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Free radicals in oxidations

Minisci F, Fontana F. Free radicals in oxidation processes. La Chimica e l lndustria 1998 80 1309-1316. [Pg.233]

Simoes, C., Domingues, P, Domingues, M.R.M. (2012) Identification of Free Radicals in Oxidized and Glycoxidized Phosphatidylethanolamines by Spin Trapping Combined with Tandem Mass Spectrometry. Rapid Commun. Mass Spectrom. 26 931-939. [Pg.130]

The lubricant oxidation mechanism is free-radical in nature and the additives act on the kinetic oxidation chain by capturing the reactive species either by decomposition of the peroxides, or by deactivation of the metal. [Pg.358]

Probably, active forms of accelerators mentioned above are capable to create compounds with PMSA and these forms ai e stabilized by activators. In such compounds the weakening of -0-0- bond of PMSA takes place, that causes a gap of this bond and free radicals OH and SO ai e created, which easily oxidize ferroin. Created free radicals can oxidize active forms of accelerators that lead to their deactivation. [Pg.61]

The most important contnbution of this technology to the science of fluonne chemistry has been its ability to probe mechanistic aspects of elemental fluorine attack on organic molecules As has been long accepted fluorine attack on nonaromatic organic molecules is free radical in nature The great oxidizing power of fluonne and... [Pg.103]

By using this technique acrylamide, acrylonitrile, and methyl acrylate were grafted onto cellulose [20]. In this case, oxidative depolymerization of cellulose also occurs and could yield short-lived intermediates [21]. They [21] reported an electron spin resonance spectroscopy study of the affects of different parameters on the rates of formation and decay of free radicals in microcrystalline cellulose and in purified fibrous cotton cellulose. From the results they obtained, they suggested that ceric ions form a chelate with the cellulose molecule, possibly, through the C2 and C3 hydroxyls of the anhy-droglucose unit. Transfer of electrons from the cellulose molecule to Ce(IV) would follow, leading to its reduction... [Pg.503]

Propyl gallate is an antioxidant. It protects against oxidation by hydrogen peroxide and oxygen free radicals in a catalytic manner similar to superoxide dismutase. [Pg.21]

For an example, see Rathore, R. Bosch, E. Kochi, J.K. Tetrahedron Lett., 1994,35, 1335. Sheldon, R.A. Kochi, J.K. Metal-Catalyzed Oxidations of Organic Compounds-, Academic Press NY, 1981, p. 368 Walling, C. Free Radicals in Solution-, Wiley NY, 1957, p. 457. [Pg.1576]

J.A. Murphy, Free Radicals in Synthesis Clean Reagents Affording Oxidative or Reductive Termination , Pure and Applied Chemistry, Special Topic Issue on Green Chemistry, 2000, 72(7) 1327. [Pg.33]

The main environmental issue concerned with VOCs is their ability to form low-level ozone and smog through free radical air oxidation processes. The EPA has published a list detailing a number of adverse health effects, which are now thought to originate from the presence of VOCs in the environment, including ... [Pg.130]

KRISTENSEN D, krOger-ohlsen m V and SKIBSTED L H (2002) Radical formation in dairy products Prediction of oxidative stability based on electron spin resonance spectroscopy, in Morello M J, Shahidi F Ho CT Free Radicals in Food, Chemistry, Nutrition and Health Effects, ACS Symposium Series 807, Washington D C, 114-25. [Pg.343]

Foote, C., Photosensitized oxidation and singlet oxygen conseqnences in biological systems, in Free Radicals in Biology, Pryor, W.A., Ed., Academic Press, New York, 1976. [Pg.68]

While many biological molecules may be targets for oxidant stress and free radicals, it is clear that the cell membrane and its associated proteins may be particularly vulnerable. The ability of the cell to control its intracellular ionic environment as well as its ability to maintain a polarized membrane potential and electrical excitability depends on the activity of ion-translocating proteins such as channels, pumps and exchangers. Either direct or indirect disturbances of the activity of these ion translocators must ultimately underlie reperfiision and oxidant stress-induced arrhythmias in the heart. A number of studies have therefore investigated the effects of free radicals and oxidant stress on cellular electrophysiology and the activity of key membrane-bound ion translocating proteins. [Pg.57]

Bellomo, G., Richelmi, P., Hirabelli, F., Marioni, V. and Abbagnano, A. (1985). Inhibition of liver microsomal calcium ion sequestration by oxidative stress role of protein sul-phydryl groups. In Free Radicals in Liver Injury (eds. G. Poli, K.H. Cheeseman, M.U. Dianzani, and T.F. Slater) pp. 139-142. IRL Press, Oxford. [Pg.93]

This is a chronic inflammatory disease, which can affect the gut as well as other organs. There is relatively little information on the role of free radicals in this condition. Neutrophil chemiluminescence was increased in patients with intestinal Behcet s compared to normal controls (Suematsu et al., 1987a) and there is some evidence for endothelial injury by neutrophil-derived oxidants (Niwa et al., 1982). Preliminary studies with lip)osomal-encapsulated SOD demonstrated marked improvement in 12 out of 16 pjatients wdth active Behcet s disease (Niwa etal., 1985). [Pg.152]

Free-radical generation occurs normally in the human body, and rates of free-radical generation are probably increased in most diseases (see Table 13.1). Their importance as a mechanism of tissue injury is still uncertain, largely because the assays used to measure them have, until recently, been primitive. The development of new assays applicable to humans (such as the assays of oxidative DNA damage described above) should allow rapid evaluation of the role of free radicals in disease pathology and provide a logical basis for the therapeutic use of antioxidants. A rationale is presented in Fig. 13.3. Attempts to use antioxidants in the treatment of human disease can be divided into three main areas ... [Pg.209]

Hepatic reperfusion injury is not a phenomenon connected solely to liver transplantation but also to situations of prolonged hypoperfusion of the host s own liver. Examples of this occurrence are hypovolemic shock and acute cardiovascular injur) (heart attack). As a result of such cessation and then reintroduction of blood flow, the liver is damaged such that centrilobular necrosis occurs and elevated levels of liver enzymes in the serum can be detected. Particularly because of the involvement of other organs, the interpretation of the role of free radicals in ischaemic hepatitis from this clinical data is very difficult. The involvement of free radicals in the overall phenomenon of hypovolemic shock has been discussed recently by Redl et al. (1993). More specifically. Poll (1993) has reported preliminary data on markers of free-radical production during ischaemic hepatitis. These markers mostly concerned indices of lipid peroxidation in the serum and also in the erythrocytes of affected subjects, and a correlation was seen with the extent of liver injury. The mechanisms of free-radical damage in this model will be difficult to determine in the clinical setting, but the similarity to the situation with transplanted liver surest that the above discussion of the role of XO activation, Kupffer cell activation and induction of an acute inflammatory response would be also relevant here. It will be important to establish whether oxidative stress is important in the pathogenesis of ischaemic hepatitis and in the problems of liver transplantation discussed above, since it would surest that antioxidant therapy could be of real benefit. [Pg.243]


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See also in sourсe #XX -- [ Pg.219 , Pg.222 , Pg.223 , Pg.224 , Pg.225 , Pg.226 ]




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Free radicals oxidation

Oxidation radical

Oxide Radicals

Oxide, free

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