Proton-Catalyzed Decomposition of Multifunctionalized Organic Hydroperoxides Derived from the Reactions of Criegee Intermediates with Ethylene Glycol in Aqueous Organic Media

Enami, Shinichi

doi:10.1021/acsearthspacechem.2c00142

Cited by 3 publications

(4 citation statements)

References 69 publications

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“…276,356 Second, PO hydrolysis is highly influenced by the condensed-phase pH. 125,135,397,399 As indicated in Figure 15, the hydrolysis of α-HAHPs 396,397 and α-AHPs 49,122,125 is catalyzed by acids. Meanwhile, a base-catalyzed aqueous-phase decomposition mechanism was proposed for α-AAHP by Zhao et al 135 In addition, temperature plays a significant role in determining the rate of PO hydrolysis (Figure 15).…”

Section: Po Hydrolysismentioning

confidence: 99%

Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere

et al. 2023

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Organic peroxides (POs) are organic molecules with one or more peroxide (−O−O−) functional groups. POs are commonly regarded as chemically labile termination products from gas-phase radical chemistry and therefore serve as temporary reservoirs for oxidative radicals (HO x and RO x ) in the atmosphere. Owing to their ubiquity, active gasparticle partitioning behavior, and reactivity, POs are key reactive intermediates in atmospheric multiphase processes determining the life cycle (formation, growth, and aging), climate, and health impacts of aerosol. However, there remain substantial gaps in the origin, molecular diversity, and fate of POs due to their complex nature and dynamic behavior. Here, we summarize the current understanding on atmospheric POs, with a focus on their identification and quantification, state-of-the-art analytical developments, molecular-level formation mechanisms, multiphase chemical transformation pathways, as well as environmental and health impacts. We find that interactions with SO 2 and transition metal ions are generally the fast PO transformation pathways in atmospheric liquid water, with lifetimes estimated to be minutes to hours, while hydrolysis is particularly important for α-substituted hydroperoxides. Meanwhile, photolysis and thermolysis are likely minor sinks for POs. These multiphase PO transformation pathways are distinctly different from their gas-phase fates, such as photolysis and reaction with OH radicals, which highlights the need to understand the multiphase partitioning of POs. By summarizing the current advances and remaining challenges for the investigation of POs, we propose future research priorities regarding their origin, fate, and impacts in the atmosphere.

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Section: Po Hydrolysismentioning

confidence: 99%

Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere

et al. 2023

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“…The mechanism in which a water molecule is incorporated into the α-Tp CIs to form α-HHs, followed by rapid decomposition into the corresponding aldehyde and isomerization into lactols is in agreement with our previous results obtained from negative-ion mass spectrometry. , The fact that the signals attributed to lactols kept increasing even after that of α-HH-Na + had disappeared (Figure A) implies that the aldehyde was MS-silent and acted as a reservoir that slowly isomerized into the lactols (Scheme ). Furthermore, we note the possibility that these lactols were also produced from the decomposition of HP-THP/THF (the conversion of ROOH to ROH) as observed in the cases of α-alkoxyalkyl hydroperoxides ,− and other ROOH . Based on the fact that the ion signals at m / z 267;269 also appeared in water:CD 3 COCD 3 solvent (see below) and the increase of the signals as a function of time was not correlated with the decay of m / z 283, we concluded that these lactols were not a decomposition product of C 13 SOZs.…”

Section: Resultsmentioning

confidence: 89%

Stability of Terpenoid-Derived Secondary Ozonides in Aqueous Organic Media

et al. 2022

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1,2,4-Trioxolanes, known as secondary ozonides (SOZs), are key products of ozonolysis of biogenic terpenoids. Functionalized terpenoid-derived SOZs are readily taken up into atmospheric aerosols; however, their condensed-phase fates remain unknown. Here, we report the results of a time-dependent mass spectrometric investigation into the liquid-phase fates of C 10 and C 13 SOZs synthesized by ozonolysis of a C 10 monoterpene alcohol (α-terpineol) in water:acetone (1:1 = vol:vol) mixtures. Isomerization of Criegee intermediates and bimolecular reaction of Criegee intermediates with acetone produced C 10 and C 13 SOZs, respectively, which were detected as their Na + -adducts by positive-ion electrospray mass spectrometry. Use of CD 3 COCD 3 , D 2 O, and H 2 18 O solvents enabled identification of three types of C 13 SOZs (aldehyde, ketone, and lactol) and other products. These SOZs were surprisingly stable in water:acetone (1:1) mixtures at T = 298 K, with some persisting for at least a week. Theoretical calculations supported the high stability of the lactol-type C 13 SOZ formed from the aldehyde-type C 13 SOZ via intramolecular rearrangement. The present results suggest that terpenoid-derived SOZs can persist in atmospheric condensed phases, potentially until they are delivered to the epithelial lining fluid of the pulmonary alveoli via inhaled particulate matter, where they may exert hitherto unrecognized adverse health effects.

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“…Thus, the signals for Levo+2O were assigned to α-hydroxy-hydroperoxides (α-HHs) possessing an −OOH and three −OH moieties that were formed by the reaction of hydroxy peroxy radicals [R(−OH)(−OO • )] with HO 2 . As previous studies have suggested, 27,38,48,49 α-HHs partly decompose into their corresponding carbonyl compounds by releasing H 2 O 2 at pH 3.7 (Scheme 1). Thus, our results suggest that H-abstractions from carbon atoms with an −OH moiety (pathway B) occurred more preferentially (∼84%) than abstractions from carbon atoms with an ether -R-O-R′-moiety (∼16%, pathway A).…”

Section: Mass Spectrometry Of Fenton Oxidation Of Levoglucosan In Watermentioning

confidence: 83%

“…They used 2,5-dihydroxybenzoic acid as the matrix and NaCl or LiCl as the catanizing agent and measured mass spectra up to a reaction time of 1 week. Because our NaCl-MS approach was capable of detecting oligomeric species such as dimers produced by the reactions of sesquiterpene Criegee intermediates with alcohols, − any oligomeric products of Levo would have been detected if they had formed. In addition, our UV–vis absorption spectroscopic analyses of the reaction mixtures also provided no evidence of the formation oligomeric products (see section ).…”

Section: Resultsmentioning

confidence: 99%

Mechanism of Fenton Oxidation of Levoglucosan in Water

2023

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Levoglucosan (Levo) is a major saccharide formed by the combustion of cellulosic materials. Levo was once considered an inert tracer of biomass-burning aerosols; however, recent studies have indicated that Levo in atmospheric condensed phases does indeed react with atmospheric reactants. Here, we report the results of a time-resolved mass spectrometric study of the oxidation of Levo in aqueous solutions with ferrous ion (Fe 2+ )/ hydrogen peroxide (H 2 O 2 ) (i.e., Fenton's reagent). The major products of the Fenton oxidation of Levo were oxygen-atomincorporated species (Levo+nO, n = 1−3). Experiments using Levo-d7 (all C−H bonds replaced by C−D) and D 2 O or H 2 18 O as the solvent revealed that OH predominantly (∼85% of all C−H bonds) abstracts H atoms attached to the carbon atoms possessing a hydroxyl moiety (−OH), which is followed by the formation of a carbonyl moiety (−C�O). Subsequent hydration of these products results in the formation of geminal diols (detected as Levo +1O species). Our results also suggest the formation of α-hydroxy-hydroperoxides (detected as Levo+2O species) that exist in equilibrium, with the compounds possessing a −C�O moiety and with H 2 O 2 . H-abstractions from −O-H were found to be a minor reaction pathway (≤5% of all H-abstractions). The present proposed oxidation mechanisms improve our understanding of how the chemical components of atmospheric condensed phases change by metal-catalyzed aging processes without sunlight.

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Proton-Catalyzed Decomposition of Multifunctionalized Organic Hydroperoxides Derived from the Reactions of Criegee Intermediates with Ethylene Glycol in Aqueous Organic Media

Cited by 3 publications

References 69 publications

Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere

Organic Peroxides in Aerosol: Key Reactive Intermediates for Multiphase Processes in the Atmosphere

Stability of Terpenoid-Derived Secondary Ozonides in Aqueous Organic Media

Mechanism of Fenton Oxidation of Levoglucosan in Water

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