Comparison of the dielectric behavior of mixtures of methanol with carbon dioxide and ethane in the mixture-critical and liquid regions

Roškar, V., Dombro, R.A., Prentice, G.A., Westgate, C.R. and McHugh, M.A., 1992. Comparison of the dielectric behavior of mixtures of methanol with carbon dioxide and ethane in the mixture-critical and liquid region. Fluid Phase Equilibria, 77: 241-259. Dielectric data are reported for the CO 2-methanol system at 35, 50 and 65°C and the ethane-methanol system at 35, 65 and 95°C at a number of composition and over a pressure range from the saturation pressure of the mixture to 300 bar. Experimental pressure-composition isotherms and molar volume data are also reported for the ethane-methanol system. The dielectric constant for both types of methanol mixtures can be increased by decreasing the temperature or by increasing the permanent dipole concentration of the mixture through increasing the mixture density or the methanol mole fraction. The dielectric constants for CO 2-methanol mixtures are consistently greater than those for ethanemethanol mixtures over the entire pressure-temperature-composition space investigated in this study. The higher dielectric constants for CO 2-methanol mixtures are conjectured to be a consequence of the quadrupole interactions between CO 2 and methanol and to the contribution from the CO 2 -methanol complex which is present in these mixtures.