Equilibrio liquido-liquido em sistemas aquosos bifasicos agua + PEG 8000 + sal : determinação experimental e modelagem termodinamica / Liquid-liquid equilibrium in aqueous bifasic systems water + PEG 8000 + salt : experimental determination and thermodynamic modelling

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

In this work, experimental data of the liquid-liquid equilibrium for the aqueous twophase systems water + PEG8000 + magnesium sulfate and water + PEG8000 + sodium sulfate were determined at 25 e 50°C. The compositions of both equilibrium phases were obtained by a gravimetric method, using the lyofilization (freeze-drying) technique for the water determination and the calcination in a muffle furnace for the PEG determination; in this way the salt was determined by mass difference. The experimental data were modeled by the NRTL and UNIFAC models for the activity coefficient. The NRTL model, with new energy interaction parameters, showed excellent correlation results, with low deviations between experimental and calculated compositions. The UNIFAC model, which is a predictive one, was able to represent the studied systems with some energy interaction parameters form the literature and others estimated from the experimental data determined in this work

ASSUNTO(S)

termodynamics polymers polimeros - termodinamica liquid-liquid equilibrium equilibrio liquido-liquido

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