Phase equilibria and thermophysical properties of carbon dioxide-expanded fluorinated solvents

The volume expansion behavior and liquid molar compositions of several fluorinated solvents (methoxynonafluorobutane, C4F9OCH3; ethoxynonafluorobutane, C4F9OC2H5; 1,1,1,2,3,4,4,5,5,5-decafluoropentane, C5F10H2; and perfluorohexane, C6F14) expanded by pressurized carbon dioxide were measured at temperatures of 298 and 308 K and pressures up to 72 bar. The densities and viscosities of the expanded liquid phases were also determined. Fluorinated solvents undergo greater solvent-dependent volume expansion (as defined by de la Fuente Badilla et al. [J. Supercrit. Fluids 17 (2000) 13]) relative to traditional organic solvents. The Peng–Robinson equation of state (PR-EOS) satisfactorily described the liquid phase composition of the expanded fluorinated solvents. The viscosity reduction of the expanded fluorinated solvents was modeled by extending the method of Orbey and Sandler [Can. J. Chem. Eng. 71 (1993) 437] to fluorinated solvents. The model predicted the viscosities of the CO2-expanded solvents with an absolute average relative deviation (%AARD) of 6–12%.