Peroxides, in nature

Draper WM, Crosby DG. 1983. The photochemical generation of hydrogen peroxide in natural waters. Arch Environ Contam Toxicol 12 121-126. 

Note Autoxidation is usually the result of chain-reaction with air or oxygen, and the intermediate products are usually peroxidic in nature. 

The present section is an overview of the varied involvement of peroxides in natural phenomena, ranging from atmospheric chemistry to important physiological systems in all living organisms, and the functions fulfilled by these compounds in industry. All this requires adequate analytical methods to identify, determine and characterize peroxides. This section should not be considered as a comprehensive review on natural and industrially relevant peroxides, but rather as a structured set of examples related to analytical methods described in the sequel. 

T 2. — Crosslinking efficiency of dicumyl peroxide in natural rubber. J. Appl. Polymer Sci. 6, 613 (1962). 

Another metal which is known to activate peroxide in nature is manganese. Indeed, the interest in using manganese complex as catalysts for the... 

The main source of hydrogen peroxide in natural waters is through its photochemical production [113]. Elowever, as will be discussed below, other processes also affect concentrations of H2O2 in the water column. These include dry and wet atmospheric deposition, and biological release. 

E.V. Shtamm, A.P. Purmal, Y.I. Skurlatov (1991). The role of hydrogen peroxide in natural aquatic media. Russ. Chem. Rev., 60,1228-1248. 

Several pathways can account for the decomposition of hydrogen peroxide In natural waters. Some of these decay processes not only remove H2O2, but also result In the oxidation of chemicals, possibly Including various pollutants, that are present In natural waters. These processes Include direct oxidation (5), peroxidase-catalyzed oxidation (6), and free radical oxidation Initiated by photochemical or metal-catalyzed decomposition (7). Little Is known about the significance and rates of these various processes under environmental conditions, but they have all been shown to occur rapidly with certain organic substrates In the laboratory. 

Few monomeric radicals are lost by coupling with polymeric radicals when dialkyl peroxides are used as the curative. Also, if the elastomer is properly chosen, the scission reaction is not excessive [82-88]. For dicumyl peroxide in natural rubber, the crossUnking efficiency has been estimated at about 1.0. One mole of crosslinks is formed for each mole of peroxide crossUnking is mainly by the coupling of two polymeric radicals [89,90]. One peroxide moiety gives two monomeric free radicals, which react with rubber to give two polymeric radicals that couple to form one crosslink. 

Eskendirov 1, Coville NJ, Parmaliana A, Sokolovski VD. Direct oxidative conversion of methane into higher hydrocarbons and oxy-products in the presence of hydrogen peroxide. In Natural gas conversion IV. Studies in surface science and catalysis, vol. 107. Elsevier Sci. B.V 1997. 301—306. 

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