Kinetic evidence for the occurrence of trianionic tetrahedral intermediate in the hydroxide ion-catalyzed cleavage of 1, 2-benzisothiazolin-3-one-1, 1-dioxide (saccharin)
✍ Scribed by M. Niyaz Khan; M. S. O. O
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 574 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0538-8066
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✦ Synopsis
The kinetics of hydrolytic cleavage of saccharin has been studied at 60°C within the [GH] range of 0.1 to 3.0 M. The observed pseudo first-order rate constants, kobs, follow an empirical relationship: k,,, = B[6H] + [C[aH]'. TheB and C terms are attributed to the formation of dianionic and trianionic tetrahedral intermediates on the reaction path. It is conclilded that the ionized form of saccharin is the major reacting species under the present experimental conditions. The positive ionic strength effect and the negative effect of 1,4-dioxan on the rate of hydrolysis favor the proposed reaction mechanism. The analysis of the observed activation parameters indicates that the increase in the contribution of C term to koba causes the slight increase in both AH* and A S *. A significantly large negative value of A S * favors the proposed mechanism.