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| Using a static analytical model, experimental solubility data were obtained for capsaicin in n-hexane, cyclohexane, carbon disulfide, butyl ether, and isopropyl ether at temperatures ranging from 278.15 K to 323.15 K. The melting temperature and fusion enthalpy of capsaicin were measured using differential scanning calorimetry. The measured solubility data were well correlated by the van't Hoff, modified Apelblat, λh (Buchowski), Wilson, and NRTL models, with the Wilson model showing the best agreement. The activity coefficients of capsaicin and the mixing Gibbs free energies, enthalpies, and entropies of the resulting solutions were predicted based on the Wilson model parameters at measured solubility points. In addition, the infinite-dilution activity coefficients and excess enthalpies of capsaicin were estimated. Finally, the effects of solute-solvent intermolecular repulsive interactions on the solubility behavior and the values of mixing Gibbs free energy were discussed. |
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| Keywords:industry crystallization; capsaicin; solubilities; Wilson model and NRTL model |
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