Determination and correlation of solubility and solution thermodynamics of ethenzamide in different pure solvents

The solubility of ethenzamide in methanol, ethanol, 1-propanol, isobutanol, ethyl acetate and acetonitrile was determined via the gravimetric method in the temperature range from 288.15 K to 323.15 K at atmospheric pressure. Five thermodynamic models were employed to correlate the experimental solubility data. The correlated results were analyzed and compared with the experimental results. It was found that all the thermodynamic models give satisfactory correlation results, in which the modified Apelblat model shows the best fitting result. In addition, the molecular modeling studies were carried out to give the explanation for the sequence of solubility in various solvents. The dissolution enthalpy and entropy of ethenzamide were obtained by using the Van't Hoff equation. Furthermore, the mixing thermodynamic properties of ethenzamide, including the mixing Gibbs energy, the mixing enthalpy and entropy, as well as the infinite-dilution activity coefficient and the infinitesimal concentration reduced excess enthalpy, were also obtained by using the Wilson model and the experimental solubility values. (C) 2016 Elsevier B.V. All rights reserved.