A new kinetic model for the acid-catalysed reactions of N-(2-aminophenyl)phthalamic acid in aqueous media
作者:Christopher J. Perry
DOI:10.1039/a606699b
日期:——
The acid-catalysed breakdown of
N-(2-aminophenyl)phthalamic acid has been studied in
dilute aqueous acids in the pH range 0–6. The dominant reaction is
the formation of N-(2-aminophenyl)phthalimide (between
∼80 and ∼100% yields in the pH range
studied) and its subsequent rearrangement to
2-(2-carboxyphenyl)benzimidazole, occurring as consecutive
pseudo-first-order processes. Anomalously, only a minor hydrolysis
reaction is observed.A kinetic model for these processes has been constructed and rate
constants and activation parameters evaluated. Mechanisms involving
pre-equilibria to form the kinetically significant species have been
proposed for the consecutive processes. The approach has been adapted to
account for the observed kinetics of acid catalysed formation of
benzimidazoles from o-aminoanilides.