Dimethyl sulfide (DMS) or methylthiomethane is an
organosulfur compound with the formula (CH
3)
2S. Dimethyl sulfide is a
flammable liquid that boils at and has a characteristic disagreeable odor. It is a component of the smell produced from cooking of certain vegetables, notably
maize
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...
, cabbage,
beetroot
The beetroot is the taproot portion of a beet plant, usually known in North America as beets while the vegetable is referred to as beetroot in British English, and also known as the table beet, garden beet, red beet, dinner beet or golden beet ...
, and seafoods. It is also an indication of
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
l contamination in
malt
Malt is germinated cereal grain that has been dried in a process known as " malting". The grain is made to germinate by soaking in water and is then halted from germinating further by drying with hot air.
Malted grain is used to make beer, wh ...
production and
brewing
Brewing is the production of beer by steeping a starch source (commonly cereal grains, the most popular of which is barley) in water and #Fermenting, fermenting the resulting sweet liquid with Yeast#Beer, yeast. It may be done in a brewery ...
. 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. DMS is the most abundant biological sulfur compound emitted to the
atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
. Emission occurs over the
ocean
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wo ...
s by
phytoplankton
Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'.
Ph ...
. DMS is also produced naturally by bacterial transformation of
dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula ( CH3)2. This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds a ...
(DMSO) waste that is disposed of into sewers, where it can cause environmental odor problems.
DMS is oxidized in the marine atmosphere to various sulfur-containing compounds, such as
sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...
,
dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula ( CH3)2. This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds a ...
(DMSO),
dimethyl sulfone
Methylsulfonylmethane (MSM) is an organosulfur compound with the formula (CH3)2SO2. It is also known by several other names including methyl sulfone and dimethyl sulfone (DMSO2). This colorless solid features the sulfonyl functional group and is t ...
,
methanesulfonic acid
Methanesulfonic acid (MsOH) or methanesulphonic acid (in British English) is an organosulfuric, colorless liquid with the chemical formula and structure . It is the simplest of the alkylsulfonic acids (). Salts and esters of methanesulfonic aci ...
and
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
. Among these compounds, sulfuric acid has the potential to create new
aerosols
An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas. Aerosols can be natural or anthropogenic. Examples of natural aerosols are fog or mist, dust, forest exudates, and geyser steam. Examples of anthrop ...
which act as
cloud condensation nuclei
Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2 µm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This c ...
. It usually results in the formation of
sulfate particles in the troposphere. Through this interaction with
cloud
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may co ...
formation, the massive production of atmospheric DMS over the oceans may have a significant impact on the Earth's
climate
Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...
. The
CLAW hypothesis suggests that in this manner DMS may play a role in planetary
homeostasis
In biology, homeostasis (British English, British also homoeostasis) Help:IPA/English, (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physics, physical, and chemistry, chemical conditions maintained by organism, living systems. Thi ...
.
Marine phytoplankton also produce dimethyl sulfide, and DMS is also produced by bacterial cleavage of extracellular DMSP. 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
pheromones such as
dictyopterenes.
Dimethyl sulfide,
dimethyl disulfide, and
dimethyl trisulfide
Dimethyl trisulfide (DMTS) is an organic chemical compound and the simplest organic trisulfide, with the chemical formula CH3SSSCH3. It is a flammable liquid with a foul odor, which is detectable at levels as low as 1 part per trillion.
Occurren ...
have been found among the volatiles given off by the fly-attracting plant known as
dead-horse arum
''Helicodiceros muscivorus'', the dead horse arum lily, is an ornamental plant native to Corsica, Sardinia and the Balearic Islands. It is the only species in the genus ''Helicodiceros''. Within the family Araceae the plant is part of the subfa ...
(''
Helicodiceros muscivorus
''Helicodiceros muscivorus'', the dead horse arum lily, is an ornamental plant native to Corsica, Sardinia and the Balearic Islands. It is the only species in the genus ''Helicodiceros''. Within the family Araceae the plant is part of the subfa ...
''). Those compounds are components of an
odor
An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds ...
like rotting meat, which attracts various
pollinators that feed on carrion, such as many species of flies.
Industrial processes
In industry dimethyl sulfide is produced by treating
hydrogen sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...
with excess
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
over an
aluminium oxide catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
:
:
Dimethyl sulfide is emitted by
kraft pulping mills as a side product from
delignification.
Physiology of dimethyl sulfide
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.
At pathologically dangerous concentrations, this is known as dimethylsulfidemia. This condition is associated with
blood borne halitosis and dimethylsulfiduria.
In people with chronic liver disease (cirrhosis), high levels of dimethyl sulfide may be present in the breath, leading to an unpleasant smell (
fetor hepaticus
Fetor hepaticus or foetor hepaticus (Latin, "fetid liver") (see spelling differences), also known as breath of the dead or hepatic foetor, is a condition seen in portal hypertension where portosystemic shunting allows thiols to pass directly into ...
).
Odor
Dimethyl sulfide has a characteristic odor commonly described as
cabbage
Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&nb ...
-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 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. Dimethyl sulfide is also available as a food additive to impart a savory flavor; in such use, its concentration is low. Beetroot, asparagus, cabbage, corn and seafoods produce dimethyl sulfide when cooked.
Dimethyl sulfide is also produced by marine
plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...
ic microorganisms such as the
coccolithophore
Coccolithophores, or coccolithophorids, are single celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingdo ...
s and so is one of the main components responsible for the characteristic odor of
sea water
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approx ...
aerosol
An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be natural or Human impact on the environment, anthropogenic. Examples of natural aerosols are fog o ...
s, which make up a part of
sea air. In the
Victorian era
In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwardia ...
, before DMS was discovered, the origin of sea air's 'bracing' aroma was attributed to
ozone
Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
.
Industrial uses
Dimethyl sulfide is considered the most important thioether produced industrially. One major use is for the production of
borane dimethyl sulfide
Borane dimethylsulfide (BMS) is a complexed borane reagent that is used for hydroborations and Organic redox reaction, reductions. The advantages of BMS over other borane reagents, such as borane-tetrahydrofuran, are its increased stability and h ...
from
diborane:
[
:
Oxidation of dimethyl sulfide gives the solvent ]dimethyl sulfoxide
Dimethyl sulfoxide (DMSO) is an organosulfur compound with the formula ( CH3)2. This colorless liquid is the sulfoxide most widely used commercially. It is an important polar aprotic solvent that dissolves both polar and nonpolar compounds a ...
. Further oxidation affords dimethyl sulfone
Methylsulfonylmethane (MSM) is an organosulfur compound with the formula (CH3)2SO2. It is also known by several other names including methyl sulfone and dimethyl sulfone (DMSO2). This colorless solid features the sulfonyl functional group and is t ...
.
Chemical reactions
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)
Chloro(dimethyl sulfide)gold(I) is a coordination complex of gold. It is a white solid. This compound is a common entry point into gold chemistry.
Structure
As for many other gold(I) complexes, the compound adopts a nearly linear (176.9°) geome ...
.
Dimethyl sulfide is used in the workup of the ozonolysis of alkenes
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond.
Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
. 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
Chloromethyl methyl sulfide is the organosulfur compound with the formula . In terms of functional groups, it is a thioether and an alkyl chloride. The compound is structurally related to sulfur mustards, i.e., it is a potentially hazardous alkyl ...
:
:
Like other methylthio compounds, DMS is deprotonated by butyl lithium:
:
Safety
Dimethyl sulfide is highly flammable
A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...
and an eye and skin irritant. It is harmful if swallowed. It has an unpleasant odor at even extremely low concentrations. Its ignition temperature is 205 °C.
See also
* Coccolithophore
Coccolithophores, or coccolithophorids, are single celled organisms which are part of the phytoplankton, the autotrophic (self-feeding) component of the plankton community. They form a group of about 200 species, and belong either to the kingdo ...
, a marine unicellular planktonic photosynthetic algae, producer of DMS
* Dimethylsulfoniopropionate, a parent molecule of DMS and methanethiol in the oceans
* ''Emiliania huxleyi
''Emiliania huxleyi'' is a species of coccolithophore found in almost all ocean ecosystems from the equator to sub-polar regions, and from nutrient rich upwelling zones to nutrient poor oligotrophic waters. It is one of thousands of different ...
'', a coccolithophorid producing DMS
* Swern oxidation
* Gaia hypothesis
The Gaia hypothesis (), also known as the Gaia theory, Gaia paradigm, or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that help ...
* Geosmin
Geosmin ( ) is an irregular sesquiterpenoid, produced from the universal sesquiterpene precursor farnesyl pyrophosphate (also known as farnesyl diphosphate), in a two-step -dependent reaction. Geosmin, along with the irregular monoterpene 2-met ...
, the substance responsible for the odour of earth
* Petrichor
Petrichor () is the earthy olfaction, scent produced when rain falls on dry soil. The word is constructed , the ichor, ethereal fluid that is the blood of the gods in Greek mythology.
Origins
Long before this phenomenon received its name in 19 ...
, the earthy scent produced when rain falls on dry soil
References
External links
Dimethylsulfide (DMS) in the Bering Sea and Adjacent Waters: In-situ and Satellite Observations
{{Authority control
Climate
Thioethers
Foul-smelling chemicals
Trace gases