Abstract
The strongly basic poly(vinylbenzyltriethylammonium hydroxide) has been prepared, as an aqueous solution, from chloromethylated polystyrene, and has been used as a catalyst for the decomposition of nitrosotriacetonamine in aqueous solution. The first-order rate constants, determined by measurements of rates of nitrogen-evolution, observed in the presence of the polymeric hydroxide solution are higher than the corresponding values in the presence of sodium hydroxide and benzyltriethyl-ammonium hydroxide (which are nearly identical) by a factor of 1.7 at a hydroxyl-ion concentration of 0.01N. A marked decrease in the rate constant of the polymeric hydroxide-catalysed reaction is produced by the addition of sodium chloride and of sodium sulphate, and also by the incorporation of 1,4-dioxan. Evaluation of the activation parameters shows that the higher catalytic efficiency of the polymeric hydroxide is reflected in a higher entropy of activation. The products of the above decomposition have been investigated. Acetone, mesityl oxide, phorone, semiphorone and, probably, 2,6-dimethyl-1,5-heptadiene-4-one have been identified. A mechanism has been proposed for the reaction, and the higher catalytic efficiency of the polymeric hydroxide has been attributed to an increase in the concentrations of both nitrosotriacetonamine molecules and hydroxyl ions in the regions of solution in and around the polymeric cations, under the influence of the electrostatic fields created by these poly-cations. The rate constants of the isomerisation of cinchonine into cinchotoxine have been measured, with acetic acid and poly(methacrylic acid) as the catalysts. This investigation (commenced before the work described above) was discontinued because of the experimental difficulties encountered.