LAUSR

Abstract Solubility of morin hydrate was measured in five pure alcohols (methanol, ethanol, propan-1-ol, propan-2-ol, and butan-1-ol) at 298.15 K as well as in different aqueous solutions of ethanol in a temperature range from 298.15 to 313.15 K and constant ionic strength (0.1 mol·dm − 3 NaCl) using spectrophotometric method. The obtained results have shown that by increasing both temperature and ethanol percent as well as decreasing the dielectric constant of the medium causes an increase in solubility of the flavonoid. The solubility of morin hydrate was analyzed in different aqueous solutions of ethanol using normalized polarity and its blend with the Kamlet, Abboud, and Taft parameters. The experimental data in the binary systems were fitted using the Apelblat equation. The model was proven to give good representation of the experimental data. The thermodynamic functions of dissolution were calculated at different percent of ethanol using the modified van't Hoff equation. The dissolution process was endothermic and entropy-driving. Finally, the thermodynamic functions of morin hydrate were determined at 0% ethanol which are: Δ H ° = 54.53, Δ G ° = 24.87 kJ·mol − 1 and Δ S ° = 97.04 J·mol − 1 ·K − 1 at the mean harmonic temperature.