Thiosulfate, formation from sulfide

The liquid is circulated at such a rate that a two- to threefold excess of ferric hydroxide over the stoichiometric quantity necessary for the complete reaction with hydrogen sulfide is present. Gollmar (1945) states that the process can be operated with less than the stoichiometric concentration of iron oxide and interprets the function of the iron as a catalytic oxygen carrier. Available historical data from several plants indicate that operation with an excess of iron oxide over the stoichiometric amount was commonly practiced. This excess seems to be required for complete removal of hydrogen sulfide and, also, to minimize thiosulfate formation in the thionizer. For a coal gas plant with a 10 MMsef/day capacity and a hydrogen sulfide removal rate of 400 grains/lOO scf, the chemical requirements are approximately 3,500 Ib/day of sodium carbonate and 2,800 Ib/day of iron. 

The mechanism of thiosulfate formation in animals is still obscure. Three theories can actually be proposed for this problem according to one by Medes and Floyd (86), thiosulfate would be formed from sulfoxylic acid according to one by Fromageot and Royer (51), it would be formed by oxidation of hydrogen sulfide and finally one may think thiosulfate would result froifi the reaction between free sulfur and sulfite. 

Barium sulfide solutions undergo slow oxidation in air, forming elemental sulfur and a family of oxidized sulfur species including the sulfite, thiosulfate, polythionates, and sulfate. The elemental sulfur is retained in the dissolved bquor in the form of polysulfide ions, which are responsible for the yellow color of most BaS solutions. Some of the mote highly oxidized sulfur species also enter the solution. Sulfur compound formation should be minimized to prevent the compounds made from BaS, such as barium carbonate, from becoming contaminated with sulfur. 

Power GP, Peggs DR, Parker AJ (1981) The Cathodic formation of photoactive cadmium sulfide films from thiosulfate solutions. Electrochim Acta 26 681-682... 

Clear white to yellow-pink deliquescent crystals with an odor like rotten eggs due to formation of hydrogen sulfide. Commercial material may be yellow or brick-red lumps or flakes. It is unstable and discolors upon exposure to air. It undergoes autoxidation to form polysulfur, thiosulfate, and sulfate. It absorbs carbon dioxide from the air to form sodium carbonate. Moist sodium sulfide is spontaneously flammable upon drying in air. This material is hazardous through ingestion and produces local skin/eye impacts. 

The average concentrations of reduced inorganic sulfur species in the anoxic zone of the Black Sea measured using a new colorimetric method developed by Volkov [61,62] are summarized in Table 3. Presented elemental sulfur data refer to the stun of elemental sulfur allotropes (zero-valent sulfur) and the zero-valent sulfur derived from some fraction (n - 1) of the original polysulfide S 2. Thiosulfate data in the table represent the total amount of thiosulfate, sulfite, and polythionates. At some stations in the Black Sea, Volkov [61] observed a concentration maximum of elemental sulfur at the oxic/anoxic interface associated with sulfide oxidation by dissolved oxygen and/or Mn oxyhydroxides. Increasing with depth, elemental sulfur concentrations are probably explained by the ongoing process of polysulfide formation... 

Visible Light-Induced Formation of Addition of sulfite shown to enhance the clea-Hydrogen and Thiosulfate from vage of H2S into H2 and S. See also Refs. 495-Aqueous Sulfide/Sulfite Solutions 497 and Ref. 500 for follow-up work, in CdS Suspensions. 499... 

The formation of desaurins from ketones, carbon disulfide, and base 1275,1281,1282,1285-1290 believed to involve nucleophilic attack on a thioketene by the dianion of a 1,1-dimercaptoalkene, as shown for the synthesis of 572. Related syntheses involve the use of thiophosgene instead of carbon disulfide and the use of diazoalkanes or phosphonium and sulfonium ylides instead of a ketone and base. Treatment of perfluoroiso-butylene with fluoride ion and elemental sulfur in a dipolar, aprotic solvent ° °° or with sources of anionic sulfur (potassium sulfide, sodium hydrosulfide,potassium thiocyanate,sodium thiosulfate, dithiocarbamate salts, dithiophosphate salts ) give the dimer (573) of bis(trifIuoromethyl)-thioketene. Similarly, other 2,4-bis(methylene)-l,4-dithietanes are obtained by treating 2,2-dichlorovinyl ketones with anionic sulfur re-... 

Kobayashi, K., Seki, Y. and Ishimoto,M., 1974. Biochemical studies on sulfate-reducing bacteria. XIII Sulfite reductase from Desulfovibrio vulgaris — mechanism of trithio-nate, thiosulfate and sulfide formation and enzymatic properties. J. Biochem., Tokyo, 75 519—529. 

The reaction of polysulfides with peroxide depends on the polysulfide ion present (see above). Once higher polysulfides are produced, the reaction should result in a peroxide-polysulfide intermediate (similar to II) that transfers two electrons from the polysulfide ion to the peroxide as readily as the sulfide and peroxide reaction. At low peroxide levels, partial oxidation of the polysulfide ions should result in the direct formation of sulfate (through thiosulfate and perhaps sulfite) and S ... 

It forms large, colorless, efflorescent prisms fuses at 45° (113° F.) very soluble in HjO insoluble in alcohol. Its solutions precipitate alumina from solutions of A1 salts, without precipitating-Fe or Mn they dissolve many compounds insoluble in HsO cuprous hydroxid, iodids of Pb, Ag and Hg, sulfids of Ca and Pb. It acts as a disinfectant and antiseptic. HjSOa and most other acids decompose NaaSaOs according to the equation NaaSaOa-)-HaSOi = NaaS04-l-S0a-(-S- - HaO. Oxalic, and a few other acids, decompose the thiosulfate with formation of HaS as well as SOa and S. 

Chemical oxidizers can remove hydrogen sulfide from oilfield waterflood operations but can produce undesirable side effects such as corrosion and the formation of unwanted solids. Examples of oxidizers include chlorine, chlorine dioxide, hypochlorite, hydrogen peroxide, and thiosulfate. 

The formation of sulfur atomic layers on Au from alkaline solutions of sulfide and thiosulfate has been studied, and the relevance of these experiments to thiol-based SAMs was pointed out [38]. These studies are relevant to the formation of SAMs, as sulfide can be thought of as the simplest thiol and, thus, sulfur atomic layers as the shortest chain SAM. Sulfur atomic layers are also of interest... 

Whatever the explanation for the color change, the interesting fact remains that in molten potassium or sodium thiocyanate the sulphur is highly reactive and displays reactions which are not realizable in aqueous solutions of alkali thiocyanates. Among such reactions are formation of silver sulfide from metallic silver formation of sodium thiosulfate with sodium sulfite conversion of metal oxides and sulfates (even lead sulfate)... 

This deposition of tellurium from sulfalkaline solution is strictly specific and permits the detection of tellurium in the presence of large quantities of sulfur and selenium, which are dissolved by alkali sulfide with formation of polysulfide or selenosulfide. The yellow solutions of polysulfide or the red-brown solutions of selenosulfide yield no precipitate with alkah sulfite instead their color is discharged by the formation of alkali thiosulfate or selenosulfate. 

The need to employ dilute solutions to prevent the formation of thiosulfate resulted in very large circulation rates and considerable power consumption. Furthermore, the formation of elemental sulfur was slow from an industrial standpoint, requiring large reaction tanks and large liquid inventories. In addition, to obtain satisfactory rates of hydrogen sulfide absorption when treating gas streams containing appreciable amounts of carbon dioxide, partial decarbonation of the solution was required before recycle to the absorber. 

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