Journal of Chemical & Engineering Data · 2009 · 48 citations · 28 references
Natural SciencesBiochemistryChemistryAnalytical ChemistryPhysical ChemistrySolid-state ChemistryAqueous Two-phase SystemsPhase DiagramsPhase EquilibriaPhase EquilibriumSolution ChemistryThermodynamics Of Phase EquilibriaActivity Coefficient ModelsComposition-dependent Interaction ParametersEnthalpic InteractionsEquilibriumInteraction ParametersNonrandom Two-liquid ModelPhase Equilibria In SolutionsTemperature Effects On Phase Behavior
Phase diagrams of aqueous two-phase systems (ATPS) composed of 400 g·mol −1 poly(ethylene glycol) (PEG) + sodium sulfate or magnesium sulfate were determined at (298.15, 308.15, and 318.15) K. The temperature effect on the biphasic area was not relevant, indicating a small enthalpic contribution associated with the phase separation. The ability of the salts in inducing the formation of the ATPS with PEG 400 followed the order sodium sulfate < magnesium sulfate. The liquid−liquid equilibrium experimental data were correlated using the NRTL (nonrandom two-liquid) activity coefficient model, and new interaction parameters were estimated. The mean deviations between calculated and experimental compositions were lower than 0.99 %, showing the good descriptive quality and applicability of the NRTL model.
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