A THERMODYNAMIC STUDY OF THE REACTIONS OF CYCLODEXTRINS WITH PRIMARY AND SECONDARY ALIPHATIC-ALCOHOLS, WITH D-PHENYLALANINE AND L-PHENYLALANINE, AND WITH L-PHENYLALANINEAMIDE

Equilibrium constants and standard molar enthalpies of reaction have b een determined by titration calorimetry for the reactions of 1-propano l, 2-propanol, 1-butanol, (R)-(+)-2-butanol, (S)-((-))-2-butanol, (+/- )-butanol, (R)-(+)-2-pentanol, (S)-((-))-2-pentanol, (R)-(+)-2-hexanol , (S)-((-))-2-hexanol, (R)-(+)-2-heptanol, (S)-((-))-2-heptanol, D-phe nylalanine, L-phenylalanine, and L-phenylalanineamide with alpha-cyclo dextrin and beta-cyclodextrin. The standard molar Gibbs energies, stan dard molar enthalpies, and standard molar entropies for these reaction s correlate well with respect to the number of carbon atoms in the che mical formula of the alcohol and form a series of distinct curves for the different types of alcohols. The results are also discussed in rel ation to hydrophobic, steric, and charge effects and the exchange reac tion for a ligand from alpha-cyclodextrin to beta-cyclodextrin. With t he exception of the results for the standard molar enthalpies of react ion of the 2-butanols with alpha-cyclodextrin, the results obtained in this study show that, within the indicated uncertainties, there are n o differences in any of the thermodynamic quantities for the reactions of these ligands with either alpha- or beta-cyclodextrin due to the c hange in the location of a hydrogen atom on an optically active carbon atom.