Overall rate constant measurements of the reaction of hydroxy- and chloroalkylperoxy radicals derived from methacrolein and methyl vinyl ketone with nitric oxide
The overall rate constants of the reactions of NO with hydroxy- and chloroalkylperoxy radicals, derived from the OH- and Cl-initiated oxidation of methacrolein and methyl vinyl ketone, respectively, were directly determined for the first time using the turbulent-flow technique and pseudo-first-order kinetics conditions with high-pressure chemical ionization mass spectrometry for the direct detection of peroxy radical reactants. The individual 100 Torr, 298 K hydroxyalkylperoxy + NO rate constants for the methacrolein [(0.93 ± 0.12) (2σ) × 10-11 cm3 molecule-1 s-1] and methyl vinyl ketone [(0.84 ± 0.10) × 10-11 cm3 molecule-1 s-1] systems were found to be identical within the 95% confidence interval associated with each separate measurement, as were the chloroalkylperoxy + NO rate constants for both methacrolein [(1.17 ± 0.11) × 10-11 cm3 molecule-1 s-1] and methyl vinyl ketone [(1.14 ± 0.14) × 10-11 cm3 molecule-1 s-1]. However, the difference in the rate constants between the hydroxyperoxy + NO and chloroalkylperoxy + NO systems was found to be statistically significant, with the chloroalkylperoxy + NO rate constants about 30% higher than the corresponding hydroxyalkylperoxy + NO rate constants. This substitutent effect was rationalized via a frontier molecular orbital model approach.
Hsin, Hong Yuan, and Matthew J. Elrod. 2007. "Overall Rate Constant Measurements of the Reaction of Hydroxy- and Chloroalkylperoxy Radicals Derived from Methacrolein and Methyl Vinyl Ketone with Nitric Oxide." Journal of Physical Chemistry A 111(4): 613-619.
American Chemical Society
Journal of Physical Chemistry A
Chemistry and Biochemistry