Studies on enthalpy of solution for ionic liquid: The system of 1-methyl-3-ethylimidazolium tetrafluoroborate (EMIBF4)

The molar solution enthalpies of ionic liquids (IL) EMIBF4 (1-methyl-3-ethylimidazolium tetrafluoroborate), EMIC (1-methyl-3-ethylimidazo-lium chloride) and ionic solid NaBF4 at various molalities were determined by the solution-reaction isoperibol calorimeter in water at 298.15 K. In terms of a Debye–Hückel limiting term, the molar solution enthalpies of EMIBF4, EMIC and NaBF4 at infinite dilution, ΔsHm°, were obtained. Then the values of apparent relative molar enthalpy were calculated. Hydration heat of both cation EMI+ and anion BF4− was discussed. In terms of values of ΔsHm°, the reaction heat of NaBF4 + EMIC → EMIBF4 + NaCl was estimated.