The solubilities of l-serine, l-threonine and l-isoleucine in the aqueous systemsof ethanol, 1-propanol and
2-propanolwere measured at 298.15, 313.15 and 333.15Kby means of gravimetric and spectrophotometric
ninhydrin based method measurements.
In order to represent the solid–liquid equilibria in those systems the excess solubility approach was
combined with the NRTL, the modified NRTL, the modified UNIQUAC equations and also with the model
presented by Gude et al. [M.T. Gude, L.A.M. Wielen, K.Ch.A.M. Luyben, Fluid Phase Equilibr. 116 (1996)
110–117]. Their correlation performance showed global average relative deviations of 15.3, 13.7, 13.4 and
15.8%, respectively, while their application in the prediction of l-threonine solubility in water/ethanol
mixed solvent mixtures, at two different temperatures, showed average relative deviations of 18.8, 9.1,
28.9, and 38.4%, respectively.
