Kinetic study of the decomposition ofN-chloramines

The decomposition of various N-chloroalkylamines and N-chloroalcoholamines was investigated kinetically at pH 4–12 and in strongly alkaline media. The rate of N-chloramine decomposition increased with increasing pH above pH 10, remained virtually constant over the pH range 7–10 and again increased with decreasing pH in the acidic zone. The results are described by a rate equation involving general base catalysis terms. Experimental evidence suggests that the decomposition of N-haloamines proceeds via an elimination mechanism that yields an imine. This β-elimination process is a non-synchronized concerted mechanism where cleavage of the N(SINGLE BOND)X bond has progressed to a greater extent than that of the Cα(SINGLE BOND)H by the time the transition state is reached, which is therefore ‘E1-like’ (i.e. with a transition state having a certain nitrenium character).