Catalysis of the ammonium cyanate-urea conversion by polyelectrolytes

The ammonium cyanate-urea conversion is decelerated by various types of foreign salts. The negative catalysis by polyelectrolytes and micelle-forming ionic surfactants is distinctly larger than that by low molecular mass electrolytes. The decelerating effects are shown to be due to a lowering of the entropy of activation. The kinetic data are discussed in terms of the Bronsted theory and the activity coefficients of the reactant ions and of the critical complex. By choosing model systems, these activity coefficients were estimated and the rate constant was calculated therefrom and compared with that observed kinetically.