Solubility and solution thermodynamics of novel pyrazolo chalcone derivatives in various solvents from 298.15 K to 328.15 K

Some novel pyrazolo chalcone derivatives have been synthesized and characterization of these synthesized compounds was done by IR, H-1 NMR, C-13 NMR and mass analysis. The solubility of pyrazolo chalcone derivatives in methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, ethyl acetate and acetonitrile was measured by gravimetric method over a temperature range (298.15 to 328.15) K at atmospheric pressure. The solubility of synthesized compounds is found to increase linearly with temperature. Further, in alcoholic solvents, solubility is maximum in 1-pentanol and minimum in methanol whereas in non-alcoholic solvents, solubility is greater in ethyl acetate and minimum in acetonitrile. The experimental solubility data were correlated with temperature by modified Apelblat and Buchowski-Ksiazczak lambda h equations. The experimental data and model parameters would be useful for optimizing the process of purification. Some thermodynamic parameters such as dissolution enthalpy, Gibbs free energy and entropy of mixing have also been calculated by Van't Hoff analysis. Further, excess enthalpy of solutions has been calculated using Buchowski-Ksiazczak lambda h equation. (C) 2018 Published by Elsevier B.V.