PHASE-EQUILIBRIA OF CO2 PLUS DL-ALPHA-TOCOPHEROL AT TEMPERATURES FROM 292-K TO 333-K AND PRESSURES UP TO 26-MPA

Phase equilibria for the system carbon dioxide + dl-alpha-tocopherol were studied, at temperatures from 292 K to 333 K and pressures up to 26 MPa. Pressure-composition isotherms were measured for the liquid and vapour phases in equilibrium, using the analytical method, from 9 MPa to 26 MPa, and at five temperatures between 298 K and 333 K. The projection of the liquid-liquid-vapour three phase equilibrium surface on the pressure-temperature plane has been followed from 292 K up to the critical end point, close to the critical temperature Of CO2. The results were modelled using the Peng-Robinson equation of state and the composition-dependent mixing rules of Panagiotopoulos and Reid. Good agreement with experimental results was obtained.