Free radical reactions with

Reactions with Free Radicals and Other Electron Deficient Species... 

Vitamin E actually consists of a family of compounds, the most active of which is a-tocopherol. The mechanism of the vitamin s action is not completely certain, but it seems likely that it might undergo hydrogen atom transfer reactions with free radicals to give a stable radical (see also Chapter 17, Problem 7). 

The oxides are gaseous and do not undergo reactions in the atmosphere that produce aerosol particles. Carbon monoxide is a relatively inert material with its main sinks in the atmosphere via reactions with free radicals, e.g.,... 

For some organic compounds, such as phenols, aromatic amines, electron-rich olefins and dienes, alkyl sulfides, and eneamines, chemical oxidation is an important degradation process under environmental conditions. Most of these reactions depend on reactions with free-radicals already in solution and are usually modeled by pseudo-first-order kinetics ... 

Due to high activity in reactions with free radicals, ozone undergoes the chain decomposition in solutions also. The chain reaction of ozone decomposition was evidenced in 1973 in the kinetic study of cyclohexane and butanone-2 oxidation by a mixture of 02 and 03 [146-151], It was observed that the rate of ozone consumption obeys the equation [112] ... 

Scheme B. Oxidation occurs as a chain reaction in scheme A. However, hydroperoxide formed is decomposed not by the reaction with free radicals but by a first-order molecular reaction with the rate constant km [3,56]. This scheme is valid for the oxidation of hydrocarbons where tertiary C—H bonds are attacked. For km 3> k i[RH] the maximum [ROOH] is attained at the hydroperoxide concentration when the rate of the formation of ROOH becomes equal to the rate of ROOH decay fl[RH](kj [ROOH][RH])l/2 km[ROOH] therefore, [ROOH]max = a2kn km 2 [RH]3. The kinetics of ROOH formation and RH consumption are described by the following equations [3],...

In addition to the classification of inhibitors according to their mechanisms of the action on oxidation, they can be classified into consumable and long-lived inhibitors. A consumable inhibitor is irreversibly consumed in its reactions with free radicals (R or RCV) or hydroperoxide. The stoichiometric coefficient of inhibition of such inhibitors is typically equal to one or two per inhibitory functional group. However, in some systems (for example RH 02 InH), an inhibitor can act cyclically so that, getting repeatedly regenerated, the... 

Parameters of Phenols (A OH) and Sterically Hindered Phenols (Ar2OH) Reactions with Free Radicals in IPM Model [33,34]... 

As a result, the decay of antioxidant proceeds via two ways, namely, by the reaction with free radicals and by the oxidation by hydroperoxide on the surface of Cu with the summary rate... 

It must be noted that the inhibitory effects of flavonoids and other antioxidants in nonhomogenous biological systems can depend not only on their reactivities in reactions with free radicals (the chain-breaking activities) but also on the interaction with biomembranes. Thus, Saija et al. [137] compared the antioxidant effects and the interaction with biomembranes of four flavonoids quercetin, hesperetin, naringen, and rutin in iron-induced... 

The reaction with free radicals plays an important role in the interaction of carbon black with rubber (103) and with styrene (58, 102). 

For air, the major degradation process involves reactions with free radicals such as hydroxyl groups (Atkinson 1985). For other media, it is clear that chloroform can be mineralized through both abiotic and biotic processes. Information in the available literature (Bouer and McCarty 1983 Rhee and Speece 1992) documents the disappearance of chloroform in water and soil media under both aerobic and anaerobic conditions as well as identification of the end products. 

Similar results were achieved in a free-radical chain addition reaction with free radicals generated from an EtsB-air or EtsB-air/alkyl iodide system (equation 76). ... 

Reactions with Free Radicals, Carbenes and Nitrenes, and at Surfaces 389... 

REACTION WITH FREE RADICALS HYDROGEN ATOM ABSTRACTION AND ONE- OR THREE-ELECTRON BONDING... 

---