Free Radical Bromination of Saturated Hydrocarbons using Bromine and Mercuric Oxide

1972 ◽  
Vol 50 (19) ◽  
pp. 3109-3116 ◽  
Author(s):  
N. J. Bunce
Keyword(s):  
Free Radical ◽  
Hydrogen Abstraction ◽  
Chain Process ◽  
Mercuric Oxide ◽  
Saturated Hydrocarbons ◽  
Radical Chain ◽  
Radical Bromination ◽  
Mercury Oxide ◽  
Alkyl Bromides ◽  
Radical Chain Process

The reaction of alkanes with a mixture of bromine and mercuric oxide gives alkyl bromides in preparatively useful yields. The reagent is significantly more reactive than elemental bromine, and it is believed that bromine monoxide, formed insitu by the interaction of bromine and mercury oxide, is the reactive intermediate. Bromination by bromine monoxide is a free radical chain process in which hydrogen abstraction is carried out predominantly by bromoxy (BrO•) radicals, and to a lesser extent by bromine atoms.

The Free Radical Photooximation of Alkanes by Nitrosyl Chloride

1971 ◽  
Vol 49 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Melvyn W. Mosher ◽  
N. J. Bunce
Keyword(s):  
Free Radical ◽  
Hydrogen Abstraction ◽  
Chain Process ◽  
Nitrosyl Chloride ◽  
Deuterium Isotope Effect ◽  
Radical Chain ◽  
Elemental Chlorine ◽  
Probable Reaction ◽  
Radical Initiators ◽  
Atomic Chlorine

The mechanism of the photooximation of alkanes with nitrosyl chloride has been reinvestigated. The lack of initiation of the reaction with free radical initiators suggests that a free radical chain pathway is not involved. Nevertheless, the relative reactivities of hydrocarbons of different structure and the deuterium isotope effect are very similar to those obtained in chlorinations with elemental chlorine, and in particular, primary and tertiary hydrogens are not inert to photooximation as has been previously supposed. A probable reaction mechanism involves hydrogen abstraction from the substrate by atomic chlorine in a free radical non-chain process. This hydrogen abstraction step is shown not to be significantly reversible.

A kinetic study of the reaction of adamantanethione with 2-adamantanethiol

1976 ◽  
Vol 54 (21) ◽  
pp. 3407-3411 ◽  
Author(s):  
J. C. Scaiano ◽  
J. P.-A. Tremblay ◽  
K. U. Ingold
Keyword(s):  
Benzene Solution ◽  
Hydrogen Abstraction ◽  
Chain Process ◽  
Radical Chain ◽  
Diffusion Controlled ◽  
Carbon Centered Radical ◽  
Photochemical Initiation ◽  
Kinetics Of ◽  
Radical Chain Process ◽  
Termination Process

The title reaction is a free radical chain process which yields di(2-adamantyl)disulfide(2). The kinetics of this reaction have been studied in benzene solution at 50 °C using both thermal and photochemical initiation. Thermal initiators which yield resonance stabilized carbon-centered radicals were surprisingly inefficient at starting the reaction. The kinetics indicate that the rate controlling propagation step is hydrogen abstraction from the thiol, AdHSH, by the carbon-centered radical, AdHSSAd•. Rotating sector studies gave a rate constant for this step, k2 = 4 × 104 M−1 s−1. There is some kinetically first order chain termination, but the predominant termination process involves the diffusion-controlled bimolecular self-reactions of AdHSSAd• radicals, 2kt = 1.8 × 1010 M−1 s−1.

The First Polycondensation through a Free Radical Chain Process

1997 ◽  
Vol 119 (37) ◽  
pp. 8718-8719 ◽  
Author(s):  
Takeshi Endo ◽  
Nobuo Torii ◽  
Toshikazu Takata ◽  
Tsutomu Yokozawa ◽  
Toshio Koizumi
Keyword(s):  
Free Radical ◽  
Chain Process ◽  
Radical Chain ◽  
Radical Chain Process

The pyrolytic reactions of acetaldehyde in presence of nitric oxide

1958 ◽  
Vol 245 (1243) ◽  
pp. 456-469 ◽  
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Abstraction ◽  
Chain Process ◽  
Molecular Rearrangement ◽  
Radical Chain ◽  
Low Concentrations ◽  
Rearrangement Mechanism ◽  
A Chain ◽  
Induced Decomposition ◽  
Radical Chain Process

Except at very low concentrations where a slight inhibition is observable nitric oxide strongly catalyses the decomposition of acetaldehyde. The rate of the induced reaction is approximately proportional to [aldehyde] 3/2 [NO] ½ . The ratio of nitric oxide consumed to aldehyde decomposed remains small even in conditions where the corresponding ratio for the nitric-oxide-induced ether decomposition approaches unity. The induced decomposition is reduced in rate to a limit by the addition of propylene. From kinetic and analytical measurements it is concluded that the thermal acetaldehyde decomposition occurs partly by a molecular rearrangement mechanism and partly by a radical chain process. The catalysis by nitric oxide involves a chain reaction initiated by hydrogen abstraction, and probably also an acceleration of the molecular process under the influence of collisions with the nitric oxide. The steps of the nitric-oxide-induced chain process are discussed.

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