmometry technique (VPO). The equimolar mixture of ionic liquids are formed by 1-alkyl-3-methylimidazolium and/or 1-alkyl-3-methylpyridinium-based ionic liquids with bis(trifluoromethylsulfonyl)imide as anion. The results obtained are compared with the behavior of the systems containing the same alcohol and the pure ionic liquids from the binary mixture of ionic liquids in order to analyze the effect that mixing two ionic liquids can have on the osmotic and activity coefficients and vapor depression of the solvent. The Pitzer model for mixed electrolytes has been applied to represent the experimental data, obtaining standard relative deviations from the experimental osmotic coefficients lower than 0.062.