A completely miscible, binary liquid mixture of water and an organic solvent can reveal a liquid-liquid phase split, when it is pressurised with a 'near-critical' gas. The coexisting liquid phases in such a high-pressure three-phase equilibrium can be used to enable an extraction of biomolecules from an aqueous phase into a water-like organic phase. The basic design of such a process requires, at first, information on the behaviour of the phase forming ternary system of 'near critical' gas + water + water-soluble organic solvent, at second, experimental data on the partitioning of biomolecules to the coexisting phases and, at third, a method to correlate and predict such phase equilibrium. After a short introduction to the basic phase equilibrium phenomena, experimental results are reported for the partitioning of small amounts of six biomolecules - adenine, caffeine, methyl anthranilate, L-phenylalanine, salicyl alcohol and vanillin - on coexisting liquid phases in high-pressure three-phase vapour-liquid-liquid equilibrium of the ternary system 'near critical' carbon dioxide + water + 1-propanol at 313 and 333 K. The experimental results for the partition coefficients are correlated with a semi-empirical approach, which combines an equation of state for describing the high-pressure multiphase equilibrium and the UNIQUAC excess Gibbs energy equation for describing the partitioning of the biomolecules. (C) 2000 Elsevier Science B.V.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below