Basic Hydrogen Peroxide Research Articles

Reactive Oxygen Species and Reactive Nitrogen Species in Peroxisomes. Production, Scavenging, and Role in Cell Signaling

Peroxisomes can be broadly defined as subcellular organelles bounded by a single membrane that contain as basic enzymatic constituents catalase and hydrogen peroxide (H2O2)-producing flavin oxidases and occur in almost all eukaryotic cells ([Baker and Graham, 2002][1]). In recent years, it has

A New Approach to the Furan Degradation Problem Involving Ozonolysis of the trans-Enedione and Its Use in a Cost-Effective Synthesis of Eplerenone

[reaction: see text] Whereas ozonization of furan 3a affords little or no carboxylic acid 5, ozonization of the corresponding trans-enedione 6 afforded carboxylic acid 5 in 82.4% yield (cryst., overall from furan, 100 g scale; after workup with dimethyl sulfide, followed by mildly basic hydrogen peroxide). This new approach to furan degradation is showcased in a cost-effective synthesis of eplerenone, an important new medicine for cardiovascular indications.

Efficient and Rapid Method for the Oxidation of Electron‐Rich Aromatic Aldehydes to Carboxylic Acids Using Improved Basic Hydrogen Peroxide

An efficient and rapid method for oxidation of electron‐rich aromatic aldehydes to their corresponding carboxylic acids in excellent yields was developed. It is based on the oxidation of methoxy‐substituted benzaldehydes in methanol with an improved aqueous basic hydrogen peroxide system. Benzaldehydes with electron‐withdrawing substituents are oxidized to the corresponding carboxylic acid in excellent yields under mild reaction conditions.

Reagent-Controlled Asymmetric Homologation of Boronic Esters by Enantioenriched Main-Group Chiral Carbenoids

[reaction: see text] Putative enantioenriched carbenoid species, (R)-1-chloro-2-phenylethylmagnesium chloride (9) and (S)-1-chloro-2-phenylethyllithium (26), generated in situ by sulfoxide ligand exchange from (-)-(R(S),R)-1-chloro-2-phenylethyl p-tolyl sulfoxide (8), effected the stereocontrolled homologation of boronic esters. sec-Alcohols derived from the product boronates by oxidation with basic hydrogen peroxide exhibited % ee closely approaching that of sulfoxide 8 in examples employing Li-carbenoid 26.

Convergent synthesis of two14C-labeled β3-adrenergic receptor agonists

The synthesis of β3-adrenergic receptor agonists A and B with radiolabeled amide fragment, required for drug disposition studies, was accomplished based on initial formation of 2-(4-(2-amino-2-methylpropyl)phenoxy)-5-[14C]-cyanopyridine by the reaction of 2-bromo-5-iodopyridine with para-substituted phenol, and following cyanation of aromatic iodide with potassium cyanide-[14C]. After the coupling of the resulted amine with glycidyl derivatives of 4-hydroxyindole and 4-hydroxycarbazole, the corresponding nitriles were hydrolyzed with basic hydrogen peroxide to obtain target amides A and B. Copyright © 2006 John Wiley & Sons, Ltd.

A Versatile One‐Pot Synthesis of Dialkyl Disulfides and Sulfides.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Efficient chemical oxygen-iodine laser powered by a centrifugal bubble singlet oxygen generator

Efficient production of singlet delta oxygen in a bubble singlet oxygen generator (BSOG) under the influence of centrifugal acceleration, 136g, has been obtained. An output power of 770W with chemical efficiency of 25.6% has been achieved in a small-scale, supersonic chemical oxygen-iodine laser supplied by the centrifugal BSOG. The ratio of the output power to the basic hydrogen peroxide volumetric flow rate was 4.3KJ∕liter. Efficient chemical oxygen-iodine laser (COIL) operation with the centrifugal BSOG demonstrates the potential for mobile COIL applications.

A Versatile One‐Pot Synthesis of Dialkyl Disulfides and Sulfides

Conversions of monofluoroalkyl and alkyl bromides to the corresponding dialkyl disulfides in a one‐pot synthesis using thiourea followed by basic hydrogen peroxide are described. Modified methods afford access to unsymmetrical disulfides and sulfides.

Characterization and Studies on Hydro Dynamically Stable Operation of an Angular Jet SOG for COIL

Chemical oxygen-iodine Laser (COIL) is one of the fast emerging high power laser source for near Infrared (λ=1.315μm) laser generation. The heart of the system is the singlet oxygen generator (SOG) which is a pumping source for this laser. A Jet type SOG with a novel approach was designed and fabricated. Singlet oxygen was taken out of the SOG at an angle of 40° thus avoiding the carry over of droplets, which is one of the major drawbacks of horizontal system. The preliminary results have been reported in our earlier publication. The present paper discusses the performance of this generator for various operational conditions viz. diluent's gas nitrogen / helium, basic hydrogen peroxide composition, generator pressure and gas velocity. Further, conditions for the stable operation from generator as well as chlorine injection point of view have been identified.

Analysis of cross-flow jet-type singlet oxygen generator

A cross-flow jet-type singlet oxygen generator has been developed, tested and analyzed in order to characterize the dependence of output performance on major input parameters. A thermal-balance model, which can predict O/sub 2/(/sup 1//spl Delta/) yield, gas temperature, and gas residence time, is proposed, and the resultant theoretical results are compared to the experimental data. Combined with computational fluid dynamics-based gas residence-time analysis, the model provides good agreement with the measured value of the O/sub 2/(/sup 1//spl Delta/) yield and the gas temperature. The surface chemistry model was applied to the measured Cl/sub 2/ utilization data, and was found to be inconsistent in the regime of high Cl/sub 2/ loading on the basic hydrogen peroxide jet, indicating that depletion of HO/sub 2//sup -/ is taking place.

Removal of Water Vapor in a Mist Singlet Oxygen Generator for Chemical Oxygen Iodine Laser

The mist singlet oxygen generator (Mist-SOG) for a chemical oxygen iodine laser (COIL) has been developed in order to increase basic hydrogen peroxide (BHP) utilization. It was clarified that the Mist-SOG generated much more water vapor than conventional SOGs because the heat capacity of BHP is small. The water vapor deactivates the excited iodine and depresses the laser power. Therefore, a jet-cold trap was developed in order to remove the water vapor while maintaining a minimum deactivation of singlet oxygen. In this method, a nozzle was used to spray chilled H2O2 at 238 K as a thin layer directly to the gas flow to achieve a large specific surface area for water vapor. As a result, the water vapor mole fraction was reduced to 7% from 18% with the BHP utilization of 21% at the Cl2 consumption rate of 3.5 mmol/s (Cl2 input flow rate of 8.0 mmol/s) for 65-µm-diameter BHP droplets.

A 2-kW COIL with a square pipe-array JSOG and nitrogen buffer gas

A 2-kW-class chemical oxygen-iodine laser (COIL) using nitrogen buffer gas has been developed and tested since industrial applications of COIL devices will require the use of nitrogen as the buffer gas. The laser, with a gain length of 11.7 cm, is energized by a square pipe-array jet-type singlet oxygen generator (SPJSOG) and employs a nozzle bank with a designed Mach number of 2.5. The SPJSOG has advantages over the traditional plate-type JSOG in that it has less requirements on basic hydrogen peroxide (BHP) pump, and more important, it has much better operational stability. The SPJSOG without a cold trap and a gas-liquid separator could provide reliable operations for a total gas flow rate up to 450 mmol/s and with a low liquid driving pressure of around 0.7 atm or even lower. The nozzle bank was specially designed for a COIL using nitrogen as the buffer gas. The cavity was designed for a Mach number of 2.5, in order to provide a gas speed and static temperature in the cavity similar to that for a traditional COIL with helium buffer gas and a Mach 2 nozzle. An output power of 2.6 kW was obtained for a chlorine flow rate of 140 mmol/s, corresponding to a chemical efficiency of 20.4%. When the chlorine flow rate was reduced to 115 mmol/s, a higher chemical efficiency of 22.7% was attained. Measurements showed that the SPJSOG during normal operation could provide a singlet oxygen yield Y/spl ges/55%, a chlorine utilization U/spl ges/85%, and a relative water vapor concentration w=[H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O]/([O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ]+[Cl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ])/spl les/0.1.

Highly Catalytic Enantioselective Epoxidation of Enones with Weak Base Bicarbonate and Hydrogen Peroxide.

The weak basic bicarbonate-activated hydrogen peroxide is applied to the catalytic asymmetric epoxidation of the enones, and the catalyst polyleucine cannot be deteriorated and can successfully be reused in this asymmetric reaction. The ee value of the optically active epoxidation product is up to 95%.

Highly Catalytic Enantioselective Epoxidation of Enones with Weak Base Bicarbonate and Hydrogen Peroxide

The weak basic bicarbonate-activated hydrogen peroxide is applied to the catalytic asymmetric epoxidation of the enones, and the catalyst polyleucine cannot be deteriorated and can successfully be reused in this asymmetric reaction. The ee value of the optically active epoxidation product is up to 95%.

Singlet Delta Oxygen Production from a Gas—Solid Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Modeling Cl2 formation from aqueous NaCl particles: Evidence for interfacial reactions and importance of Cl2 decomposition in alkaline solution

A series of experiments have demonstrated that a significant yield of chlorine gas is produced when mixtures of ozone and sodium chloride particles above their deliquescence point are irradiated at 254 nm. In order to obtain expressions for future modeling studies, a comprehensive model is used to analyze the system and to determine its sensitivity. This work reexamines and expands previous studies [Knipping et al., 2000]. The enhanced model, described in detail herein, reaffirms that current known physical and chemical processes fail to reproduce the observed Cl2 formation in the experiments. A methodological analysis, proposed as a framework for similar studies, of the physicochemical system supports the accountability of an overall mechanism initiated by the formation of a relatively stable complex of the hydroxyl radical and chloride ions at the gas–liquid interface for the observed chlorine generation. Different potential fates of the OH•••Clsurface•− intermediate are discussed. A rate expression and kinetic parameters are presented for the overall reaction of the interfacial mechanism. In addition, sensitivity studies underscore the importance of accurately modeling chlorine decomposition processes in alkaline solution—in particular, the reactions of chlorine with hydroxide, carbonate, and basic hydrogen peroxide. Recommended aqueous‐phase rate constants for these reactions are drawn from a literature evaluation illustrating the limited availability and lack of agreement of related kinetic data.

Development of a Mist Singlet Oxygen Generator

The singlet oxygen generator (SOG) generates singlet oxygen for a chemical oxygen iodine laser (COIL), using the gas-liquid reaction between basic hydrogen peroxide (BHP) and Cl2 gas. The Jet-SOG has been widely used, wherein jet BHP from small orifices reacts with Cl2 gas, and the BHP utilization is less than 1% in a single pass through the reaction zone. To improve BHP utilization, the reaction surface with Cl2 gas should be increased, and the droplet diameter of BHP should be decreased. In this study, two types of mist generators were tested for the SOG, with which 65-µm- and 15-µm-diameter droplets were generated. In the 65 µm mist generator, BHP utilization was 22.5% at the Cl2 flow rate of 8.3 mmol/s, and in the 15 µm mist generator, BHP utilization was 41.5% at the Cl2 flow rate of 9.0 mmol/s, that is, BHP utilization of the new SOG, Mist-SOG, markedly exceeded that of the conventional Jet-SOG.

Results of small-signal gain measurements on a supersonic chemical oxygen iodine laser with an advanced nozzle bank

High-resolution diode laser spectroscopy has been used to probe the gain in the active medium formed by an advanced supersonic chemical oxygen iodine laser (COIL), ejector nozzle bank. The probe beam was directed through the medium at 90/spl deg/ (normal) to the flow velocity and at an angle of 27.5/spl deg/ away from normal incidence. Analysis of the small-signal gain spectrum allowed for the determination of the gain, average gas velocity, static pressure, and temperature. The dependence of gain, temperature, and gas velocity on the primary nitrogen molar flow rate and basic hydrogen peroxide temperature was obtained. A maximum small-signal gain of 7 /spl times/ 10/sup -3/ cm/sup -1/, average gas velocity of 575 m/s, static temperature of 172 K were measured for flow rates of 270 mmole/s of primary nitrogen, 39.2 mmole/s of chlorine, 11 mmole/s of secondary nitrogen, and 0.8 mmole/s of iodine. Estimation of the static pressure in the flow core from spectroscopic data is very close to the static sidewall pressure. The role of transverse velocity components in the gas flow and their effect on the interpretation of gain profiles is discussed.

Numerical Simulation of a Mist Singlet Oxygen Generator

A numerical simulation code for a mist singlet oxygen generator (SOG) is developed. Unlike previous SOGs, a mist SOG utilizes fine droplets of basic hydrogen peroxide (BHP) to achieve a stoichiometric reaction with chlorine gas in a single pass through a reaction zone. The numerical model presented in the present paper deals with the depletion of superficial HO2- density and the diffusive redistribution of each droplet, water evaporation, temperature variation of the droplet due to chemical reaction and evaporation, and heat exchange between the gas and liquid phases. Under identical initial conditions, the calculated results are consistent with the results from previous experiments. The heterogeneous quenching probability of O2(1Δ) to the BHP surface (γ) was determined by a comparison between the experimental and calculated results, and was found to be 2×10-3. The process conditions were then varied to establish the theoretical limit of BHP utilization. For a very small (15 µm) droplet diameter, it was shown that 50% BHP could be utilized with an output of 64% O2(1Δ) yield and 88% Cl2 utilization.

霧化型励起酸素発生器の基礎研究 ＩＩＩ

A new type mist singlet oxygen generator (Mist-SOG) for the chemical oxygen-iodine laser (COIL) has been developed. This SOG is devoted to make the liquid recirculation unnecessary with the complete reaction through a single pass of basic hydrogen peroxide (BHP). In order to determine the quantity of water vapor, a gas sampling system has been introduced newly. In this experiment, 43% of Cl2 utilization and 39% of singlet oxygen yield were obtained with Cl2 molar flow rate of 4.7mmol/s. H2O2 utilization in the BHP was achieved as high as 9.6%.