Morpholinium and piperidinium based ionic liquids: Vaporization thermodynamics

Abstract

Ionic liquids (ILs) have gained increasing attention in a wide range of material synthesis related applications. For the first time, vapor pressures and vaporization enthalpies of four morpholinim based ILs with a common bis(trifluoromethylsulfonyl)imide ([NTf2]−) or trifluorotris(perfluoroethyl)phosphate ([FAP]−) anions were measured using a Quartz Crystal Microbalance (QCM). The enthalpies of vaporization measured at elevated temperatures have been adjusted to the reference temperature 298 K. The experimental vaporization enthalpies were compared with theoretical values available in the literature, as well as with empirical values derived from a gas-liquid-chromatographic method based on activity coefficients at infinite dilution. New experimental vaporization enthalpies were tested for consistency with help of structure property-relationships.