Reactions of Hydrogen Peroxide

The stoicheiometry and kinetics of reduction of Cu dmp complexes (dmp = 2,9-dimethyl-l,10-phenanthroline) by H2O2 have been reported in borato-buffered media over the range pH == 6.6—8.6. The overall reaction may be represented as 

Juznic and M. Senegacnik, Inorg. Nuclear Chem. Letters, 1975, 11, 349. 

The rate is strictly first-order in Ha02 at fixed [H+] and high [dmp], indicating the absence of any stoicheiometrically important metal peroxo-complexes. The mechanism postulated may be represented by the equations 

This system is of interest in that not only does the [Cu (dmp)2] + concentration represent virtually all the copper ions present, but that no involvement of the borate buffer is detectable, in contrast to other reactions of this type. It would appear from this study that the main requirement for efficient catalytic activity is related to the rate with which the copper-(i) and -(ii) co-ordination spheres can be made to resemble each other. Copper(ii) ions have been shown to catalyse the oxidation of ascorbic acid by hydrogen peroxide. In the corresponding reaction with hydrazine as substrate, the rate law ([Cu ]t=total [Cu ] present), 

The catalytic decomposition of HgOa by copper(n) ammine complexes has been described in terms of an ion-radical chain mechanism involving OH, Oa , and [Cu(NH3)a]+ as intermediates. In the reactions of HgOa with [Cu(bipy)a]+, there is no evidence for the OH radical as an intermediate. An oxygen transfer process is postulated, 

The oxidation of alcohols in iron(n)-hydrogen peroxide systems has been re-examined, and the effects of copper(ii) ions described. A new kinetic analysis has been developed, and the nature of the interactions of the radicals produced on reaction of the peroxide with the metal ion indicates that, in the reaction with isopropyl alcohol, )S-hydroxyalkyl radicals are not oxidized by iron(m) but dimerize, whereas in the presence of copper(n) they are oxidized to glycols. It is suggested that oxidation of radicals by iron(m) involves an electron-transfer process, which may in some cases be reversible, 

The catalytic decomposition of cobaloximes in the hydrogen peroxide decomposition has been described. For a series of complexes of the type CoX(dmgH)2(base), where dmgH represents the dimethylglyoximinato-anion and X = Cl, CN, OH, or Me, with bases such as pyridine, imidazole, and water, the effect of changing the axial bases is considered to be small. The activity for the cyano-cobaloxime complex is markedly less than those for the other species. In the case of the chloroaquo-complex, the rate law is of the type 

In the iron(iii)-catalysed oxidation of acetoin by hydrogen peroxide, the rate law 

A ternary vanadium(v)-edta-hydrogen peroxide complex of the type [V(edta)(Ha02)] has been characterized in solutions of pH 1.0—3.4 with little evidence for the occurrence of an intramolecular redox reaction. The reaction with neptunium(v) has been shown to result in an equilibrium between Np and HgOg slowly reduces Np to Np in strongly 

The oxidations, which are acid catalysed, are considered to involve a nucleophilic attack on the oxidizing agent by either the free sulphide or the adduct, and may be represented as n — 1) 

Continuous-flow e.s.r. studies have been made on the oxidation of vanadium(iv) by hydrogen peroxide.Both the VO + ion and the intermediate complex formed, [OVOO] +, have been monitored over a wide range of initial V, H2O2, and H+ concentrations. In the presence of excess H2O2, a mechanism accounting for the deviation from pseudo-first-order kinetics may be represented as 

The kinetics and mechanism of formation of the complex between plutonium(iv) and HgOa,  

Several forms of the reductant are present under the experimental conditions used, the hydrogen-ion dependences being ascribed to the reaction of hydroxo-complexes  

No difference in values was observed in perchlorate or sulphate media (O.IM). In conditions of excess oxidant, however, the decay of Cr fitted neither first- nor second-order rate laws, possibly as a result of side reactions of the type 

The corresponding reaction with titaniura(iii) in excess exhibited second-order behaviour, the production of OH radicals as intermediates being confirmed by the addition of propan-2-ol, which reacts rapidly with HO and thereby decreased (by a factor of 2) the rate of decay of reductant. Confirmation that any secondary rate constants (k are much greater than that for the ratedetermining initial step have been derived from a study of the reductants with hydroxyl radicals. The values for the reactions of Cr and Ti f are 1.2 x 10  

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Lithium Peroxide. Lithium peroxide [12031 -80-0] Li202, is obtained by reaction of hydrogen peroxide and lithium hydroxide in ethanol (72) or water (73). Lithium peroxide, which is very stable as long as it is not exposed to heat or air, reacts rapidly with atmospheric carbon dioxide releasing oxygen. The peroxide decomposes to the oxide at temperatures above 300°C at atmospheric pressure, and below 300°C under vacuum. 

Peroxyoxalate. The chemical activation of a fluorescer by the reactions of hydrogen peroxide, a catalyst, and an oxalate ester has been the object of several mechanism studies. It was first proposed in 1967 that peroxyoxalate (26) was converted to dioxetanedione (27), a highly unstable intermediate which served as the chemical activator of the fluorescer (fir) (6,9). 

Peroxomonophosphoric acid can be prepared by the hydrolysis of peroxodiphosphates ia aqueous acid and by the reaction of hydrogen peroxide with phosphorus pentoxide (45). It is not produced or used commercially and the salts that have been prepared are unstable and impure. 

Synthesis. Dialkyl peroxides are prepared by the reaction of various substrates with hydrogen peroxide, hydroperoxides, or oxygen (69). They also have been obtained from reactions with other organic peroxides. For example, dialkyl peroxides have been prepared by the reaction of hydrogen peroxide and alkyl hydroperoxides with alMating agents, eg, RX and olefins (33,66,97) (eqs. 24—27). 

Strontium peroxide, Sr02, is a white powder with a specific gravity of 4.56 that decomposes in water. It is made by the reaction of hydrogen peroxide with strontium oxide and is used primarily in pyrotechnics and medicines. 

The catalytic activity of PCSs results from their semiconductor properties. The first studies in this field date from 1959—1961. Thus, we have demonstrated catalytic activity of products of the thermal transformation of PAN in the decomposition reactions of hydrogen peroxide, hydrazine hydrate, and formic acid270, 271. There is an indication of catalytic activity of poly(aminoquinone) in the reactions of the hydrogen peroxide decomposition272. ... 

The Free Radical Mechanism in the Reactions of Hydrogen Peroxide Joseph Weiss... 

In related work, the reactions of hydrogen peroxide with iron(II) complexes, including Feu(edta), were examined.3 Some experiments were carried out with added 5.5"-dimethyl-1-pyrroline-N-oxide (DMPO) as a trapping reagent fa so-called spin trap) for HO. These experiments were done to learn whether HO was truly as free as it is when generated photochemically. The hydroxyl radical adduct was indeed detected. but for some (not all) iron complexes evidence was obtained for an additional oxidizing intermediate, presumably an oxo-iron complex. 

Though we and others (27-29) have demonstrated the utility and the improved sensitivity of the peroxyoxalate chemiluminescence method for analyte detection in RP-HPLC separations for appropriate substrates, a substantial area for Improvement and refinement of the technique remains. We have shown that the reactions of hydrogen peroxide and oxalate esters yield a very complex array of reactive intermediates, some of which activate the fluorophor to its fluorescent state. The mechanism for the ester reaction as well as the process for conversion of the chemical potential energy into electronic (excited state) energy remain to be detailed. Finally, the refinement of the technique for routine application of this sensitive method, including the optimization of the effi-ciencies for each of the contributing factors, is currently a major effort in the Center for Bioanalytical Research. 

The reaction of hydrogen peroxide with an alcohol in the presence of sulphuric acid gives rise to the corresponding hydroperoxide ... 

Strong evidence in favor of mechanism B was obtained when it was discovered that singlet oxygen produced chemically by the reaction of hydrogen peroxide and sodium hydrochlorite or from gaseous oxygen excited by an electrodeless discharge yields the same products as the direct photolysis/85-8 ... 

In addition to protection from breakage, the brown plastic bottles in which hydrogen peroxide is commonly sold enhance the shelf-life of this product. Packaging plays an important role in limiting the light-induced chemical reactions of hydrogen peroxide. 

Mallet reported in 1927 that the intensity of light emitted in the reaction of hydrogen peroxide and the hypochlorite ion was enhanced when eosin, fluorescein, anthracene, quinine sulfate, or aesculin (Fig. 3) was added to the reaction medium [62],... 

Chain Generation by Reaction of Hydrogen Peroxide with Carbonyl Compound... 

It is well known that most of the antioxidant enzymes and substrates can exhibit prooxidant activity under certain conditions, mainly because many stages of the reactions catalyzed by such enzymes are reversible. The question of possible prooxidant effects of SODs and the ability of SODs to react with the other substrates than superoxide have been studied for a long time. It is known that CuZnSOD is inactivated by the hydrogen peroxide formed. Hodgson and Fridovich [3] proposed that this inactivation depends on the reaction of hydrogen peroxide with the oxidized form Cu(II)ZnSOD yielding the bound hydroxyl radicals. 

In the reaction of hydrogen peroxide with iodic acid in acidic solution, the relevant half-reactions... 

Solv-X A pulp-bleaching process which prevents the transition-metal catalyzed side reactions of hydrogen peroxide which would otherwise occur. 

The catalytic capabilities of rhenium compounds burst on the scene about one decade ago, featuring MeRe03 as a catalyst for reactions of hydrogen peroxide. It was quickly verified that peroxorhenium(VII) compounds were the active intermediates. With them, practical reactions and fundamental questions of mechanism could then be resolved. 

The chemiluminescence of the reaction of hydrogen peroxide with luminol (69) is catalyzed by metalloporphyrins 70a and 70b. This chemiluminescence is quenched by... 

DR. REX SHEPHERD (University of Pittsburgh) About a year ago, we started to look at the reaction of hydrogen peroxide... 

The evolution of fluoride ions in actual fuel cell effluent and during laboratory accelerated life studies has been reported. One common example of radical generation from peroxide decomposition is in the Fenton test, where peroxyl or hydroxyl radicals can be formed through the reaction of hydrogen peroxide with Fe(II) (Scheme 3.2). 

Consider the problem of synthesizing a controller in order to track a periodic temperature profile in the decomposition reaction of hydrogen peroxide,... 

The kinetics of the reaction between metMb and peroxides has attracted attention in studies that have focused on the role of the distal H64 ligand and other amino acid residues present in the distal heme pocket. Brittain et al. reported stopped-flow studies of the reaction of hydrogen peroxide with seven variants in which the distal H64 residue was replaced with a series of residues of var5fing polarity (194). Although the H64Y variant was unreactive toward peroxide, the other... 

This enzyme [EC 1.11.1.10], also called chloride peroxidase, catalyzes the reaction of hydrogen peroxide with two RH and two Cl to produce two R—Cl and two water molecules. A heme group is one of the cofactors. This enzyme can also catalyze bromination and iodin-ation, but not fluorination. 

This enzyme [EC 1.11.1.7] catalyzes the reaction of hydrogen peroxide with a donor to produce two water and the oxidized donor. 

Peroxides in combination with a reducing agent are a common source of radicals for example, the reaction of hydrogen peroxide with ferrous ion... 

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