Journal of Chemical Thermodynamics, Vol.83, 90-96, 2015
Phase equilibria study of binary systems comprising an (ionic liquid plus hydrocarbon)
In this study, the interaction of two ionic liquids with hydrocarbons has been investigated. With this aim, (solid + liquid) equilibria (SLE) and (liquid + liquid) equilibria (LLE) for binary systems of {1-methyl-1-propyl-pyrrolidinium triflate [PMPyr][CF3SO3] + heptane, or benzene, or thiophene, or benzothiophene} and {N-butyl-4-cyanopyridinium tricyanomethanide [(BCNPy)-Py-4][TCM] + heptane, or toluene, or 2-methylthiophene, or benzothiophene} were measured at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (T = 270 to 370) K. An upper critical solution temperature (UCST) was detected for all mutually immiscible systems. The immiscibility gap for [(BCNPy)-Py-4][TCM] in benzene and thiophene is larger than those for [PMPyr][CF3SO3]. Conversely, in heptane it is slightly larger for [PMPyr][CF3SO3]. The basic thermal properties of the pure ILs, i.e. melting and glass-transition temperatures as well as the enthalpy of fusion have been measured using a differential scanning microcalorimetry technique (DSC). The well-known NRTL model has been used to correlate the experimental SLE data points. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords:Pyrrolidinium and pyridinium ionic liquids;(Solid/liquid plus liquid) phase diagrams;Thermodynamics