Mechanism of the acid catalysed pathway for the nitrosation of hydroxylamine

Abstract

The profile of rate constant versus [H+] for the acid catalysed pathway of the nitrous acid reaction with the hydroxyammonium ion can be quantitatively interpreted in terms of a reversible 0nitrosation, followed by an 0 to N migration of the nitroso group in the conjugate base species NH,ONO. There is no need to assume a non-steady-state mechanism involving NO', as has been proposed previously.

Bistability in the nitric acid‐hydroxylamine CSTR system

“…When [NH30H+lo is sufficiently large, the protonated hydroxylamine will transform a substantial amount of nitric acid to nitrous acid which, in turn, will destroy more NH30H' by eq. (6). This leads to the limiting stoichiometry…”

“…This reaction is also a complex one, and its mechanism has been discussed [6,71. The behaviour of the whole nitric acid-hydroxylamine system depends on the balance between processes (5) and (6).…”

“…The behaviour of the whole nitric acid-hydroxylamine system depends on the balance between processes (5) and (6).…”

Nitrosation of dialkylhydroxylamines, and computational and NMR investigations of the interconversion of conformational isomers of N‐nitroso‐dimethylhydroxylamine

“…[6] Under acidic conditions, nitrous acid has been reported to be in equilibrium with its protonated form, (H 2 NO 2 ) + , [4] its anhydride (N 2 O 3 ), [7,8] and the nitrosonium ion (NO + ), [9] all of which are potential nitrosating agents; in addition, it undergoes decomposition to nitric oxide and nitric acid. There have been many wide-ranging discussions of nitrosation of amino compounds (including hydroxylamine) notably by Ridd and Stedman and their colleagues, [9][10][11][12] and the field has been comprehensively reviewed by…”

“…[13] Particularly relevant to our current investigation is the effect of acidity upon the rate of nitrosation of O-alkylhydroxylamines by nitrous acid reported by Stedman. [10,11] We reported recently an investigation of the mechanism of the acid-catalysed decomposition of a series of N-nitroso-dialkylhydroxylamines. [14,15] We now report the We also report an investigation of the conformational properties of N-nitrosodimethylhydroxylamine (5) by NMR spectroscopy and theoretical methods; dynamic, thermodynamic, and structural parameters have been determined.…”