- ELECTROCHEMICAL OXIDATION OF HYPOCHLORITE AT PLATINUM ANODES.
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Oxidation of hypochlorite has been studied by cyclic voltammetry with a rotating-ring-disc assembly. Experiments were carried out with sodium chloride or sodium sulphate solutions with hypochlorite present or absent. Hypochlorite is oxidized at the platinum disc anode and the species formed by this oxidation are detected with the platinum ring cathode. From the shape of the current-potential curves at the ring electrode and from the relation between the ring and the disc currents, it has been concluded that the first step of the hypochlorite oxidation is the formation of the chloroxyl radical (ClO).
- Czarnetzki, L.,Janssen, L. J. J.
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- Electrochemistry of chloride in ambient room temperature ionic liquids: Formation of oxychloride species
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The electrochemistry of chloride in water-containing hydrophobic ([Emim][NTf2] and [BmPyrr][NTf2]) and hydrophilic ([Emim][OAc]) ionic liquids (ILs) has been described in detail for the first time. Cyclic voltammetric studies at a glassy carbon electrode note the significant effect of ambient water on the electrochemistry of chloride, with different outcomes based upon the hydrophilicity (c.f. water content) of the hygroscopic ILs. Added hydroxide highlighted this as a reactive species. Evaluation of chloride, hypochlorite, chlorite, chlorate and perchlorate electrochemistry (chlorine oxidation states -1, +1, +3, +5 and +7) was performed. Ultimately, the electrochemically formed chlorine (Cl2) was determined to react with water or hydroxide to yield higher oxidation state species via oxychloride intermediates (e.g. hypochlorite) through multiple EC steps, likely resulting in chlorate as the final product.
- Hossain, Md. Mokarrom,Anari, Elham Hosseini Bab,Aldous, Leigh
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- Oxidative conversion of N-substituted 3-aminopyrazoles to azopyrazoles using electrogenerated NaOCl as the mediator
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The possibility of electrooxidative one-stage (one-pot) and two-stage conversion of N-alkylated aminopyrazoles to azopyrazoles involving electrogenerated NaOCl as the mediator has been studied for the first time. It has been found that the process involvi
- Lyalin, Boris V.,Sigacheva, Vera L.,Kokorekin, Vladimir A.,Petrosyan, Vladimir A.
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- Preparation of GaAs surfaces of desired composition
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The influence of various treatments on the chemical state of the GaAs surface is considered. The formation and removal of an elemental arsenic layer and gallium and arsenic oxides, sulfurization of the surface, and its passivation with elemental arsenic a
- Bekezina,Mokrousov
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- Synthesis of Graphene Oxide by Oxidation of Graphite with Ferrate(VI) Compounds: Myth or Reality?
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It is well established that graphene oxide can be prepared by the oxidation of graphite using permanganate or chlorate in an acidic environment. Recently, however, the synthesis of graphene oxide using potassium ferrate(VI) ions has been reported. Herein, we critically replicate and evaluate this new ferrate(VI) oxidation method. In addition, we test the use of potassium ferrate(VI) for the synthesis of graphene oxide under various experimental routes. The synthesized materials are analyzed by a number of analytical methods in order to confirm or disprove the possibility of synthesizing graphene oxide by the ferrate(VI) oxidation route. Our results confirm the unsuitability of using ferrate(VI) for the oxidation of graphite on graphene oxide because of its high instability in an acidic environment and low oxidation power in neutral and alkaline environments.
- Sofer, Zdeněk,Luxa, Jan,Jankovsky, Ond?ej,Sedmidubsky, David,Bystroň, Tomá?,Pumera, Martin
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- Oxidative N—N coupling of N-alkyl-3-aminopyrazoles to azopyrazoles in aqueous solutions of NaOCl and NaOBr
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The influence of the structures of N-alkyl-3-aminopyrazoles on their transformation into azopyrazoles on treatment with sodium hypohalogenites was studied. The reaction of 3-aminopyrazoles unsubstituted at position 4 containing donor substituents with neu
- Lyalin,Sigacheva,Ugrak,Petrosyan
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p. 164 - 170
(2021/03/02)
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- Kinetics and mechanism of N-chloromethylamine decomposition in solutions
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Kinetics of N-chloromethylamine decomposition in an aqueous base medium and chloroform at different temperatures is studied. The decomposition of N-chloromethylamine is found to obey a second order equation in an aqueous base medium at an equimolar ratio of the reagents and a first order equation in chloroform with excess base. The activation energy of N-chloromethylamine decomposition in the both solvents is determined. A mechanism for the reaction is proposed. N-Chloromethylamine is shown to have approximately equal stability in these solvents within the studied temperature range.
- Kuznetsov,Vedenyapina,Pleshchev,Gashev,Makhova,Vedenyapin
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p. 541 - 544
(2016/02/27)
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- DUAL BIOCIDE GENERATOR
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Methods and apparatus for generation of dual biocides are provided. The electrolytic generation of chlorine as a biocide is employed for further generation of additional biocides within a single system or generator, including bromine, iodine, chlorine dioxide, fluorine, or chloramines from their respective salts and/or precursors. A single on-site generating system produces a combination of biocides for applications of use providing cost, safety and efficacy improvements. Methods of using the disinfecting biocides provide a synergistic effect through simultaneous or sequential applications.
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Paragraph 0096; 0097; 0098; 0099
(2016/02/21)
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- Oxidation of 1,3,7-trimethylxanthine by hypochlorite ion
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The kinetics of the oxidative conversion of 1,3,7-trimethylxanthine upon treatment with hypochlorite ions (OCl-) in aqueous medium at 283-298 K and pH 8.2 was studied. The reaction order with respect to each component was determined and proved to be 1. It was established that the temperature dependence of the reaction rate follows the Arrhenius equation. The activation parameters of the reaction were measured: E a = 33.58 kJ/mol, ΔH ≠ = 31.12 kJ/mol, ΔS ≠ = -170.02 J/(K mol), ΔG ≠ = 81.45 kJ/mol. The stoichiometry of the reaction was studied, and the chemistry of the oxidative conversion of caffeine treated with OCl- is discussed.
- Kheidorov,Ershov,Chalyi,Titorovich
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p. 1358 - 1362
(2011/10/05)
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- Reactive sulfur species: Kinetics and mechanisms of the oxidation of cysteine by hypohalous acid to give cysteine sulfenic acid
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Cysteine sulfenic acid has been generated in alkaline aqueous solution by oxidation of cysteine with hypohalous acid (HOX, X = Cl or Br). The kinetics and mechanisms of the oxidation reaction and the subsequent reactions of cysteine sulfenic acid have been studied by stopped-flow spectrophotometry between pH 10 and 14. Two reaction pathways were observed: (1) below pH 12, the condensation of two sulfenic acids to give cysteine thiosulfinate ester followed by the nucleophilic attack of cysteinate on cysteine thiosulfinate ester and (2) above pH 10, a pH-dependent fast equilibrium protonation of cysteine sulfenate that is followed by rate-limiting comproportionation of cysteine sulfenic acid with cysteinate to give cystine. The observation of the first reaction suggests that the condensation of cysteine sulfenic acid to give cysteine thiosulfinate ester can be competitive with the reaction of cysteine sulfenic acid with cysteine.
- Nagy, Peter,Ashby, Michael T.
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p. 14082 - 14091
(2008/04/04)
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- A study of mercury dissolution in aqueous solutions of sodium hypochlorite
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Dissolution of mercury in aqueous solutions of sodium hypochlorite at pH 5.9-8.5, the corresponding reaction order, and the mechanism of this process were studied. The ratio of the rates of mercury oxidation and sodium hypochlorite decomposition was analyzed.
- Sizeneva,Val'tsifer,Strel'nikov
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p. 546 - 548
(2007/10/03)
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- Spontaneous decomposition of industrially manufactured sodium hypochlorite solutions
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Spontaneous decomposition of industrially manufactured aqueous solutions of sodium hypochlorite was studied. The rate constants of the decomposition reactions were calculated for different pH values.
- Sizeneva,Kondrashova,Val'tsifer
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p. 541 - 545
(2007/10/03)
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- The kinetics of thermal decomposition of sodium hypochlorite in aqueous solutions at various medium acidities
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The kinetics of thermal decomposition of sodium hypochlorite (HC) in aqueous solutions was studied at 403-463 K and various pH values. In a closed system, HC decomposed at a noticeable rate at T> 400 K. The rate of the decomposition depended on medium pH. The kinetic parameters of thermal decomposition of HC in the presence of admixtures were calculated. The kinetics of the reaction was described by an equation of the first order in HC. Acidifying solutions increased the rate of the decomposition of HC and decreased the activation energy of the reaction. Conversely, alkalizing the medium to pH 12 decreased the decomposition rate and increased the activation energy. The presence of the NaCl and NaClO3 decomposition products had virtually no effect on the rate of the reaction.
- Kheidorov,Ershov,Zyabkina,Gorbatov
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p. 734 - 737
(2007/10/03)
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- Process research and large-scale synthesis of a novel 5,6-dihydro-(9H)-pyrazolo[3,4-c]-1,2,4-triazolo[4,3-a]pyridine PDE-IV inhibitor
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An efficient synthesis of the PDE IV inhibitor, 9H-cyclopentyl-7-ethyl-3-(thiophen-2-yl)-pyrazolo[3,4-c]-1,2,4-triazolo-5,6- dihydro-[4,3-a]pyridine 1 is described. Starting from commercially available γ-caprolactone, the synthesis was carried out in 10 steps. Key transformations were the selective O-methylation of diketone, 3-hydroxy-1-(4-methoxybenzyl)-4-propionyl-5,6-dihydro-1H-pyridin-2-one, with dimethyl sulfate and cesium carbonate in dimethylformamide, a one-pot pyrazole formation with subsequent acidic deprotection to provide lactam, 1-cyclopentyl-3-ethyl-1,4,5,6-tetrahydropyrazolo[3,4-c]pyridin-7-one, and finally the utilization of imidate, 1-cyclopentyl-7-ethoxy-3-ethyl-4,5-dihydro-1H-pyrazolo[3,4-c]pyridine for the introduction of the triazole moiety. This process avoided the use of harsh reaction conditions, undesirable reagents and overcame the environmental concerns in the original synthesis.
- Urban, Frank J.,Anderson, Bruce G.,Orrill, Susan L.,Daniels, Peter J.
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p. 575 - 580
(2013/09/07)
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- Reactions between some inorganic radicals and oxychlorides studied by pulse radiolysis and laser photolysis
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Rate constants for the reactions of free radicals, including eaq-, .OH, SO4.-, NO3. and Cl2.- (Cl.), with oxychloride compounds have been determi
- Zuo, Zhihua,Katsumura, Yosuke,Ueda, Kiyotaka,Ishigure, Kenkichi
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p. 1885 - 1891
(2007/10/03)
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- Reactions of Calcium and Barium Peroxides with Sodium Hypochlorite
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The reactions of peroxides CaO2 and BaO2 with solutions of sodium hypochlorite are studied at various concentrations and pH of the starting solution of NaClO. It is shown that formation of hydrogen peroxide is the rate-limiting step of the process.
- Loginova, E. N.,Psikha, S. B.,Loginov, S. H.
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p. 1049 - 1053
(2008/10/08)
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- HYPOCHLORITE OXIDATION OF AMMONIA. EFFECTIVE REMOVAL OF AMMONIA FROM WASTE WATER BY UV-IRRADIATION.
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The hypochlorite oxidation of ammonia giving rise to nitrogen evolution was carried out in the dark or under irradiation in order to study the reaction mechanism and application to waste water treatment. UV-irradiation accelerates remarkably the rate of decomposition of unfavorable chloramines. The acceleration covers the pH region 2-12, where corresponding dark reactions are slow. The irradiation also affects the formation of byproducts such as NO//2** minus and NO//3** minus , the effect being a slight increase in NO//2** minus formation in the pH range 2-12. These results suggest an effective industrial application to avoid eutrophication in seas and lakes. The irradiation effect is discussed in relation to reaction mechanism, in which the irradiation possibly facilitates the N-N bond formation after chloramine formation.
- Kimura,Suzuki,Ogata
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p. 3198 - 3201
(2007/10/02)
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