14808-79-8Relevant articles and documents
Nonaqueous Heterogeneous Oxidation of Sulfur Dioxide
Halstead, Judith Ann,Armstrong, Roger,Pohlman, Bruce,Sibley, Scott,Maier, Robert
, p. 3261 - 3265 (1990)
The nonaqueous oxidation of SO2 on various solid catalysts was investigated in the presence of oxygen and ozone.The amount of product formed was investigated as a function of catalyst mass and the duration of experiment.For alumina catalysts a surface saturation value of approximately 0.5 mg of SO42-/m2 of alumina was found for a variety of different aluminas independent of surface area, surface pH, and water content.This result corresponds to a monolayer of SO42- if a surface area of 0.3 nm2/SO42- is assumed.For an activated carbon catalyst a surface saturation value of 0.25 mg of SO42-/m2 of carbon was found under wet nonaqueous conditions.For the activated carbon catalysts, unlike the alumina catalysts, the presence of at least a few layers of readily desorbable water is a significant variable for the oxidation of sulfur dioxide.
Noyes, A. A.,Steinoor, H. H.
, p. 1409 - 1428 (1929)
Aqueous photochemical reactions of chloride, bromide, and iodide ions in a diode-array spectrophotometer. Autoinhibition in the photolysis of iodide ions
Kalmar, Jozsef,Doka, Eva,Lente, Gabor,Fabian, Istvan
, p. 4862 - 4870 (2014)
The aqueous photoreactions of three halide ions (chloride, bromide and iodide) were studied using a diode array spectrophotometer to drive and detect the process at the same time. The concentration and pH dependences of the halogen formation rates were studied in detail. The experimental data were interpreted by improving earlier models where the cage complex of a halogen atom and an electron has a central role. The triiodide ion was shown to exert a strong inhibiting effect on the reaction sequence leading to its own formation. An assumed chemical reaction between the triiodide ion and the cage complex interpreted the strong autoinhibition effect. It is shown that there is a real danger of unwanted interference from the photoreactions of halide ions when halide salts are used as supporting electrolytes in spectrophotometric experiments using a relatively high intensity UV light source.
Lang, R.
, p. 1 - 15 (1925)
Multicomponent convection in the chlorite-tetrathionate reaction
Bánsági Jr., Tamás,Horváth, Dezso,Tóth, ágota
, p. 153 - 156 (2004)
The effect of chemical composition on the density fingering arising in the acid-catalyzed reaction of chlorite and tetrathionate ions is investigated experimentally. The increase in the concentration of reactants increases the region of convective instabi
Pryor, W. A.
, p. 4794 - 4797 (1960)
Sorum, C. H.,Charlton, F. S.,Neptune, J. A.,Edwards, J. O.
, p. 219 - 221 (1952)
Kurtenacker,Kubina
, p. 14 - 36 (1931)
Birchall, J. D.,Glidewell, C.
, p. 103 - 106 (1978)
A three-variable model for the explanation of the supercatalytic effect of hydrogen ion in the chlorite-tetrathionate reaction
Horvath, Attila K.
, p. 5124 - 5128 (2005)
It has been shown that not only the slow direct but also the indirect (HOCl-catalyzed) reaction between chlorite and tetrathionate ions is second order with respect to hydrogen ion. Since the direct reaction was found to be orders of magnitude slower than the parallel HOCl-catalyzed pathway, a three-variable model is derived from the previously published five-step model taking into account the experimentally determined H+ concentration dependence of its rate coefficients by neglecting the direct reaction. The new three-variable model indicates that the supercatalytic effect of the hydrogen ion in the HOCl-catalyzed pathway arises from the pH dependence of the individual reactions of the five-step model. The new three-variable model also accounts for the continuous change of the stoichiometric ratio of the reactants and provides a simple kinetic law for involving it in the partial differential equation systems widely used in the study of spatiotemporal behavior of the chlorite-tetrathionate reaction.
Diffusion-Driven Front Instability in a Three-Dimensional Medium
Toth, Agota,Veisz, Bernadett,Horvath, Dezso
, p. 5157 - 5159 (1998)
Lateral instability in reaction-diffusion fronts of the chlorite oxidation of tetrathionate is studied experimentally in three dimensions. A simple two-variable model based on the empirical rate law of the reaction is utilized to reproduce the experimental observations. The onset of instability does not change by extending the system from two to three dimensions; the natural wavelength associated with the cellular structure, however, slightly decreases.
Determination of reaction energy values for biological pyrite oxidation by calorimetry
Rohwerder, Thore,Schippers, Axel,Sand, Wolfgang
, p. 79 - 85 (1998)
The reaction energy values for pyrite oxidation by chemolithotrophic leaching bacteria (pure cultures of Thiobacillus ferrooxidans, Leptospirillum ferrooxidans, and mixed cultures of L. ferrooxidans and T. thiooxidans) were calorimetrically measured in batch experiments. The obtained data were compared with the nonconservative values for the corresponding abiotic processes that were calculated from standard enthalpies and chemical analyses of the leaching products. Due to the different abilities of the investigated species to oxidize the sulphur moiety of pyrite, the measured reaction energy values ranged from - 1100 to - 1600 kJ/mol with an accuracy of 4-16%. In samples with T. ferrooxidans and with the mixed cultures, no significant difference between the calorimetric and theoretical reaction energy values occurred. In contrast, pure cultures of L. ferrooxidans exhibited measured values which were up to 200 kJ/mol lower than the theoretical ones. It is highly unlikely that this difference may be explained by a higher energy conservation efficiency of L. ferrooxidans compared to the one of T. ferrooxidans or T. thiooxidans. Besides use in efficiency studies, the collected data can be used to determine the activity of leaching bacteria in natural biotopes by calorimetric measurements.
The photocatalytic autoxidation of sulfur oxoanions by water-soluble porphyrin complexes
Chen, Shen-Ming
, p. 1 - 13 (1999)
The photocatalytic autoxidation of S4O62- and S2O32- by water- soluble porphyrin complexes Fe(2-TMPyP), Mn(4-TMPyP), and Co(2-TMPyP) were compared under illumination with a 419 nm visible light in oxygen-saturated aqueous solutions at room temperature. The process involves S2O32- as an intermediate product and SO42- is the final oxidation product. The trend in photocatalytic activity of the porphyrin complexes for S4O62- oxidation is Co(2-TMPyP) > Mn(4-TMPyP) > Fe(2-TMPyP). For S2O32- oxidation, the trend is Co(2-TMPyP) > Fe(2-TMPyP) > Mn(4-TMPyP).
Photoelectrochemical Oxidation of Sulfur Dioxide in Strong Acid Solution: Iodide-Mediated Oxidation at Illuminated Metal Dichalcogenide Electrodes
Calabrese, Gary S.,Wrighton, Mark S.
, p. 6273 - 6280 (1981)
In strong acid solution, n-type MoS2, MoSe2, or WS2 can be used as a photoanode to effect the oxidation of SO2 to SO4(2-).The oxidation can be driven with visible light, hν > 1.1 eV, with an output photovoltage of ca. 0.6 V relative to Er(SO4(2-)/SO2) in 6 M H2SO4.The oxidation of SO2, however, requires the presence of I(-) as a mediator serving to (1) alter the MY2/liquid energetics to shift the band edges to a more negative potential to yield a photovoltage relative to Er(SO4(2-)/SO2) and (2) improve the kinetics for SO2 oxidation presumably through the intermediate formation of I3(-).It is noteworthy that MY2 is stable in the presence of strong acid, even concentrated H2SO4; the photooxidation of SO2 can be sustained without photoanodic corrosion of the MY2 at current densities of 20 mA/cm2 and at potentials ca. 0.6 V more negative than Er(SO4(2-)/SO2).The cathode reaction is H2 evolution, and the overall reaction is 2H2O + SO2 -> H2SO4 + H2 that comprises one part of a hybrid cycle for splitting H2O to H2 + 1/2 O2.The cycle is completed, in principle, by thermolyzing H2SO4 to H2O + SO2 + 1/2 O2.Thus, light and heat can be used to effect water splitting.Fundamentally, the noteworthy finding is that I(-) allows a good rate (current) for SO2 oxidation and also favorably affects the energetics to improve the photovoltage.This new concept may be exploited to illustrate processes that can be uniquely done at semiconductor photoelectrodes.The efficiency for conversion of 632.8-nm light (ca. 50mW/cm2) in 6 M H2SO4/ca.1 M SO2/5 mM I(-) is ca. 8percent using an n-type WS2 photoanode.
Chemical Oscillators in Group VIA: The Cu(II)-Catalyzed Reaction between Thiosulfate and Peroxodisulfate Ions
Orban, Miklos,Epstein, Irving R.
, p. 2891 - 2896 (1989)
Sustained oscillations in redox potential, pH, and the concentration of dissolved O2 are reported in the Cu(II)-catalyzed reaction between K2S2O8 and Na2S2O3 in a stirred tank reactor.A range of steady states is found, most of which can be unambiguously designed as either high or low pH, but there is no evidence of bistability.A free-radical mechanism in which Cu(I), Cu(III), and radicals SO4.- and S2O3.- play key roles appears to be capable of accounting both for the observed kinetics (first order in S2O8(2-) and Cu(II), zeroth order in S2O3(2-)) for the batch reaction and for the oscillations in the flow system.
Low-temperature oxidation of sulfur dioxide by molecular oxygen in aqueous solutions of non-transition metals trifluoroacetates
Vishnetskaya,Murtazina, Yu. V.,Skrepleva, I. Yu.,Mel'Nikov, M. Ya.
, p. 777 - 779 (2011)
Oxidation of SO2 was shown to occur in aqueous solutions of Li, Na, and K trifluoroacetates at room temperature. Oxidative activity of the non-transition metal trifluoroacetates increases on decreasing pH of solution and at equal pH values, it follows the sequence: Li Na K.
Hoenig, M.,Zatzek, E.
, (1883)
Preparation, Characterization, and Electrocatalytic Properties of mvRuO/RuCN and RP Hybrid Film-Modified Electrodes
Chen, Shen-Ming,Hsueh, Sheh-Hung
, p. E168-E178 (2004)
Ruthenium oxide/ruthenocyanide (ruthenium oxide/hexacyanoruthenate, or mvRuO/RuCN) and iron(III) ruthenocyanide (ruthenium purple, or RP) hybrid films have been prepared using consecutive cyclic voltammetry, and the deposition process and the films' elect
Sander, A.
, p. 340 - 342 (1916)
The Bromate-Sulfide System. A Particularly Simple Chemical Oscillator.
Simoyi, Reuben H.,Noyes, Richard M.
, p. 2689 - 2690 (1987)
In a batch system, elementary bromine rapidly oxidizes the sulfide ion, HS-, mostly to elementary sulfur and only a little further even though the redox potentials suggest the sulfide could be oxidized all the way to sulfate, SO42-.A stoichiometric excess of acidic bromate, BrO3-, does oxidize batch sulfide all the way to sulfate.The potential of a platinum electrode in such a system exhibits two successive autocatalytic rises with an intervening plateau; visible evidence of elementary bromine does not appear until the start of the second rise.In a flow reactor, this ostensibly simple system exhibits oscillations with constant periods but somewhat erratic amplitudes.We are initiating a study to elucidate the mechanism of the reaction, which seems to differ in behavior from bromate-driven oscillators involving elements other than sulfur.
S-oxygenation of thiocarbamides II: Oxidation of trimethylthiourea by chlorite and chlorine dioxide
Chigwada, Tabitha R.,Simoyi, Reuben H.
, p. 1094 - 1104 (2005)
The kinetics of the oxidation of a substituted thiourea, trimethylthiourea (TMTU), by chlorite have been studied in slightly acidic media The reaction is much faster than the comparable oxidation of the unsubstituted thiourea by chlorite. The stoichiometry of the reaction was experimentally deduced to be 2C1O2- + Me2N(NHMe)C=S + H2O → 2Cl- + Me2N(NHMe)C=O + SO42 + 2H+. In excess chlorite conditions, chlorine dioxide is formed after a short induction period. The oxidation of TMTU occurs in two phases. It starts initially with S-oxygenation of the sulfur center to yield the sulfinic acid, which then reacts in the second phase predominantly through an initial hydrolysis to produce trimethylurea and the sulfoxylate anion. The sulfoxylate anion is a highly reducing species which is rapidly oxidized to sulfate. The sulfinic and sulfonic acids of TMTU exists in the form of zwitterionic species that are stable in acidic environments and rapidly decompose in basic environments. The rate of oxidation of the sulfonic acid is determined by its rate of hydrolysis, which is inhibited by acid. The direct reaction of chlorine dioxide and TMTU is autocatalytic and also inhibited by acid. It commences with the initial formation of an adduct of the radical chlorine dioxide species with the electron-rich sulfur center of the thiocarbamide followed by reaction of the adduct with another chlorine dioxide molecule and subsequent hydrolysis to yield chlorite and a sulfenic acid. The bimolecular rate constant for the reaction of chlorine dioxide and TMTU was experimentally determined as 16 ± 3.0 M-1 s-1 at pH 1.00.
Oxidation of Sulfur Dioxide in Sodium and Calcium Fluorides
Ivanova, M. S.,Savitskaya, Yu. V.,Tomskii, K. O.,Vishnetskaya, M. V.
, p. 513 - 517 (2021/08/23)
Abstract: It was established that the oxidation reactions of sulfur dioxide occur in aqueous solutions of sodium fluoride and in suspensions of calcium fluoride at room temperature and atmospheric pressure. It was found that the solutions of NaF and CaFs
Synthesis, characterization of a ternary Cu(II) Schiff base complex with degradation activity of organophosphorus pesticides
Li, Xin,Zhang, Dandan,Liu, Zihui,Xu, Ying,Wang, Dongfeng
, p. 280 - 289 (2017/11/23)
Organophosphorus pesticides are a class of the most important groups of insecticides and are widely applied to pest and plant diseases control in agriculture. The extensive application of organophosphorus pesticides can subsequently release organophosphorus pesticides into environment which may pose a seriously adverse impact to non-target organisms and humans. However, we could not ban organophosphorus pesticides at present as they are very efficient. Therefore, the new technique of degradation of organophosphorus pesticides must be studied. In this paper, a ternary copper Schiff base complex 2Cu(C14H8NO3Cl)(C12H8N2)·3CH3OH was synthesized and characterised by physico-chemical and spectroscopic methods. The degraded effects of 4 pesticides by the complex were investigated. The results showed that the degraded rates of every organophosphorus pesticide were increased. However, the effects of degradation were varied because of the different molecule structures of organophosphorus pesticides. Gas chromatography-mass spectrometry (GC–MS) and ion chromatography were used to analyze the degradation products by the complex, and then the catalytic mechanism of degradation was proposed. The study results suggest that the Schiff base copper complex, as a potent catalyzer, may find its applications in catalytic degradation area.
