The mechanism of hydrolysis of phthalamic and N-phenylphthalamic acid
1977; Elsevier BV; Volume: 6; Issue: 1 Linguagem: Inglês
10.1016/0045-2068(77)90009-8
ISSN1090-2120
AutoresRichard A.M. Blackburn, Brian Capon, Allan C. McRitchie,
Tópico(s)Analytical Chemistry and Chromatography
ResumoPhthalic anhydride has been detected spectrophotometrically in the hydrolysis of phthalamic acid and N-phenylphthalamic acid in solutions which were made up to 5 M with sodium perchlorate. In solutions of lower ionic strength the variation of kobs with acid concentration follows the equation, kobs=(k1 + k2 [H3O+])/(1 + Ka/[H3O+]), and the values of k1 and k2 are both enhanced. The p values for the variation of k1 and k2 with the aryl group for the hydrolysis of N-arylphthalamic acids are −1.23 and −0.94. A mechanism involving nucleophilic catalysis by the carboxyl group in which breakdown of the tetrahedral intermediate is rate-limiting was proposed.
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