Reaction of organic peroxyl radicals with (NO2)-N-center dot and (NO)-N-center dot in aqueous solution: Intermediacy of organic peroxynitrate and peroxynitrite species
2004 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 108, no 10, 1719-1725 p.Article in journal (Refereed) Published
In this work, we studied the reactions of alkyl peroxyl radicals with (NO2)-N-. and (NO)-N-. using the pulse radiolysis technique. The rate constants for the reaction of (NO2)-N-. with (CH3)(2)C(OH)CH2OO., CH3OO. and c-C5H9OO. vary between 7 x 10(8) and 1.5 x 10(9) M-1 s(-1). The reaction produces relatively long-lived alkyl peroxynitrates, which are in equilibrium with the parent radicals and have no appreciable absorption above 270 nm. It is also shown that (NO)-N-. adds rapidly to (CH3)(2)C(OH)CH2OO. and CH3OO. to form alkyl peroxynitrites. The rate constants for these reactions were determined to be 2.8 x 10(9) and 3.5 x 10(9) M-1 s(-1), respectively. However, in contrast to alkyl peroxynitrates, alkyl peroxynitrites do not accumulate. Rather, they decompose rapidly via homolysis along the relatively weak O-O bond, initially forming a geminate pair. Most of this pair collapses in the cage to form an alkyl nitrate, RONO2, and about 14% diffuses out as free alkoxyl and (NO2)-N-. radicals. A thermokinetic analysis predicts the half-life of CH3OONO in water to be less than 1 mus, an estimate that agrees well with previous experimental findings of ours for other alkyl peroxynitrites. A comparison of aqueous and gaseous thermochemistry of alkyl peroxynitrates reveals that alkyl peroxyl radicals and the corresponding alkyl peroxynitrates are similarly solvated by water.
Place, publisher, year, edition, pages
2004. Vol. 108, no 10, 1719-1725 p.
pulse-radiolysis, nitric-oxide, lipid-peroxidation, thermal-decomposition, thermochemical properties, radiation-chemistry, alkoxyl radicals, alpha-tocopherol, ho2 elimination, acid
IdentifiersURN: urn:nbn:se:kth:diva-23247DOI: 10.1021/jp037431zISI: 000220094100013ScopusID: 2-s2.0-1842531469OAI: oai:DiVA.org:kth-23247DiVA: diva2:341945
QC 20100525 QC 201110272010-08-102010-08-102011-10-27Bibliographically approved