| Having many benefits, being a very strong antioxidant, and being a high-value natural product, extracting and concentrating natural vitamin E becomes a hotspot research for many scientists and industrial technologists. In our country, there are lots of oil deodorizer distillates (in short as 'DOD') from which concentrating this high-value material---- natural vitamin E can not only bring higher economical benefits, but also decrease the environment pollution causing by deserting oil DOD.Although the technology of supercritical carbon dioxide (in short as 'SC-CO2') has been widely applied to extract and concentrate natural vitamin E from DOD, and many achievements have also been reported, there are some drawbacks such as the absence of phase equilibrium for pretreatment of DOD/CO2 system. Therefore, this paper comprehensively investigates the determination of phase equilibrium including binary and multi-compound systems; the calculation and correlation of solubilities of vitamin E are also discussed; finally three different extraction technologies are compared using SC-CO2, and the two-column countercurrent extraction and fractionation (in short as 'TCCCEF') technology is primarily studied in this paper. Main research contents and results are as follows:Gas-liquid equilibrium data are reported for tocopherol/CO2 and methyl oleate/CO2 two binary systems at 313.15K, 323.15K and 343.15K, respectively. A new gas and liquid phase circulation apparatus coupled with gravimetric method is employed for solubility measurement. The quantity of dissolved solute per 100 gram CO2 and distribution coefficients of solutes are calculated from the P-V-T relationship for CO2 in gas phase. All experimental results are compared with values reported in the literatures under the similar conditions. The results show that the solubility of methyl oleate is much higher than that of tocopherol. From the data of solubilities, there is too little tocopherol in SC-CO2 to be determined by gravimetric method under the conditions of 313.15K, below 10MPa, 323.15K and 343.15K below 15MPa. Critical pressure of methyl oleate in SC-CO2 increases with pressure, for example 313.15K-13MPa, 323.15K-15MPa, and 343.15K-20MPa respectively. Based on the solubilities and distribution coefficients between tocopherol and methyl oleate in SC-CO2, It is feasible to isolate and separate tocopherol from these two compounds mixture.It is concluded that the solubility of DOD alcoholysate in SC-CO2 is much higher than these of DOD esterification, DOD, and plant oil, therefore, it is very important to esterify and alcoholism DOD from which concentrating natural vitamin E by SC-CO2 fractionation method. This paper presents that del valle and Aguilera model is not suitable to correlate the solubility of soybean oil DOD alcoholysate in SC-CO2.Gas-liquid equilibrium data are determined for SC-CO2 and fatty acid methyl ester (FAME) in soybean oil DOD pretreatment under isothermal, isobaric and isochoric conditions of pressure ranging from 9MPa~17MPa and temperature from 313.15K~333.15K. Gas Chromatography (GC) analyzes samples from liquid and gas phases. The solubilities, distribution coefficients and relative separation factors for seven main FAME are calculated. The results show that the solubilities of methyl oleate are no influential variance between in pretreatment of DOD/CO2 and in methyl oleate/CO2 systems, which testifies that the solubilities of more soluble components in mixture are not obviously affected by the presence of less soluble components. At isotherm, the distribution coefficient of palmitic acid methyl ester increases with pressure, but others decrease with pressure. At isochoric, the distribution coefficients of all seven main fatty acid methyl esters increase with temperature. All in all, for a family of linear long-chain saturated methyl esters, the smaller chain length, the higher the solubility of the methyl ester in the gas phase; for the equal-chain methyl esters (here, C18), the larger the unsaturation, the lower the solubili...
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