Kinetics of the solvolytic reaction between polymer hydrogels carrying oxime groups and O,O′-diethyl-O- p-nitrophenyl phosphate

Abstract

The kinetics of the reaction between linear and crosslinked hydrophilic copolymers carrying aldoxime- or ketoxime-pyridinium bromide groups and O,O′-diethyl-O- p-nitrophenyl phosphate has been studied in aqueous media. The reactivity of the copolymers was found to be given not only by the nucleophilic properties and basicity of the oxime group but by the substrate-binding ability of the polymer matrix as well. A kinetic scheme of solvolysis has been proposed and the rate constants of dissociation of the catalytic complex as well as of its first-order decomposition have been determined. It has been shown that oxime-containing copolymers catalyse hydrolysis of organophosphates. The rate constant of the first-order hydrolytic reaction of phosphorylated polymeric oximes has been determined and the efficiency of the catalyst has been estimated.