Measurement and thermodynamic functions of solid–liquid phase equilibrium of d-(−)-quinic acid in H2O, methanol, ethanol and (H2O + methanol), (H2O + ethanol) binary solvent mixtures

Abstract

The solubility of d-(−)-quinic acid in H2O, methanol, ethanol and (H2O+methanol), (H2O+ethanol) binary solvent mixtures was measured at temperatures from (298.15 to 328.15 or 348.15)K by using the HPLC method under atmospheric pressure. The experimental values indicate that the solubility of d-(−)-quinic acid in the binary mixed solvents increases with the increasing temperature and decreases with the rise of molar concentration of organic solvents. The Apelblat model, λh model, Wilson model and NRTL model were used to correlate the experimental results and the relative average deviation (RAD) between the experimental and calculated values is less than 0.0358, 0.0421, 0.0359 and 0.0397 for the Apelblat model, λh model, Wilson model and NRTL model, respectively. Furthermore, thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were also calculated and analyzed.