Kinetics, hydrogen peroxide-sulfur

L. Kinetics of the hydrogen peroxide-sulfur(lV) reaction in rainwater collected at a northeastern U.S. site. J. Geophys. Res. 1986, 9JL, 13264-13274. 

Lee, T. J. and A. P. Rendell (1993) Ab initio characterization of peroxyhypochlorous acid implications for atmospheric chemistry. Journal of Physical Chemistry 97, 6999-7002 Lee, Y- N., J. Shen, P. J. Klotz, S. E. Schwartz and L. Newman (1986) Kinetics of hydrogen peroxide - sulfur(IV) to sulfur(VI) reaction in rainwater collected at a northwestern US. site. Journal of Geophysical Research 91, 13264-13274... 

Kinetic study of the self-oscillating reaction observed in a potassium iodate-hydrogen peroxide-cysteine-sulfuric acid (acid medium) system was carried out [57], It is found that according to an adequate model the feedback mechanism is associated with autocatalytic reaction... 

Recently, L-amino acid deaminase (EC 1.4.3.x) activities have been identified, particularly from the Proteus genus [59]. This enzyme, constituted by 370 residues, is an FAD-containing L-amino acid oxidase flavoprotein that uses molecular oxygen to convert L-amino acids into the corresponding a-keto adds and ammonia but does not produce hydrogen peroxide. L-amino acid deaminase prefers amino acids with aliphatic, aromatic, and sulfur-containing side chains (the best substrates are L-heu, L-Phe, L-Met, and L-Trp) and its kinetic efficiency is quite low because of the low Vnm value (<2 units/mg protein). 

Hoffmann, M. R. and Edwards, J. 0. "Kinetics and Mechanism of the Oxidation of Sulfur Dioxide by Hydrogen Peroxide in Acidic Solution," J. Phys. Chem. 1975, 7, 2096-2098. 

Hoffmann (1977) has explored the kinetics of the H2S and hydrogen peroxide reaction. In his careful study over a wide range of pH, he noted the formation of elemental sulfur (S8) as the major end product (70%) of the oxidation with... 

Hoffmann, M. R. (1977) Kinetics and mechanism of oxidation of hydrogen sulphide by hydrogen peroxide in acidic solution. Environmental Science and Technology 11, 61-66 Hoffmann, M. R. (1986) On the kinetics and mechanism of the oxidation of aquated sulfur dioxide by ozone. Atmospheric Environment 20, 1145-1154 Hoffmann, M. R. (1990) Catalysis in aquatic environment. In Aquatic chemical kinetics (Ed. 

McArdle, J. V. and M. R. Hoffmann (1983) Kinetics and mechanism of the oxidation of aquated sulfur dioxide by hydrogen peroxide. Journal of Physical Chemistry 87, 5425-5429... 

McArdle, J.V., Hoffmann, M.R. Kinetic and mechanism of oxidation of aquated sulfur dioxide by hydrogen peroxide at low pH. J. Phys. Chem. 87, 5425-5429 (1983)... 

Several approaches have been described for the preparation of optically active sulfoxides [5-7]. The three main routes to obtain these compounds are as follows (i) the asymmetric sulfoxidation of prochiral sulfides, (ii) nucleophilic substitution using a chiral sulfur precursor, and (iii) the kinetic resolution of racemic sulfoxides. The first of tiiese methods involves the use of various oxidants and catalysts and has been the most extensively employed. There are many examples in the scientific literature and reviews are available on this approach. In recent years, much attention has been focused on the synthesis of organic sulfoxides by emplo5dng conditions compatible with the green chemistry procedures [8-10]. For this reason, mild oxidants such as molecular oxygen or hydrogen peroxide are considered in combination with novel catalysts in order to develop a mild and environmentally friendly process. 

It is sometimes difficult to understand the action of additives in deformed rubber vulcanizates [40]. This is because different kinds of radicals can be formed, for example, sulfur radicals (—RS ) as well as hydrocarbon radicals (—R ). The former do not react with oxygen the second type forms peroxide radicals (—ROO ). The kinetics of degradation for the different types of radicals is shown in Fig. 3.41. From this plot, the activation energy for radical decomposition can be calculated. It was found that the order of radical decay is peroxy > carboxy > polysulfide. It has also been observed that the reactivities for secondary processes (i.e., extraction of labile hydrogen atoms) are just in the reverse order. 

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