Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Phase behavior of beta -d galactose pentaacetate-carbon dioxide binary system is investigated by dew-point and bubble-point measurements conducted in a high pressure variable volume sapphire cell. The phase envelope for solutions of -d galactose pentaacetate in supercritical CO2 is obtained for beta -d galactose pentaacetate concentrations between 2 and 26 wt%, and for the temperature range of 308-323 K. The system exhibits lower critical solution temperature (LCST) behavior and high solubility of beta -d galactose pentaacetate is observed. The densities of the system are also measured, and liquid-like densities (near 1 g/cm3) are observed for single-phase solutions of beta -d galactose pentaacetate in supercritical CO2 at concentrations of 18 wt% and higher. Viscosity is measured for solutions of 18 and 25 wt% beta-d galactose pentaacetate in the single-phase region at 313K and 17MPa and the viscosity values, 0.095 and 0.103 cp, respectively, are similar in magnitude to the viscosity of pure carbon dioxide.