Phase equilibria for binary systems of methyl oleate–supercritical CO2 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.