Isoperibolic Titration Calorimetry as a Tool for the Prediction of Thermodynamic Properties of Cyclodextrins

Abstract

Abstract:The interaction of guest molecules ranging from pentan-1-ol to octan-1-ol with α-cyclodextrin (α-CD) in water of has been studied calorimetrically at 283.15, 288.15, 293.15, 298.15 and 308.15 K with an isoperibolic titration calorimeter designed in our laboratory. The calorimetric method employed allows the determination of the thermodynamic parameters characterizing the binding process, ∆G°m, ∆H°m, ∆S°m and ∆Cp°, namely free energy, enthalpy, and calorific capacity. These results show that in the temperature range investigated, the entropy change increased with chain length. This is in line with what is expected for a hydrophobic dehydration process. However, that effect is not expected to lead to the more pronounced negative CH 2 -increment observed for n c > 5 or 6. As for many other ligand binding processes, we can observe a significant enthalpyentropy compensation for this system, both with respect to temperature and structure.

Design and building of an isoperibolic calorimeter: measurements of enthalpy of formation for derivatives of glycidol

“…Isoperibolic calorimeters have been used to study several processes, including exothermic reactions [1][2][3], laser ray power [4], the measurement of the hydration heat of concretes [5], calorimetric titrations [6] and mainly in evaluation of the heat of combustion [7][8][9][10]. From the combustion reaction, it is possible to determine the enthalpy of formation in the standard state for chemical compounds.…”