MICROCALORIMETRIC TITRATION OF ALPHA-CYCLODEXTRIN WITH SOME STRAIGHT-CHAIN ALKAN-1-OLS AT 288.15-K, 298.15-K AND 308.15-K

The binding of a series Of alkan-1-ols, n(c) = 3-7, to alpha-cyclodextrin has been investigated by microcalorimetric titration at 288.1 5, 298.1 5 and 308.1 5 K. For n(c) less-than-or-equal-to 6, the results agree well with a 1 : 1 binding model but for n(c) = 7, contributions from the formation of 1 : 2 (one alkanol, two alpha-CD) complexes have to be assumed. Apparent values for changes in standard molar Gibbs energies, enthalpies, entropies and heat capacities have been derived. The values obtained are consistent with the commonly held view that hydrophobic interactions are important in the formation of alkanol-alpha-CD complexes. However, the results clearly indicate that other effects are also of some importance.