Polyelectrolyte catalysis of the alkaline hydrolysis of neutral and anionic esters

Abstract

Alkaline hydrolysis of p-nitrophenyl acetate (PNPA), 4-acetoxy-3-nitrobenzoic acid (NABA). and 4-acetoxy-3-nitrobenzenearsonic acid (NABAA), has been carried out in the presence of cationic polyelectrolytes of varying degree of hydrophobic character or micelles. Ion–molecule and ion–ion reactions are accelerated by cationic polyelectrolytes, and the acceleration becomes larger with increasing hydrophobic character of the esters and/or polyelectrolytes. Polyelectrolyte catalysis is analysed in terms of saturation kinetics, and the equilibrium association constant and the rate coefficients of the polyelectrolyte–ester complex are calculated. The relative catalytic contributions of the electrostatic and hydrophobic interactions is discussed.