The kinetics and mechanism by which monochloramine is reduced by hydroxylamine in aqueous solution over the pH range of 5-8 are reported. The reaction proceeds via two different mechanisms depending upon whether the hydroxylamine is protonated or unprotonated. When the hydroxylamine is protonated, the reaction stoichiometry is 1:1. The reaction stoichiometry becomes 3:1 (hydroxylamine:monochloramine) when the hydroxylamine is unprotonated. The principle products under both conditions are Cl -, NH + 4 , and N 2 O. The rate law is given byAt an ionic strength of 1.2 M, at 25 • C, and under pseudo-first-order conditions, k + = (1.03 ± 0.06) ×10 3 L · mol −1 · s −1 and k 0 = 91 ± 15 L · mol −1 · s −1 . Isotopic studies demonstrate that both nitrogen atoms in the N 2 O come from the NH 2 OH/NH 3 OH + . Activation parameters for the reaction determined at pH 5.1 and 8.0 at an ionic strength of 1.2 M were found to be H ‡ = 36 ± 3 kJ · mol -1 and S ‡ = −66 ± 9 J · K −1 · mol −1 , and H ‡ = 12 ± 2 kJ · mol −1 and S ‡ = −168 ± 6 J · K −1 · mol −1 , respectively, and confirm that the transition states are significantly different for the two reaction pathways. C 2005 Wiley Periodicals, Inc. Int J Chem Kinet 38: [124][125][126][127][128][129][130][131][132][133][134][135] 2006
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.