Changes in the Thermodynamic Properties of the Ionic Liquid 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)amide Upon Addition of Primary Alcohols

In this work, the thermodynamic properties of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide/primary alcohol (methanol to 1-nonanol) mixtures were studied. The densities, viscosities, and electrical conductivities of the mixtures were determined for a range of compositions up to the solubility limit of the alcohol in the ionic liquid at room temperature. From these data, excess molar volumes and viscosity deviations were calculated. The changes in the structure of the ionic liquid upon addition of the primary alcohols are discussed. We also considered the relationship between the macroscopic properties observed in the present study and the Raman spectral changes reported in our previous study. We explained the behavior of the systems at the molecular level, especially at lower alcohol concentrations, by a concept where the alcohols occupy spaces formed inside the nanoheterogeneous structure of the ionic liquid.