scholarly journals EPR Spin-Trapping Study of Free Radical Intermediates in Polyalphaolefin Base Oil Autoxidation

2021 ◽  
pp. 109687
Author(s):  
Nikola Babić ◽  
Simon Pondaven ◽  
Hervé Vezin
Keyword(s):  
Free Radical ◽  
Spin Trapping ◽  
Base Oil ◽  
Radical Intermediates ◽  
Epr Spin Trapping

Thermolysis of α-hydroperoxyalkyl diazenes. Spin trapping of radical intermediates and spin trapping kinetics

1991 ◽  
Vol 69 (9) ◽  
pp. 1398-1402 ◽  
Author(s):  
Lukose Mathew ◽  
Emmanuel Y. Osei-Twum ◽  
John Warkentin
Keyword(s):  
Free Radical ◽  
Rate Constant ◽  
Ring Opening ◽  
Spin Trapping ◽  
Ethyl Vinyl Ether ◽  
Trapping Rate ◽  
Ethyl Vinyl ◽  
Enol Ethers ◽  
Radical Intermediates ◽  
Radical Trapping

α-Hydroperoxyalkyl diazenes (Me2C(OOH)N=NR, 1, R = CH2CF3, CH2CH2OMe, CH(Me)2, CMe3, CH2Ph, Ph, CH2CH2OPh, and c-C3H5CD2) decompose in benzene, at 50 °C or less, by a mechanism involving free radical (R•) intermediates. The radicals were trapped with 1-methyl-4-nitroso-3,5-diphenylpyrazole, 2, to afford spin adducts (nitroxyls) that were observed by ESR spectroscopy. When the solvent was ethyl vinyl ether, radicals from 1 (R = CH2CH2OPh) were trapped by the solvent and the adduct radicals so formed were spin trapped by 2. These observations support free radical mechanisms for thermolysis of 1 and for the hydroxyalkylations that occur when 1 are decomposed in solutions containing enol ethers or other unsaturated substrates. The ring-opening of cyclopropylmethyl radicals (cpm) to 3-butenyl radicals was used to estimate the rate constant for radical trapping by 2. For cpm the rate constant is given by log kcpm = (10.7 ± 0.4) − (3.9 ± 0.5)/θ where θ = 2.3 RT kcal mol−1. At 25 °C, the spin trapping rate constant has the value 6.9 × 107 M−1 s−1. Key words: hydroperoxyalkyl diazenes; radicals, spin trapping; spin trapping, rate constant.

scholarly journals Free radical generation induced by ultrasound in red wine and model wine: An EPR spin-trapping study

2015 ◽  
Vol 27 ◽  
pp. 96-101 ◽  
Author(s):  
Qing-An Zhang ◽  
Yuan Shen ◽  
Xue-hui Fan ◽  
Juan Francisco García Martín ◽  
Xi Wang ◽  
...  
Keyword(s):  
Free Radical ◽  
Red Wine ◽  
Spin Trapping ◽  
Free Radical Generation ◽  
Radical Generation ◽  
Epr Spin Trapping

EPR spin trapping evidence of radical intermediates in the photo-reduction of bicarbonate/CO2 in TiO2 aqueous suspensions

2015 ◽  
Vol 14 (5) ◽  
pp. 1039-1046 ◽  
Author(s):  
Alessandra Molinari ◽  
Luca Samiolo ◽  
Rossano Amadelli
Keyword(s):  
Spin Trapping ◽  
Reaction Intermediates ◽  
Reductive Activation ◽  
Radical Intermediates ◽  
Aqueous Suspensions ◽  
Epr Spin Trapping

Storage of CO2 as carbonates is a strategy for its reductive activation. Carbonates are reduced at pH 5.5–7.5 with photoexcited TiO2. EPR is convenient for detecting reaction intermediates.

scholarly journals Reaction between Peroxynitrite and Boronates: EPR Spin-Trapping, HPLC Analyses, and Quantum Mechanical Study of the Free Radical Pathway

2011 ◽  
Vol 24 (5) ◽  
pp. 687-697 ◽  
Author(s):  
Adam Sikora ◽  
Jacek Zielonka ◽  
Marcos Lopez ◽  
Agnieszka Dybala-Defratyka ◽  
Joy Joseph ◽  
...  
Keyword(s):  
Free Radical ◽  
Spin Trapping ◽  
Quantum Mechanical ◽  
Mechanical Study ◽  
Quantum Mechanical Study ◽  
Epr Spin Trapping ◽  
Hplc Analyses
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