N-tert-Butyl-${\alpha}$-Phenylnitrone 유도체의 가수분해 반응메카니즘과 반응속도론적 연구

A Study on the Kinetics and Mechanism of Hydrolysis of N-tert-Butyl-${\alpha}$-Phenylnitrone Derivatives

The rate constants of hydrolysis of N-tert-butyl-${\alpha}$-phenylnitrone and its derivatives have been determined by UV spectrophotometry at $25^{\circ}C$ and a rate equation which can be applied over a wide pH range was obtained. On the basis of rate equations derived and judging from the hydrolysis products obtained and general base and substituent effects, plausible mechanism of hydrolysis in various pH range have been proposed. Below pH 4.5, the hydrolysis was initiated by the protonation and followed by the addition of water to ${\alpha}-carbon$. Above pH 10.0, the hydrolysis was proceeded by the addition of hydroxides ion to ${\alpha}-carbon$. In the range of 4.5${\sim}$10.0 the addition of water to nitrone was rate controlling step.