title: Non-ideal mixing behaviour of hydrogen bonding in mixtures of protic ionic liquids.
abstract: Ionic liquids (ILs) attract interest in science and technology as a result of their unique properties. Binary and ternary mixtures of ILs significantly increase the number of possible cation/anion combinations, resulting in targeted physical and chemical properties. In this work, we study the mixing behaviour of two protic ILs: triethyl ammonium methylsulfonate [Et3 NH][CH3 SO3 ] and triethylammonium triflate [Et3 NH][CF3 SO3 ]. We find a characteristic deviation from ideal mixing by means of low-frequency infrared spectroscopy. By using molecular dynamics simulations, we explain this behaviour as being the result of different strengths of anion/cation hydrogen bonding. This non-ideality of non-random H-bond mixing is also reflected in macroscopic properties such as the viscosity. Mixing suitable ILs may, thus, result in new ILs with targeted physical properties.
authors.affiliation: Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 1, 18059, Rostock (Germany), Tel: (+49) 381-498-6517.
authors.forename: Koichi
authors.initials: K
authors.lastname: Fumino
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Bonsa
authors.forename: Benjamin
authors.initials: B
authors.lastname: Golub
authors.forename: Dietmar
authors.initials: D
authors.lastname: Paschek
authors.forename: Ralf
authors.initials: R
authors.lastname: Ludwig
keywords: IR spectroscopy; ionic liquids; mixing behaviour; molecular dynamics; solvation chemistry