Mechanism of the acid hydrolysis of aromatic o‐carboxyamides and relative imides

Abstract

The kinetics of N-phenylphthalamic acid and of N-phenylphthalimide hydrolysis in aqueous solutions of sulfuric acid has been studied. A reaction mechanism is proposed implying that unreactive forms of the reactant appear by protonization of the amide bond at the carbonyl oxygen and by dissociation of the o-carboxyl group (N-phenylphthalamic acid). Attack of the nonprotonized amide bond by the hydroxonium ion is suggested to be the rate-limiting step.

Infrared spectra analysis of OH on aggregate structure formation of oleamide in sulfuric acid solution

“…The most favorable site for protonation is commonly believed to be the carbonyl oxygen atom [18][19][20][21]. Nuclear magnetic resonance (NMR) studies have shown that virtually all amides in concentrated sulfuric acid solutions are of the O-protonated form [22,23]. Huang et al [24] and Mindrup and Schneider [25] believed that the reaction of neutral amides with electrophiles such as H + occurs on O instead of N. A typical amide, N,NDimethylformamide (DMF), interacts with H + and forms DMFH + [26] as Fig.…”