Enthalpy of solution of α- and β-cyclodextrin in water and in some organic solvents

• A great influence of crystalline water on the energetic of dissolving compounds.
• The strongest interaction between β-cyclodextrin and DMSO.
• The enthalpic pair interaction coefficient, hβCD-EtOH, obtained is positive.
• Predominating effects of the partial dehydration of the molecules – βCD-EtOH.

The calorimetric measurements of solution enthalpy of α-cyclodextrin, β-cyclodextrin in water (H2O), dimetyloformamid (DMF), dimethyl sulfoxide (DMSO) and aqueous ethanol solutions (H2O + EtOH) at 298.15 K were made. The experimental results were used to calculate the enthalpic coefficients of the interactions between cyclodextrin and ethanol molecules in water based on McMillan–Mayer’s model. The results were compared with literature data and with hydrodynamic radii of cyclodextrin in examined solvents and with donor numbers of these solvents. In order to check, if the inclusion complex formation between the solvent with the highest enthalpy of solution and cyclodextrin has happened, the calorimetric isothermal titration measurements were made and the results were interpreted.

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