Thermochemical Properties, ΔfH°(298),S°(298), andCp°(T), forn-Butyl andn-Pentyl Hydroperoxides and the Alkyl and Peroxy Radicals, Transition States, and Kinetics for Intramolecular Hydrogen Shift Reactions of the Peroxy Radicals

2007 ◽  
Vol 111 (28) ◽  
pp. 6361-6377 ◽  
Author(s):  
Li Zhu ◽  
Joseph W. Bozzelli ◽  
Lisa M. Kardos
Keyword(s):  
Transition States ◽  
Thermochemical Properties ◽  
Peroxy Radicals ◽  
Hydrogen Shift ◽  
Intramolecular Hydrogen

The atmospheric oxidation of dimethyl, diethyl, and diisopropyl ethers. The role of the intramolecular hydrogen shift in peroxy radicals

2016 ◽  
Vol 18 (11) ◽  
pp. 7707-7714 ◽  
Author(s):  
Sainan Wang ◽  
Liming Wang
Keyword(s):  
Atmospheric Oxidation ◽  
Peroxy Radicals ◽  
Hydrogen Shift ◽  
Intramolecular Hydrogen ◽  
Clean Atmosphere

Ethers can be auto-oxidized with no O3 formation in a ‘clean’ atmosphere.

scholarly journals Intramolecular Hydrogen Shift Chemistry of Hydroperoxy-Substituted Peroxy Radicals

2018 ◽  
Vol 123 (2) ◽  
pp. 590-600 ◽  
Author(s):  
Eric Praske ◽  
Rasmus V. Otkjær ◽  
John D. Crounse ◽  
J. Caleb Hethcox ◽  
Brian M. Stoltz ◽  
...  
Keyword(s):  
Peroxy Radicals ◽  
Hydrogen Shift ◽  
Intramolecular Hydrogen

Calculated Hydrogen Shift Rate Constants in Substituted Alkyl Peroxy Radicals

2018 ◽  
Vol 122 (43) ◽  
pp. 8665-8673 ◽  
Author(s):  
Rasmus V. Otkjær ◽  
Helene H. Jakobsen ◽  
Camilla Mia Tram ◽  
Henrik G. Kjaergaard
Keyword(s):  
Rate Constants ◽  
Peroxy Radicals ◽  
Hydrogen Shift ◽  
Alkyl Peroxy Radicals

Hydrogen shift reactions in four methyl-buten-ol (MBO) peroxy radicals and their impact on the atmosphere

2016 ◽  
Vol 147 ◽  
pp. 79-87 ◽  
Author(s):  
Hasse C. Knap ◽  
Johan A. Schmidt ◽  
Solvejg Jørgensen
Keyword(s):  
Peroxy Radicals ◽  
Hydrogen Shift

Importance of isomerization reactions for the OH radical regeneration from the photo-oxidation of isoprene investigated in the atmospheric simulation chamber SAPHIR

2020 ◽  
Author(s):  
Anna Novelli ◽  
Luc Vereecken ◽  
Birger Bohn ◽  
Hans-Peter Dorn ◽  
Georgios Gkatzelis ◽  
...  
Keyword(s):  
Oh Radicals ◽  
Oh Radical ◽  
Peroxy Radicals ◽  
Atmospheric Conditions ◽  
Unimolecular Reactions ◽  
Model Calculations ◽  
Hydrogen Shift ◽  
Wide Range ◽  
Regeneration Efficiency ◽  
Simulation Chamber

<p>Theoretical, laboratory and chamber studies have shown fast regeneration of hydroxyl radical (OH) in the photochemistry of isoprene largely due to previously disregarded unimolecular reactions which were previously thought not to be important under atmospheric conditions. Based on early field measurements, nearly complete regeneration was hypothesized for a wide range of tropospheric conditions, including areas such as the rainforest where slow regeneration of OH radicals is expected due to low concentrations of nitric oxide (NO). In this work the OH regeneration in the isoprene oxidation is directly quantified for the first time through experiments covering a wide range of atmospheric conditions (i.e. NO between 0.15 and 2 ppbv and temperature between 25 and 41°C) in the atmospheric simulation chamber SAPHIR. These conditions cover remote areas partially influenced by anthropogenic NO emissions, giving a regeneration efficiency of OH close to one, and areas like the Amazonian rainforest with very low NO, resulting in a surprisingly high regeneration efficiency of 0.5, i.e. a factor of 2 to 3 higher than explainable in the absence of unimolecular reactions. The measured radical concentrations were compared to model calculations and the best agreement was observed when at least 50% of the total loss of isoprene peroxy radicals conformers (weighted by their abundance) occurs via isomerization reactions for NO lower than 0.2 parts per billion (ppbv). For these levels of NO, up to 50% of the OH radicals are regenerated from the products of the 1,6 α-hydroxy-hydrogen shift (1,6-H shift) of Z-δ-RO<sub>2 </sub>radicals through photolysis of an unsaturated hydroperoxy aldehyde (HPALD) and/or through the fast aldehyde hydrogen shift (rate constant ~10 s<sup>-1</sup> at 300K) in di-hydroperoxy carbonyl peroxy radicals (di-HPCARP-RO<sub>2</sub>), depending on their relative yield. The agreement between all measured and modelled trace gases (hydroxyl, hydroperoxy and organic peroxy radicals, carbon monoxide and the sum of methyl vinyl ketone, methacrolein and hydroxyl hydroperoxides) is nearly independent on the adopted yield of HPALD and di-HPCARP-RO<sub>2</sub> as both degrade relatively fast (< 1 h), forming OH radical and CO among other products. Taking into consideration this and earlier isoprene studies, considerable uncertainties remain on the oxygenated products distribution, which affect radical levels and organic aerosol downwind of unpolluted isoprene dominated regions.</p>

Nonclassical Aryl Radicals:  Intermediates or Transition States for the Hydrogen Shift Reactions?

1996 ◽  
Vol 61 (12) ◽  
pp. 4111-4114 ◽  
Author(s):  
Jerzy Cioslowski ◽  
Guanghua Liu ◽  
David Moncrieff
Keyword(s):  
Transition States ◽  
Hydrogen Shift ◽  
Aryl Radicals
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