Equilibrio liquido-liquido em sistemas eletroliticos aquosos




: In this work, the effect of the addition of the salts potassium chloride, potassium sulphate and potassium bromide on the liquid-liquid equilibrium of the ternary system water/ethanol/1-pentanol, was experimentally determined, with a revision of the data collection methodology for the liquid-liquid equilibrium of quaternary systems. The experimental procedure was carried out in equilibrium cells at the constant temperature of 25 DEGREES C and 40 DEGREES C, with salt concentrations of 0%, 5% and 10% in weight. The liquid components were analyzed by gas chromatography, while the salt was analyzed by gravimetry. The following effects of the addition of the salt have been observed: increase of the partial miscibility region and decrease in the distribution coefficient. Such effects have shown the salting out of the ethanol in the system. Later, the experimental data were correlated through the NRTL and UNIFAC-Dortmund models for the activity coefficient, with the estimation of new binary interactions parameters for both models, corresponding the salt-solvent and solvent-solvent interactions for the NRTL model and the ion-ion and solvent-ion interaction for the UNIFAC-Dortmund model. The results obtained have shown that the NRTL model was able represent better equilibrium data of the studied systems.


termodinamica eletrolitos equilibrio liquido-liquido