The isobaric heat capacities and thermodynamic properties of ionic liquid 1-ethylpyridinium bis(trifluoromethylsulfonyl)imide

Ionic liquid 1-ethylpyridinium bis(trifluoromethylsulfonyl)imide ([C(2)py][NTf2]) was synthesized and characterized by H-1 NMR spectroscopy, C-13 NMR spectroscopy and thermal gravity analysis. The molar heat capacities of [C(2)py][NTf2] were measured using a heat-flow calorimeter with "3D Calvet" calorimetric sensor from (293 to 312) K. The experiment value of molar heat capacity 502.15 J K-1 mol(-1) at 298.15 K was obtained. Moreover, the estimation values of molar heat capacity were calculated by using 4 methods at 298.15 K, and the result showed the Paulechka et al.'s method was more appropriate for predicting the molar heat capacity of IL [C(2)py][NTf2], and the error was less than 2%. In addition, the freezing point T (*) was calculated by freezing point depression, which was approximately equal to experimental value 305.08 K. The molar enthalpy of fusion Delta(f) H (m) = 26.77 kJ mol(-1), molar melting entropy Delta(de) S (m) = 90.60 J mol(-1) K-1 and the freezing constant K (f) were also calculated.