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Journal of Supercritical Fluids, Vol.26, No.3, 181-191, 2003
Phase equilibria in systems containing alpha-tocopherol and dense gas
Solubility of alpha-tocopherol in CO2 and propane was determined at temperatures 303, 313, 333 and 353 K and over a pressure range from 79 to 286 bar for CO2 and 16 to 112 bar for propane. A static-analytic method was applied. The solubility of alpha-tocopherol in dense CO2 under the conditions investigated was in the range of 0.2-17.0 mg/g CO2. The maximal solubilities of alpha-tocopherol in propane were approximately up to ten times higher than in CO2 and were in the range from 38.9 to 171.9 mg/g propane. Phase equilibrium data for Milk Thistle seed oil in supercritical CO2 were determined at temperatures 313, 333 and 353 K and pressures ranging from 100 to 300 bar. The oil was previously additionally vitaminized and contained 1.9 wt.% of alpha-tocopherol and 1.7 wt.% of free fatty acids (FFA). The solubility of oil in CO2 was in the range from 1.3 to 17.9 mg/g CO2. The distribution coefficients of alpha-tocopherol and FFA between light and heavy phase were determined on a solvent free basis. The obtained separation factors increased with temperature and pressure to approximately 160-200 bar and decreased with a further increase of pressure. (C) 2002 Elsevier Science B.V. All rights reserved.