An Electron Spin Resonance Study of the Arylsilyl Adducts of Phenyl tert-Butyl Nitrone and Their Decomposition Kinetics

1974 ◽  
Vol 52 (16) ◽  
pp. 2901-2905 ◽  
Author(s):  
Babatunde B. Adeleke ◽  
Sau-King Wong ◽  
Jeffrey K. S. Wan
Keyword(s):  
Decomposition Kinetics ◽  
Electron Spin Resonance Study ◽  
Silyl Group ◽  
First Order ◽  
Tert Butyl ◽  
First Order Kinetics ◽  
Spin Resonance ◽  
Butyl Peroxide ◽  
The Stability ◽  
Spin Resonance Study

The formation and the stability of some arylsilyl adducts of phenyl tert-butyl nitrone were studied in a photochemical system using di-tert-butyl peroxide as solvent. The β-proton splittings of all the arylsilyl adducts, ranging from 5.6 to 8.3 G, are relatively larger than their carbon analogs, which are usually less than 4 G. The arylsilyl adducts are found to decompose in di-tert-butyl peroxide solvent by a first-order kinetics. The activation energy involved in the decomposition of a series of arylsilyl adducts varies from about 14 to about 9 kcal/mol, as the size of the silyl group increases. In all cases, very low values of the A factors (between 106 and 1010) were observed.

An Electron Spin Resonance Study of the tert-Butylsulfinyl Radical

1974 ◽  
Vol 52 (4) ◽  
pp. 555-556 ◽  
Author(s):  
James A. Howard ◽  
Edward Furimsky
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Low Temperatures ◽  
Half Life ◽  
Electron Spin Resonance Study ◽  
Tert Butyl ◽  
Field Center ◽  
Spin Resonance ◽  
Butyl Peroxide ◽  
Spin Resonance Study

The tert-butylsulfinyl radical, (CH3)3CSO•, can be prepared directly in the cavity of an e.p.r. spectrometer by photolysis of di-tert-butyl peroxide in a solution of tert-butylsulfenic acid in toluene or isopentane at low temperatures (−40° to−100°). The e.s.r. spectrum consists of a rather broad singlet (ΔHmis ∼ 1.9 G) with the field center at g = 2.0106.This radical undergoes self-reaction by a bimolecular process and a 2.5 × 10−7 M solution has a half-life of 0.07 s at −100 °C. It is, therefore, much shorter-lived than the iso-structural tert-butylperoxy radical, (CH3)3COO•.

An Electron Spin Resonance Study of Some Reactions of Pentafluorosulfuranyl (SF5)

1975 ◽  
Vol 53 (16) ◽  
pp. 2361-2364 ◽  
Author(s):  
John Charles Tait ◽  
James Anthony Howard
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Rate Constants ◽  
Arrhenius Equation ◽  
Kinetic Studies ◽  
Electron Spin Resonance Study ◽  
Order Process ◽  
First Order ◽  
Spin Resonance ◽  
Spin Resonance Study

A kinetic electron spin resonance study of the self-reaction of SF5 and a spectroscopic and kinetic e.s.r. study of the reaction of SF5 with 1,1-di-t-butylethylene are reported. This radical undergoes self-reaction by a second-order process and the rate constants are given by the Arrhenius equation log 2k1(M−1 s−1) = (10.3 ± 0.5) − (1.7 ± 0.5)/θ where θ = 2.303RT kcal mol−1. It adds to 1,1-di-t-butylethylene to give (t-Bu)2CCH2SF5 which decomposes by a first-order process with rate constants that obey the expression log k2(s−1) = (13 ± 0.4) − (10 ± 0.2)/θ. Both these rate constants are pertinent to kinetic studies of the photoinduced addition of SF5C1 to olefins.

Peri interactions in the 1,3,6,8-tetra-tert-butyl- and 1,3,8-tri-tert-butylnaphthalene anions. Electron spin resonance study

1975 ◽  
Vol 79 (16) ◽  
pp. 1740-1746 ◽  
Author(s):  
Ira B. Goldberg ◽  
Harry R. Crowe ◽  
Richard W. Franck
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Electron Spin Resonance Study ◽  
Tert Butyl ◽  
Spin Resonance ◽  
Spin Resonance Study

Di-tert-butyl peroxide decomposition behind shock waves

1976 ◽  
Vol 54 (4) ◽  
pp. 581-585 ◽  
Author(s):  
David K. Lewis
Keyword(s):  
Thermal Decomposition ◽  
Gas Phase ◽  
Single Pulse ◽  
First Order ◽  
Tert Butyl ◽  
First Order Kinetics ◽  
Peroxide Decomposition ◽  
Butyl Peroxide ◽  
Temperature Work ◽  
Lower Temperature

The homogeneous, gas phase thermal decomposition of di-tert-butyl peroxide has been studied in a single pulse shock tube. Samples containing 0.05% to 0.5% reactant in argon were heated to 528–677 K at total pressures of about 1 atm. Acetone and ethane were the only significant products. The reaction obeyed first order kinetics. The Arrhenius parameters, log A (s−1) = 15.33 ± 0.50, Eact (kJ/mol) = 152.3 ± 5.8, are in agreement with the bulk of the earlier reported results of lower temperature work, and with a recently reported result obtained via the very low pressure pyrolysis technique. Indications from some of the earlier work that the A factor may decline at high temperatures are not supported by the present study.

Electron spin resonance study of 2,6-di-tert-butyl-4-methylphenol oxidation on alumina

1970 ◽  
Vol 74 (15) ◽  
pp. 2923-2928 ◽  
Author(s):  
Isao Suzuki ◽  
Yoshio Ono ◽  
Tominaga Keii
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Electron Spin Resonance Study ◽  
Tert Butyl ◽  
Spin Resonance ◽  
Spin Resonance Study

Electron Spin Resonance Study of Phenolic Antioxidants. II. Free Radical Structures Arising from Antioxidants Containing the 3,5-DI-Tert.-Butyl-4-Hydroxy-Benzyl Group

1973 ◽  
Vol 46 (5) ◽  
pp. 1134-1155 ◽  
Author(s):  
J. C. Westfahl
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Esr Spectroscopy ◽  
Quinone Methide ◽  
Electron Spin Resonance Study ◽  
Phenolic Antioxidants ◽  
Primary Radical ◽  
Tert Butyl ◽  
Spin Resonance ◽  
Spin Resonance Study

Abstract Oxidation of a series of phenolic antioxidants, or compounds related to antioxidants, was carried out using ferricyanide ion in dimethylsulfoxide solution. The free radicals produced were studied by ESR spectroscopy. Most of the antioxidants examined contained one or more 3,5-di-tert-butyl-4-hy-droxybenzyl groups. Based on their behavior on oxidation, the compounds can be divided into two classes. One class forms a relatively unstable primary radical which decomposes to give 2,6-di-tert-butyl quinone methide.

Sign in / Sign up

Export Citation Format

Share Document