Physical properties of the pure 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid and its binary mixtures with alcohols

Highlights: • Thermo-physical properties of the pure ionic liquid were experimental determined. • Physical properties of binary mixtures (alcohol + ionic liquid) were measured. • From experimental data, excess properties (VE and KS,mE) were calculated. • The excess properties were fitted using the Redlich–Kister equation. • The effect of the ions and temperature on the VE and KS,mE was also discussed. -- Abstract: In this paper, experimental densities, speeds of sound, dynamic viscosities, refractive indices and molar isobaric heat capacities of the pure 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid, [PMpyr][NTf2], are reported as a function of temperature from T = (293.15 to 343.15) K and at atmospheric pressure. From density and refractive index data, the thermal expansion coefficient, molar refractions and molar refractions for the pure ionic liquid were calculated. Besides, a thermal analysis was carried out for the pure ionic liquid using a differential scanning calorimeter. Linear equations were used to fit the density, speed of sound, refractive index and molar isobaric heat capacity data, while the viscosity data were fitted using common equations such as Arrhenius, Vogel−Fulcher−Tamman (VFT), Litovitz, and fluidity. Furthermore, experimental density, speed of sound and refractive index data for binary mixtures with alcohols and their derived properties (excess molar volume, and excess molar isentropic compression) were determined over the whole composition range from T = (298.15, 303.15 and 308.15) K. The excess properties were satisfactorily fitted by Redlich–Kister equation