Dimethyl sulfide

Structural formula
General
Surname	Dimethyl sulfide
other names	(Methylsulfanyl) methane ( IUPAC ) ; Methylthiomethane; 2-thiopropane; Methyl sulfide; Sulfur methyl; Dimethyl thioether;
Molecular formula	C 2 H 6 S
Brief description	colorless liquid with an unpleasant odor
External identifiers / databases
EC number	200-846-2
ECHA InfoCard	100,000,770
PubChem	1068
ChemSpider	1039
Wikidata	Q423133
properties
Molar mass	62.14 g mol −1
Physical state	liquid
density	0.85 g cm −3 (20 ° C)
Melting point	−98.3 ° C
boiling point	37 ° C
Vapor pressure	527 h Pa (20 ° C)
solubility	poor in water (2 g l −1 at 20 ° C); soluble in diethyl ether and ethanol ;
Refractive index	1.4438 (20 ° C)
safety instructions
H and P phrases	H: 225-319
	P: 210-280-305 + 351 + 338-337 + 313-403 + 235
MAK	not yet classified
Toxicological data	3300 mg kg −1 ( LD 50 , rat , oral )
Thermodynamic properties
ΔH f 0	−65.3 kJ / mol
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Dimethyl sulfide (DMS), also Methylthiomethan is a sulfur-containing organic compound with the chemical formula ( CH ₃ ) ₂S . It is the simplest thioether , the most common biogenic sulfur compound emitted into the atmosphere, and is responsible for the typical smell of the sea. DMS is created, among other things, when cooking various vegetables, especially cereals and cabbage, as well as seafood. It also serves as an indicator of bacterial infection during malt production . Dimethyl sulfide is a decomposition product of dimethyl sulfonium propionate (DMSP), but it can also arise from the bacterial metabolism of methanethiol .

DMS from the sea

DMS is formed by phytoplankton and is dissolved in a few n mol / l in the surface water of the oceans , of which around 30 million tons are released into the atmosphere every year. There, DMS oxidizes via dimethyl sulfoxide (DMSO) and sulfur dioxide to sulfuric acid , which condenses into droplets. Above the oceans, this is the dominant source of condensation nuclei for cloud formation and thus has a significant influence on the earth's climate, see CLAW hypothesis .

Importance as an odorous substance

Krill eats phytoplankton and therefore smells of DMS, which some seabirds in search of food perceive. Due to phytoplankton growth, floating rubbish also smells like DMS and is mistaken for krill.

DMS is also a component of flatulence gases and bad breath in human breath; it is produced by anaerobic bacteria in the mouth and tongue area or is excreted in the lungs as a breakdown product of drugs.

Manufacturing

DMS is produced from hydrogen sulfide and methanol using aluminum oxide as a catalyst .

use

In industry , DMS is used in the refining of petroleum and in petrochemical production processes to control the formation of coke and carbon monoxide . It is also used for dust control in steel rolling mills and in a number of organic syntheses . Another area of application is in the food industry as a spice component .

Dimethyl sulfide can be naturally or artificially oxidized to dimethyl sulfoxide , which has various important properties as a solvent.

safety instructions

Dimethyl sulfide is a highly flammable chemical ( flash point : −45 ° C in a closed cup; ignition temperature : 205 ° C) and classified as harmful. It is very volatile, the vapors are heavier than air and form an explosive mixture with it. The lower explosion limit is 2.2, the upper 19.7 percent by volume DMS.

The LD ₅₀ for oral administration for mice is 3700 mg / kg, the values for rats range from 535 to 3300 mg / kg.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Entry on dimethyl sulfide in the GESTIS material database of the IFA , accessed on January 10, 2017(JavaScript required) .
↑ Entry on dimethyl sulfide. In: Römpp Online . Georg Thieme Verlag, accessed on November 11, 2014.
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-210.
↑ Entry on dimethyl sulfide in the ChemIDplus database of the United States National Library of Medicine (NLM)
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-23.
^ A. Lana et al .: An updated climatology of surface dimethlysulfide [sic!] Concentrations and emission fluxes in the global ocean , Global Biogeochemical Cycles 25, 2011, GB1004, doi : 10.1029 / 2010GB003850 .
↑ Research highlight: Plastic smells good to marine birds . Nature 539, 2016, doi: 10.1038 / 539332a .
↑ Wolfgang Legrum: Fragrances, between stink and fragrance , Vieweg + Teubner Verlag (2011) pp. 61–62, ISBN 978-3-8348-1245-2 .
↑ Kathrin-Maria Roy: Thiols and Organic Sulfides . In: Ullmann's Encyclopedia of Industrial Chemistry . 2000. doi : 10.1002 / 14356007.a26_767 .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Entry on dimethyl sulfide in the GESTIS material database of the IFA , accessed on January 10, 2017(JavaScript required) .

[2] Entry on dimethyl sulfide. In: Römpp Online . Georg Thieme Verlag, accessed on November 11, 2014.

[CRC90_3_210-3] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-210.

[4] Entry on dimethyl sulfide in the ChemIDplus database of the United States National Library of Medicine (NLM)

[CRC90_5_23-5] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-23.

[6] A. Lana et al .: An updated climatology of surface dimethlysulfide [sic!] Concentrations and emission fluxes in the global ocean , Global Biogeochemical Cycles 25, 2011, GB1004, doi : 10.1029 / 2010GB003850 .

[7] Research highlight: Plastic smells good to marine birds . Nature 539, 2016, doi: 10.1038 / 539332a .

[Legrum-8] Wolfgang Legrum: Fragrances, between stink and fragrance , Vieweg + Teubner Verlag (2011) pp. 61–62, ISBN 978-3-8348-1245-2 .

[9] Kathrin-Maria Roy: Thiols and Organic Sulfides . In: Ullmann's Encyclopedia of Industrial Chemistry . 2000. doi : 10.1002 / 14356007.a26_767 .