The Cannizzaro reaction of glyoxal effected by poly(vinylbenzyltriethylammonium hydroxide), and related studies.

The strongly basic poly(vinylbenzyltriethylammonium hydroxide) has been prepared, as an aqueous solution, from chloromethylated polystyrene, and has been used to effect the Cannizzaro reaction of glyoxal in aqueous solution. The third-order rate constants, determined conducti-metrically, observed in the presence of the polymeric hydroxide solution, are higher than the corresponding values in the presence of sodium hydroxide and benzyltriethylammonium hydroxide (which are nearly identical) by a factor of approximately 26 at a hydroxyl ion concentration of 0.003N and a glyoxal concentration of 0.0015M. A very marked decrease in the specific rate constant of the polymeric hydroxide catalysed reaction is produced by the addition of 0.0006 to 0.003 equivalents (with respect to the alkali) of sodium chloride; sodium sulphate gives an even larger effect. This behaviour is in contrast to the positive salt effect encountered for the sodium hydroxide catalysed reaction. The activation parameters have been evaluated and the higher catalytic efficiency of the polymeric hydroxide is reflected in the higher entropy of activation. A mechanism has been proposed for the reaction, and the higher catalytic activity of the polymeric hydroxide has been attributed to an increase in the concentrations of both hydroxyl ions and a negatively charged reaction intermediate, in the regions in and around the polymeric cations, under the influence of the electrostatic fields of the poly-cations