Journal of Chemical and Engineering Data, Vol.53, No.11, 2683-2691, 2008
Liquid-Liquid Equilibria in Binary Mixtures Containing Fluorinated Benzenes and Ionic Liquid 1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide
Binary liquid-liquid equilibria in mixtures of fluorinated benzenes and ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), have been measured using the volumetric method over a temperature range from about (283 to 373) K. A general trend between the magnitude of the dipole moment (polarity) and the miscibility was found, although other intermolecular interactions (higher-order moments, pi-electron effects, and hydrogen bonding) may also be playing a role for a more detailed trend. The fluorinated benzenes having the largest dipole moments (1,2-difluorobenzene, 1,2,3,4-tetrafluorobenzene, and 1,2,3-trifluorobenzene) were completely miscible in the [emim][Tf2N]. The binary systems (1,4-difluorobenzene, 1,3,5-trifluorobenzene, and 1,2,4,5-tetrafluorobenzene) with zero dipole moments, and the binary systems (1,2,4-trifluorobenzene, fluorobenzene, 1,3-difluorobenzene, pentafluorobenzene, and 1,2,3,5-tetrafluorobenzene) with dipole moments of about 1.4 D were only partially miscible in [emim][Tf2N] (immiscibility gaps from about (11 to 50) mol % in [emim][Tf2N]). The binary system (1,2,4-trifluorobenzene + [emim][Tf2N]) shows a lower critical solution temperature (LCST) of about 354 K. The excess molar volumes range from (-1 to -10) cm(3).mol(-1). Observed LLE are well correlated by use of the nonrandom two liquid (NRTL) solution model.