Dielectric constant behavior of carbon dioxide—methanol mixtures in the mixture-critical and liquid-phase regions

Abstract

The dielectric constant, measured with a frequency-domain technique, is reported for saturated mixtures of carbon dioxide and methanol from 90 to 115° C and at 0.28, 0.325, 0.40 and 0.65 mole fraction methanol. Isothermal dielectric information is obtained for the same compositions at 90 °C and at pressures from the saturation pressure to 240 bar. The data are interpreted using the Kirkwood-Fröhlich equation, which incorporates the structure correlation factor, g, that depends on density and temperature. The behavior of g provides information on the type of fluid environment encountered in the mixture-critical and liquid-phase regions.