Kinetic study of beta-cyclodextrin-dye system by high-pressure temperature-jump method.
The pressure dependence of the formation and dissociation rate constants of the inclusion reaction between beta-cyclodextrin and phenolphthalein was investigated with a newly constructed high-pressure temperature-jump apparatus. The jump height of temperature was 2.8 degrees C within 1 microsecond under pressure up to 2,000 kg/cm2. The reaction was analyzed as a simple reversible bimolecular reaction. The activation volume was 1.78 +/- 0.85 cm3/mol for the forward reaction and 10.65 +/- 1.40 cm3/mol for the backward reaction. The values of activation volumes suggest that desolvation from the phenolphthalein molecule and release of hydrating water molecules from the beta-cyclodextrin cavity occur at the transition state.
D055598:Chemical Phenomena; D002621:Chemistry; D003505:Cyclodextrins; D003912:Dextrins; D007700:Kinetics; D008433:Mathematics; D008956:Models, Chemical; D020113:Phenolphthalein; D010635:Phenolphthaleins; D011312:Pressure; D013213:Starch; D013696:Temperature; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D003912:Dextrins; D010635:Phenolphthaleins; D047392:beta-Cyclodextrins; D020113:Phenolphthalein; D013213:Starch; C031215:betadex