Temperature Effects on Thermodynamic Parameters and Solubility of Curcumin O/W Nanodispersions Using Different Thermodynamic Models

Solubility of curcumin at different temperatures is of great importance in subcritical water extraction systems. We newly developed an approach for the solid–liquid equilibrium under subcritical condition to determine the solubility of curcumin. The experimental results were correlated successfully with thermodynamics models such as Van’t Hoff, modified Apelblat equation, Wilson, non-random two-liquid (NRTL) and λh equation and the interaction parameters’ values of curcumin-water were acquired. Good agreement between the experimental and calculated values with λh equation was observed at different temperatures (373.15–433.15 °K) at 1.5 bar. The obtained value of the relative average deviation was 2.29 × 10 –5 . The molar enthalpy (Δ H 0 ), entropy (Δ S 0 ), Gibbs energy (Δ G 0 ) and their relative fraction of the total process were calculated. The calculated enthalpy with the Van’t Hoff equation (25.32 kJ/mol) agreed well with the differential scanning calorimetry analysis data (26.15 kJ/mol).