SOLUBILITY OF CO2 IN WATER AND DENSITY OF AQUEOUS CO2 NEAR THE SOLVENT CRITICAL-TEMPERATURE

For [(1-x)H2O + xCO2] solutions, 0.005 < x < 0.009, the difference in density between water and the solution was measured at different pressures and at three temperatures near the solvent's critical temperature, 623, 631.7 and 642.5 K. The bubble-point pressure was measured at the same temperatures. To perform the experiments a combination of a new version of the vibrating tube densitometer (Majer, Crovetto and Wood, 1991a, J. Chem. Thermodyn., 23:333-334) and a new detection method for determining phase boundaries (Crovetto and Wood, 1991, Fluid Phase Equilibria, 65: 253-261), both developed in our laboratory, were used. From the resulting data apparent molar volume, density, average compressibility and Henry's constant can be calculated. The greatest source of error is reproducibility, accounting for errors of 0.05-0.3% in density, 0.5-1% in bubble-point pressure, +/-3-+/-8% in Henry's constant, and 5-10% in compressibility.