Solubility and Dissolution Thermodynamic Properties of 3,3',4,4'-Oxydiphthalic Anhydride in Binary Aqueous Solutions of Acetic Acid and Propionic Acid from (278.15 to 313.15) K

The solubility of 3,3',4,4'-oxydiphthalic anhydride in binary solvents of (acetic acid + water) and (propionic acid + water) at temperatures ranging from 278.15 to 313.15 K were measured using a gravimetric method. The measured solubility data of 3,3',4,4'-oxydiphthalic anhydride in (acetic acid + water) and (propionic acid + water) mixed solvents exhibit monotonic behavior under the studied conditions. The solubilities increased with increasing of both temperature and mass fraction of acetic acid or propionic acid. The solubility values were correlated by the three parameters equation, the equation, the NRTL model and the binary solvent models, the Ma model and the Sun model. The calculated values by the five models agreed well with the experimental data for the solubility of 3,3',4,4'-oxydiphthalic anhydride in (acetic acid + water) and (propionic acid + water) solutions. The standard thermodynamic properties of dissolution of 3,3',4,4'-oxydiphthalic anhydride, including the dissolution Gibbs energy change (),molar dissolution enthalpy change () and molar dissolution entropy change () were calculated from the experimentally measured solubility data. The values of the change of standard molar enthalpy are positive, which shows that the dissolution process of 3,3',4,4'-oxydiphthalic anhydride in the binary system of (acetic acid + water) and (propionic acid + water) is endothermic.