High-Pressure Densities of 2,2,2-Trifluoroethanol + Ionic Liquid Mixtures Useful for Possible Applications in Absorption Cycles

Abstract

2,2,2-Trifluoroethanol (TFE) + ionic liquids constitute new possible refrigerant/absorbent pairs in refrigeration and heat absorption systems. In this work, volumetric data were measured on these systems in order to estimate their potential as alternatives to the commonly used fluids. Original high-pressure (up to 40 MPa) density data of mixtures 2,2,2-trifluoroethanol (TFE) + 1-methyl-3-ethylimidazolium tetrafluoroborate, [EMIm][BF4], or 1-methyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, [BMIm][NTf2], have been measured in the temperature ranges 293.15–333.15 K and 283.15–333.15 K, respectively. Mixtures with [BMIm][NTf2] present higher densities and thus are more adequate for refrigeration systems. Excess molar volumes, VmE, and derived properties (isothermal compressibility, κT, and thermal expansion, αp) were calculated from experimental density data fitted to the Tait equation. αp and κT of the pure ionic liquids are smaller than those of the pure alcohol. Mixtures present derived proper...