N‐Chlorination rate of five‐membered heterocyclic nitrogen compounds

The kinetics of N‐chlorination reaction of pyrrolidine, pyrrolidone, succinimide, 5,5,‐dimethyloxazolidine‐2,4‐dione, 5,5‐dimethylhydantoin and 1‐hydroximethyl‐5,5‐dimethylhydantoin with HOCl in aqueous solution were studied at 25 °C, constant ionic strength and under isolation conditions in a wide pH range. The set of compounds studied in this paper is characterized by having different functional groups and the same cyclic structure, consisting of a five‐member ring with a nitrogen atom in the ring, which is susceptible to be chlorinated. This series of compounds covers nine pK_a units, and the kinetic studies allow us to know, like, the presence of an amino, amide or imide group modify the reactivity of nitrogenous compound. Experimental data were fitted to the first‐order kinetic equation. All reactions were found to be of first order in both HOCl and nitrogenous compound concentration. Kinetics studies demonstrate that some of these compounds are hydrolyzed in alkaline medium. In each case, reaction mechanism in agreement with the experimental results is proposed. The results were compared with other compounds with similar cyclic structure (2‐oxazolidinone and proline). Copyright © 2016 John Wiley & Sons, Ltd.