The Dissolution Behavior and Intermolecular Interactions of Coumarin-3-carboxylic Acid in 12 Mono-solvents

The solubility properties of coumarin-3-carboxylic acid (CCA) was studied in 12 kinds of alcohol and ester solvents at p = 100 kPa with the temperature range from 278.15 to 318.15 K. It was found that the solubility of CCA increases with the temperature raises. Among the selected solvents, methyl acetate showed the best dissolving ability for CCA, while 2-propanol showed the worst dissolving ability. The obtained data are neatly correlated with four models, including van’t Hoff, λ h , Wilson, and NRTL models, with λ h equation yielding the most accurate predicted results. The dissolving mechanism of CCA was investigated with intermolecular interaction between CCA and solvents by using the COSMO-RS model, and the results indicating that the dissolving process is affected by the intermolecular interaction, molecular polarity, and size of both solvents and CCA. The dissolution thermodynamics analysis shows that the dissolving process of CCA in the twelve solvents is spontaneous, endothermic, and enthalpy driven.