Measurement and correlation of solubility of o-vanillin in different pure and binary solvents at temperatures from 273.15 K to 303.15 K

The equilibrium solubility is the basis for purification and further theoretical studies of o-vanillin. In this paper, the solubility data of o-vanillin in three pure solvents, including water, ethanol, n-propanol, and two binary solvents of water + ethanol and water + n-propanol has been experimented under atmospheric pressure (p = 0.1 MPa) in the temperature range from 273.15 K to 303.15 K. The experimental results proved that the rising temperature leads to increased solubility of o-vanillin in all selected solvents. All the solubility data in different pure and binary solvents was correlated by the modified Apelblat equation. The computational values were in good agreement with the experimental results according to the calculations. In addition, some thermodynamic parameters of o-vanillin including dissolution enthalpy (Delta H-sol), entropy (Delta(sol)) and the Gibbs energy (Delta G(sol)) were obtained via the Van't Hoff analysis. The positive values of Delta H-sol and Delta G(sol) indicated that the dissolution process of o-vanillin is endothermic. (C) 2020 Elsevier Ltd.