25052-55-5Relevant academic research and scientific papers
AQUEOUS COMPOSITION AND METHOD OF PRODUCING CHLORINE DIOXIDE USING AQUEOUS COMPOSITION
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, (2018/07/15)
An aqueous composition includes an activator, a chlorite ion source, and water. The aqueous composition is alkaline. The aqueous composition produces chlorine dioxide upon contact with an acid. A method of producing chlorine dioxide includes contacting the aqueous composition with an acid.
DUAL BIOCIDE GENERATOR
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Paragraph 0100; 0101, (2016/02/21)
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.
Kinetics and Mechanism of the Chlorite-Periodate System: Formation of a Short-Lived Key Intermediate OClOIO3 and Its Subsequent Reactions
Baranyi, Nóra,Cseko, Gy?rgy,Valkai, László,Xu, Li,Horváth, Attila K.
, p. 2436 - 2440 (2016/03/19)
The chlorite-periodate reaction has been studied spectrophotometrically in acidic medium at 25.0 ± 0.1 °C, monitoring the absorbance at 400 nm in acetate/acetic acid buffer at constant ionic strength (I = 0.5 M). We have shown that periodate was exclusive
Mechanistic study of a manganese porphyrin catalyst for on-demand production of chlorine dioxide in water
Hicks, Scott D.,Xiong, Silei,Bougher, Curt J.,Medvedev, Grigori A.,Caruthers, James,Abu-Omar, Mahdi M.
, p. 492 - 499 (2015/05/05)
A water-soluble manganese porphyrin complex was examined for the catalytic formation of chlorine dioxide from chlorite under ambient temperature at pH 5.00 and 6.90. Quantitative kinetic modeling allowed for the deduction of a mechanism that accounts for all experimental observations. Catalysis is initiated via an OAT (Oxygen Atom Transfer) reaction resulting in formation of a putative manganese(V) oxo species, which undergoes ET (Electron Transfer) with chlorite to form chlorine dioxide. As chlorine dioxide accumulates in solution, chlorite consumption slows down and ClO2 reaches a maximum as the system reaches equilibrium. In phosphate buffer at pH 6.90, manganese(IV) oxo accumulates and its reaction with ClO2 gives ClO3-. However, at pH 5.00 acetate buffer proton coupled electron transfer (PCET) from chlorite to manganese(IV) oxo is fast and irreversible leading to chlorate formation only via the putative manganese(V) oxo species. These differences underscore how PCET rates affect reaction pathways and mechanism. The ClO2 product can be collected from the aqueous reaction mixture via purging with an inert gas, allowing for the preparation of chlorine dioxide on-demand.
Chemoselective catalytic oxidation of 1,2-diols to α-hydroxy acids controlled by TEMPO-ClO2 charge-transfer complex
Furukawa, Keisuke,Shibuya, Masatoshi,Yamamoto, Yoshihiko
supporting information, p. 2282 - 2285 (2015/05/13)
Chemoselective catalytic oxidation from 1,2-diols to α-hydroxy acids in a cat. TEMPO/cat. NaOCl/NaClO2 system has been achieved. The use of a two-phase condition consisting of hydrophobic toluene and water suppresses the concomitant oxidative cleavage. A study of the mechanism suggests that the observed selectivity is derived from the precise solubility control of diols and hydroxy acids as well as the active species of TEMPO. Although the oxoammonium species TEMPO+Cl- is hydrophilic, the active species dissolves into the organic layer by the formation of the charge-transfer (CT) complex TEMPO-ClO2 under the reaction conditions.
NOVEL REDUCING AGENTS FOR PRODUCING CHLORINE DIOXIDE
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, (2015/09/22)
Methods of producing chlorine dioxide including providing an acid, a chlorate salt and an organic water treatment additive that can form a reducing agent in situ, mixing the acid, the chlorate salt and the organic water treatment additive, and reacting th
Photoreduction of Pt(IV) halo-hydroxo complexes: Possible hypohalous acid elimination
Wickramasinghe, Lasantha A.,Sharp, Paul R.
, p. 1430 - 1442 (2014/03/21)
Concentrated hydrogen peroxide addition to trans-Pt(PEt3) 2Cl(R) [1 (R = 9-phenanthryl), 2 (R = 4-trifluoromethylphenyl)] yields hydroxo-hydroperoxo complexes trans-Pt(PEt3) 2(Cl)(OOH)(OH)(R) [5 (R = 9-phenanthryl), 4 (R = 4- trifluoromethylphenyl)], where the hydroperoxo ligand is trans to R. Complex 5 is unstable and reacts with solvent CH2Cl2 to give trans,cis-Pt(PEt3)2(Cl)2(OH)(9-phenanthryl) (3). Treatment of 4 with HCl yields analogous trans,cis-Pt(PEt3) 2(Cl)2(OH)(4-trifluoromethylphenyl) (6) and HBr gives trans-Pt(PEt3)2(Br)(Cl)(OH)(4-trifluoromethylphenyl) (7), where the Br and 4-trifluoromethylphenyl ligands are trans. Photolysis of 3 or 6 at 313 or 380 nm causes reduction to trans-Pt(PEt3)2Cl(R) (1 or 2, respectively). Expected coproduct HOCl is not detected, but authentic solutions of HOCl are shown to decompose under the reaction conditions. Chlorobenzene and other unidentified products that oxidize PPh3 to OPPh3 are detected in photolyzed benzene solutions. Photolysis of 3 or 6 in the presence of 2,3-dimethyl-2-butene (TME) yields the chlorohydrin (2-chloro-2,3-dimethyl-3-butanol), 3-chloro-2,3-dimethyl-1-butene, and acetone, all expected products from HOCl trapping, but additional oxidation products are also observed. Photolysis of mixed chloro-bromo complex 7 with TME yields the bromohydrin (2-bromo-2,3-dimethyl-3-butanol) and 2, consistent with cis-elimination of HOBr. Computational results (TDDFT and DFT) and photochemistry of related complexes suggest a dissociative triplet excited state reaction pathway and that HOCl elimination may occur by an incipient hydroxo radical abstraction of an adjacent halogen atom, but a pathway involving hydroxo radical reaction with solvent or TME to generate a carbon-based radical followed by halogen abstraction from Pt cannot be eliminated.
METHOD FOR PRODUCING AN AQUEOUS STABLE CHLORINE DIOXIDE SOLUTION
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Page/Page column, (2013/11/06)
The invention relates to a method for producing an ultrapure, aqueous, long-term- and storage-stable, and thus transportable, chlorine dioxide solution, comprising the steps of: providing chlorite, providing peroxodisulfate, and combining chlorite and peroxodisulfate in an aqueous system and in a molar ratio of peroxodisulfate to chlorite [S2O82?]/[ClO2?] of greater than 1, forming the aqueous chlorine dioxide solution, wherein no additional buffer is added to produce the aqueous chlorine dioxide solution. The invention further relates to a corresponding chlorine dioxide solution, to the use of said chlorine dioxide solution, and to a device for producing the chlorine dioxide solution.
A much-needed mechanism and reaction rate for the oxidation of phenols with ClO2: A joint experimental and computational study
Aguilar, Carlos Alberto Huerta,Narayanan, Jayanthi,Manoharan, Mariappan,Singh, Narinder,Thangarasu, Pandiyan
, p. 814 - 824 (2013/08/23)
The oxidation of phenols with chlorine dioxide, a powerful means to eliminate phenol pollutants from drinking water, is explored. Kinetic experiments reveal that 2,4,6-trichlorophenol exhibits a lower oxidation rate than other phenols because the chlorine atoms (σ≤0.22) at ortho and para-positions decrease the benzene's electron density, in agreement with the Hammett plot. The oxidation of phenol was found to be second order with respect to phenol and first order with respect to ClO2 and a possible mechanism is proposed. The phenol/ClO2 oxidation was found to be pH-dependent since the reaction rate constant increases with increasing pH. The oxidation rate was also significantly enhanced with an increasing methanol ratio in water. The oxidation products, such as benzoquinones, were analysed and confirmed by liquid chromatography and gas chromatography-mass spectrometry. Density functional theory computations at both the B3LYP/6-311+G(d,p) and M06-2X.6-311+G(d,p) levels with the SCRF-PCM solvation model (i.e. with water) further supported the proposed mechanisms in which activation barriers predicted the right reactivity trend as shown by the kinetic experiments. CSIRO 2013.
Dissection of the mechanism of manganese porphyrin-catalyzed chlorine dioxide generation
Umile, Thomas P.,Wang, Dong,Groves, John T.
, p. 10353 - 10362 (2011/11/29)
Chlorine dioxide, an industrially important biocide and bleach, is produced rapidly and efficiently from chlorite ion in the presence of water-soluble, manganese porphyrins and porphyrazines at neutral pH under mild conditions. The electron-deficient manganese(III) tetra-(N,N-dimethyl)imidazolium porphyrin (MnTDMImP), tetra-(N,N-dimethyl)benzimidazolium (MnTDMBImP) porphyrin, and manganese(III) tetra-N-methyl-2,3-pyridinoporphyrazine (MnTM23PyPz) were found to be the most efficient catalysts for this process. The more typical manganese tetra-4-N-methylpyridiumporphyrin (Mn-4-TMPyP) was much less effective. Rates for the best catalysts were in the range of 0.24-32 TO/s with MnTM23PyPz being the fastest. The kinetics of reactions of the various ClOx species (e.g., chlorite ion, hypochlorous acid, and chlorine dioxide) with authentic oxomanganese(IV) and dioxomanganese(V)MnTDMImP intermediates were studied by stopped-flow spectroscopy. Rate-limiting oxidation of the manganese(III) catalyst by chlorite ion via oxygen atom transfer is proposed to afford a trans-dioxomanganese(V) intermediate. Both trans-dioxomanganese(V)TDMImP and oxoaqua-manganese(IV)TDMImP oxidize chlorite ion by 1-electron, generating the product chlorine dioxide with bimolecular rate constants of 6.30 × 10 3 M-1 s-1 and 3.13 × 103 M-1 s-1, respectively, at pH 6.8. Chlorine dioxide was able to oxidize manganese(III)TDMImP to oxomanganese(IV) at a similar rate, establishing a redox steady-state equilibrium under turnover conditions. Hypochlorous acid (HOCl) produced during turnover was found to rapidly and reversibly react with manganese(III)TDMImP to give dioxoMn(V)TDMImP and chloride ion. The measured equilibrium constant for this reaction (Keq = 2.2 at pH 5.1) afforded a value for the oxoMn(V)/Mn(III) redox couple under catalytic conditions (E′ = 1.35 V vs NHE). In subsequent processes, chlorine dioxide reacts with both oxomanganese(V) and oxomanganese(IV)TDMImP to afford chlorate ion. Kinetic simulations of the proposed mechanism using experimentally measured rate constants were in agreement with observed chlorine dioxide growth and decay curves, measured chlorate yields, and the oxoMn(IV)/Mn(III) redox potential (1.03 V vs NHE). This acid-free catalysis could form the basis for a new process to make ClO2.
