Synthetic application of α-hydroxydiazene systems. I. Esters from radical chain reactions of unsaturated compounds with 2-hydroxy-2,5,5-trimethyl-Δ3-1,3,4-oxadiazoline

1976 ◽  
Vol 54 (9) ◽  
pp. 1341-1344 ◽  
Author(s):  
Peter Knittel ◽  
John Warkentin
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Multiple Bond ◽  
Hydroxyl Group ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Stable Free Radical ◽  
Chain Reactions ◽  
Unsaturated Compounds ◽  
Synthetic Application

2-Hydroxy-2,5,5-trimethyl-Δ3-1,3,4-oxadiazoline (1) reacts with acetylenic and olefinic unsaturated systems by addition of the 2-acetoxy-2-propyl group and a hydrogen atom, respectively, to the two atoms forming the multiple bond. The regiochemistry of addition to unsymmetric unsaturated systems is that predicted for a radical chain mechanism, in which the 2-acetoxy-2-propyl radical adds to the multiple bond so as to form the more stable free radical which then abstracts a hydrogen atom from the hydroxyl group of 1. Polymerization of the unsaturated substrate, as well as abstraction of allylic hydrogen (if any) are competing processes. Yields of adducts, based on 1, ranged from 80% in reaction with crotonaldehyde to 10% in reaction with cyclohexene.

On the chemistry of iodonyl radicals. The oxidation of iodobenzene by t-butyl hypochlorite

1968 ◽  
Vol 46 (22) ◽  
pp. 3537-3544 ◽  
Author(s):  
Dennis D. Tanner ◽  
Geoffrey C. Gidley
Keyword(s):  
Free Radical ◽  
Molecular Oxygen ◽  
Chlorinated Hydrocarbons ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Thermally Induced ◽  
Chain Reactions ◽  
Hydrocarbon Substrates ◽  
Principal Chain ◽  
Sole Product

The reaction of iodobenzene with t-butyl hypochlorite proceeds by a free radical chain mechanism, forming as the sole product iodobenzene t-butoxy chloride (IBBC). The photoinduced or thermally induced reactions of IBBC with hydrocarbon substrates yield chlorinated hydrocarbons by a radical chain halogenation sequence involving t-butoxyiodonyl benzene as the principal chain-carrying species. The photolysis or thermolysis of IBBC in the absence of molecular oxygen yields products resulting from a variety of free radical chain reactions, while thermolysis in the presence of oxygen yields only iodobenzene and t-butyl hypochlorite.

Thiyl Radicals. II. Reactions of meso-Substituted Anthracene Derivatives with Oxygen and Mercaptoacetic Acid

1963 ◽  
Vol 16 (5) ◽  
pp. 845 ◽  
Author(s):  
ALJ Beckwith ◽  
LB See
Keyword(s):  
Acetic Acid ◽  
Free Radical ◽  
Hydrogen Atom ◽  
Alkyl Substituent ◽  
Mercaptoacetic Acid ◽  
Hydrogen Atom Abstraction ◽  
Chain Mechanism ◽  
Radical Chain ◽  
Thiyl Radicals ◽  
Anthracene Derivatives

9-Methyl- and 9-benzylanthracene each react readily with mercaptoacetic acid and oxygen in benzene yielding (9-methyl-10-anthry1thio)acetic acid and(9-benzyl-10-anthry1thio)acetic acid respectively. There is no evidence for hydrogen atom abstraction from the alkyl substituent by free thiyl radicals. 9,10-Dimethylanthracene, when similarly treated, affords α-(carboxymethylthio)-9,10-dimethylanthracene, but 9,10-diphenylanthracene remains unaffected. These results are consistent with the free-radical-chain mechanism previously suggested.1

scholarly journals The detection and inhibition of free radical chain reactions

1942 ◽  
Vol 180 (982) ◽  
pp. 237-256 ◽  
Keyword(s):  
Nitric Oxide ◽  
Free Radical ◽  
Chemical Analysis ◽  
Diethyl Ether ◽  
Pressure Increase ◽  
Stationary States ◽  
Decomposition Rates ◽  
Radical Chain ◽  
Chain Reactions ◽  
Limiting Values

Part I. Comparison of nitric oxide and propylene as inhibitors The reduction by propylene of the rate of pressure increase in the decomposition of propaldehyde at 550° has been shown by chemical analysis to represent a true inhibition of the reaction, and not to be due n an important degree to an induced polymerization of the propylene. With propaldehyde and with diethyl ether the limiting values to which the decomposition rates are reduced by nitric oxide and by propylene respectively are the same, although much more propylene is required to produce a given degree of inhibition. From this it is concluded that the limiting rates are more probably those of independent non-chain processes, than those characteristic of stationary states where the inhibitor starts and stops chains with equal efficiency.

scholarly journals The hydrogen atom transfer reactivity of sulfinic acids

2018 ◽  
Vol 9 (36) ◽  
pp. 7218-7229 ◽  
Author(s):  
Markus Griesser ◽  
Jean-Philippe R. Chauvin ◽  
Derek A. Pratt
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Radical Chain ◽  
Chain Reactions ◽  
Sulfinic Acids

Sulfinic acids are characterized to be very good H-atom donors to each of alkyl and alkoxyl radicals. In order to participate in useful radical chain reactions, the sulfonyl radicals must undergo fast propagating reactions to avoid autoxidation, which is surprisingly rate-limited by the reaction of sulfonyl radicals with oxygen.

scholarly journals Evidence that Criegee intermediates drive autoxidation in unsaturated lipids

2020 ◽  
Vol 117 (9) ◽  
pp. 4486-4490 ◽  
Author(s):  
Meirong Zeng ◽  
Nadja Heine ◽  
Kevin R. Wilson
Keyword(s):  
Free Radical ◽  
Radical Chain ◽  
Chain Reactions ◽  
Unsaturated Lipids ◽  
Criegee Intermediates ◽  
Age Related ◽  
Lipid Autoxidation ◽  
Free Radical Chain Reaction ◽  
Cyclic Network ◽  
Radical Chain Reaction

Autoxidation is an autocatalytic free-radical chain reaction responsible for the oxidative destruction of organic molecules in biological cells, foods, plastics, petrochemicals, fuels, and the environment. In cellular membranes, lipid autoxidation (peroxidation) is linked with oxidative stress, age-related diseases, and cancers. The established mechanism of autoxidation proceeds via H-atom abstraction through a cyclic network of peroxy–hydroperoxide-mediated free-radical chain reactions. For a series of model unsaturated lipids, we present evidence for an autoxidation mechanism, initiated by hydroxyl radical (OH) addition to C=C bonds and propagated by chain reactions involving Criegee intermediates (CIs). This mechanism leads to unexpectedly rapid autoxidation even in the presence of water, implying that as reactive intermediates, CI could play a much more prominent role in chemistries beyond the atmosphere.

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.

Free radical chain reactions involving alkyl- and alkenylmercurials

1989 ◽  
Vol 22 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Glen A. Russell
Keyword(s):  
Free Radical ◽  
Radical Chain ◽  
Chain Reactions

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.

Sign in / Sign up

Export Citation Format

Share Document