抄録
Reaction of substituted aniline liberation from its methanesulfonic acid derivative (MSD) was studied in acid region. From the ultraviolet spectral changes, the extraction of liberated parental anilines by 1, 2-dichloroethane, and thin-layer chromatography, it was suggested that a consecutive reaction other than direct hydrolysis of MSD occurs in acid range. Reaction scheme for the liberation of free amine was proposed and the analytical method of kinetic data was presented. The pH-profile of total decreasing rate of p-chloroaniline MSD had a slope of -1 below pH 3.5 and it was pH-independent above pH 5.0. The pH-profile of the direct hydrolysis around pH 2.0-1.0 had a slope steeper than -1 and it was -1 below pH 1.0, while the estimated profile of the indirect pathway had a slope of -1 and it became pH-independent below pH 1.0. For the explanation of these pH-profiles the protonation of MSD was considered and its dissociation constant was estimated.
