Oxygen-18 Tracer Evidence for the Termination Mechanism in the Photochemical Oxidation of Acetaldehyde

McDowell, C. A.; Sifniades, Stylianos

doi:10.1139/v63-046

Cited by 34 publications

(17 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The absence of a high-temperature limit to the cool-flame region of figure 5 is in agreement with the results of experimental studies of the acetaldehyde + oxygen system. There are indications (Mile, Pollard & Wilson 1970) th a t for a t least one alkane oxidation system the high-temperature limit found in an earlier study (Fish 1967) resulted from a failure to detect weak pulses early in the reaction.…”

Section: Discussionmentioning

confidence: 82%

A mathematical model of the cool-flame oxidation of acetaldehyde

Halstead

Prothero

Quinn

1971

Proc. R. Soc. Lond. A

View full text Add to dashboard Cite

A detailed mathematical model of the non-isothermal oxidation of acetaldehyde has been found to give a realistic simulation of (i) single and multiple cool flames, their limits, amplitudes and induction periods; (ii) two-stage ignition; and (iii) the negative temperature coefficient for the maximum rate of slow combustion. A simplified form of the model, valid over a limited range of conditions, has been subjected to mathematical analysis to provide interpretations of the effects simulated by the detailed model. It is concluded that cool flames are thermokinetic effects often, but not exclusively, of an oscillatory nature, and that a satisfactory account of cool-flame phenomena must necessarily take reactant consumption into account.

show abstract

Section: Discussionmentioning

confidence: 82%

A mathematical model of the cool-flame oxidation of acetaldehyde

Halstead

Prothero

Quinn

1971

Proc. R. Soc. Lond. A

View full text Add to dashboard Cite

show abstract

“…The homogeneous recombination of two C 9 H 13 O 5 · radicals via elimination of O 2 produces a covalently bound diacyl peroxide. Note that this reaction pathway was proposed as a radical chain termination step from oxidation of aldehydes in both gas and liquid phases (18,19). The covalent dimer homologs have been observed in the gas phase from the ozonolysis of α-pinene ranging from ∼500 parts per trillion (ppt) to ∼30 parts per billion (ppb) (13,20).…”

Section: Resultsmentioning

confidence: 99%

Formation and evolution of molecular products in α-pinene secondary organic aerosol

Zhang

McVay

Huang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

272

401

View full text Add to dashboard Cite

Much of our understanding of atmospheric secondary organic aerosol (SOA) formation from volatile organic compounds derives from laboratory chamber measurements, including mass yield and elemental composition. These measurements alone are insufficient to identify the chemical mechanisms of SOA production. We present here a comprehensive dataset on the molecular identity, abundance, and kinetics of α-pinene SOA, a canonical system that has received much attention owing to its importance as an organic aerosol source in the pristine atmosphere. Identified organic species account for ∼58-72% of the α-pinene SOA mass, and are characterized as semivolatile/low-volatility monomers and extremely low volatility dimers, which exhibit comparable oxidation states yet different functionalities. Features of the α-pinene SOA formation process are revealed for the first time, to our knowledge, from the dynamics of individual particle-phase components. Although monomeric products dominate the overall aerosol mass, rapid production of dimers plays a key role in initiating particle growth. Continuous production of monomers is observed after the parent α-pinene is consumed, which cannot be explained solely by gasphase photochemical production. Additionally, distinct responses of monomers and dimers to α-pinene oxidation by ozone vs. hydroxyl radicals, temperature, and relative humidity are observed. Gas-phase radical combination reactions together with condensed phase rearrangement of labile molecules potentially explain the newly characterized SOA features, thereby opening up further avenues for understanding formation and evolution mechanisms of α-pinene SOA.secondary organic aerosol | particulate matter | air quality | climate S econdary organic aerosol (SOA), comprising a large number of structurally different organic oxygenates, is a dominant constituent of submicrometer atmospheric particulate matter (1). Molecular characterization of SOA has been a major research goal in atmospheric chemistry for several decades (2), owing to the importance of organic aerosol in air quality and Earth's energy budget. Both biogenic (e.g., isoprene, monoterpenes) and anthropogenic (e.g., aromatics, large alkanes) organic compounds are well-established precursors to SOA. Knowledge of the SOA molecular composition is crucial for elucidation of its underlying formation mechanisms.The most abundant monoterpene in the troposphere is α-pinene (3). The oxidation of α-pinene by ozone has become a canonical SOA system (4-12). Identification of multifunctional particlephase products has been reported, including monomers with carboxylic acid moieties (4, 6) and high-molecular-weight compounds (7,8,12), although molecular structures and formation pathways of oligomers remain uncertain (5). Recently, a class of extremely low-volatility gas-phase organic compounds (ELVOCs) has been identified as an important component in the α-pinene ozonolysis chemistry (13). Identification of the ELVOCs in the particle phase and elucidation of the mechanism of their format...

show abstract

“…High termination constants have also been reported for the gas phase oxidation of acetaldehyde and propionaldehyde (8.9 x 10'' and 2.7 x 1010 M -' s-', respectively (21)). In the gas phase, it has been shown by means of "0, labeling of peroxyacetyl radicals that the molecular oxygen evolved in termination comes from both radicals (22). Even if the same holds true for the liquid phase, it does not allow a distinction to be made between a concerted process analogous to the Russell mechanism for secondary peroxy radicals (191, i.e.…”

Section: Introductionmentioning

confidence: 99%

Absolute rate constants for hydrocarbon autoxidation. XIII. Aldehydes: photo-oxidation, co-oxidation, and inhibition

Заиков¹,

Howard²,

Ingold³

1969

Can. J. Chem.

View full text Add to dashboard Cite

The oxidations of acetaldehyde, heptanal, octanal, cyclohexanecarboxaldehyde, pivaldehyde, and benzaldehyde in chlorobenzene at 0 "C have been studied. These aldehydes oxidize at similar rates under similar conditions because there are compensating changes in the rate constants for chain propagation (k,) and chain termination (2k,). The termination rate constants increase from -7 x lo6 M-I S-I f or pivaldehyde and cyclohexanecarboxaldehyde to -2 x lo9 M-' s-' f or benzaldehyde. The propagation rate constants increase from -1 x lo3 M-'s-' for pivaldehyde to -1 x lo4 M-l s-' f ox benzaldehyde.The rate of oxidation of the aldehydes was decreased by the addition of 1,4-cyclohexadiene, tetralin, tetralin hydroperoxide, cumene, cumene hydroperoxide, t-butyl hydroperoxide, and 2,6-di-t-butyl-4-methylphenol. As a result of product analysis and absolute rate constant measurements, it is concluded that the peroxy radicals derived from aldehydes are considerably more reactive in hydrogen atom abstraction from hydrocarbons than are the peroxy radicals derived from the hydrocarbons. In the abstraction from cyclohexadiene, the acylperoxy radicals appear to be from 15 to 70 times as reactive, and the benzoylperoxy radicals about 8W900 times as reactive, as the hydroperoxy radical. The differences in reactivity are very much less pronounced in the abstraction from 2,6-di-t-butyl-4-methylphenol.The great ease of oxidation of all aldehydes, and particularly benzaldehyde, is due at least in part to the high reactivity of the peroxy radicals formed in these reactions.

show abstract

Oxygen-18 Tracer Evidence for the Termination Mechanism in the Photochemical Oxidation of Acetaldehyde

Cited by 34 publications

References 5 publications

A mathematical model of the cool-flame oxidation of acetaldehyde

A mathematical model of the cool-flame oxidation of acetaldehyde

Formation and evolution of molecular products in α-pinene secondary organic aerosol

Absolute rate constants for hydrocarbon autoxidation. XIII. Aldehydes: photo-oxidation, co-oxidation, and inhibition

Contact Info

Product

Resources

About