DIELECTROMETRY IN SUPERCRITICAL FLUIDS - A NEW APPROACH TO THE MEASUREMENT OF SOLUBILITY AND STUDY OF DIPOLE-MOMENT BEHAVIOR OF POLAR COMPOUNDS

Radio frequency (rf) dielectrometry has been used to study the solubil ity and dipole moment behavior of polar compounds in supercritical flu id. The isothermic equilibrium solubility and dipole moments of aceton itrile, acetone, cyclopentadienyl manganese tricarbonyl (CpMn(CO)(3)), and copper(II) hexafluoroacetylacetonate hydrate (Cu(hfac)(2) . H2O) in near- and supercritical CO2 were measured at 313 K over the pressur e range 5-15 MPa.; It was found that dipole moment values for acetonit rile, acetone, and CpMn(CO)(3) in CO2 are close to those in benzene an d cyclohexane, in contrast to Cu(hfac)(2) . H2O, which has an enhanced dipole moment indicating strong interaction with carbon dioxide molec ules.