Thermal conductivity and thermal diffusivity of Pyrrolidinium-BasedIonic liquids at atmospheric pressure

Abstract

The thermal conductivity of two pyrrolidinium-based ionic liquids (ILs) 1-propyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (short name is [C3C1pyr][NTf2]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (short name is [C4C1pyr][NTf2]) have been measured over the temperature range from (279–438) K at atmospheric pressure. Measurements were made using the steady-state hot-wire technique. The combined expanded uncertainty of the temperature and thermal conductivity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.02 K and 3.2%, respectively.The measured thermal conductivities (λ) together with our previously reported heat capacity (CP) and density (ρ) data were used to calculate thermal diffusivity (a) of the ILs using well-known thermodynamic relation a=λ/ρCP.The new measured values of the thermal conductivity have been also used to check the reliability and accuracy of the various predictive methods (generalized model, group contribution method).