Insights on [BMIM][BF4] and [BMIM][PF6] ionic liquids and their binary mixtures with acetone and acetonitrile

Abstract

The properties of ionic liquid plus acetone or acetonitrile mixtures were studied from the macro and microscopic levels by the measurement of relevant thermophysical properties and through molecular modelling studies. The liquid mixtures were considered in the whole composition range and analysed in terms of possible hydrogen bonding between the ions and ions with the molecular solvents. The reported results show how the large non-ideality of these systems stands on the high affinity of acetone and acetonitrile for the imidazolium hydrogen bond donor sites, which allow competition with the corresponding anions for these sites specially but not limited to molecular solvent rich mixtures. The reported results allow to quantify the relevance of hydrogen bonding for the properties of ionic liquid – molecular solvent mixtures, which can be fine-tuned through the amounts of cosolvent present in the mixture as a mechanism to control mixed fluids organization.