Effect of Temperature and Composition on the Transport and Thermodynamic Properties of Binary Mixtures of Ionic Liquid N-Butyl-N-methylpyrrolidinium bis(Trifluoromethanesulfonyl)imide and Propylene Carbonate

The thermodynamic and transport proprieties have been determined for the whole concentration range of N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P-14) and propylene carbonate (PC) binary mixtures in the temperature range 293.15-318.15 K. Strong effects of the mole fraction and temperature on these properties have been observed. The isobaric expansivities and excess properties have been evaluated. Their corresponding coefficients were positive but the excess volume had both negative and positive values. The viscosity parameter was found to be temperature-dependant and followed the Arrhenius law. The variation of activation energies for viscous flow E (a,eta) versus the ILs concentration exhibited a change in the medium structure. The conductivity-temperature relationship was found to have a better fitting on the Vogel-Tammann-Fulcher model than on the Arrhenius law. In addition, the variation of conductivity with the molar fraction was well described by the Casteel-Amis equation. Finally, the Walden product showed significant dependence of the conductivity on the viscosity of the medium. The results allowed good characterisation of both the ruling interactions and the medium structure.