Influence of the structure of the cation of ionic liquids on the vapor pressure and osmotic coefficients in their binary mixtures with 1-propanol

Abstract

The osmotic and activity coefficients and vapor pressures of binary mixtures containing the alcohol 1-propanol and the ionic liquids 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, C2MpyNTf2, 1-propyl-3- methylpyridinium bis(trifluoromethylsulfonyl)imide, C3MpyNTf2, 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, C4MpyNTf2 and 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, C4MpyrNTf2 were determined at T = 323.15 K using the vapor pressure osmometry technique. The experimental osmotic coefficients were correlated using the Extended Pitzer model of Archer obtaining standard deviations lower than 0.060. The mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures were calculated from the parameters of the Extended Pitzer model of Archer. From the experimental determination, the influence of the alkyl-side chain of the cation and of the cation itself on the osmotic and activity coefficients and on the vapor pressures can be analyzed