Is there any sense to investigate volumetric and acoustic properties of more binary mixtures containing Ionic Liquids?

• Calculations of excess quantities of binary mixtures of IL + molecular solvent.
• Analysis of excess properties for mixtures in order to find some regularities.
• Balankina’s functions as tool to systematize excesses of IL + solvent mixtures.
• Discussion of calculated absolute and relative excesses.
• Prediction of absolute and relative excesses for similar binary systems.

The excess speed of sound, excess molar volume and excess molar isentropic compressibility of 52 binary mixtures containing Ionic Liquids at T = 298.15 K were calculated using selected literature speed of sound and density data. The second components were alcohols: methanol, or ethanol, or 1-propanol, or 2-propanol, or 1-butanol or other solvents: acetone, acetonitrile, tetrahydrofuran, dichloromethane and dimethylsulfoxide. The Balankina’s relative excesses, Xbal, i.e. the ratios between excess and ideal quantities XE/Xid were also determined to reduce the structural impact of pure components to absolute excesses. Analysis of quantities determined shows some patterns for concentration dependences of large groups of mixtures; thus, the scheme for influence of anion or cation of Ionic Liquids and solvent on Balankina’s relative excesses was proposed. It seems that presented analysis provide the knowledge about absolute and relative excess quantities for other mixtures without doing the experimental work. It is also visible that analysis of excess molar quantities and Xbal parameters can support the interpretation of interactions which occur between Ionic Liquids and solvent.