Rate Of Peroxide Decomposition Research Articles

Decomposition rate of hydrogen peroxide bleaching agents under various chemical and physical conditions

The decomposition rate of 30% hydrogen peroxide was measured when hydrogen peroxide was mixed with 36% hydrochloric acid and anaesthesia ether in 5:5:1 solution and in a solution of 20% sodium hydroxide at temperatures of 16 ° to 20 ° C and at 45 °C, respectively. The effect of ferris chloride on the decomposition of hydrogen peroxide was also observed. The decomposition of 30% hydrogen peroxide in sodium hydroxide solution was faster than that in the mixture of hydrochloric acid and ether at low temperature (16 ° to 20 °C). The decomposition of hydrogen peroxide was accelerated by heat. The experiment implies that the bleaching effect of hydrogen peroxide can be achieved without heat by use of a sodium hydroxide solution. Further study on the rationale of the compound of the McInnes solution (hydrogen peroxide, hydrochloric acid, and anaesthesia ether mixed at a ratio of 5:5:1) is needed.

Study of the heterogeneous decomposition of hydrogen peroxide: its application to the development of catalysts for carbon-based oxygen cathodes

The heterogeneous decomposition of hydrogen peroxide was studied in alkaline electrolytes on LaFe x Ni 1- x O 3 perovskite-type oxides. The reaction is first order in HO 2 − concentration. Maximum catalytic activity was found for x = 0.25. This increase in activity was attributed to the appearance of mixed oxidation states of iron and nickel. The optimum temperature of synthesis was between 600°C and 700°C, this being a compromise between a sufficiently high temperature to synthesize the perovskite structure and a sufficiently low temperature to produce a high surface area catalyst with a low number of oxygen vacancies. The catalytic activity for O 2 reduction on carbon-based electrodes correlates very well with the catalytic activity for HO 2 − decomposition. A linear relationship was derived between the electrode potential at constant current and the logarithm of the peroxide decomposition rate constant. This relationship is followed quite well at relatively low current densities.

Use of hydrogen peroxide as an oxygen source for in situ biodegradation : Part I. Field studies

Hydrogen peroxide, which is commonly used as an oxygen source for in situ biodegradation, tends to decompose into water and oxygen gas. The rate of this decomposition relative to the oxygen demand of the contaminated aquifer is important to the success of an in situ process. The objective of this study, which was performed at Eglin Air Force Base in northwest Florida, was to evaluate in situ hydrogen peroxide stability and biological oxygen utilization for the biodegradation of JP-4 jet fuel. Hydrogen peroxide was injected into the subsurface, concentrations of hydrogen peroxide and oxygen were measured in monitoring wells, and in situ tests were conducted to determine hydrogen peroxide decomposition and oxygen use rates at the well locations. Because the rates of hydrogen peroxide decomposition were consistently found to be much higher than the rates of oxygen utilization, it is unlikely that any significant part of the oxygen from the hydrogen peroxide in excess of that initially required to saturate the groundwater was used to degrade jet fuel.

Determination of the actual photocatalytic rate of hydrogen peroxide decomposition over suspended titania. Fitting to the Langmuir-Hinshelwood form

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of the actual photocatalytic rate of hydrogen peroxide decomposition over suspended titania. Fitting to the Langmuir-Hinshelwood formBeat. Jenny and Pierre. PichatCite this: Langmuir 1991, 7, 5, 947–954Publication Date (Print):May 22, 1991Publication History Published online1 May 2002Published inissue 22 May 1991https://doi.org/10.1021/la00053a023RIGHTS & PERMISSIONSArticle Views573Altmetric-Citations69LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Oxidation of polyethylene surface by corona discharge and the subsequent graft polymerization

AbstractOxidation of a polyethylene (PE) surface by corona discharge and the subsequent graft polymerization of acrylamide (AAm) were studied. The maximum amount of peroxides introduced by corona treatment at a voltage of 15 kV was about 2.3 × 10−9 mol cm−2. The decomposition rate of peroxide and the dependence of graft amount on the storage period of the corona‐treated PE films showed that there were several kinds of peroxides, the labile one being mainly responsible for the initiation of graft polymerization. When the corona‐treated film was brought into contact with a deaerated aqueous solution of AAm, graft polymerization took place more strongly with the treatment time, but was reduced after passing a maximum. Although the x‐ray photoelectron spectroscopic analyses of the corona‐treated PE films showed homogeneous oxidation of the outer polymer surface by corona discharge, optical microscopy on the cross section of the grafted film revealed the graft polymerization to be limited to a very thin surface region.

Perovskite-type oxides: Oxygen electrocatalysis and bulk structure

Perovskite-type oxides have been considered for use as oxygen reduction and generation electrocatalysts in alkaline electrolytes. This paper is concern Perovskite oxides have not been found, in general, to be very active for oxygen reduction, although substantial catalytic activity for hydrogen peroxid A series of compounds of the type LaFe x Ni 1- x O 3 has been used as a model system to gain information on the possible relationships be MES also shows that the introduction of Ni into the FE(III) matrix of LaFeO 3 forces some of the FE(III) into the unusual FE(IV) state, while part o The hydrogen peroxide decomposition rates have been found to undergo a substantial change in the range 0.25 < x < 0.5. A correlation has been f

A Water Radiolysis Model in a Circulating Flow System with a Boiling Region and Its Application to Hydrogen Alternate Water Chemistry of Boiling Water Reactors

A gaseous mass transfer model has been proposed for quantitative evaluation of the chemical chain-back reaction system with volatile species in a boiling channel. Theoretical expression for concentration transients in liquid and vapor phases were obtained. The model was applied to water radiolysis in a boiling water reactor core channel with Bankoff's two-phase flow treatment. Hydrogen injection tests in the Oskarshamn-2 and Dresden-2 units were simulated. The calculated results showed that gas release and absorption rates in the boiling channel were not consistent with Henry's law. By using optimized parameters related to the gaseous mass transfer, calculated results agreed within a factor of 2 for lower hydrogen injection rates at the two plants. It was determined that more exact treatments are needed to determine the radiation level in the downcomer and catalytic decomposition rate of hydrogen peroxide in order to provide better evaluations of water radiolysis phenomena.

Kinetics of Bleaching Agent Decomposition in a Single-Stage Preparatory Process

In a single-stage preparatory process, hydrogen peroxide decomposes at a faster rate in the presence of pH buffers, whereby the activation energy is lowered. A relatively slower rate of peroxide decomposition is achieved in fabrics containing acrylic size. The damage to cellulose assessed in terms of the copper number and carboxyl content is slightly higher for acrylic-sized fabrics than starch-sized fabrics.

Inhibition of acrylic acid polymerization by phenothiazine and p‐methoxyphenol

AbstractThe major features of polymerization induction periods for acrylic acid inhibited with phenothiazine and p‐methoxyphenol have been characterized at 100°C, including duration of the induction periods, and rates of inhibitor disappearance, molecular oxygen absorption, and peroxide formation. Surprisingly, thermally produced radicals react more rapidly with phenothiazine than with oxygen since there is no detectable oxygen absorption or peroxide for mation during phenothiazine‐induced induction periods. Thus, phenothiazine has been used to estimate the thermal rate of radical formation. Phenothiazine's effectiveness as an inhibitor is not directly affected by oxygen, although it does undergo oxygen‐promoted, noninhibition‐related side reactions. p‐Methoxyphenol, on the other hand, depends entirely on the presence of oxygen to function as an inhibitor. Compared with equivalent concentrations of p‐methoxyphenol, induction periods obtained with phenothiazine are very long, and the rate of inhibitor disappearance is slower by at least an order of magnitude. The characteristics of p‐methoxyphenol inhibition reflect a greater radical flux deriving from the significant rates of oligomeric peroxide formation and decomposition which we measured during p‐methoxyphenol‐induced induction periods at 100°C. MEHQ is an effective inhibitor at ambient temperatures in part because of the greater stability of the peroxides at these lower temperatures.

Thermal Decomposition of Hydrogen Peroxide and Its Effect on Reactor Water Monitoring of Boiling Water Reactors

The thermal decomposition rate of hydrogen peroxide (H2O2) was measured in the aqueous phase at an elevated temperature. It was shown that the reaction follows first-order kinetics, and the rate constant was determined as a function of temperature. The mechanism of the aqueous phase decomposition is discussed, particularly in relation to the activation energy of the reaction.Calculations were carried out for the reactions of O2, H2, and H2O2 in the boiling water reactor sampling line. It was shown that H2O2 disappears, and the back reaction of H2 and O2 to water proceeds in the line. This was interpreted on the basis of the radical mechanism of H2O2 decomposition.

Reactions of oxidized lipids with protein. Part 13. Autoxidation of hexanal in presence of nonlipidic components.

Hexanal is rapidly autoxidized in mixture with nonlipidic substrates even at 25 degrees C. The formation of peroxides follows the kinetics of a first order reaction with respect to hexanal (k1 about 10(-5) min-1), and is higher in mixture with casein or lysine-impregnated cellulose than with cellulose. In mixtures containing pure hexanal, peroxides are decomposed more rapidly after second-order reaction with respect to peroxides (k2 about 10(-3) mmol X kg-1 X min-1) while only slowly by the first-order reaction (k3 about 10(-5) min-1). In presence of small amounts of hexanoic acid the rate of second-order peroxide decomposition remained unaffected while the rate of the first-order peroxide decomposition increased by 4 orders (k3 about 10(-1) min-1). The presence of peroxides was percepted in the odour by sensory analysis contrary to nonvolatile lipid hydroperoxides.

Evaluation of the Yields from the Radiolysis of Water in Boiling Water Reactors by Neutron and Gamma Radiation

A computer program package AQUARY has been developed for quantitative evaluation of concentration distributions of the radiolytic species in overall boiling water reactor primary systems. The hydrogen peroxide decomposition rate k, the gas release coefficient ϵ, and the accumulation of products through recirculation of the coolant were taken into consideration. The following relations were found:1. Hydrogen and hydrogen peroxide concentrations in the core are substantially high, and the following relation holds in the core,2[O2] = [H2] < [H2O2].2. The hydrogen peroxide concentration contributes markedly to the oxygen concentration at the water sampling stations in a plant. In particular, the following equation holds if k > 0.1 s-1,2[O2] at the sampling station = [H2O2] at the core exit.

Electrochemistry of oxygen and hydrogen peroxide at clean and at halide-covered polycrystalline silver

The effect of halide adsorption on the rate of hydrogen peroxide decomposition in alkaline solution has been studied. The reduction of oxygen at clean silver in acidic, alkaline, and unbuffered electrolytes has also been investigated for comparison. On prereduced electrodes the amount of hydrogen peroxide observed during the reduction of oxygen is related to pH and adventitious contamination. Specific adsorption by halides decreases the efficiency of the “four-electron” reduction of oxygen with concomitant formation of hydrogen peroxide. With iodide, the reduction of oxygen to hydrogen peroxide is nearly 100% efficient. Coverages of Iads approaching 0.2 monolayer are sufficient to create an energy barrier for breaking of the oxygen-oxygen bond and effectively poison the catalytic surface of silver.

Electrochemistry of oxygen and hydrogen peroxide at clean and at halide-covered polycrystalline silver

The effect of halide adsorption on the rate of hydrogen peroxide decomposition in alkaline solution has been studied. The reduction of oxygen at clean silver in acidic, alkaline, and unbuffered electrolytes has also been investigated for comparison. On prereduced electrodes the amount of hydrogen peroxide observed during the reduction of oxygen is related to pH and adventitious contamination. Specific adsorption by halides decreases the efficiency of the “four-electron” reduction of oxygen with concomitant formation of hydrogen peroxide. With iodide, the reduction of oxygen to hydrogen peroxide is nearly 100% efficient. Coverages of I ads approaching 0.2 monolayer are sufficient to create an energy barrier for breaking of the oxygen-oxygen bond and effectively poison the catalytic surface of silver.

Effect of shear rate on the rate of polymerization of styrene

Application of shear was found to have considerable effect on the radical polymerization of styrene initiated by benzoyl peroxide. The initial rate of polymerization decreases by as much as 30% for low shear rates (γ), but on further increasing γ it increases slightly, levelling ultimately at the 10% reduction level. The effect of solvent was shown to have negligible effect, in direct contrast to that observed by Kumar et al. 1–3 for methyl methacrylate and acrylonitrile. Experiments confirm that the reduction in the rate of initial polymerization can be attributed largely to the change in initiator efficiency on the application of shear rate. As a further test, the decomposition rate of benzoyl peroxide in nitrobenzene at 80°C was measured and was found to increase significantly on application of shear. This confirms the importance of mass transfer resistance in removal of CO 2. The reduction in the rate of polymerization of styrene can now be explained as follows. In the reaction mass, there are benzoyloxy as well as phenyl radicals and styrene molecules have been shown by Bevington 4 to react preferentially with the former. The fall in the rate of polymerization of styrene occurs because, on the application of shear, decomposition of benzoyloxy radicals is favoured in the forward direction and its concentration in the reaction mass falls. As a result the initiation of polymer radicals reduces, which in turn gives a lower rate of polymerization.

Investigations of changes in the oxidation state of the catalyst during the OsO4-catalysed decomposition of hydrogen peroxide

Abstract By using different methods, such as spectrophotometry, potentiometric titration, polarography and extraction, it was found that at pH 8.5 osmium (VIII) is reduced by hydrogen peroxide to osmium(VI) to various extents. At pH 10.6, where the rate of the OsO4-catalysed decomposition of hydrogen peroxide reaches its maximum, the concentration ratio of osmium (VIII) and osmium (VI) was found to be nearly one. This favours the explanation that the maximum rate of hydrogen peroxide decomposition is found at the pH where the rate of reduction of osmium (VIII) by hydrogen peroxide just becomes equal to the rate of oxidation of osmium (VI) by hydrogen peroxide.

High pressure effect on polyethylene crosslinking initiated by benzoyl peroxide

High pressure effects (300, 600, and 800 MPa) on polyethylene crosslinking initiated by benzoyl peroxide have been studied at 120°C. An increase in pressure leads to a decrease in yield of the insoluble gel; the yields at 300, 600, and 800 MPa were respectively 96, 86, and 79%. With increasing pressure the rate of polyethylene crosslinking decreases and the rate of benzoyl peroxide decomposition at 300, 600, 800 MPa can be anticipated from the time of crosslinking. The activation volume ΔV ‡=9.1 cm 3 mol −1 was determined for benzoyl peroxide decomposition on polyethylene at 120°C.

Crosslinking of polypropylene in the presence of polyfunctional monomers

AbstractThe crosslinking of atactic and isotactic polypropylene initiated by organic peroxides in presence of diallyl maleate or pentaerythrityl tetramethacrylate was studied. The influence of concentration of the components of the crosslinking system as well as the effect of temperature and reaction time was followed. For high yield of gel, a high rate of initiation is necessary. Also the rate of reaction of double bonds must be similar to the rate of peroxide decomposition.

Catalytic activity of Cu(II)–poly(vinyl alcohol) complex for decomposition of hydrogen peroxide

AbstractDecomposition of hydrogen peroxide was examined was examined by using Cu(II)–poly(vinyl alcohol) (PVA) as catalyst. The rates of decomposition were measured. Electronic spectra and infrared spectra of Cu(II)–PVA complex systems were determined at various stages of decomposition. Effect of addition of various amines to the Cu(II)–PVA system on catalytic action was considered. The relation between the initial rate and the initial concentration of hydrogen peroxide varied in accordance with the rate expression of Michaelis‐Menten type. Cu(II)–PVA complex was found to have a large catalytic activity, while the polymeric PVA ligand and copper(II) ion exhibited less activity than Cu(II)–PVA complex. For hydrogen peroxide decomposition, Cu(II)–PVA complex showed catalytic activity when a stable complex of planar structure formed, while many other polymer complexes reported by other authors showed the catalytic activity when they were in unstable complex forms. An amine substituent has a critical influence on the rate of hydrogen peroxide decomposition. The mechanism in the first step of reaction for hydrogen peroxide decomposition is discussed.

Kinetics and mechanism of the thermal reaction between tert‐butyl perbenzoate and n‐alkanes: A model system for the crosslinking of polyethylene

AbstractThe thermal reaction between tert‐butyl perbenzoate and n‐alkanes has been studied under conditions as close as possible to those during actual crosslinking of polyethylene. Product analysis allowed a description of the fate of 90–95% of the peroxide fragments. Approximately 50–60% of the substrate radicals, formed upon hydrogen abstraction, were found to combine and give crosslinks, whereas about 30% showed disproportionation, thus leading to substrate unsaturation. The two competing reactions account for 85–90% of the generated substrate radicals. The model system provides a simple and convenient method for comparing the crosslink efficiencies of peroxides; these data are reported for some commercial peroxides. In order to facilitate an extrapolation of the results in liquid alkanes towards solid polyethylene (PE), the influence of substrate viscosity and temperature on the peroxide decomposition rate, product distribution, and crosslink efficiency was studied. In n‐alkanes peroxide decomposition follows first‐order kinetics well, with an Arrhenius activation energy of 32.9 ± 0.5 kcal/mole. In addition, the kinetics in the model system are compared with those calculated from Rheometer (torque vs. time) measurements on the curing of unfilled PE and ethylene‐propylene‐dicyclopentadiene terpolymer (EPDM). Only minor differences in peroxide decomposition rate and overall activation energy were found.