Acid-catalyzed hydrolysis of bridged bi- and tricyclic compounds. XXXV. Applications of the excess acidity method to the hydrolysis of 3-nortricyclanone at different temperatures

摘要

The kinetics of hydrolysis of 3-nortricyclanone was studied using capillary gas chromatography in concentrated aqueous perchloric acid at various temperatures (303-348 K) and acid concentrations (6.1-11.7 M). According to the entropies and enthalpies of activation at different acid concentrations, the mechanism of the reaction is A-2, or more precisely A-2(carbocation), under all conditions. An excess acidity equation, derived for the A-2 mechanism, fits in well with the experimental data. Two of the parameters obtained, namely m* (0.75+/-0.02) and m(not equal) (1.35+/-0.01; one exceptional value, 1.25, excluded), are practically independent of temperature, and two, namely pK(SH)+ (-5.7-5.0) and log(k(o)/K-SH+) (-9.0-6.2), are reasonably dependent on temperature. [References: 24]