Phase equilibria for binary systems of methyl oleate-supercritical CO ₂ and α-tocopherol-supercritical CO₂

In order to study the possibility of using supercritical CO₂ to concentrate tocopherols from soybean oil de-odorizer distillate (DOD), the binary phase equilibrium data for methyl oleate-CO₂ and α-tocopherol-CO₂ were measured at 313.15-353.15 K in the pressure ranges of 5-23 MPa for methyl oleate and 5-30 MPa for α-tocopherol, respectively. The measured data were well correlated using the Soave-Redlich-Kwong (SRK) equation of state (EOS) with the Adachi-Sugie (AS) mixing rule. The solubilities and distribution coefficients of methyl oleate and α-tocopherol in CO₂ were investigated. Finally, on the basis of these results, a conclusion was preliminarily drawn, supercritical CO₂ can be used to concentrate natural tocopherols from the esterified DOD in the experimental range investigated. In addition, the critical points of methyl oleate-CO₂ at three temperatures were estimated.