Activity and Osmotic Coefficients of Binary Mixtures of NTf2- Ionic Liquids with a Primary Alcohol

Abstract

The vapor pressure osmometry technique (VPO) was used in this study to determine the osmotic and activity coefficients of several mixtures which contain 1-propanol and an equimolar mixture of two ionic liquids at T = 323.15 K. The equimolar mixture of ionic liquids is formed by 1-alkyl-3-methylimidazolium and/or 1-alkyl-3-methylpyridinium-based ionic liquids with bis(trilluoromethylsulfonyl)imide as anion. A comparison between the results obtained in this work and those for mixtures with the same alcohol and the corresponding pure ionic liquids forming the equimolar mixture was carried out so the effect that mixing two ionic liquids can have on the osmotic and activity coefficients and vapor depression of the solvent can be analyzed. The Pitzer model for mixed electrolytes has been applied to represent the experimental data, and the standard relative deviations obtained between the calculated and experimental osmotic coefficients were found to be less than 0.075.