Hydrogen peroxide catalyzed decomposition

The superoxide anion radical and hydrogen peroxide are not particularly harmful to cells. It is the product of hydrogen peroxide decomposition, the hydroxyl radical (HO ), that is responsible for most of the cytotoxicity of oxygen radicals. The reaction can he catalyzed hy several transition metals, including copper, manganese, cohalt, and iron, of which iron is the most ahimdant in the human body (Reaction 2 also called the Fenton reaction). To avoid iron-catalyzed reactions, iron is transported and stored chiefly as Fe(III), although redox active iron can be formed in oxidative reactions, and Fe(III) can be reduced by semiquinone radicals (Reaction 3). 

DHAP can be prepared by oxidation of L-glycerol-3-phosphate (L- G3P) catalyzed by glycerophosphate oxidase, coupled with hydrogen peroxide decomposition in the presence of catalase (Scheme 4.5) [14]. More recently, this synthetic route has... 

The most numerous cases of homogeneous catalysis are by certain ions or metal coordination compounds in aqueous solution and in biochemistry, where enzymes function catalytically. Many ionic effects are known. The hydronium ion H3O and the hydroxyl ion OH catalyze hydrolyses such as those of esters ferrous ion catalyzes the decomposition of hydrogen peroxide decomposition of nitramide is catalyzed by acetate ion. Other instances are inversion of sucrose by HCl, halogenation of acetone by H and OH , hydration of isobutene by acids, hydrolysis of esters by acids, and others. 

Reaction (8) and the reverse of Reaction (7) result in hydrogen peroxide decomposition and lower current efficiencies. Decomposition of hydrogen peroxide can also be catalyzed by trace metal ions [72] ... 

The oxygen is generated by the decomposition of hydrogen peroxide solution catalyzed by basic manganese dioxide in an automatic hydrogenator. 

The activity of an enzyme is affected by environmental factors such as pH and temperature. Every enzyme has optimum conditions at which its reaction rate is fastest. In this ChemLab, you will study the decomposition of hydrogen peroxide as catalyzed by the catalase in carrot cells, and you will determine the optimum temperatures under which this enzyme works. 

FIGURE 13.19 The decomposition of hydrogen peroxide is catalyzed by the iodide ion. A few drops of liquid soap have been added to the solution to dramatize the evolution of oxygen gas. (Some of the iodide ions are oxidized to molecular iodine, which then reacts with iodide ions to form the brown triiodide ion, l. j... 

The decomposition of hydrogen peroxide is catalyzed by iodide ion. The catalyzed reaction is thought to proceed by a two-step mechanism ... 

Hitt DL, Zakrzwski CM, Thomas MK (2001) MEMS-based satellite micropropulsion via catalyzed hydrogen peroxide decomposition. J Smart Mater Struct 10 1163-1175... 

Metal salts combined with hydrogen peroxide also catalyze SO3 insertion into C—H bond of methane (eq. (30)) (50). It is noteworthy that the reaction occurs even without a metal salt. A plausible mechanism is the in situ generation of radical species through the decomposition of metal-peroxo species. 

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