Hydrolysis of cyanazine in aqueous solutions of weak acids

In the presence of mineral acids or bases the cyano group is the primary point of hydrolysis of cyanazine. However, in solutions of weak acids, carboxylic acids or phenols, the chloro group becomes labile even in essentially neutral solutions. The rates of this catalysed hydrolysis reaction have been determined with a number of carboxylic acids and 2,4-dinitrophenol. The calculated rates of catalysis follow the Brönsted relationship with a value of ～0.7. The reaction with 2,4-dinitrophenol produces an isolatable ether intermediate. Comparison of the rates of hydrolysis catalysed by crotonic acid in deuterium oxide and in water suggests that the mechanism may be of the type specific acid/general base (or nucleophilic) catalysis rather than general acid catalysis.