A Theoretical Study of the Photoisomerization of Glycolaldehyde and Subsequent OH Radical-Initiated Oxidation of 1,2-Ethenediol

So, Sui; Wille, Uta; Silva, Gabriel da

doi:10.1021/acs.jpca.5b06854

Cited by 23 publications

(22 citation statements)

References 65 publications

(113 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…we calculate a threshold of 272 kJ/mol, has been postulated as an atmospheric route to formation of HO • and formic acid (So et al, 2015), although it has not been experimentally observed.…”

Section: Other Carbonylsmentioning

confidence: 76%

“…S4l). This pathway has not been previously proposed for glycolaldehyde (Wallington et al, 2018;Bacher et al, 2001;Zhu and Zhu, 2010;Cui and Fang, 2011;So et al, 2015) and occurs via a 5-centre TS, which is lower in energy than the 4-centre TF TS for H 2 formation from the formyl and a β CH 2 hydrogen. Indeed it is the lowest energy dissociation pathway we have found in gylcolaldehyde.…”

mentioning

confidence: 66%

See 1 more Smart Citation

Photo-initiated ground state chemistry: How important is it in the atmosphere?

Rowell

Kable

Jordan

2021

Preprint

View full text Add to dashboard Cite

Abstract. Carbonyls are among the most abundant volatile organic compounds in the atmosphere. They are central to atmospheric photochemistry as absorption of near-UV radiation by the C=O chromophore can lead to photolysis. If photolysis does not occur on electronic excited states, non-radiative relaxation to the ground state will form carbonyls with extremely high internal energy. These “hot” molecules can access a range of ground state reactions. Up to nine potential ground state reactions are investigated at the B2GP-PLYP-D3/def2-TZVP level of theory for a dataset of 20 representative carbonyls. Almost all are energetically accessible under tropospheric conditions. Comparison with experiment suggests the most significant ground state dissociation pathways will be concerted triple fragmentation in saturated aldehydes, Norrish type III dissociation to form another carbonyl, and H2-loss involving the formyl H atom in aldehydes. Tautomerisation, leading to more reactive unsaturated species, is also predicted to be energetically accessible and is likely to be important when there is no low-energy ground state dissociation pathway, for example in α,β-unsaturated carbonyls and some ketones. The concerted triple fragmentation and H2-loss pathways have immediate atmospheric implication to global H2 production and tautomerisaton has implication to the atmospheric production of organic acids.

show abstract

Section: Other Carbonylsmentioning

confidence: 76%

mentioning

confidence: 66%

Photo-initiated ground state chemistry: How important is it in the atmosphere?

Rowell

Kable

Jordan

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…This alternative TF pathway has not been previously proposed in the photolysis of glycolaldehyde. 45,[63][64][65][66] Predicted S 0 TF thresholds are shown in Figure 3 below. In all cases but one, TF involves a sterically favourable 5-centre concerted TS involving H-loss from a β-hydrogen.…”

Section: Decarbonylation (Co-loss)mentioning

confidence: 99%

The Under-Explored Possibilities of Ground State Carbonyl Photochemistry

Rowell

Kable²,

Jordan³

2020

Preprint

View full text Add to dashboard Cite

Carbonyls are among the most abundant volatile organic compounds in the atmosphere, and their C=O chromophores allow them to photolyse. However, carbonyl photolysis reactions are not restricted to the excited state: the C=O chromophore allows relaxation to, and reaction on, the ground state, following photon absorption. <div><br></div><div>In this paper, the energetic thresholds for eight ground state reactions across twenty representative carbonyl species are calculated using double-hybrid density functional theory. Most reactions are found to be energetically accessible within the maximum photon energy available in the troposphere, but are absent in contemporary atmospheric chemistry models. </div><div><br></div><div>Structure–activity relationships are then elucidated so that the significance of each reaction pathway for particular carbonyl species can be predicted based upon their class. The calculations here demonstrate that ground state photolysis pathways are ubiquitous in carbonyls and should not be ignored in the analysis of carbonyl photochemistry.</div>

show abstract

“…Recently, we reported on the isomerization mechanism of glycolaldehyde (HOCH 2 CHO), the archetypal α‐hydroxy carbonyl and an important tropospheric compound in its own right . This work revealed that glycolaldehyde could undergo keto‐enol tautomerization via intramolecular transfer of two H atoms, mediated by the hydroxyl group.…”

Section: Introductionmentioning

confidence: 99%

The gas phase aldose‐ketone isomerization mechanism: Direct interconversion of the model hydroxycarbonyls 2‐hydroxypropanal and hydroxyacetone

Sun

Silva

2017

Int J Quantum Chem

Self Cite

View full text Add to dashboard Cite

We report a novel mechanism for the interconversion of 2-hydroxypropanal with its more-stable ketone isomer hydroxyacetone. Reaction proceeds via concerted transfer of two H atoms, requires a barrier of only 40 kcal mol 21 , bypasses the enediol intermediate, and is general for a-hydroxy carbonyls. A similar isomerization mechanism is shown to persist for b, g, and d-hydroxy carbonyls; these compounds are skeletal forms of the monosaccharides and this work, therefore, discloses the gas-phase mechanism for aldose-ketose isomerization. As an example, the isomerization of glyceraldehyde to dihydroxyacetone is shown to proceed via this mechanism with a barrier of 31 kcal mol 21 . Rate coefficients and thermochemical properties are reported for the isomerization of 2-hydroxypropanal and hydroxyacetone for use in detailed kinetic models. Additionally, RRKM theory k(E) values for this reaction suggest that it may transpire in the troposphere following solar excitation. K E Y W O R D S computational chemistry, gas-phase reactions, pyrolysis, reaction mechanisms 1 | I N T R O D U C T I O N Hydroxycarbonyls are common oxygenated intermediates formed in the photochemical oxidation of volatile organic compounds and in the thermal processing of lignocellulosic material. Hydroxyacetone (HOCH 2 C(O)CH 3 ), the simplest a-hydroxy ketone, is a widely-detected trace gas in the troposphere, [1] and its photochemical oxidation mechanisms have been studied extensively. [2-5] 2-Hydroxypropanal (CH 3 CHOH-CHO), an isomer of hydroxyacetone, is an intermediate in the pyrolysis and combustion chemistry of glyceral. [6] More broadly, the open-chain forms of the monosaccharides are hydroxycarbonyls, with an aldehyde (aldose) or ketone (ketose) moiety and a hydroxyl group at each remaining carbon. Hydroyxacetone and 2-hydroxypropanal thus serve as model compounds for the a-hydroxy carbonyl functionality in these simple sugars.Recently, we reported on the isomerization mechanism of glycolaldehyde (HOCH 2 CHO), [7] the archetypal a-hydroxy carbonyl and an important tropospheric compound in its own right. [8] This work revealed that glycolaldehyde could undergo keto-enol tautomerization via intramolecular transfer of two H atoms, mediated by the hydroxyl group. This process is reminiscent of a bimolecular mechanism previously shown to catalyze keto-enol tautomerizations. [9] In the course of our investigation into glycolaldehyde it became apparent that this compound could undergo degenerate isomerization reactions in which the unique O atoms (i.e., the alcohol and aldehyde functional groups) were effectively scrambled. The present work extends this analysis to hydroxycarbonyl compounds in which the alcohol and aldehyde/ketone groups are not interchangeable, starting with the hydroxyacetone/2-hydroxypropanal pairing, through the application of ab initio calculations and reaction rate theory modelling. This study expands our understanding of rearrangement reactions available to hydroxycarbonyl compounds in thermal environments and in the troposph...

show abstract

A Theoretical Study of the Photoisomerization of Glycolaldehyde and Subsequent OH Radical-Initiated Oxidation of 1,2-Ethenediol

Cited by 23 publications

References 65 publications

Photo-initiated ground state chemistry: How important is it in the atmosphere?

Photo-initiated ground state chemistry: How important is it in the atmosphere?

The Under-Explored Possibilities of Ground State Carbonyl Photochemistry

The gas phase aldose‐ketone isomerization mechanism: Direct interconversion of the model hydroxycarbonyls 2‐hydroxypropanal and hydroxyacetone

Contact Info

Product

Resources

About