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 [C 3 C 1 pyr][NTf 2 ]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (short name is [C 4 C 1 pyr][NTf 2 ]) 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 ( C P ) and density ( ρ ) data were used to calculate thermal diffusivity ( a ) of the ILs using well-known thermodynamic relation a = λ / ρ C P .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).