Dimethyl sulfide, oxidation

Barnes, I., K. H. Becker, D. Martin, P. Carlier, G. Mouvier, J. L. Jourdain, G. Laverdet, and G. Le Bras, Impact of Halogen Oxides on Dimethyl Sulfide Oxidation in the Marine Atmosphere, in Biogenic Sulfur in the Environment, Chapter 29, pp. 464-475, 1989. 

Corey and Kim described an oxidation,6a in which activated DMSO is not generated by activation of DMSO, but by oxidation of dimethyl sulfide. Although, they described only the use of chlorine and /V-chlorosuccinimidc as dimethyl sulfide oxidants, we propose that the name Corey-Kim oxidations be applied to alcohol oxidations, in which activated DMSO is generated by oxidation of dimethyl sulfide, regardless of the oxidant employed. 

Impact of Halogen Oxides on Dimethyl Sulfide Oxidation in the Marine Atmosphere... 

Bandy, A. R., Scott, D.L., Blomquist, B.W., Chen, S.M., and Thornton, D.C. (1982) Low yields from dimethyl sulfide oxidation in the marine boundary layer, Geophys. Res. Lett. 19, 1125-1127. 

A mixture of N-chlorosuccinimide and dimethyl sulfide oxidizes alcohols to ketones under very mild conditions and in high yields. The treatment of 4-tm-butylcyclohexanol with this mixture in toluene at 0-25 °C, followed by the addition of triethylamine in toluene, results in a 90-93% yield of 4-tert-butylcyclohexanone [721]. 

Ozone dimethyl sulfide Oxidative ring opening Diacetals from cyclic ethylene derivs. 

Aldehydes are easily oxidized to carboxylic acids under conditions of ozonide hydroly SIS When one wishes to isolate the aldehyde itself a reducing agent such as zinc is included during the hydrolysis step Zinc reduces the ozonide and reacts with any oxi dants present (excess ozone and hydrogen peroxide) to prevent them from oxidizing any aldehyde formed An alternative more modem technique follows ozone treatment of the alkene m methanol with reduction by dimethyl sulfide (CH3SCH3)... 

Usually, organoboranes are sensitive to oxygen. Simple trialkylboranes are spontaneously flammable in contact with air. Nevertheless, under carefully controlled conditions the reaction of organoboranes with oxygen can be used for the preparation of alcohols or alkyl hydroperoxides (228,229). Aldehydes are produced by oxidation of primary alkylboranes with pyridinium chi orochrom ate (188). Chromic acid at pH < 3 transforms secondary alkyl and cycloalkylboranes into ketones pyridinium chi orochrom ate can also be used (230,231). A convenient procedure for the direct conversion of terminal alkenes into carboxyUc acids employs hydroboration with dibromoborane—dimethyl sulfide and oxidation of the intermediate alkyldibromoborane with chromium trioxide in 90% aqueous acetic acid (232,233). 

Through reaction with sulfide or elemental sulfur at 215°C, lignosulfonates can also be used in the commercial production of dimethyl sulfide and methyl mercaptan (77). Dimethyl sulfide produced in the reaction is further oxidized to dimethyl sulfoxide (DMSO), a useful industrial solvent (see Sulfoxides). 

Another product from kraft black Hquor is dimethyl sulfide. This chemical, which is added to natural gas to give it odor, is also oxidized to produce the versatile solvent, dimethyl sulfoxide (see Sulfoxides). 

Dimethyl sulfoxide occurs widely at levels of <3 ppm. It has been isolated from spearmint oil, com, barley, malt, alfalfa, beets, cabbage, cucumbers, oats, onion, Swiss chard, tomatoes, raspberries, beer, coffee, milk, and tea (5). It is a common constituent of natural waters, and it occurs in seawater in the 2one of light penetration where it may represent a product of algal metaboHsm (6). Its occurrence in rainwater may result from oxidation of atmospheric dimethyl sulfide, which occurs as part of the natural transfer of sulfur of biological origin (7,8). 

In the alcohol oxidations, the sulfonium intermediate (2, nucleophile = R2C(OH)) loses a proton and dimethyl sulfide to give the carbonyl compound (42). The most common mechanism for the decomposition of (2) is attack by a mild base to remove a proton from one of the methyl groups. Subsequent cycHc coUapse leads to the carbonyl compound and dimethyl sulfide (eq. 9) ... 

Processes involving oxygen and nitrogen oxides as catalysts have been operated commercially using either vapor- or Hquid-phase reactors. The vapor-phase reactors require particularly close control because of the wide explosive limit of dimethyl sulfide in oxygen (1—83.5 vol %) plants in operation use Hquid-phase reactions. Figure 2 is a schematic diagram for the Hquid-phase process. The product stream from the reactor is neutralized with aqueous caustic and is vacuum-evaporated, and the DMSO is dried in a distillation column to obtain the product. 

Sulfur dioxide occurs in industrial and urban atmospheres at 1 ppb—1 ppm and in remote areas of the earth at 50—120 ppt (27). Plants and animals have a natural tolerance to low levels of sulfur dioxide. Natural sources include volcanoes and volcanic vents, decaying organic matter, and solar action on seawater (28,290,291). Sulfur dioxide is beHeved to be the main sulfur species produced by oxidation of dimethyl sulfide that is emitted from the ocean. 

Atmosphere—Water Interaction. Although water is a very minor component of the atmosphere, less than 10 vol % of the atmosphere consisting of water, many important reactions occur ki the water droplets of cloud, fog, and rain. The atmosphere is an oxic environment ki its water phase, gigantic quantities of reductants, such as organic substances, Fe(II), SO2, CH SCH (dimethyl sulfide), and nitrogen oxides, are oxidized by oxidants such as oxygen, OH radicals, H2O2, and Fe(III). 

The most intensively studied oxidizing system is that developed by Pfitzner and Moflatt in which the oxidation is carried out at room temperature in the presence of dicyclohexylcarbodiimide (DCC) and a weak acid such as pyridinium trifluoroacetate or phosphoric acid. The DCC activates the DMSO which in turn reacts with the carbinol to give an oxysulfonium intermediate. This breaks down under mild base catalysis to give the desired ketone and dimethyl sulfide. 

Dimethyl sulfide is added as a safety precaution. It reduces any highly oxidized and potentially dangerous by-products that might have formed during ozonolysis. 

Dimethyl sulfide [Methane, thiobis-], 16 Dinitrogen tetroxide [Nitrogen oxide (Na 04)], 65 Disulfide, dimethyl-, 9... 

Figure 4-13 shows an example from a three-dimensional model simulation of the global atmospheric sulfur balance (Feichter et al, 1996). The model had a grid resolution of about 500 km in the horizontal and on average 1 km in the vertical. The chemical scheme of the model included emissions of dimethyl sulfide (DMS) from the oceans and SO2 from industrial processes and volcanoes. Atmospheric DMS is oxidized by the hydroxyl radical to form SO2, which, in turn, is further oxidized to sulfuric acid and sulfates by reaction with either hydroxyl radical in the gas phase or with hydrogen peroxide or ozone in cloud droplets. Both SO2 and aerosol sulfate are removed from the atmosphere by dry and wet deposition processes. The reasonable agreement between the simulated and observed wet deposition of sulfate indicates that the most important processes affecting the atmospheric sulfur balance have been adequately treated in the model. 

The vast majority of sulfur at any given time is in the lithosphere. The atmosphere, hydrosphere, and biosphere, on the other hand, are where most transfer of sulfur takes place. The role of the biosphere often involves reactions that result in the movement of sulfur from one reservoir to another. The burning of coal by humans (which oxidizes fossilized sulfur to SO2 gas) and the reduction of seawater sulfate by phytoplankton which can lead to the creation of another gas, dimethyl sulfide (CH3SCH3), are examples of such processes. 

Hyphomicrobium sp. strain EG is able to grow at the expense of dimethyl sulfide or dimethyl sulfoxide (DMSO) and prodnces methanethiol initially. This is then further oxidized to formaldehyde, sulfide, and Ft202 by an oxidase that has been purified (Suylen etal. 1987). 

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