The peculiar nature of molecular interactions between an imidazolium ionic liquid and acetone.

We present novel insights into the molecular interactions between polar solvents and imidazolium ionic liquids using the example of 1-ethyl-3-methylimidazolium ethyl sulfate and acetone. Recently published volumetric property data of this particular system have revealed peculiarities which could not be fully explained by steric effects. In order to shed light on the behavior at a molecular level, we apply IR spectroscopy and analyze solvent-induced line shifts as well as the excess IR spectra.