Radical mechanisms reactions

Many nitrones and nitroso-compounds have been exploited as spin traps in elucidating radical reaction mechanisms by EPR spectroscopy (Section 3.5.2.1). The initial adducts are nitroxides which can trap further radicals (Scheme 5.17). 

Carbon insertion reaction The addition of a carbon atom to an existing carbon chain, usually by a radical reaction mechanism. 

The radical reaction mechanism was confirmed by polymerizing a mixture of styrene and methyl methacrylate. The ratio of the monomers in the copolymer (1.15) was nearly equal to the value (1.05) calculated from the reactivity ratio for radical copolymerization and differed considerably from the value of 10.5 for the cationic copolymerization and from the value 0.15 for anionic copolymerization (78). 

These results indicate that vacuum curing occurs through a radical reaction mechanism and is terminated by reaction of the ring-opened epoxy group with the azide group (not nitrene) under exposure. There is a possibility that polymerization initiated by an exposure-induced radical cation may occur. Furthermore, it is thought that reaction products from both the azide and epoxide serve as dissolution inhibitors, because the sensitivity of EAP is almost the same as that of EP, as shown in Figures 1 and 2. 

We investigated the oxidation of only propane at the high temperature (430°C.) pic darret—first with factors affecting the type of reaction, then with analyses for some reaction products (aldehydes, hydrogen peroxide, alcohols, and hydrocarbons). All experimental data can be explained by a radical reaction mechanism which is discussed. 

Eliasson et al. [1, 73-77] reported a silent discharge C02 hydrogenation in the presence or absence of a catalyst to produce methanol. A radical reaction mechanism [75] has been presented to explain the observed phenomena, and can be expressed as ... 

The conversion of diarylpropane structures into stilbenes during refining as well as during bleaching has previously been observed in model compound studies. In a recent report (26), diarylpropane model compounds were impregnated onto coarse mechanical pulp which was subsequently further refined in a laboratory refiner. Stilbenes were found to be produced in yields ranging from 11 to 19%. The conversion was believed to proceed via a radical reaction mechanism. A stilbene was also formed when a diarylpropane model compound was treated with alkaline hydrogen peroxide at 30°C and at a pH above 12 (27). 

FUNCTIONALIZATION OF SEMICONDUCTOR SURFACES BY ORGANIC LAYERS CONCERTED CYCLOADDITION VERSUS STEPWISE FREE-RADICAL REACTION MECHANISMS... 

Functionalization of Semiconductor Surfaces by Organic Layers Concerted Cycloaddition versus Stepwise Free-Radical Reaction Mechanisms 333... 

The aziridination works for both aromatic and aliphatic olefins, including less active linear terminal olefins. Most reactions proceed in good yield at room temperature. The use of ci.v-stilbene at 0°C gives predominately cis aziridine product in about 90 10 cis trails ratio (Table 6.1). The conservation of cis structure suggests that a discrete silver nitrene intermediate is involved in the reaction path. Because of the unique disilver structure and unlikely formation of a silver(III) species, the authors suspect that a bridged nitrene intermediate between the two silver atoms may be responsible for this transformation in which each silver atom donates one electron to the nitrenoid. However, further research is necessary to prove this hypothesis and a fast radical reaction mechanism cannot be eliminated on the basis of current evidence. 

Radical reaction mechanisms of and at organic germanium, tin and lead... 

Vogin et al. [235] have created a program for the computer design of a free radical reaction mechanism in the gas phase, in agreement with the rules formulated in Sect. 2.5.3. An algorithm has been devised to transform by the computer the formula of a compound, written in the linear notation described in Sect. 6.2.1 [182], into a canonical notation. Thus, the system both preserves the flexibility of a simple natural language and gains the sophistication of a canonical notation. 

The ability of radicals to propagate by abstraction is a key feature of radical chain reactions, which we shall come to later. There is an important difference between homolysis and abstraction as a way of making radicals homolysis is a reaction of a spin-paired molecule that produces two radicals abstraction is a reaction of a radical with a spin-paired molecule that produces one new radical and a new spin-paired molecule. Radical abstractions like this are therefore examples of your first radical reaction mechanism they are in fact substitution reactions at H and can be compared with proton removal or even with an Sfj2 reaction. 

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