Abstract
The present work deals with the modeling of solid-liquid equilibria (SLE) using the NRTL and the UNIFAC thermodynamic models for activity coefficient calculation, for a number of ternary systems involving pharmaceutical and food compounds such as salicylic acid, nicotic acid, caffeine, urea, vanillin, etc. as the solutes and water-ethanol and water-methanol as the solvent pairs, at different temperatures.
For the UNIFAC model interaction parameters were available whereas for the NRTL model they were retrieved from the experimentally measured values using the Simplex method to minimize an objective function expressed as a summation of the squared differences between the experimental and the calculated values, to be used to predict the SLE data for the considered systems with a quite good agreement.
