Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Liquid-liquid equilibrium data for water + acetic acid + {ethyl or butyl or isobutyl of isoamyl or heptyl acetate} systems at T = {293.2 and 313.2} K and atmospheric pressure (P = ~95 kPa) were determined by density and refractive index measurements. Binodal curves were constructed utilizing cloud point method and tie lines were determined using equations obtained through cloud point data fit. Partition coefficients, ester selectivities and percent of extraction were calculated in order to compare the solvents employed. It was verified that immiscibility region increases in the order: ethyl less than butyl about the same as isobutyl less than isoamyl less than heptyl. Partition coefficients were higher for systems with ethyl acetate. Selectivity values achieved were all above 1, and heptyl acetate presented greater values among all solvents studied. Percent of extraction for acetic acid feed molar between 0.05 and 0.12 is greater for ethyl acetate; from 0.12 to 0.20, it is greater for butyl acetate; and, from 0.24 to 0.30, only data for heptyl could be determined. Different temperatures utilized did not presented significant variation in the results obtained. Experimental data were correlated with NRTL model, presenting root mean square deviation equal to 1.074 for 55 tie lines. NRTL was also used to estimate plait points for all systems.