Why are aromatic compounds more soluble than aliphatic compounds in dimethylimidazolium ionic liquids? A simulation study

Molecular dynamics simulations of solutions of benzene in dimethylimidazolium chloride and dimethylimidazolium hexafluorophosphate have been performed with a view to answering the question posed in the title. The difference between the chemical potential of a normal model of benzene and one with no charges was found to depend on the solvent but is at least 4 kBT. This difference is sufficient to account for the observed solubility differences. There are substantial changes in the local structure around benzene with and without charges.