The yield for hydroxyl radical from the decomposition of peroxynitrous acid

Journal Article · Mon Sep 20 04:00:00 EDT 1999 · Inorganic Chemistry

DOI:https://doi.org/10.1021/ic990384y· OSTI ID:20003189

Gerasimov, O V; Lymar, S V

Mechanistic predictions, based upon the assumption that free {sm{underscore}bullet}OH and {sm{underscore}bullet}NO{sub 2} radicals are formed as intermediates during the ONOOH decay, were tested using inorganic radical scavengers. Both the rates and the yields of Fe(CN){sub 6}{sup 4{minus}} and IRcl{sub 6}{sup 3{minus}} oxidation by ONOOH were independent of their concentrations in submillimolar range. A 55 {+-} 7% Fe(CN){sub 6}{sup 3{minus}} yield and 25 {+-} 3% IrCl{sub 6}{sup 2{minus}} were measured at pH 5.7, 22 C. A yields ratio close to 2 is expected, because, of the two radicals produced, only {sm{underscore}bullet}OH can rapidly oxidize IRCl{sub 6}{sup 3{minus}}. The competition kinetic studies demonstrated that the relative reactivities of the oxidizing intermediate generated by ONOOH toward IrCl{sub 6}{sup 3{minus}} and NO{sub 2}{sup {minus}} were identical with the reactivities of the authentic {sm{underscore}bullet}OH radical generated by pulse radiolysis. It is concluded that ONOOH decomposes via its peroxo bond homolysis producing a pair of discrete {sm{underscore}bullet}OH and {sm{underscore}bullet}NO{sub 2} radicals with 28 {+-} 4% yield. A bimolecular reaction between ONOOH and Fe(CN){sub 6}{sup 4{minus}} with the rate constant (8.2 {+-} 0.4) M{sup {minus}1} s{sup {minus}1} significantly increases both oxidation yield and rate at high [Fe(CN){sub 6}{sup 4{minus}}].

• Research Organization: Brookhaven National Lab., Upton, NY (US)
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 20003189
• Journal Information: Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 19 Vol. 38; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CHEMICAL REACTION YIELD
DECOMPOSITION
HYDROXYL RADICALS
KINETICS
NITROGEN OXIDES
PEROXY RADICALS