The Mechanism of Methoxy Radical Oxidation by O2in the Gas Phase. Computational Evidence for Direct H Atom Transfer Assisted by an Intermolecular Noncovalent O···O Bonding Interaction

1999 ◽  
Vol 121 (6) ◽  
pp. 1337-1347 ◽  
Author(s):  
Josep M. Bofill ◽  
Santiago Olivella ◽  
Albert Solé ◽  
Josep M. Anglada
Keyword(s):  
Gas Phase ◽  
Atom Transfer ◽  
Radical Oxidation ◽  
Bonding Interaction ◽  
Methoxy Radical

scholarly journals Evaluation of the chemical composition of gas- and particle-phase products of aromatic oxidation

2020 ◽  
Vol 20 (16) ◽  
pp. 9783-9803
Author(s):  
Archit Mehra ◽  
Yuwei Wang ◽  
Jordan E. Krechmer ◽  
Andrew Lambe ◽  
Francesca Majluf ◽  
...  
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer ◽  
Urban Areas ◽  
Minor Component ◽  
Proton Transfer Reaction ◽  
Chemical Mechanism ◽  
Particle Phase ◽  
Experimental Conditions ◽  
Radical Oxidation ◽  
Product Ions

Abstract. Aromatic volatile organic compounds (VOCs) are key anthropogenic pollutants emitted to the atmosphere and are important for both ozone and secondary organic aerosol (SOA) formation in urban areas. Recent studies have indicated that aromatic hydrocarbons may follow previously unknown oxidation chemistry pathways, including autoxidation that can lead to the formation of highly oxidised products. In this study we evaluate the gas- and particle-phase ions measured by online mass spectrometry during the hydroxyl radical oxidation of substituted C9-aromatic isomers (1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, propylbenzene and isopropylbenzene) and a substituted polyaromatic hydrocarbon (1-methylnaphthalene) under low- and medium-NOx conditions. A time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) with iodide–anion ionisation was used with a filter inlet for gases and aerosols (FIGAERO) for the detection of products in the particle phase, while a Vocus proton-transfer-reaction mass spectrometer (Vocus-PTR-MS) was used for the detection of products in the gas phase. The signal of product ions observed in the mass spectra were compared for the different precursors and experimental conditions. The majority of mass spectral product signal in both the gas and particle phases comes from ions which are common to all precursors, though signal distributions are distinct for different VOCs. Gas- and particle-phase composition are distinct from one another. Ions corresponding to products contained in the near-explicit gas phase Master Chemical Mechanism (MCM version 3.3.1) are utilised as a benchmark of current scientific understanding, and a comparison of these with observations shows that the MCM is missing a range of highly oxidised products from its mechanism. In the particle phase, the bulk of the product signal from all precursors comes from ring scission ions, a large proportion of which are more oxidised than previously reported and have undergone further oxidation to form highly oxygenated organic molecules (HOMs). Under the perturbation of OH oxidation with increased NOx, the contribution of HOM-ion signals to the particle-phase signal remains elevated for more substituted aromatic precursors. Up to 43 % of product signal comes from ring-retaining ions including HOMs; this is most important for the more substituted aromatics. Unique products are a minor component in these systems, and many of the dominant ions have ion formulae concurrent with other systems, highlighting the challenges in utilising marker ions for SOA.

scholarly journals Probing ‘Spin-Forbidden’ Oxygen-Atom Transfer: Gas-Phase Reactions of Chromium−Porphyrin Complexes

2010 ◽  
Vol 132 (12) ◽  
pp. 4336-4343 ◽  
Author(s):  
Maria Elisa Crestoni ◽  
Simonetta Fornarini ◽  
Francesco Lanucara ◽  
Jeffrey J. Warren ◽  
James M. Mayer
Keyword(s):  
Oxygen Atom ◽  
Gas Phase ◽  
Atom Transfer ◽  
Oxygen Atom Transfer ◽  
Gas Phase Reactions

Mechanistic Aspects of Gas-Phase Hydrogen-Atom Transfer from Methane to [CO].+and [SiO].+: Why Do They Differ?

2013 ◽  
Vol 19 (21) ◽  
pp. 6662-6669 ◽  
Author(s):  
Nicolas Dietl ◽  
Anna Troiani ◽  
Maria Schlangen ◽  
Ornella Ursini ◽  
Giancarlo Angelini ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer

scholarly journals The gas phase oxidation of HCOOH by Cl and NH2 radicals. Proton coupled electron transfer versus hydrogen atom transfer

2019 ◽  
Vol 117 (9-12) ◽  
pp. 1430-1441 ◽  
Author(s):  
Josep M. Anglada ◽  
Ramon Crehuet ◽  
Albert Solé
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Proton Coupled Electron Transfer ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

scholarly journals Electron-Proton Decoupling in Excited-State Hydrogen Atom Transfer in the Gas Phase

2015 ◽  
Vol 127 (50) ◽  
pp. 15304-15308 ◽  
Author(s):  
Mitsuhiko Miyazaki ◽  
Ryuhei Ohara ◽  
Kota Daigoku ◽  
Kenro Hashimoto ◽  
Jonathan R. Woodward ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Proton Decoupling

Gas-phase Ion-molecule Interactions involving Atom Transfer; Limitations of the Orbiting Theory in accounting for the Variation of Cross-section with Energy

Nature ◽  
1964 ◽  
Vol 202 (4934) ◽  
pp. 795-797 ◽  
Author(s):  
J. B. HOMER ◽  
R. S. LEHRLE ◽  
J. C. ROBB ◽  
D. W. THOMAS
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Atom Transfer ◽  
Molecule Interactions ◽  
Gas Phase Ion

Oxygen Atom Transfer to Positive Ions: A Novel Reaction of Ozone in the Gas Phase

1998 ◽  
Vol 120 (31) ◽  
pp. 7869-7874 ◽  
Author(s):  
Maria Anita Mendes ◽  
Luiz Alberto B. Moraes ◽  
Regina Sparrapan ◽  
Marcos N. Eberlin ◽  
Risto Kostiainen ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Gas Phase ◽  
Atom Transfer ◽  
Oxygen Atom Transfer ◽  
Positive Ions

The mechanism of methoxy radical oxidation: hydrogen abstraction versus trioxy radical formation

1996 ◽  
Vol 263 (3-4) ◽  
pp. 371-378 ◽  
Author(s):  
Tim P.W. Jungkamp ◽  
John H. Seinfeld
Keyword(s):  
Hydrogen Abstraction ◽  
Radical Formation ◽  
Radical Oxidation ◽  
Methoxy Radical
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