Formation of Hydrogen Peroxide under the Action of Microwave Radiation in Aqueous Solutions of Vanadyl and Permanganate Ions

Russian Journal of Applied Chemistry - The amount of hydrogen peroxide formed in aqueous solutions directly in the course of microwave irradiation is considerably larger than the amounts detected...     

Peroxide Coordination of Tellurium in Aqueous Solutions

Tellurium–peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH₄)₄Te₂(μ‐OO)₂(μ‐O)O₄(OH)₂ ( 1 ) and (NH₄)₅Te₂(μ‐OO)₂(μ‐O)O₅(OH)?1.28 H₂O?0.72 H₂O₂ ( 2 ) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single‐crystal and powder X‐ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te₂(μ‐OO)₂(μ‐O)O₄(OH)₂]^4?. The structure of 2 consists of an unsymmetrical [Te₂(μ‐OO)₂(μ‐O)O₅(OH)]^5? anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te₂(μ‐OO)₂(μ‐O) fragment with one μ‐oxo‐ and two μ‐peroxo bridging groups. ¹²⁵Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3–40 %wt H₂O₂ and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium–peroxide coordination in any aqueous system and the first report of inorganic tellurium–peroxo complexes. General features common to all reported p‐block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates.     

Effect of Inorganic Phosphate on the Photoproduction of Hydrogen Peroxide in Frozen Aqueous Solutions of Adenine Derivatives

Russian Journal of Physical Chemistry A - The content of hydrogen peroxide in 2 × 10−4 M aqueous solutions of adenine (A), adenosine (Ado) and adenosine-5'-diphosphate (ADP)...     

The Reaction of Muonium with Hydrogen Peroxide in Aqueous Solution

Rate constants for the reactions of muonium (Mu) (the ultralight isotope of the hydrogen atom) with H₂O₂ in H₂O and D₂O₂ in D₂O have been determined at various temperatures and pH (pD) values. The data are consistent with the three reactions: , , and the equivalent for the deuterated entities. A significant positive H/D isotope effect was found for the undissociated peroxide, while for the anions the effect was negligible or slightly in the opposite direction. In addition, for concentrated solutions of peroxide a study of the muon spin polarization as a function of applied transverse magnetic field yielded results consistent with the rate constants determined from the direct decay measurements, and indicated that the reaction products are diamagnetic, most likely MuH and MuOH, i. e., no muoniated radical products are formed. These results are potentially relevant for management of the radiolysis products in nuclear industry.     

4-Chlorophenol Degradation and Hydrogen Peroxide Formation Induced by DC Diaphragm Glow Discharge in an Aqueous Solution

In the present study, formation of hydrogen peroxide (H₂O₂) and degradation of 4-chlorophenol (4-CP) induced by DC diaphragm glow discharge (DGD) in a sodium sulfate solution were investigated. The discharge was generated in a small hole on a quarts plate interposed between two submersed graphite electrodes. Experimental results showed that 750 V was the optimum voltage for H₂O₂ formation and 4-CP degradation. Both the H₂O₂ formation and the 4-CP degradation proceeded faster in cathodic compartment than in anodic compartment. Lowering the solution pH was favorable for 4-CP degradation but showed no appreciable effect on H₂O₂ formation. Addition of hydroxyl radical scavenger (methanol) to the solution decreased the H₂O₂ formation and the 4-CP degradation. Iron species especially ferric ions enhanced the 4-CP degradation markedly. Based on the analyzes of Current–Voltage characteristics and chemical effects, it was deduced that the mechanism of DGD was similar to that of contact glow discharge electrolysis.     

Effect of the Irradiation Conditions on the Yield of Hydrogen Peroxide in Frozen Aqueous Solutions of Adenine Derivatives

Russian Journal of Physical Chemistry A - Comparative results are presented from detecting hydrogen peroxide (H2O2) in aqueous solutions of adenine derivatives irradiated at 77 K in the near-UV...     

266 nm光照下水溶液中氯苯与H2O2的反应机理研究

利用瞬态吸收光谱技术研究了不同条件下C₆H₅Cl与H₂O₂水溶液的激光闪光光解情况, 初步考察了其瞬态物种的生长和衰减等行为. 研究表明, •OH自由基和C₆H₅Cl反应生成C₆H₅Cl-OH adduct, 其反应速率常数在近中性、酸性条件下约为(5.89±0.65)×10⁹和(7.07±0.61)×10⁹ L•mol^－1•s^－1; 其衰减则符合双分子二级反应, 速率常数2k/εl＝1.1×10⁶ s^－1, 而在碱性时则为(4.34±0.51)×10⁹ L•mol^－1•s^－1, 衰减呈准一级反应, 速率常数为2.11×10⁵ s^－1. 在有氧条件下, O₂与C₆H₅Cl-OH adduct反应生成C₆H₅Cl-OHO₂ adduct, 其反应速率常数为6.8×10⁸ L•mol^－1•s^－1.     

The Prospects of the in situ and ex situ Use of Aqueous Solutions of Hydrogen Peroxide Electrogenerated from Oxygen

Russian Journal of Electrochemistry - The results and prospects of the in situ (in the cell volume) and ex situ (outside the cell) use of aqueous solutions of hydrogen peroxide electrogenerated...     

Hydrogen Peroxide Formation in Boiling Water Plasma of Electrolyte-Cathode Discharge

A mechanism is proposed for the formation of hydrogen peroxide in an electrolyte-cathode atmospheric-pressure direct-current discharge. A local increase in the temperature of water in the area of liquid contact with the gas discharge causes its boiling, and strong electric fields due to unevenness of the turbulent surface appear on the splashes. As a result, a local breakdown of the hemispherical region of boiling water beneath the electrolyte-cathode spot is possible. The kinetic scheme of the reactions for water vapor plasma has been considered, and hydrogen peroxide concentrations have been calculated, the calculation results being in satisfactory agreement with experimental data.     

Hydrogen Peroxide Formation by Electric Discharge with Fine Bubbles

Pulsed discharge plasma is typical oxidation technology for disposing organic compounds in aqueous solutions. When this electrical discharge plasma was applied in water, it may produce hydrogen peroxide (H₂O₂) without any catalyst or chemical agent. In order to increase H₂O₂ production by electrical discharge plasma in water, fine bubbles were introduced into the electrical discharge plasma in this experiment. Bipolar pulsed voltages were applied to cylindrical electrodes in the water while Ar or O₂ bubbles were introduced, generating a pulsed discharge plasma. The introduction of the bubbles seemed to enhance the dissociation of water molecules and increased H₂O₂ formation, especially with O₂ bubbling. Dissolved oxygen in the water contributed to H₂O₂ formation by pulsed discharge plasma with the bubbles, while dissociation of water molecules was the cause of H₂O₂ formation by pulsed discharge plasma without bubbles. More H₂O₂ was formed by pulsed discharge plasma with O₂ bubbles, because the amount of dissolved oxygen in the water increased upon bubbling with O₂.     

Investigation of Hydrogen Peroxide Formation After Underwater Plasma Discharge

Plasma Chemistry and Plasma Processing - This paper reports investigations on the formation of hydrogen peroxide resulting from micro-pulse plasma discharges obtained in pin-to-pin configuration...     

Photochemical Degradation of Aqueous Solutions of Organic Dyes under Exposure to Vacuum Ultraviolet Radiation

A xenon excimer silent-discharge lamp of original design intended for use in photochemical processes is described. The wavelength of excited xenon excimers is 172 nm with a full width at half maximum of 16 nm. The operating efficiency of the lamp was demonstrated using the decolorization of aqueous solutions of the azo dye Acid Yellow 99 as an example. The photodegradation kinetics of the dye obeys an exponential law, as determined by measuring color decay at _max1 = 22000 cm^–1, and depends on the interaction of dye molecules with OH^· radicals.     

葡萄糖水溶液氢键结构和动力分析

利用分子动力学模拟方法研究了不同浓度下葡萄糖水溶液的氢键结构和氢键生存周期. 分析了参与i个氢键(分子内、分子间、所有类型)的葡萄糖分子和水分子的百分比分布. 研究发现存在一个特征数N, 参与N个氢键的分子的比例最高, 当iN时, 参与i个氢键的分子的比例随着浓度的增加而减小. 还分析了不同类型氢键(葡萄糖分子内、葡萄糖分子间、水分子间、葡萄糖分子与水分子间、所有类型)的连续和截断自相关函数, 并计算了对应的氢键生存周期.     

Stationary Kinetics of Light Olefin Oxidation by Hydrogen Peroxide in Aqueous Alkali Solutions in the Presence of Fe(III) Oxide

The steady-state kinetics of ethylene and propylene oxidation by hydrogen peroxide in the presence of Fe(III) oxide in aqueous solutions with the permanent adding of H₂O₂ to the reaction medium was studied. The use of an original method for the study of the steady-state reaction kinetics with gas chromatographic detection of substrate consumption from the gas phase made it possible to estimate the apparent rate constants of ethylene oxidation, the ratio of the rate constants of propylene and ethylene oxidation, the reaction orders with respect to the substrate and oxidant concentration, the dependence of the apparent rate constant of ethylene oxidation on the catalyst weight and on the pH of solution, and the apparent activation energy of the process under condition of substrate distribution between the gas and liquid phases. It was found that the kinetic isotope effect in ethylene oxidation is almost absent when completely deuterated ethylene is used.