New vapour-liquid equilibrium data on the ternary system carbon dioxide – methanol – dimethyl sulphoxide

Knowing high-pressure phase equilibrium is essential for the numerous applications of organic solvent-entrained supercritical carbon dioxide, as well for extraction as for antisolvent procedures. Phase equilibrium measurements on the carbon dioxide – methanol – dimethyl sulphoxide mixture are presented in the range of 308 K–323 K and 7.5 to approx. 11.5 MPa. Composition (mole fraction) was varied for each component in the ranges xCO2:0.75−0.88; xMeOH:0.042−0.21; and xDMSO:0.025−0.12. Measurements were done using a static synthetic method based on the observations of cloud points and redissolution points. Measurement results were well approximated by the Peng-Robinson equation of state.