Dielectric and volumetric properties of supercritical carbon dioxide(1)+methanol(2) mixtures at 323.15 K

The static dielectric constant and density of carbon dioxide-methanol mixtures were measured at 323.15 K as a function of pressure in the range 10–18 MPa, and methanol mole fraction up to 0.16. The results, along with those obtained by other authors, allow a complete description of the dielectric and volumetric properties of the mixture on the entire range of composition. Two empirical equations of state are presented. The first one describes the critical region, including data of the phase boundary. The second equation is valid for the entire range of composition. The excess volume is negative and its absolute value decreases as the pressure goes up. The dielectric constant increases slightly with methanol content up to mole fraction 0.2, and more steeply at higher mole fractions.