Macroscopic and microscopic properties of solutions of aromatic compounds in an ionic liquid

Abstract

Molecular dynamics simulations of binary mixtures of benzene, 1,3,5-trifluorobenzene and hexafluorobenzene with dimethylimidazolium hexafluorophosphate were carried out to examine their macroscopic and microscopic properties. The energies and volumes of mixing of these mixtures correlate well with observed microscopic properties including coordination number about the aromatic compound. The local ordering of the ions about an aromatic molecule was found to depend on the quadrupole moment of the aromatic species and to remain qualitatively the same on varying the mole fraction of the aromatic species. Interaction energies showed the most significant interactions to be between the aromatic molecule and the ions located about its equator. These findings have implications for the practical use of ionic liquids as solvents for chemical processes.

Acknowledgments

Support from the Engineering and Physical Sciences Research Council (grant GR/M/72401) and the School of Chemical Sciences, University of New South Wales (travel funding, J.B.H.) is gratefully acknowledged, as are the ongoing useful discussions with Dr Chris Hardacre and Professor Ken Seddon (Queen's University Ionic Liquid Laboratory).