Catalysis by Cyclodextrins in Nucleophilic Aromatic Substitution Reactions

RITA H. DE ROSSI; MONICA BARRA; ELBA I. BUJÁN

AMER CHEMICAL SOC

Lugar: Washington; Año: 1986 vol. 51 p. 2157 - 2157

he kinetics of the hydrolysis of 1-X-2,4-dinitrobenzene (X = Cl, F) were studied in the presence of β-cyclodextrin. The overall rate of hydrolysis is catalyzed by the added compound, and the observed catalysis is pH dependent. For the reaction of the fluoro derivative the catalytic factor at 0.01 M β-cyclodextrin changes from 7 at M NaOH to 2.5 at 10-1 M NaOH. Part of the catalysis is due to nucleophilic reaction of β-cyclodextrin with the substrate and part of it is attributed to the reaction of an inclusion complex formed between the substrate and the β-cyclodextrin. The catalytic factor corresponding to the reaction in the cavity is 1.4 and 2 for the fluoro and chloro derivative, respectively.