Atmospheric fate of methacrolein: 1. Peroxy radical isomerization following addition of OH and O₂

TY - JOUR

T1 - Atmospheric fate of methacrolein

T2 - 1. Peroxy radical isomerization following addition of OH and O2

AU - Crounse, John D.

AU - Knap, Hasse Christian

AU - Ørnsø, Kristian B.

AU - Jørgensen, Solvejg

AU - Paulot, Fabien

AU - Kjærgaard, Henrik Grum

AU - Wennberg, Paul O.

PY - 2012/6/21

Y1 - 2012/6/21

N2 - Peroxy radicals formed by addition of OH and O 2 to the olefinic carbon atoms in methacrolein react with NO to form methacrolein hydroxy nitrate and hydroxyacetone. We observe that the ratio of these two compounds, however, unexpectedly decreases as the lifetime of the peroxy radical increases. We propose that this results from an isomerization involving the 1,4-H-shift of the aldehydic hydrogen atom to the peroxy group. The inferred rate (0.5 ± 0.3 s -1 at T = 296 K) is consistent with estimates obtained from the potential energy surface determined by high level quantum calculations. The product, a hydroxy hydroperoxy carbonyl radical, decomposes rapidly, producing hydroxyacetone and re-forming OH. Simulations using a global chemical transport model suggest that most of the methacrolein hydroxy peroxy radicals formed in the atmosphere undergo isomerization and decomposition.

AB - Peroxy radicals formed by addition of OH and O 2 to the olefinic carbon atoms in methacrolein react with NO to form methacrolein hydroxy nitrate and hydroxyacetone. We observe that the ratio of these two compounds, however, unexpectedly decreases as the lifetime of the peroxy radical increases. We propose that this results from an isomerization involving the 1,4-H-shift of the aldehydic hydrogen atom to the peroxy group. The inferred rate (0.5 ± 0.3 s -1 at T = 296 K) is consistent with estimates obtained from the potential energy surface determined by high level quantum calculations. The product, a hydroxy hydroperoxy carbonyl radical, decomposes rapidly, producing hydroxyacetone and re-forming OH. Simulations using a global chemical transport model suggest that most of the methacrolein hydroxy peroxy radicals formed in the atmosphere undergo isomerization and decomposition.

U2 - 10.1021/jp211560u

DO - 10.1021/jp211560u

M3 - Journal article

C2 - 22452246

SN - 1089-5639

VL - 116

SP - 5756

EP - 5762

JO - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

JF - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

IS - 24

ER -