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Dimethyl sulfide ( DMS) or methylthiomethane is an organosulfur compound with the formula . It is the simplest thioether and has a characteristic disagreeable odor. It is a flammable liquid that boils at . It is a component of the smell produced from cooking of certain vegetables (notably maize, cabbage, and beetroot) and seafoods. It is also an indication of contamination in malt production and brewing. It is a breakdown product of dimethylsulfoniopropionate (DMSP), and is also produced by the bacterial metabolism of methanethiol.
DMS is oxidized in the marine atmosphere to various sulfur-containing compounds, such as sulfur dioxide, dimethyl sulfoxide (DMSO), dimethyl sulfone, methanesulfonic acid and sulfuric acid. Among these compounds, sulfuric acid has the potential to create new aerosols which act as cloud condensation nuclei. It usually results in the formation of Sulfate aerosol in the troposphere. Through this interaction with cloud formation, the massive production of atmospheric DMS over the oceans may have a significant impact on the Earth's climate. The CLAW hypothesis suggests that in this manner DMS may play a role in planetary homeostasis.
Marine phytoplankton also produce dimethyl sulfide, and DMS is also produced by bacterial cleavage of extracellular DMSP. Biologists W. D. Hamilton and Tim Lenton have proposed that this may be an adaptive trait, as the algae can use the resulting clouds to disperse themselves around the world. DMS has been characterized as the "smell of the sea", though it would be more accurate to say that DMS is a component of the smell of the sea, others being chemical derivatives of DMS, such as oxides, and yet others being algal such as .
Dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide have been found among the volatiles given off by the fly-attracting plant known as dead-horse arum ( Helicodiceros muscivorus). Those compounds are components of an odor like rotting meat, which attracts various Pollination that feed on carrion, such as many species of flies.
At pathologically dangerous concentrations, this is known as dimethylsulfidemia. This condition is associated with halitosis and dimethylsulfiduria.
The James Webb Space Telescope has possibly detected evidence of DMS in the atmosphere of the exoplanet K2-18b.
Dimethyl sulfide is also produced by marine microorganisms such as the . It contributes to the characteristic odor of sea air. In the Victorian era, before DMS was discovered, the origin of sea air's 'bracing' aroma was misattributed to ozone.
Dimethyl sulfide is the main volatile product various of . It is the compound that animals trained to uncover the fungus (such as and detection dogs) sniff out when searching for them.
Oxidation of dimethyl sulfide gives the solvent dimethyl sulfoxide. Further oxidation affords dimethyl sulfone.
As illustrated above by the formation of its adduct with borane, dimethyl sulfide is a Lewis base. It is classified as a HSAB theory (see also ECW model). It forms complexes with many transition metals but such adducts are often labile. For example, it serves a displaceable ligand in chloro(dimethyl sulfide)gold(I).
Dimethyl sulfide is used in the workup of the ozonolysis of alkenes. It reduces the intermediate trioxolane. The Swern oxidation produces dimethyl sulfide by reduction of dimethylsulfoxide.
With chlorinating agents such as sulfuryl chloride, dimethyl sulfide converts to chloromethyl methyl sulfide:
Like other methylthio compounds, DMS is deprotonated by butyl lithium:
Safety
Dimethyl sulfide is highly flammable; its flash point is or . Its self-ignition temperature is . It is an eye and skin irritation and is harmful if swallowed. It has an unpleasant odor at even extremely low concentrations.
See also
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