I&EC 82 |
| The global phase behavior and phase equilibrium have been determined for several ionic liquids with the refrigerant R-134a (1,1,1,2-tetrafluoroethane) in imidazolium based ionic liquids. Low-pressure solubility measurements of R-134a in imidazolium based ionic liquids have been performed using a gravimetric microbalance at temperatures of from about 283-345 K and pressures up to about 2 MPa. High-pressure solubility measurements have been measured using a static stoichiometric method from about 313 to 373 K and pressures up to about 25 MPa. Both low and high-pressure solubility (pressure-temperature-composition) data have been well correlated with an equation-of-state (EOS) model. The EOS has predicted Type-V phase behavior according to the Konynenburg-Scott classification for some of the ionic liquids. In order to prove this prediction, liquid-liquid equilibrium (LLE), vapor-liquid-liquid (VLLE) and critical point measurements have been measured experimentally to confirm the phase behavior classification. In addition, large negative excess molar volumes have been observed for the ionic liquid-rich solutions. Keywords: ionic liquid, equation of state, solubility, hydrofluorocarbon, liquid-liquid separation, vapor liquid equilibria, vapor liquid liquid equilibrium, critical points. |
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Green Chemistry and Engineering with Gas Expanded Liquids and Near-Critical Media
8:00 AM-11:25 AM, Wednesday, August 22, 2007 Boston Park Plaza -- Clarendon Rm, Oral
Division of Industrial & Engineering Chemistry |