Solubility prediction in water-ethanol mixtures based on the excess free energy approach using a minimum number of experimental data

Abstract

The solubility of nalidixic acid in water-ethanol mixtures has been determined at 25 degreesC. The generated solubility data sets have been used to assess the accuracy of different numerical analyses for the excess free energy model and a new numerical method for solubility prediction in water-ethanol mixtures based on four experimental determinations is proposed. The accuracy of a previously presented numerical method to fit all data points is compared with that of a proposed analysis using average percentage deviation (APD). The APD obtained are 14.6 (+/- 8.0) and 8.4 (+/- 4.1), respectively for previous and proposed methods. A minimum number of three and four data points employed to train the original forms of the excess free energy model and the solubility at other solvent compositions were predicted. The APDs obtained were 61.4 and 23.0%, respectively. The APD produced for the proposed numerical method was 16.1%.