Aqueous Sulfite Solution Research Articles

Dynamic analysis of homogeneous reactions in a stirred bubble reactor: Oxidation of sulfite

A new dynamic model is presented for the behavior of a homogeneous reaction in a stirred bubble reactor. The general case of the model accounts for reaction in both the well-stirred liquid and in the liquid film surrounding each bubble, and shows the relative effects of reaction and mass transfer in the two-phase system. A two-step mechanism is assumed for the reaction in the liquid phase. The mechanism consists of the formation of a complex by reversible association, followed by irreversible first-order decomposition of the complex to the product. The results of the mathematical analysis show that with dynamic experimental data it could be possible to evaluate rate constants for both the association and irreversible reaction steps. The theory is applied to experimental data obtained by introducing pulses of oxygen into aqueous sulfite solutions containing catalytic cobalt ions to increase the conversion. Overall rate constants for the combined non-catalytic and catalytic reactions are measured. For our experimental conditions, reaction in the bulk stirred liquid is dominant so that a special case of the general model for the slow-reaction regime is applicable. The overall rate constant for the reaction determined from the dynamic experiments was confirmed by independent steady-state experiments. Individual values of the rate constants ( k a and k r ) for the association and decomposition steps could not be evaluated because the equilibrium constant for the association step is unknown. However, analysis of the data indicates that k a > 10 −2 s −1 and k r < 10 −2 s −1.

One-electron redox reactions in aqueous solutions of sulfite with hydroquinone and other hydroxyphenols

One-electron redox reactions in aqueous solutions of sulfite with hydroquinone and other hydroxyphenols

An investigation of sulphite ion oxidation as an alternative anodic reaction in fluidized bed electrowinning or other high rate electrolysis cells

The oxidation of sulphite ion to sulphate ion appears to offer attractions as an anodic reaction for cells operated at high current density such as those used in the fluidized bed electrodeposition of metals. In the present investigation several anodes were tried in a cell where the anolyte was aqueous ammonium sulphite solution and copper was electrowon from acidified aqueous cupric sulphate solution onto a fluidized cathode. The cell voltage was determined as a function of current density and a porous anode consisting of reticulated vitreous carbon with a lead coating was found to yield low cell voltages as did a DSA anode. The former anode did not evolve oxygen in the current density range up to 5500 A m−2 whereas the latter showed the onset of oxygen evolution as the current density was raised. Some effects of anolyte flow rate and extent of conversion of sulphite to sulphate, as well as the distribution of potential drops in the cell were determined. Below 3500 Am−2, sulphite ion oxidation using the reticulated vitreous carbon anode resulted in cell voltages below those of conventional commercial cells for copper electrowinning.

Cadmium sulfide photocatalyzed hydrogen production from aqueous solutions of sulfite: effect of crystal structure and preparation method of the catalyst

ADVERTISEMENT RETURN TO ISSUEArticleNEXTCadmium sulfide photocatalyzed hydrogen production from aqueous solutions of sulfite: effect of crystal structure and preparation method of the catalystMichio Matsumura, Satoru Furukawa, Yukinari Saho, and Hiroshi TsubomuraCite this: J. Phys. Chem. 1985, 89, 8, 1327–1329Publication Date (Print):April 1, 1985Publication History Published online1 May 2002Published inissue 1 April 1985https://doi.org/10.1021/j100254a001RIGHTS & PERMISSIONSArticle Views1226Altmetric-Citations254LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (338 KB) Get e-Alerts

Degradation of (+)-cyanidanol-3 by sodium sulfite in aqueous solution. II. Reactivity of several (+)-cyanidanol-3 derivatives with sodium sulfite.

The reactivity of several (+)-cyanidanol-3 (cianidanol) derivatives with sodium sulfite in aqueous solution was investigated at pH 7.5 and 60°C. 5, 7-O-Dimethylcianidanol was degraded by sodium sulfite to yield a water-soluble degradation product, which was assumed to be 5, 7-O-dimethylepicatechin carrying the sodium sulfonate function in place of the aliphatic hydroxy group at the C-3 position. The degradation by sodium sulfite was inhibited by the addition of boric acid and by lowering the pH of the solution to 3.0. On the other hand, 3', 4'-O-dimethylcianidanol and 5, 7, 3', 4'-O-tetramethylcianidanol were very stable in aqueous solution containing sodium sulfite. The mechanism of the attack of sulfite ion and/or bisulfite ion at the C-3 position of the dissociated form of cianidanol or 5, 7-O-dimethylcianidanol is discussed.

A new enzymatic method for determination of sulphite in food

A novel enzymatic method for determining sulphite is described. Using the enzyme sulphite oxidase (EC 1.8.3.1) isolated from chicken liver, sulphite is oxidised to sulphate and hydrogen peroxide is formed. This is allowed to react with reduced nicotinamide-adenine dinucleotide (NADH) in the presence of NADH-peroxidase from microorganisms (EC 1.11.1.1). The decrease of NADH, which is proportional to the concentration of sulphite, is measured photometrically. In spite of doubts about determining sulphite quantitatively according to this principle, the reaction conditions could be optimised: sulphite is oxidised in triethanolamine buffer (TEA) at pH8·0 with 40 mU/ml sulphite oxidase and 47 mU/ml NADH-peroxidase quantitatively within a period of 20 min. The precision of measurement is very high in the range 13–205 μmol sulphite/litre test solution. The coefficient of variation is found to be CV = 0·67% in a solution of 67 μmol SO 2/litre. The accuracy of the enzymatic measurements in pure aqueous sulphite solutions is confirmed by comparison with chemical determination. The correlation with the iodimetric method is R = 0.995. High specificity for sulphite is found when applying the enzymatic test described here. Carbonyl/sulphite addition compounds (e.g. those occurring in wine) are converted to sulphate and the free carbonyl compound. The majority of sulphur-containing compounds do not react in the test. Only glycosides of isothiocyanates (e.g. in mustard) are oxidised like sulphite, though more slowly. The majority of substances occurring in food do not interfere significantly with the test. Ascorbic acid influences the determination if it is present in high concentrations. Therefore, it should be removed from the sample before measuring sulphite. The method has been proven in use for a large number of foodstuffs. By using the method described here, sulphite can be determined in food rapidly and with high reliability.

Sensitivity of lichen phycobionts to dissolved air pollutants

Cultured phycobionts of various epiphytic lichens were exposed to aqueous solutions of either sulfite, nitrite, sulfate, or nitrate, simulating an acute pollutant stress for a short time. The impact of these pollutants was determined by measuring the chlorophyll content and the 14C-incorporation rates. Nitrate and sulfate proved to be nontoxic at pH 4, whereas distinct differences were noted in the sensitivity of the various phycobionts to sulfite and nitrite. In many of the species examined there were clear correlations with data available on the sensitivity of the whole lichen thallus. In some species, however, the phycobiont was either distinctly less sensitive or less tolerant than would be expected from ecological studies on the geographical distribution of the lichen.

Degradation of (+)-cyanidanol-3 by sodium sulfite in aqueous solution.

The reaction of (+)-cyanidanol-3 with sodium sulfite in aqueous solution was investigated. (+)-Cyanidanol-3 was degraded by sodium sulfite in aqueous solution to afford a water-soluble degradation product, which was assumed to be (+)-cyanidanol-3 carrying the sodium sulfonate function in place of the aliphatic hydroxy group at the C-3 position. Further, it was found that the rate of degradation of (+)-cyanidanol-3 by sodium sulfite was approximately the same as that of epicatechin, that the rate was proportional to the concentration of sodium sulfite and to the sum of the concentrations of (+)-cyanidanol-3 and sodium sulfite, and that (+)-cyanidanol-3 or epicatechin was degraded more rapidly by sodium sulfite as the pH was increased. The activation energy of the degradation was calculated to be 28 kcal/mol at pH 8.0 from Arrhenius plots.

Slowly Dechlorinated Organic Chloramines

Dechlorination of some organic chloramines with aqueous sulfite solutions does not take place instantaneously as previously assumed. Field dechlorination times on the order of hours for some compounds that are found in chlorinated effluents appear likely on the basis of laboratory studies. These chlorinated compounds are not detected by standard analytical methods in the presence of sulfite ion.

Mercury displacement detection for the determination of picogram amounts of sulfite ion or sulfur dioxide by atomic spectrometry

An analytical method has been developed that can determine picogram amounts of sulfite in aqueous solution or sulfur dioxide in solution. The technique is based on the reaction of sulfite ion in solution with mercury(I) ion to promote its disproportionation to metallic mercury and mercury(II) ions. By monitoring the Hg/sup 0/ released it is possible to determine the concentration of sulfite added. The method gives a linear calibration over the range tested (0 to 5 ng of sulfite) and the within-batch cefficients of variation for the determination of 0.5, 1.0, 2.0, and 5.0 ng of sulfite are 4, 3, 2.5, and 1.8%, respectively. Fifteen analyses can be carried out each hour. The limit of detection is 30 pg of sulfite, which is several orders of magnitude lower than can be obtained by other manual methods of sulfite determination. The method is very selective. Sulfate ion does not interfere, which is especially important in the determination of atmospheric sulfur dioxide.

Kinetics of Absorption of Oxygen in Aqueous Solutions of Ammonium Sulfite

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of Absorption of Oxygen in Aqueous Solutions of Ammonium SulfiteK. Neelakantan and J. K. GehlawatCite this: Ind. Eng. Chem. Fundamen. 1980, 19, 1, 36–39Publication Date (Print):February 1, 1980Publication History Published online1 May 2002Published inissue 1 February 1980https://doi.org/10.1021/i160073a007RIGHTS & PERMISSIONSArticle Views206Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (410 KB) Get e-Alerts

Tautomeric equilibria and pKa values for 'sulfurous acid' in aqueous solution: a thermodynamic analysis

The free energy of formation of dimethyl sulfite in aqueous solution can be calculated as −91.45 ± 0.79 kcal/mol; this calculation required measurement of the solubility of dimethyl sulfite. From this value and the pKa of SO(OH)2, using previously reported methods, the free energy of formation of SO(OH)2 can be calculated to be −129.26 ± 0.89 kcal/mol. Comparison of this value with the value obtained from the free energy of formation of 'sulfurous acid' solutions, calculated from the free energy of formation of sulfite ion and the apparent pKa, values, permits evaluation of the free energy of covalent hydration of SO2 as 1.6 + 1.0 kcal/mol, in agreement with earlier qualitative spectroscopic observations. From the apparent pKa and the anticipated pKa values for the tautomers (SO(OH)2, pK1 = 2.3; HSO2(OH), pK1 = −2.6) it is possible to calculate the free energy change for tautomerization of SO(OH)2 to H—SO2(OH) as +4.5 ± 1.2 kcal/mol. All equilibrium constants required for Scheme 1, describing the species present in dilute aqueous solutions of SO2, have been calculated. In agreement with previous Raman studies the major tautomer of 'bisulfite ion' is calculated to be H—SO3−.

Kinetics of oxidation of ammonium sulfite by rapid-mixing method

The kinetics of the reaction of oxygen with ammonium sulfite in aqueous solution have been studied by the rapid-mixing method of Hartridge and Roughton at 30°C. The rate of oxidation of ammonium sulfite was found to be approximately twice as low as that of sodium sulfite. The experimental findings showed that the reaction rate was zero order with respect to oxygen and three-halves order with respect to sulfite, and the promoting effect of cobalt ions was proportional to the square root of the total concentration of cobalt added to the reacting solution. The apparent activation energy for the overall oxidation was calculated to be 21·5 kcal per gmole. A reaction mechanism has been proposed and a rate expression derived is in good agreement with the experimental data.

Measurement of interfacial area in bubble columns by the sulphite method

The reaction rate constant and the reaction order with respect to oxygen and sulphite are determined in the paper from the rate of absorption of oxygen into aqueous sulphite solutions catalyzed by cobalt ions. The measurements were carried out in a mixed cell with quiescent liquid level. The utility of the results is discussed for the measurement of interfacial area in bubble columns. The knowledge of the interfacial area is important both for design and calculation of chemical gas-liquid reactors. A most convenient method of determining this parameter is indirect evaluation from the absorption rates of a suitable model reaction. With regard to the various requirements put on such reaction (the knowledge of the reaction mechanism and kinetics, reasonable costs of the chemicals used for large-scale experiments) the choice is rather limited. The study of such model reactions has been the subject of numerous papers; the most significant ones are summarized in the monograph by Danckwerts 1. The often cited reaction is oxidation of sulphite ions by oxygen catalyzed by salts of heavy metals. The reaction scheme may be written as'

The Prevention of Oxidation of Sodium Sulfite in Aqueous Solution

The prevention of oxidation of sodium sulfite solution was investigated. As an antioxidant of sodium sulfite solution, Span 80 (a nonionic surfactant of the type of sorbitan fatty acids ester) was extremely effective. In the case of sulfite solution containing such metal ions as Fe2+, Ni2+, and VO43-, it was necessary to use a masking agent or a precipitant of metal ions in addition tothe above-mentioned antioxidant, and sodium tripolyphosphate and Allon 10 H wereespecially useful for a masking agent and a precipitant respectively.

Preparation and characterisation of cis- and trans-tetra-amminebis(sulphito)cobaltate(III) anions and the kinetics of redox decomposition aqueous acid solution

In aqueous sulphite solution, trans-[Co(NH3)4(H2O)(SO3)]+ rapidly forms the bis(sulphito) complex which has been isolated as an unstable yellow solid, trans-Na[Co(NH3)4(SO3)2],2H2O. The cis-isomer has been prepared as the brown salts cis-Na[Co(NH3)4(SO3)2],2H2O and cis-NH4[Co(NH3)4(SO3)2],3H2O. I.r. and u.v.–visible spectra are reported. The latter are in disagreement with literature spectra and cis–trans-assignments based on them are reversed. In perchloric acid solution, aquation of ligands trans to sulphite results in rapid formation of trans-[Co(NH3)4(H2O)(SO3)]+ and [Co(NH3)2(H2O)2(SO3)2]– from the trans- and cis-isomers respectively. Rate constants, kobs, for redox decomposition of the cis-isomer under air-free conditions are of the form (i) at [H+]= 0·02–0·20M; at 20·0 °C and I= 1·00M(LiClO4), k=(1·39 ± 0·02)× 10–2 l mol–1 s–1, ΔH‡= 26·5 kobs=k[H+]+kI(i)± 0·4 kcal mol–1, and ΔS‡= 23·4 ± 1·3 cal K–1 mol–1. The acid-independent term contributes only ca. 3% of the observed rate at 0·1M-HClO4.

KINETIC STUDY OF A COMPLEX FORMATION FROM 1,3,5-TRINITROBENZENE AND SODIUM SULFITE

Abstract A kinetic study on the formation of a σ-complex from 1,3,5-trinitrobenzene (TNB) and sodium sulfite in aqueous solution was carried out in the temperature range, 10.0–30.0°C by the stopped-flow method. The kinetic and thermodynamic parameters were considered in comparison with those of the σ-complex from TNB and hydroxide ion.

Electron spin resonance study of the photolysis of aqueous sulfite solutions

Electron spin resonance study of the photolysis of aqueous sulfite solutions

The oxidation of aqueous sulphite solutions

The oxidation of aqueous sulphite solutions

The kinetics of oxidation of aqueous sulphite solutions in the presence of cobalt(II) sulphate

The kinetics of oxidation of aqueous sulphite solutions in the presence of cobalt(II) sulphate