| Abstract |
Vapour-liquid equilibrium compositions were measured for mixtures of delta-tocopherol and carbon dioxide, at pressures from 9 up to 27 MPa, and four temperatures between 306 and 333 K. The system exhibits liquid-liquid equilibrium at high pressures, similarly to previous results for mixtures of alpha-tocopherol with carbon dioxide. The results were correlated with the Peng-Robinson equation of state, using the Panagiotopoulos-Reid combination rules. Comparison of the solubilities of delta-tocopherol and alpha-tocopherol in supercritical carbon dioxide was performed using Chrastil s equation to correlate the data. The number of solvent CO2 molecules per solute molecule was calculated in both cases. An enthalpy of solvation per mole of CO2 of -10 kJ mol(-1) was obtained. (C) 2003 Elsevier B.V. All rights reserved. |
