Abstract
The effect of cyclodextrin (CyD) on the alkaline hydrolysis of various ethyl cinnamates was investigated. The inclusion by χ-CyD retarded the hydrolysis in all cases but that by β-CyD accelerated for esters bearing electron withdrawing substituents. Stability constant, Kc, and rate constant, kc, of the complexes were determined kinetically on the basis of 1 : 1 complexation. To elucidate the reaction mechanism the hydrolysis rates of para substituted ethyl benzoates, ethyl phenylacetate, ethyl phenylpropionate, and ethyl phenylbutyrate in the presence of β-CyD were examined. Results showed that the effect of the inclusion primarily could be attributed to the magnification of electrostatic effect in hydrophobic cavity of CyD, i.e. "microsolvent effect", rather than complex stability.
