Kinetics and Mechanism of the Reaction of NH2 with O2 in Aqueous Solutions

Published

July 15, 1998

Author(s)

B Laszlo, Z B. Alfassi, Pedatsur Neta, Robert E. Huie

Abstract

The reaction of NH₃ with OH or SO₄ radicals produces the aminyl radical, NH₂. Pulse radiolysis and laser flash photolysis techniques were utilized to study the formation of this radical, its absorption spectrum, its reaction with O₂, and the mechanism of formation of subsequent intermediates and the main final product, peroxynitrite. The rates of formation of NH₂ and its absorption spectrum are in agreement with previous reports. The reaction of NH₂ with O₂, however, was observed to take place much more rapidly than reported before and to involve an equilibrium of these reactants with the aminylperoxyl radical, NH₂O₂ . The equilibrium is shifted toward completion of the reaction via catalyzed decomposition of this peroxyl radical, and this decomposition affects the observed rate of reaction of NH₂ with O₂ . The peroxyl radical deprotonates and isomerizes, and finally forms NO. In the presence of O₂ , NO is rapidly converted to peroxynitrite, ONO₂ . This product, which is stable at alkaline PH, was confirmed by γ-radiolysis of aerated ammonia solutions.

Citation

Journal of Physical Chemistry

Volume

102

Pub Type

Journals

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Keywords

free radicals, kinetics, mechanism, photolysis, radiolysis

Citation

Laszlo, B. , Alfassi, Z. , Neta, P. and Huie, R. (1998), Kinetics and Mechanism of the Reaction of NH₂ with O₂ in Aqueous Solutions, Journal of Physical Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=831494 (Accessed May 11, 2024)