PHASE-EQUILIBRIA OF TERNARY AND QUATERNARY SYSTEMS CONTAINING CARBON-DIOXIDE, WATER, ISOPROPANOL, AND GLUCOSE

Vapor-liquid equilibrium data have been measured for the ternary carbon dioxide-isopropanol-water system and for the quaternary carbon dioxide-isopropanol-water-glucose system at 313 and 333 K and at pressures between 13.8 and 30.0 MPa. For the quaternary system, densities were also obtained. A special high-pressure apparatus with vapor-phase recirculation and a sample bomb placed in the recirculation loop was used for the measurements.1 The results show a phase behavior in the ternary system similar to that described in the literature at lower pressures. In the quaternary system, glucose concentrations in the vapor phase vary between 4.4 x 10(-4) and 0.11 mol %. While the glucose concentration is strongly dependent on the vapor-phase concentration of isopropanol and water, pressure and vapor-phase density do not influence the solubility of glucose in the vapor phase significantly. Comparing the effect of isopropanol and ethanol on the entrainment of glucose in the vapor phase, it is evident that while the measured maximum glucose solubilities in the vapor phase are of the same order of magnitude (0.11 mol % at 13.79 MPa, 313.15 K for the isopropanol system and 0.17 mol % at 25.0 MPa, 313.15 K for the ethanol system), higher pressures are needed with ethanol as a cosolvent to achieve the same glucose solubilities possible with isopropanol.