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

Energies

Juan Carlos Moreno-Piraján¹ 

[1] Universidad de los Andes, Bogotá, Colombia, Grupo de Investigación en Sólidos Porosos y Calorimetría, Departamento de Química, Facultad de Ciencias / Carrera 1 No.18 A10, Bogotá, Colombia

关键词: Isoperibolic titration calorimetry;    Cyclodextrins;    Thermodynamic properties;   

DOI  :  10.3390/en1030093

来源: mdpi

【 摘 要 】

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, ΔG°_m, ΔH°_m, ΔS°_m and ΔCp°, 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 CH₂-increment observed for n_c > 5 or 6. As for many other ligand binding processes, we can observe a significant enthalpy - entropy compensation for this system, both with respect to temperature and structure.

【 授权许可】

CC BY   
© 2008 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.