Excess chemical potential of thiophene in [C4MIM] [BF4, Cl, Br, CH3COO] ionic liquids, determined by molecular simulations

Abstract

The excess chemical potential of thiophene in imidazolium-based ionic liquids [C₄mim][BF₄], [C₄mim][Cl], [C₄mim][Br], and [C₄mim][CH₃COO] were determined by means of molecular dynamics in conjunction with free energy perturbation techniques employing non-polarizable force fields at 300 K and 343.15 K. In addition, energetic and structural analysis were performed such as: interaction energies, averaged noncovalent interactions, radial, and combined distribution functions. The results from this work revealed that the ionic liquids (ILs) presenting the most favorable excess chemical potentials ([C₄mim][BF₄], [C₄mim][CH₃COO]) are associated with the strongest energetic interaction between the thiophene molecule and the ionic liquid anion, and with the weakest energetic interaction between the thiophene molecule and the ionic liquid cation.