scholarly journals Unusual Kinetic Isotope Effects of Deuterium Reinforced Polyunsaturated Fatty Acids in Tocopherol-Mediated Free Radical Chain Oxidations

2014 ◽  
Vol 136 (3) ◽  
pp. 838-841 ◽  
Author(s):  
Connor R. Lamberson ◽  
Libin Xu ◽  
Hubert Muchalski ◽  
J. Rafael Montenegro-Burke ◽  
Vadim V. Shmanai ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Radical ◽  
Polyunsaturated Fatty Acids ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Radical Chain ◽  
Kinetic Isotope

Radiation-induced Oxidation of 2-Propanol by Nitrous Oxide in Alkaline Aqueous Solution

1972 ◽  
Vol 50 (11) ◽  
pp. 1751-1756 ◽  
Author(s):  
C. E. Burchill ◽  
G. P. Wollner
Keyword(s):  
Aqueous Solution ◽  
Rate Constant ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Kinetic Isotope ◽  
Alkaline Aqueous Solution ◽  
Radiation Induced ◽  
Solution Proceeds

The radiation-induced oxidation of 2-propanol to acetone by N2O in alkaline aqueous solution proceeds via a free radical chain mechanism independent of pH above 12.5. The results are explained by abstraction of H from 2-propanol by O− at both the α and β positions (85% α attack). Chain propagation is by reaction of the α radical anion, (CH3)2ĊO−, with N2O with a rate constant of (3.8 ± 0.4) × 104 M−1 s−1 and by reaction of the β radical, ĊH2(CH3)CHOH, with 2-propanol to give the α radical with a rate constant of 430 ± 30 M−1 s−1.The conclusions are supported by the demonstration of kinetic isotope effects for selectively deuterated alcohols.

Micelle-induced change of mechanism in the reaction of muonium with acetone

1996 ◽  
Vol 74 (11) ◽  
pp. 1945-1951 ◽  
Author(s):  
John M. Stadlbauer ◽  
Krishnan Venkateswaran ◽  
Hugh A. Gillis ◽  
Gerald B. Porter ◽  
David C. Walker
Keyword(s):  
Dielectric Constant ◽  
Free Radical ◽  
Key Words ◽  
Resonance Spectrum ◽  
Addition Reaction ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Level Crossing ◽  
Kinetic Isotope ◽  
Abstraction Reaction

Muonium atoms add to the O atom of the carbonyl group of acetone to give the muonated free radical (CH3)2Ċ-O-Mu when the reaction takes place in water or hydrocarbons, but not when the acetone is localized in micelles. Micelles have no effect on the formation of muonated cyclohexadienyl radicals when muonium reacts with benzene under similar conditions. The addition reaction with acetone appears to have been subsumed by a faster alternative reaction in the micellar environment. Evidence is presented for this interpretation rather than for an inhibition of the radical or for a shift in the muon level-crossing resonance spectrum with hydrogen (muonium) bonding, though major shifts are seen for the spectrum of this radical in pure solvents of widely different dielectric constant. It is suggested that muonium's "abstraction" reaction takes over in micelles because significant micelle-induced enhancement effects were previously observed in that type of reaction. The data are consistent with a rate constant for the abstraction reaction of muonium with acetone in micelles of >6 × 108 M−1 s−1. Key words: muonium, kinetic isotope effects, micelle enhancement, H/Mu-addition, H/Mu abstraction.

Theoretical Simulations of Heavy-Atom Kinetic Isotope Effects in Aliphatic Claisen Rearrangement

2020 ◽  
Vol 124 (51) ◽  
pp. 10678-10686
Author(s):  
Yuqing Xu ◽  
Kin-Yiu Wong ◽  
Meishan Wang ◽  
Desheng Liu ◽  
Wenkai Zhao ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Theoretical Simulations
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