Reaction of HO with Glycolaldehyde, HOCH2CHO:  Rate Coefficients (240−362 K) and Mechanism

Karunanandan, Rosalin; Hölscher, Dirk; Dillon, Terry J.; Horowitz, A.; Crowley, John N.; Vereecken, Luc; Peeters, Jozef

doi:10.1021/jp0649504

Cited by 33 publications

(49 citation statements)

References 40 publications

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“…Theoretical considerations do not support such a large hydroxyacetone formation (Dibble, 2004b). The hydroxyacetone rate constant with OH is set to k OH =5.98×10 −12 cm 3 molecule −1 s −1 (Dillon et al, 2006) and the rate constant of glycolaldehyde with OH is set to k OH =8×10 −12 cm 3 molecule −1 s −1 (Karunanandan et al, 2007). HC5 chemistry.…”

Section: Consequencesmentioning

confidence: 99%

Isoprene photooxidation: new insights into the production of acids and organic nitrates

et al. 2009

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Abstract. We describe a nearly explicit chemical mechanism for isoprene photooxidation guided by chamber studies that include time-resolved observation of an extensive suite of volatile compounds. We provide new constraints on the chemistry of the poorly-understood isoprene δ-hydroxy channels, which account for more than one third of the total isoprene carbon flux and a larger fraction of the nitrate yields. We show that the cis branch dominates the chemistry of the δ-hydroxy channel with less than 5% of the carbon following the trans branch. The modelled yield of isoprene nitrates is 12±3% with a large difference between the δ and β branches. The oxidation of these nitrates releases about 50% of the NO x . Methacrolein nitrates (modelled yield 15±3% from methacrolein) and methylvinylketone nitrates (modelled yield 11±3% yield from methylvinylketone) are also observed. Propanone nitrate, produced with a yield of 1% from isoprene, appears to be the longest-lived nitrate formed in the total oxidation of isoprene. We find a large molar yield of formic acid and suggest a novel mechanism leading to its formation from the organic nitrates. Finally, the most important features of this mechanism are summarized in a condensed scheme appropriate for use in global chemical transport models.

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Section: Consequencesmentioning

confidence: 99%

Isoprene photooxidation: new insights into the production of acids and organic nitrates

et al. 2009

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“…The PLP-LIF set-up used in these experiments has recently been used to study a number of OH reactions (Dillon et al, 2005;Dillon et al, 2006a;Dillon et al, 2007;Karunanandan et al, 2007). A detailed description including a schematic diagram of the apparatus was presented previously (Wollenhaupt et al, 2000), so only a brief description is given here.…”

Section: The Plp-lif Techniquementioning

confidence: 99%

Direct detection of OH formation in the reactions of HO2 with CH3C(O)O2 and other substituted peroxy radicals

2008

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Abstract. This work details the first direct observation of OH as a product from (R1): HO 2 +CH 3 C(O)O 2 →(products), which has generally been considered an atmospheric radical termination process. The technique of pulsed laser photolysis radical generation, coupled to calibrated laser induced fluorescence detection was used to measure an OH product yield for (R1) of α 1 (298 K)=(0.5±0.2). This study of (R1) included the measurement of a rate coefficient k 1 (298 K)=(1.4±0.5)×10 −11 cm 3 molecule −1 s −1 , substantially reducing the uncertainties in modelling this important atmospheric reaction. OH was also detected as a product from the reactions of HO 2 with three other carbonylcontaining peroxy radicals, albeit at smaller yield, e.g. (R2): HO 2 +CH 3 C(O)CH 2 O 2 →(products), α 2 ≈0.15. By contrast, OH was not observed (α<0.06) as a major product from reactions where carbonyl functionality was absent, e.g. HO 2 +HOCH 2 CH 2 O 2 (R8), and HO 2 +CH 3 CH(OH)CH 2 O 2 (R9).

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“…In the presence of NO, HOCH 2 CH 2 O radicals are produced that either decompose directly into formaldehyde and hydroxy methyl radicals (>25%), or form glycol aldehyde (HOCH 2 CHO) in the presence of O 2 . The reaction of this radical with OH leads to the production of 80% HOCH 2 CO 3 and 20% glyoxal (CHOCHO) (Bacher et al, 2001;Karunanandan et al, 2007 …”

Section: Chemical Reaction Pathwaymentioning

confidence: 99%

A consistent molecular hydrogen isotope chemistry scheme based on an independent bond approximation

2009

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Abstract. The isotopic composition of molecular hydrogen (H 2 ) produced by photochemical oxidation of methane (CH 4 ) and Volatile Organic Compounds (VOCs) is a key quantity in the global isotope budget of (H 2 ). The many individual reaction steps involved complicate its investigation. Here we present a simplified structure-activity approach to assign isotope effects to the individual elementary reaction steps in the oxidation sequence of CH 4 and some other VOCs. The approach builds on and extends the work by Gerst and Quay (2001) and Feilberg et al. (2007b). The description is generalized and allows the application, in principle, also to other compounds. The idea is that the C-H and C-D bonds -seen as reactive sites -have similar relative reaction probabilities in isotopically substituted, but otherwise identical molecules. The limitations of this approach are discussed for the reaction CH 4 +Cl. The same approach is applied to VOCs, which are important precursors of H 2 that need to be included into models. Unfortunately, quantitative information on VOC isotope effects and source isotope signatures is very limited and the isotope scheme at this time is limited to a strongly parameterized statistical approach, which neglects kinetic isotope effects. Using these concepts we implement a full hydrogen isotope scheme in a chemical box model and carry out a sensitivity study to identify those reaction steps and conditions that are most critical for the isotope composition of the final H 2 product. The reaction scheme is directly applicable in global chemistry models, which can thus include the isotope pathway of H 2 produced from CH 4 and VOCs in a consistent way.

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Reaction of HO with Glycolaldehyde, HOCH₂CHO: Rate Coefficients (240−362 K) and Mechanism

Cited by 33 publications

References 40 publications

Isoprene photooxidation: new insights into the production of acids and organic nitrates

Isoprene photooxidation: new insights into the production of acids and organic nitrates

Direct detection of OH formation in the reactions of HO<sub>2</sub> with CH<sub>3</sub>C(O)O<sub>2</sub> and other substituted peroxy radicals

A consistent molecular hydrogen isotope chemistry scheme based on an independent bond approximation

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Reaction of HO with Glycolaldehyde, HOCH2CHO: Rate Coefficients (240−362 K) and Mechanism

Cited by 33 publications

References 40 publications

Isoprene photooxidation: new insights into the production of acids and organic nitrates

Isoprene photooxidation: new insights into the production of acids and organic nitrates

Direct detection of OH formation in the reactions of HO&lt;sub&gt;2&lt;/sub&gt; with CH&lt;sub&gt;3&lt;/sub&gt;C(O)O&lt;sub&gt;2&lt;/sub&gt; and other substituted peroxy radicals

A consistent molecular hydrogen isotope chemistry scheme based on an independent bond approximation

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Product

Resources

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Reaction of HO with Glycolaldehyde, HOCH₂CHO: Rate Coefficients (240−362 K) and Mechanism

Direct detection of OH formation in the reactions of HO<sub>2</sub> with CH<sub>3</sub>C(O)O<sub>2</sub> and other substituted peroxy radicals