Synthetic catalytic polymers containing oxime groups: Effect of substrate structure on esterolysis of p-nitrophenyl esters

The catalytic activity of different polymers containing axime groups has been tested in the hydrolysis of structurally different esters of p-nitrophenol. The mechanism of hydrolysis, supported by indirect kinetic evidence, seems not to involve a pre-equilibrium with a polymer-ester complex. The reaction was investigated under pseudo-first-order conditions with an excess of oxime polymer. The values of the second-order catalytic rate coefficients suggest a reaction rate mainly controlled by steric effects and hydrophobic interaction between the ester hydrocarbon residue and the macromolecular chain.