Dimethyl sulfide (DMS) or methylthiomethane is an organosulfur compound with the formula (CH3)2S. It is the simplest thioether and has a characteristic disagreeable odor. It is a flammable liquid that boils at 37 °C (99 °F). 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 bacterial contamination in malt production and brewing. It is a breakdown product of dimethylsulfoniopropionate (DMSP), and is also produced by the bacterial metabolism of methanethiol.
Occurrence and production
DMS originates primarily from DMSP, a major secondary metabolite in some marine algae.[5] DMS is the most abundant biological sulfur compound emitted to the atmosphere.[6][7] Emission occurs over the oceans by phytoplankton. DMS is also produced naturally by bacterial transformation of dimethyl sulfoxide (DMSO) waste that is disposed of into sewers, where it can cause environmental odor problems.[8]
Marine phytoplankton also produce dimethyl sulfide,[13] and DMS is also produced by bacterial cleavage of extracellular DMSP.[14] DMS has been characterized as the "smell of the sea",[15] 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 pheromones such as dictyopterenes.[16]
On September 12, 2023, NASA announced that their investigation into exoplanet K2-18b revealed the possible presence of dimethyl sulfide, noting "On Earth, this is only produced by life."[18]
Dimethyl sulfide is normally present at very low levels in healthy people, namely less than 7 nM in blood, less than 3 nM in urine and 0.13 to 0.65 nM on expired breath.[20][21]
Dimethyl sulfide has a characteristic odor commonly described as cabbage-like. It becomes highly disagreeable at even quite low concentrations. Some reports claim that DMS has a low olfactory threshold that varies from 0.02 to 0.1 ppm[clarification needed] between different persons, but it has been suggested that the odor attributed to dimethyl sulfide may in fact be due to disulfides, polysulfides and thiol impurities, since the odor of dimethyl sulfide is much less disagreeable after it is freshly washed with saturated aqueous mercuric chloride.[25] Dimethyl sulfide is also available as a food additive to impart a savory flavor; in such use, its concentration is low. Beetroot,[26]asparagus,[27]cabbage, maize and seafoods produce dimethyl sulfide when cooked.
Dimethyl sulfide is also produced by marine planktonic microorganisms such as the coccolithophores and so is one of the main components responsible for the characteristic odor of sea wateraerosols, which make up a part of sea air. In the Victorian era, before DMS was discovered, the origin of sea air's 'bracing' aroma was attributed to ozone.[28]
Dimethyl sulfide is the main volatile chemical produced by various species of truffle, and is the compound that animals trained to uncover the fungus (such as pigs and detection dogs) sniff out when searching for them.[29]
As a marker for exoplanetary biology
The presence of dimethyl sulfide in the spectrum of an exoplanet is being used in exobiology as an indication that biology is occurring on that planet and therefore is a strong indication that the planet may contain life. [30][31]
As illustrated above by the formation of its adduct with borane, dimethyl sulfide is a Lewis base. It is classified as a soft ligand (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).[32]
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.[33]
^Kappler, U.; Schäfer, H. (2014). "Chapter 11. Transformations of Dimethylsulfide". In Kroneck, P. M. H.; Sosa Torres, M. E. (eds.). The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment. Metal Ions in Life Sciences. Vol. 14. Springer. pp. 279–313. doi:10.1007/978-94-017-9269-1_11. ISBN978-94-017-9268-4. PMID25416398.
^Glindemann, D.; Novak, J.; Witherspoon, J. (2006). "Dimethyl Sulfoxide (DMSO) Waste Residues and Municipal Waste Water Odor by Dimethyl Sulfide (DMS): the North-East WPCP Plant of Philadelphia". Environmental Science and Technology. 40 (1): 202–207. Bibcode:2006EnST...40..202G. doi:10.1021/es051312a. PMID16433352.
^Itoh, T.; Inoue, H.; Emoto, S. (2000). "Synthesis of Dictyopterene A: Optically Active Tributylstannylcyclopropane as a Chiral Synthon". Bulletin of the Chemical Society of Japan. 73 (2): 409–416. doi:10.1246/bcsj.73.409. ISSN1348-0634.
^Tangerman, A. (15 October 2009). "Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices". Journal of Chromatography B. 877 (28): 3366–3377. doi:10.1016/j.jchromb.2009.05.026. PMID19505855.
^Tangerman, A.; Winkel, E. G. (September 2007). "Intra- and extra-oral halitosis: finding of a new form of extra-oral blood-borne halitosis caused by dimethyl sulphide". J. Clin. Periodontol. 34 (9): 748–755. doi:10.1111/j.1600-051X.2007.01116.x. PMID17716310.
^Tangerman, A.; Winkel, E. G. (March 2008). "The portable gas chromatograph OralChroma: a method of choice to detect oral and extra-oral halitosis". Journal of Breath Research. 2 (1): 017010. doi:10.1088/1752-7155/2/1/017010. PMID21386154. S2CID572545.
^Morton, T. H. (2000). "Archiving Odors". In Bhushan, N.; Rosenfeld, S. (eds.). Of Molecules and Mind. Oxford: Oxford University Press. pp. 205–216.
^Parliment, T. H.; Kolor, M. G.; Maing, I. Y. (1977). "Identification of the Major Volatile Components of Cooked Beets". Journal of Food Science. 42 (6): 1592–1593. doi:10.1111/j.1365-2621.1977.tb08434.x.
^U., Detlef; Hoberg, E.; Bittner, T.; Engewald, W.; Meilchen, K. (2001). "Contribution of volatile compounds to the flavor of cooked asparagus". European Food Research and Technology. 213 (3): 200–204. doi:10.1007/s002170100349. S2CID95248775.
^Talou, T.; G aset, A.; Delmas, M.; Kulifaj, M.; Montant, C. (1990). "Dimethyl sulphide: the secret for black truffle hunting by animals?". Mycological Research. 94 (2): 277–278. doi:10.1016/s0953-7562(09)80630-8. ISSN0953-7562.
^Reich, Hans J. (2013). "Role of Organolithium Aggregates and Mixed Aggregates in Organolithium Mechanisms". Chemical Reviews. 113 (9): 7130–7178. doi:10.1021/cr400187u. PMID23941648.
^"DIMETHYL SULFIDE". OSHA Occupational Chemical Database. Occupational Safety and Health Administration, U.S. Department of Labor. 28 December 2020. Retrieved 14 January 2025.
^ ab"DIMETHYLSULPHIDE". International Chemical Safety Cards. International Labour Organization. March 1999. ICSC 0878. Retrieved 14 January 2025.
