Radiation-Chemical Techniques

A major complication in applying radiation chemical techniques to ion-molecule reaction studies is the formation of nonionic initial species by high energy radiation. Another difficulty arises from the neutralization of ions, which may also result in the formation of free radicals and stable products. The chemical effects arising from the formation of ions and their reactions with molecules are therefore superimposed on those of the neutral species resulting from excitation and neutralization. To derive information of ion-molecule reactions, it is necessary to identify unequivocally products typical of such reactions. Progress beyond a speculative rationalization of results is possible only when concrete evidence that ionic species participate in the mechanism of product formation can be presented. This evidence is the first subject of this discussion. 

Schuchmann H-P, von Sonntag C (1988) The oxidation of methanol and 2-propanol by potassium peroxodisulphate in aqueous solution free-radical chain mechanisms elucidated by radiation-chemical techniques. Radiat Phys Chem 32 149-156 Schwarz HA, Bielski BHJ (1986) Reactions of H02 and 02 with iodine and bromine and l2 and I atom reduction potentials. J Phys Chem 90 1445-1448... 

The reaction occurs rather easily in the presence of a catalyst, crystalline iodine (the chemical technique) or under ionising y-radiation (the radiation chemical technique). The use of metallic tin allows higher tin alkylhalogenides to be obtained. 

The radiation chemical technique of tin alkylhalogenide production remains not veiy promising due to economic reasons (special equipment is needed) and rigid safety requirements (additional safety measures against the effect of radiation are necessary). 

Although much of the e.s.r. work has utilized radical production methods other than radiation, such as photolysis or rapid-mix redox reactions which can give mostly similar data, we shall limit our discussion here to those topics treated by the combined e.s.r.-radiation chemical technique in aqueous solutions. Most of these studies have been carried out by the steady-state method developed by Eiben and Fessenden (1971) and have been primarily concerned... 

The most direct and unambiguous way to study the reaction of free radicals with hyaluronic acid is to use radiation-chemical techniques. In dilute aqueous solutions, ionising radiation is absorbed mainly by the water to produce water-derived radicals and molecular products ... 

The rise of reactors after the war led to one of the most important advances in radiation-chemical techniques, the Cobalt-60 and Strontium-90 sources. With a reactor, it is possible to create an... 

The chapter is divided into four main parts Sec. 2 Thiols , Sec. 3 Thioethers , Sec. 4 Disulfides , and Sec. 5 Sulfoxides and Sulfonyls . They describe how sophisticated radiation-chemical techniques have been applied to address the role of sulfur-free radicals derived from these three classes of sulfur-containing compounds, in particular, in the biological environment. Important outputs from these studies are new directions for improving our knowledge of how sulfur-centered radicals interact with major cellular targets during oxidative stress, i.e. proteins, DNA, and lipids. 

DT, which might indicate electronic participation. The recent radical chemistry studies on 1,3,5-TT performed by radiation chemical techniques, have provided further insight into the one-electron oxidation of this compound by OH radicals in aqueous solutions. Of particular interest are consecutive reactions of 1,3,5-TT. The most characteristic feature in the oxidation of 1,3,5-TT is the formation of the C-centered radical with a dithioester function CH2SCH2SCH=S (1,3,5-TE) (reactions in Scheme 3). 

Extensive studies were carried out by Garrison et in the early stages of development of radiation chemical techniques for the study of proteins. Amino acids combine to form peptides and these ultimately... 

The fundamental aspects of structure-reactivity relationships in radiation-induced oxidation of substituted benzenes, bimolecular free electron transfer on the femtosecond time scale, the chemistry of sulfur-centered radicals and the radiolysis of metalloproteins are discussed in succeeding chapters. The effects of the direct and indirect mechanisms of radiation-induced DNA damage are discussed individually in two complementary chapters. The last chapter highlights the application of radiation chemical techniques to antioxidant research. 

The purpose of the book is to expose graduate students and young scientists working in the field to recent developments in radiation chemistry research and to demonstrate to scientists, engineers and other technologists the utility of radiation chemical techniques in advancing their scientific pursuits. The fact that radiation chemistry is... 

The mechanism of electron-transfer reactions of amines has been studied by different methods, including the thermochemical, electrochemical, photochemical, and radiation chemical techniques. 

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