Formation Yields of Methyl Vinyl Ketone and Methacrolein from the Gas-Phase Reaction of O3 with Isoprene

The rate constants for the ozonolysis of isoprene (ISO), methacrolein (MACR) and methyl vinyl ketone (MVK) have been measured using the newly built large volume atmospheric simulation chamber at CNRS-Orleans (France), HELIOS (Chambre de simulation atmosphérique à irradiation naturelle d’Orléans). The OH radical yields from the ozonolysis of isoprene, MACR and MVK have also been determined, as well as the gas phase stable products and their yields. The secondary organic aerosol yield for the ozonolysis of isoprene has been tentatively measured in the presence and absence of an OH radical scavenger. The measurements were performed under different experimental conditions with and without adding cyclohexane (cHX) as an OH radical scavenger. All experiments have been conducted at 760 torr of purified dry air (RH < 1%) and ambient temperature (T = 281–295 K). The data obtained are discussed and compared with those from the literature. The use of the HELIOS facility and its associated analytical equipment enables the derivation of kinetic parameters as well as mechanistic information under near realistic atmospheric conditions.

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Kinetic Analysis of the Gas-Phase Reactions of Methyl Vinyl Ketone with the OH Radical in the Presence of NOx

Journal of the Brazilian Chemical Society ◽

10.1590/s0103-50531998000600007 ◽

1998 ◽

Vol 9 (6) ◽

pp. 551-562

Author(s):

André Silva Pimentel ◽

Graciela Arbilla

Keyword(s):

Kinetic Analysis ◽

Gas Phase ◽

Vinyl Ketone ◽

Methyl Vinyl Ketone ◽

Oh Radical ◽

Gas Phase Reactions ◽

Methyl Vinyl

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Technical note: Conversion of isoprene hydroxy hydroperoxides (ISOPOOHs) on metal environmental simulation chamber walls

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-4053-2017 ◽

2017 ◽

Vol 17 (6) ◽

pp. 4053-4062 ◽

Cited By ~ 4

Author(s):

Anne-Kathrin Bernhammer ◽

Martin Breitenlechner ◽

Frank N. Keutsch ◽

Armin Hansel

Keyword(s):

Gas Phase ◽

Technical Note ◽

Vinyl Ketone ◽

Heterogeneous Reactions ◽

Methyl Vinyl Ketone ◽

Oxidation Products ◽

Chemical Mechanism ◽

Stainless Steel Surface ◽

Methyl Vinyl

Abstract. Sources and sinks of isoprene oxidation products from low-NOx isoprene chemistry have been studied at the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber with a custom-built selective reagent ion time-of-flight mass spectrometer (SRI-ToF-MS), which allows quantitative measurement of isoprene hydroxy hydroperoxides (ISOPOOHs). The measured concentrations of the main oxidation products were compared to chemical box model simulations based on the Leeds Master Chemical Mechanism (MCM) v3.3. The modeled ISOPOOH concentrations are a factor of 20 higher than the observed concentrations, and methyl vinyl ketone (MVK) and methacrolein (MACR) concentrations are up to a factor of 2 lower compared to observations, despite the artifact-free detection method. Addition of catalytic conversion of 1,2-ISOPOOH and 4,3-ISOPOOH to methyl vinyl ketone (MVK) and methacrolein (MACR) on the stainless-steel surface of the chamber to the chemical mechanism resolves the discrepancy between model predictions and observation. This suggests that isoprene chemistry in a metal chamber under low-NOx conditions cannot be described by a pure gas phase model alone. Biases in the measurement of ISOPOOH, MVK, and MACR can be caused not only intra-instrumentally but also by the general experimental setup. The work described here extends the role of heterogeneous reactions affecting gas phase composition and properties from instrumental surfaces, described previously, to general experimental setups. The role of such conversion reactions on real environmental surfaces is yet to be explored.

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