Estimation of physico-chemical properties of ionic liquid [C7mim][BF4]

Ionic liquid (IL) [C7mim][BF4] (1-heptyl-3-methyl-imidazolium tetrafluoroborate) was prepared and characterized. The density and surface tension of the IL were determined in the temperature range of 293.15–343.15 K. In terms of Glasserʹs theory, the standard molar entropy and lattice energy of the IL were estimated. Using Kaboʹs method, the molar enthalpy of vaporization of the IL, ΔlgHm0 (298 K), was estimated. According to the interstice model, the thermal expansion coefficient of IL, α, was calculated and in comparison with experimental value, they are within one order of magnitude.