The hydroxide-assisted hydrolysis of cyanogen chloride in aqueous solution

The hydrolysis of cyanogen chloride (ClCN) was studied as a function of temperature and pH. Results were used to resolve discrepancies among previously reported kinetic constants. The pH dependence was studied over a range of 9.54-10.93 at a temperature of 21.0 °C. The effect of temperature was investigated over the range of 10-30 °C at a pH of approximately 10. Changes in the concentrations of ClCN and the reaction products cyanic acid and chloride ion were monitored with time. For the conditions corresponding to these experiments, the hydroxide-assisted hydrolysis pathway predominated. Collision frequency factor and activation energies recommended to represent the hydrolysis of ClCN in aqueous solution are A = 2.06×10¹¹ M^-1 s^-1 and E_a = 60,980 J mol^-1 for the hydroxide-ion-assisted reaction, and A = 9.97×10⁸ s^-1 and E_a = 87,180 J mol^-1 for the water-assisted reaction.