Rate constant for chlorine abstraction from CCl4 by the 5-hexenyl radical

1987 ◽  
Vol 65 (2) ◽  
pp. 311-315 ◽  
Author(s):  
Deborah Rae Jewell ◽  
Lukose Mathew ◽  
John Warkentin
Keyword(s):  
Free Radical ◽  
Double Bond ◽  
Chlorine Atom ◽  
Rate Constant ◽  
Methyl Ethyl ◽  
Chain Mechanism ◽  
Secondary Product ◽  
Radical Chain ◽  
Alkyl Radicals ◽  
Primary Products

Cyclization of the 5-hexenyl free radical to the cyclopentylmethyl free radical was used to clock chlorine atom abstraction by 5-hexenyl from carbon tetrachloride in solution. The source of 5-hexenyl radicals was 5-hexenyl[1-hydroxy-1-methyl-ethyl]diazene ((CH3)2C(OH)N=N(CH2)4CH=CH2), which decomposes thermally in CCl4 by a radical chain mechanism to afford chloroform, acetone, nitrogen, 6-chloro-1-hexene, cyclopentylchloromethane, 1-hexene, and methylcyclopentane as primary products. 6-Chloro-1-hexene is converted, in part, to a secondary product, 1,1,1,3,7-pentachloroheptane, by radical chain addition of CC14 to the double bond. The rate constant for chlorine atom abstraction, kCl, was calculated from the product composition and the known rate constant for cyclization of the 5-hexenyl radical. For the temperature range 274–353 K, kCl is given by log (kCl/M−1 s−1) = (8.4 ± 0.3) − (6.2 ± 0.4)/θ where θ = 2.3 RT kcal mol−1, which leads to [Formula: see text]. This value is significantly smaller than recently reported estimates for other primary alkyl radicals.

Metal ion initiated halogenation reaction of N-haloamines

1970 ◽  
Vol 48 (4) ◽  
pp. 544-545 ◽  
Author(s):  
F. Minisci ◽  
G. P. Gardini ◽  
F. Bertini
Keyword(s):  
Free Radical ◽  
Radical Cation ◽  
Chlorine Atom ◽  
Metal Ion ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Radical Chain Mechanism ◽  
Halogenation Reaction ◽  
Amino Radical Cation ◽  
Methyl Heptanoate

The metal ion catalyzed chlorination of 1-chlorobutane, 1-chlorohexane, methyl-pentanoate, and methyl-heptanoate by protonated N-chloroamines proceeds by a free radical chain mechanism and the chain carrying species was shown not to be a chlorine atom, but an amino radical cation.

The Reaction of Sulfur and Sulfur Compounds with Olefinic Substances. Part XI. The Mechanism of Interaction of Sulfur with Mono-Olefins and 1,5-Dienes

1958 ◽  
Vol 31 (5) ◽  
pp. 1090-1104 ◽  
Author(s):  
L. Bateman ◽  
C. G. Moore ◽  
M. Porter
Keyword(s):  
Free Radical ◽  
Double Bond ◽  
Radical Addition ◽  
Major Product ◽  
Main Constituent ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Main Route ◽  
Mechanism Of Interaction ◽  
Special Case

Abstract Believing an alkenyl alkyl polysulfide to be the major product of sulfurmono-olefin interaction at about 140° and the main constituent of the cyclic monosulfide fraction likewise obtained from 2,6-dimethylocta-2,6-diene to bo the thiacyclohex-3-ene (II), Farmer and his coworkers1 advanced the following free-radical chain mechanism for olefinic sulfuration: (see PDF for diagram) In the special case where the sulfurated radical formed in (2) contains one sulfur atom, alternative reactions to (3) and (4) were proposed, viz., capture of a hydrogen atom, followed by polar or radical addition of the alkenethiol to a second double bond, and this was regarded as the main route to the cyclic monosulfides from 1,5-dienes:

The slow combustion of aluminium trimethyl

1965 ◽  
Vol 288 (1412) ◽  
pp. 123-132 ◽  
Keyword(s):  
Free Radical ◽  
Organic Compounds ◽  
Initial Rate ◽  
Inert Gases ◽  
Spontaneous Ignition ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Ambient Temperatures ◽  
Slow Combustion ◽  
Rate Of Reaction

Kinetic and analytical studies of the gaseous oxidation of aluminium trimethyl at ambient temperatures and at pressures well below those required for spontaneous ignition have shown that, in contrast to the oxidations of less electron-deficient metal alkyls, no peroxides can be detected and no volatile oxygenated organic compounds are formed. Methane, traces of hydrogen and a solid methoxymethyl compound of aluminium are the only products. The initial rate of reaction is approximately proportional to the first power of the alkyl pressure and to the square of the oxygen pressure; it is little influenced by temperature or by inert gases but is lowered by an increase in surface. The observed kinetic and analytical results can be accounted for in terms of a free radical chain mechanism in which termination takes place predominantly at the walls.

Catalysis of hydrogen peroxide dceomposition by 2-electron oxidation and reduction

1959 ◽  
Vol 12 (2) ◽  
pp. 147 ◽  
Author(s):  
NK King ◽  
ME Winfield
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radical ◽  
Radical Formation ◽  
Single Electron ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Radical Chain Mechanism ◽  
Free Radical Formation ◽  
Decomposition Of H2o2

A thermodynamical argument is used to support the suggestion made elsewhere that the more common radical chain mechanism for catalysed decomposition of H2O2 need not predominate if the catalyst can readily undergo a reversible 2-electron oxidation. How complete the exclusion of free radical formation may be depends upon the redox characteristics of the catalyst and on whether its oxidation by two single-electron steps is readily reversible along the same path.

Insight into the free-radical chain mechanism of gold-catalyzed hydrocarbon oxidation reactions in the liquid phase

2007 ◽  
Vol 122 (3-4) ◽  
pp. 284-291 ◽  
Author(s):  
Pascal Lignier ◽  
Franck Morfin ◽  
Laurent Piccolo ◽  
Jean-Luc Rousset ◽  
Valérie Caps
Keyword(s):  
Free Radical ◽  
Liquid Phase ◽  
Hydrocarbon Oxidation ◽  
Chain Mechanism ◽  
Oxidation Reactions ◽  
Radical Chain ◽  
Radical Chain Mechanism ◽  
Insight Into

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.

scholarly journals Radical Chain Monoalkylation of Pyridines

2021 ◽  
Author(s):  
Samuel Rieder ◽  
Camilo Meléndez ◽  
Kleni Mulliri ◽  
Philippe Renaud
Keyword(s):  
Rate Constant ◽  
Iodine Atom ◽  
Radical Chain ◽  
Enol Ethers ◽  
Alkyl Radicals ◽  
Reaction Proceeds ◽  
Order Of Magnitude ◽  
Enol Esters ◽  
The One ◽  
Neutral Conditions

<p>The monoalkylation of N-methoxypyridinium salts with alkyl radicals generated from alkenes (via hydroboration with catecholborane), alkyl iodides (via iodine atom transfer) and xanthates is reported. The reaction proceeds under neutral conditions since no acid is needed to activate the heterocycle and does not require the use of an external oxidant. A rate constant for the addition of a primary radical to N-methoxylepidinium >107 M–1 s–1 was experimentally determined. This rate constant is more than one order of magnitude larger than the one measured for the addition of primary alkyl radical to protonated lepidine demonstrating the remarkable reactivity of methoxypyridinium salts towards radicals. The reaction could be extended to a three component carbopyridinylation of electron rich alkenes including enol esters, enol ethers and enamides.</p>

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