Kinetic Study of the hydrolysis of p-Anisidine Phosphoric Triamide (C—N—P) in Acid Medium

Abstract

Hydrolytic fragmentation of tri-p-anisidine orthophosphate has been pursued in the acid range 1.0 to 8.0 M-HCI in 20% acetic acid (v/v) at 65ºC (±0.5ºC). Neutral electrolyte effect study reveals the contribution of conjugate acid form with the absence of any participation of the neutral
form in the entire acid region examined. First order rate law best fits the
results in the entire acid range, leading to overall pseudo-first order rate
coefficients in the medium used. Solvent and solvent-isotope effect studies
support the existence and contribution of monoprotonated species formed
by a specific acid catalysed reaction for this triester bimolecular mode of
hydrolysis is derived by the application of Arrhenius equation and various
correlations given by Bunnett and others. The P—N bond cleavage is
confirmed by comparison of kinetic and thermodynamic parameters of the
closely related triamidates.