Kinetics and mechanism of hydrolysis of N ‐(2′‐hydroxyphenyl)phthalamic acid ( 1 ) and N ‐(2′‐methoxyphenyl)phthalamic Acid ( 2 ) in a highly alkaline medium

A kinetic study on hydrolysis of N‐(2′‐hydroxyphenyl)phthalamic acid ( 1 ), N‐(2′‐methoxyphenyl)phthalamic acid ( 2 ), and N‐(2′‐methoxyphenyl)benzamide ( 3 ) under a highly alkaline medium gives second‐order rate constants, k OH , for the reactions of HO − with 1, 2 , and 3 as (4.73 ± 0.36) × 10 −8 at 35°C, (2.42 ± 0.28) × 10 −6 and (5.94 ± 0.23) × 10 −5 M −1 s −1 at 65°C, respectively. Similar values of k OH for 3 , N‐methylbenzanilide, N‐methylbenzamide, and N,N‐dimethylbenzamide despite the difference between pK a values of aniline and ammonia of ∼10 pK units are qualitatively explained. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 1–11, 2009