High pressure density of tricyanomethanide-based ionic liquids: Experimental and PC-SAFT modelling

Abstract

Tricyanomethanide-based ionic liquids (ILs) are, probably, the most interesting ILs for separation purposes considering their low viscosity and high thermal stability, but mainly due to their enhanced performance in a wide number of applications. However, the scarce high pressure density data (ρpT) limits the development of robust models for process simulation implementation and consequently process development. In this work, high pressure density data of 1-ethyl-3-methylimidazolium tricyanomethanide ([C2C1im][TCM]) and 1-butyl-4-methylpyridinium tricyanomethanide ([4-C4C1py][TCM]) are reported in a wide range of temperature (283–363) K and pressure (0.1–95) MPa. The new ρpT data and its derivative properties, namely isothermal compressibility (kT) and isobaric thermal expansivity (αP), of the studied ILs and that reported for the 1-butyl-3-methylimidazolium tricyanomethanide ([C4C1im][TCM]), were successfully modelled using the Perturbed-Chain Statistical Association Fluid Theory (PC-SAFT). New molecular parameters for the tricyanomethanide-based ILs are here proposed allowing a good description of the studied properties while assessing the well-known non-volatile character of the ILs.