Phase Equilibria of CO2 + dl- -Tocopherol at Temperatures from 292 K to 333 K and Pressures up to 26 MPa

Phase equilibria for the system carbon dioxide + dl-α-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.