Time-Dependent Radiolytic Yield of OH•Radical Studied by Picosecond Pulse Radiolysis

2011 ◽  
Vol 115 (44) ◽  
pp. 12212-12216 ◽  
Author(s):  
Abdel Karim El Omar ◽  
Uli Schmidhammer ◽  
Pierre Jeunesse ◽  
Jean-Philippe Larbre ◽  
Mingzhang Lin ◽  
...  
Keyword(s):  
Pulse Radiolysis ◽  
Picosecond Pulse ◽  
Time Dependent ◽  
Oh Radical

Time-dependent yield of the hydrated electron and the hydroxyl radical in D2O: a picosecond pulse radiolysis study

2018 ◽  
Vol 20 (23) ◽  
pp. 15671-15679 ◽  
Author(s):  
Furong Wang ◽  
Uli Schmidhammer ◽  
Jean-Philippe Larbre ◽  
Zizhao Zong ◽  
Jean-Louis Marignier ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Pulse Radiolysis ◽  
Picosecond Pulse ◽  
Isotopic Effect ◽  
Hydrated Electron ◽  
Time Dependent ◽  
Time Resolved

Picosecond pulse radiolysis measurements were performed in neat D2O and H2O in order to study the isotopic effect on the time-resolved yield of the hydrated electron and hydroxyl radical.

Phenylalanine: Its ˙OH and SO4˙⁻-Induced Oxidation and Decarboxylation. A Pulse Radiolysis and Product Analysis Study

1993 ◽  
Vol 48 (6) ◽  
pp. 761-770 ◽  
Author(s):  
Degui Wang ◽  
Heinz-Peter Schuchmann ◽  
Clemens von Sonntag
Keyword(s):  
Radical Cation ◽  
Pulse Radiolysis ◽  
Side Reactions ◽  
Intramolecular Electron Transfer ◽  
Oh Radical ◽  
Product Analysis ◽  
Water Elimination ◽  
Deprotonation Reaction ◽  
Type Radical ◽  
Radical Yield

Phenylamine has been oxidized by radiolytically generated hydroxyl and sulfate radicals, the ensuing intermediates and their reactions have been studied by pulse radiolysis and product analysis in the absence and presence of oxidants such as Fe(CN)63- and O2. Upon OH radical attack, hydroxycyclohexadienyl-type radicals are mainly formed while Η-abstraction reactions can be neglected. In the presence of Fe(CN)63- these radicals are for the most part oxidized to the corresponding tyrosines (80%), except for the ipso-OH-adduct radicals (≈ 20%). It is concluded that ˙OH-addition is almost random, but with a slight avoidance of the metaposition relative to the ortho-, para- and ipso-positions. Oxygen adds reversibly to the OH-adduct radicals (kf = 1.8 × 108 dm3 mol-1 s-1, kr = 5.4 × 104 s-1). In this case, tyrosine formation occurs by HO2˙-elimination. However, due to side reactions, tyrosine formation only reaches 52% of the OH radical yield. The tyrosine yield drops to 10% in the absence of an oxidant.Upon SO4˙⁻-attack, decarboxylation becomes a major process (33% of SO4˙⁻) alongside the production of tyrosines (43%). Here, with Fe(CN)63- as the oxidant the formation of p-Tyr (18.5%) and m-Tyr (16.5%) is preferred over o-Tyr formation (8.5%). It is believed that in analogy to other systems a radical cation is formed immediately upon SO4˙⁻-attack which either reacts with water under the formation of hydroxycyclohexadienyl-type (“OH-adduct”) radicals, or decarboxylates after intramolecular electron transfer. The radical cation can also arise indirectly through H+-catalysed water elimination from the ˙OH-adduct radicals. At pH 2 and a dose rate of 0.0046 Gy s-1 CO2 formation matches the OH radical yield when ˙OH is the attacking radical. Below pH 2, G(CO2) decreases with falling pH. This indicates the occurrence of another, unimolecular, pathway under these conditions competing effectively with decarboxylation. This appears to be a relatively slow deprotonation reaction of the carboxylprotonated phenylalanine radical cation which gives rise to the benzyl-type radical.

Picosecond pulse radiolysis studies on geminate ion recombination in saturated hydrocarbon

1983 ◽  
Vol 21 (1-2) ◽  
pp. 45-52 ◽  
Author(s):  
S. Tagawa ◽  
M. Washio ◽  
H. Kobayashi ◽  
Y. Katsumura ◽  
Y. Tabata
Keyword(s):  
Pulse Radiolysis ◽  
Saturated Hydrocarbon ◽  
Picosecond Pulse ◽  
Ion Recombination

Time-dependent measurements of flame temperature and the OH radical in the unsteady extinction of non-premixed flames

2005 ◽  
Vol 141 (1-2) ◽  
pp. 186-190 ◽  
Author(s):  
Uen Do Lee ◽  
Kwang Chul Oh ◽  
Hyun Dong Shin ◽  
Ki Ho Lee
Keyword(s):  
Flame Temperature ◽  
Premixed Flames ◽  
Time Dependent ◽  
Oh Radical

Hydrated electron decay measurements with picosecond pulse radiolysis at elevated temperatures up to 350°C

2006 ◽  
Vol 424 (1-3) ◽  
pp. 77-81 ◽  
Author(s):  
G. Baldacchino ◽  
V. De Waele ◽  
H. Monard ◽  
S. Sorgues ◽  
F. Gobert ◽  
...  
Keyword(s):  
Pulse Radiolysis ◽  
Elevated Temperatures ◽  
Picosecond Pulse ◽  
Hydrated Electron
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