Solubility and Solution Thermodynamics of Gibberellin A₄ in Different Organic Solvents from 278.15 K to 333.15 K

Data on corresponding solid-liquid equilibrium of Gibberellin A₄ (GA₄) in different solvents is essential for a preliminary study of industrial applications. In this paper, the solid-liquid equilibrium of GA₄ in water, methanol, ethanol, isopropanol, 1-butanol, acetonitrile, acetone, and ethyl acetate was explored in the temperatures (from 278.15 K to 333.15 K) under atmosphere pressure. For the temperature range investigated, the solubility of GA₄ in the solvents increased with increasing temperature. From 278.15 K to 333.15 K, the solubility of GA₄ in isopropanol is superior to other selected solvents. The modified Apelblat model, the Buchowski-Ksiazaczak λh model, and the ideal model were adopted to describe and predict the change tendency of solubility. Computational results showed that the modified Apelblat model has advantages than the other two models. In addition, the calculated thermodynamic parameters indicated that in each studied solvent the dissolution of GA₄ is endothermic, nonspontaneous, and an entropy-driven process.