Thiosulfate reduction

Smock AM, ME Bottcher, H Cypionka (1998) Fractionation of sulfur isotopes during thiosulfate reduction by Desulfovibrio desulfuricans. Arch Microbiol 169 460-463. 

Dimethylaminonitroethylene is prepared from the anion of nitromethane and the salt prepaffed from dimethylformamide and dimethyl sulfate. The condensation step is general for other types of active methylene compounds, indicating further potential for pyrrole synthesis. A related process involves the condensation of ketones with the moao-N,N-dimethylhydrazone of glyoxal base-catalyzed condensation affords the hydrazones of a conjugated 1,4-dicarbonyl system, and sodium thiosulfate reduction then affords 2,3-disubstituted pyrroles (equation 85) (77CB491). 

Ravot, G., Ollivier, B., Magot, M., Patel, B.K.C., Crolet, J.L., Fardeau, M.L., and Garcia, J.L. (1995) Thiosulfate reduction, an important physiological feature shared by members of the order Ther-motogales. Appl Environ. Microbiol,... 

A far better sensitivity is attained for the detection of ferrocyanide in the presence of thiocyanate when use is made of the fact that ferric thiocyanate is decomposed by mercuric chloride (formation of [Hg(CNS)4] ions), sodium fluoride (production of [FeFe] ions), or sodium thiosulfate (reduction to Fe+ ions). 

Thiosulfate reduction Thioredoxin NADH oxidase Cytochrome p450... 

BrOg Reduction with arsenate(III), hydrazine, sulfite, or thiosulfate... 

Noncnzymc-Catalyzcd Reactions The variable-time method has also been used to determine the concentration of nonenzymatic catalysts. Because a trace amount of catalyst can substantially enhance a reaction s rate, a kinetic determination of a catalyst s concentration is capable of providing an excellent detection limit. One of the most commonly used reactions is the reduction of H2O2 by reducing agents, such as thiosulfate, iodide, and hydroquinone. These reactions are catalyzed by trace levels of selected metal ions. Eor example the reduction of H2O2 by U... 

Ofner Method. This method is for the determination of invert sugar in products with up to 10% invert in the presence of sucrose and is a copper-reduction method that uses Ofner s solution instead of Fehling s. The reduced cuprous oxide is treated with excess standardized iodine, which is black-titrated with thiosulfate using starch indicator. 

Ana.lytica.1 Methods. Various analytical methods involve titration with oxidants, eg, hexacyanoferrate (ferricyanide), which oxidize dithionites to sulfite. lodimetric titration to sulfate in the presence of formaldehyde enables dithionite to be distinguished from sulfite because aldehyde adducts of sulfite are not oxidized by iodine. Reductive bleaching of dyes can be used to determine dithionite, the extent of reduction being deterrnined photometrically. Methods for determining mixtures of dithionite, sulfite, and thiosulfates have been reviewed (365). Analysis of dithionite particularly for thiosulfate, a frequent and undesirable impurity, can be done easily by Hquid chromatography (366). 

Many other routes to produce thioglycohc acid have been iavestigated (9). To try to minimise by-products, nucleophilic agents other than alkah sulfhydrates have been claimed, eg, thiosulfates, sodium disulfides, thiourea, xanthogenic acid derivatives, and sodium trithiocarbonates (10). These alternative methods, which require reduction of the disulfides or hydrolysis of carboxymethylthio derivatives, seem less competitive than those usiag alkah sulfhydrates. 

Ghromium(III) Compounds. Chromium (ITT) is the most stable and most important oxidation state of the element. The E° values (Table 2) show that both the oxidation of Cr(II) to Cr(III) and the reduction of Cr(VI) to Cr(III) are favored in acidic aqueous solutions. The preparation of trivalent chromium compounds from either state presents few difficulties and does not require special conditions. In basic solutions, the oxidation of Cr(II) to Cr(III) is still favored. However, the oxidation of Cr(III) to Cr(VI) by oxidants such as peroxides and hypohaUtes occurs with ease. The preparation of Cr(III) from Cr(VI) ia basic solutions requires the use of powerful reducing agents such as hydra2ine, hydrosulfite, and borohydrides, but Fe(II), thiosulfate, and sugars can be employed in acid solution. Cr(III) compounds having identical counterions but very different chemical and physical properties can be produced by controlling the conditions of synthesis. 

Redox (reduction-oxidation) titrimetry is used primarily for nitrate detns. Five systems are in current use ferrous sulfate—dichromate, io dome trie, periodic acid oxidation (NaOH titrant), K permanganate, and titanous chloride-ferric ammonium sulfate. The ferrous sulfate— dichromate system is used for MNT DNT detns (Vol 2, C162-Lff Vol 6, F17-Rff Ref 17). In the iodometric procedure, the sample (ie, NG) is treated in a C02 atm with a satd soln of Mn chloride in coned HC1, the vol reaction products are bubbled thru a K iodide soln, and the liberated iodine is titrated with standard thiosulfate soln (Refs 1 17). The periodic... 

The benzeneseleninic acid weighs 14.4-16 g. (73-82%) and melts at 123-124°. It may be reconverted to diphenyl diselenide by reduction with sodium thiosulfate or sodium bisulfite. ... 

Process (3.8) is a total 2e per cadmium atom and indicates that CdS formation occurs via a sulfur atom abstraction from 8203 . This reaction was called for in order to suggest that the reduction of Cd " is the only electrochemical step, whereby charge is consumed, followed by a subsequent chemical step comprising sulfur association to reduced cadmium. Sulfur is generated by the decomposition of thiosulfate. On the other hand, reaction (3.9) corresponds to an overall 4e /Cd process where reduction of S2O3 itself must occur as well as that of Cd ", the former comprising actually the rate-determining step. This route becomes more favorable as pH decreases for it requires additional protons. 

Attempts to electrodeposit M0S2 in a way similar to that used for MoSe2 - in this case from solutions of molybdate and thiosulfate under various conditions of pH and temperature - have been unsuccessful. Instead, thin films of M0S2 were convenienfly deposited from tetrathiomolybdate solutions Ponomarev et al. [149] observed that reduction of MoO in slightly alkaline solutions results in the formation of an X-ray amorphous film which by annealing at 550 in Ar for 1 h... 

Determinations of 8 " S have been extensively used in studies on the sulfur cycle, including reactions involving microbial anaerobic reduction of sulfate and thiosulfate (Smock et al. 

MgS04 as stabilizers, and are non-selective in degrading also cellulose and hemicelluloses, while the reductant 820/ is more selective but less effective, and generates various sulfur-containing chemicals including thiosulfate that is corrosive to paper machines (3). 

The ammonia stabilizes Cu11 relative to Cu1 allowing it to be regenerated in the presence of air,52 and although the reduction of Cu11 by thiosulfate is normally rapid in a pure aqueous solution, in the presence of ammonia in these systems it proceeds much more slowly,43... 

Many different analytical techniques were developed for the estimation of hydroperoxides. Among them, the iodometric technique has been used for a long period of time [60]. According to this method, peroxide is reduced by HI, and diiodine is formed in stoichiometric quantity. The amount of the formed I2 is measured by reduction with thiosulfate using any titrometric technique or photometrically. 

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