title: Physicochemical properties, structure, and conformations of 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C4mim]NTf2 ionic liquid.
abstract: Thermodynamic properties of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim]NTf2) ionic liquid have been studied by adiabatic calorimetry in the temperature range of 5 to 370 K. This compound has been found to form crystal, liquid, and glass. The temperature and enthalpy of fusion for [C(4)mim]NTf(2) have been determined to be T(fus) = 270.22 +/- 0.02 K and Delta(fus)H = 23.78 +/- 0.04 kJ.mol(-1), respectively. The heat capacity of crystalline [C(4)mim]NTf(2) in the T range of 205 to 255 K may vary by a few percent, subject to the procedure of the crystal preparation. The glass transition temperature for [C(4)mim]NTf(2) has been found to be T(g) = 181.5 +/- 0.1 K. On the basis of the results of DFT quantum chemical calculations, the experimental vibrational spectra, and the available literature data, thermodynamic properties of [C(4)mim]NTf(2) in the ideal-gas state have been calculated by the statistical thermodynamic methods. The entropy values for the gaseous compound obtained from the experimental data and the calculations are in satisfactory agreement.
authors.affiliation: Chemistry Faculty, Research Institute for Physical Chemical Problems, Belarusian State University, Leningradskaya 14, 220030 Minsk, Belarus.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Blokhin
authors.forename: Yauheni U
authors.initials: YU
authors.lastname: Paulechka
authors.forename: Aliaksei A
authors.initials: AA
authors.lastname: Strechan
authors.forename: Gennady J
authors.initials: GJ
authors.lastname: Kabo