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 beta-D galactose pentaacetate in supercritical M 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/cm(3)) 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 313 K and 17 MPa and the viscosity values, 0.095 and 0.103 cp, respectively, are similar in magnitude to the viscosity of pure carbon dioxide. (c) 2005 Elsevier B.V. All rights reserved.