Organic sulfur compound formation

Sulfur constitutes about 0.052 wt % of the earth s cmst. The forms in which it is ordinarily found include elemental or native sulfur in unconsohdated volcanic rocks, in anhydrite over salt-dome stmctures, and in bedded anhydrite or gypsum evaporate basin formations combined sulfur in metal sulfide ores and mineral sulfates hydrogen sulfide in natural gas organic sulfur compounds in petroleum and tar sands and a combination of both pyritic and organic sulfur compounds in coal (qv). 

An organic sulfur compound containing an acetal function had been oxidised to the sulfone with 30% hydrogen peroxide in acetic acid. After the liquor had been concentrated by vacuum distillation at 50-60°C, the residue exploded during handling. This was attributed to formation of the peroxide of the acetal (formally a gem-diether) or of the aldehyde formed by hydrolysis, but formation and explosion of peracetic acid seems a more likely explanation. 

Organic sulfur compounds are present in gasoline and diesel. With the increased emphasis on the requirement for more environmentally friendly transportation fuels [1], oxidative desulfurization, using H202 and redox-molecular sieves [2,5,6,7], has been studied and shown to significantly reduce the sulfur content of gasoline and diesel. The reaction of thiophene and its derivatives were successfully converted to oxidized compounds, but the identification of oxidized compounds was not simple because the concentrations of individual sulfur compounds were low. Most of the previous literature has reported sulfone formation. 

Although no conclusive evidence has been reported so far, the possible importance of organic sulfur species as sulfate aerosol precursors is supported by several observations. Sulfuric acids, sulfonic acids, and other organic sulfur compounds are formed in sulfur dioxide-hydrocarbon reactions at high concentrations. Organosulfiir radical species, such as RSO2 and RO2SO2 have been postulated as intermediates for these reactions. Suzuki (see Penzhom et o/. ) observed polymer formation from... 

W.D. Good, "Correlation of Heat of Formation Data for Organic Sulfur Compounds , JPhysChem 65, 1430-32 (1961) 45) Fedo-... 

Product analyses for the reaction of CH3S with NO2 were carried out in order to elucidate the mechanism for that reaction in air. S0180 was observed by means of FT-IR spectroscopy when N0180 was used as a reactant. This is a clear evidence for the formation of CH3SO and NO as products of the above reaction. Dependence of the yield of SO2 on the initial concentration of O2 ana NO2 was observed, which indicates that the secondary reactions of CH3SO with 02 or NOz are important in the atmospheric oxidation of reduced organic sulfur compounds. 

Yurovskii (48) recognized the importance of elemental sulfur in the formation of pyritic and organic sulfur compounds and suggested that the elemental sulfur found in coal today is a primary substance formed during coal formation. However, this view is unsupported by recent data (47). 

Formation of Pyrite and Organic Sulfur Compounds in High-Sulfur Coal a Geochemical Model... 

Schouten S., De Loureiro M. R. B., Sinninghe Damste J. S., and de Leeuw J. W. (2001a) Molecular biogeochemistry of Monterey sediments, Naples Beach, California I. Distributions of hydrocarbons and organic sulfur compounds. In The Monterey Formation from Rocks to Molecules (eds. C. M. Isaacs and J. Rullkotter). Columbia University Press, New York, pp. 150-174. 

The formation of cation radicals (VI) [68-71] and of dications (VII) [72-74] during the oxidation of organic sulfur compounds has been well established. 

The formation of organic sulfur compounds in salt marsh porewaters is not as well understood(H) as the inorganic moieties although progress has been made in coastal marine sediments(12). Their presence as thiols and alkyl sulfides has been determined but generally in trace amounts(12-16). The importance of these trace organic sulfur compounds to atmospheric sulfur emissions is presently an area of intense research(, 15). Less appears to be known about organic sulfur compounds in salt marsh porewaters. 

Figure 1. The most important pathways of assimilatoiy sulfate reduction are shown. The APS pathway is utilized by oxygen-producing, phototrophic eukaryotes and some cyanobacteria. In this pathway a bifurcation occurs where, for APS, sulfur can either be reduced to the oxidation level of cysteine or converted to sulfate-ester compounds, in the PAPS pathway, utilized by some cyanobacteria, but mostly by anoxygenic microorganisms, APS formation leads, through sulfite, to the production of reduced organic sulfur compounds.

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