Hydrogen substitution effect on the solubility of perhalogenated compounds in ionic liquid [bmim] [PF6]

Solubility behaviors of binary mixtures of CFCl3 (R-11), CFCl2-CF2Cl (R-113), CHCl3 (R-20), CDCl3 (R-20-d), CHCl2-CF3 (R-123) with room-temperature ionic liquid [bmim][PF6] (1-butyl-3-methylimidazolium hexafluorohosphate) have been investigated using the volumetric and cloud-point methods, since all the systems show liquid-liquid equilibria (LLE). Large immiscibility (LLE) gaps of the perhalogenated compounds (R-11 and R-113) in the ionic liquid have been drastically reduced by the addition of only one hydrogen (or deuterium) in these compounds. The R-123 + [bmim][PF6] binary system belongs to the Type-V fluid behavior. Noticeably large negative values (-2 to -8 cm(3) mol(-1)) of the excess molar volume in the ionic liquid-rich side solution have been observed for all the present systems. Experimental LLE data have been well correlated by the use of the NRTL (non-random two liquid) activity coefficient model. (C) 2007 Elsevier B.V. All rights reserved.