Dimethyl disulfide

Dimethyl disulfide

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Names
IUPAC name (Methyldisulfanyl)methane
Other names Dimethyl disulphide; Methyl disulfide; Methyldisulfide; Dimethyldisulfide; Methyldithiomethane; 2,3-Dithiabutane
Identifiers
CAS Number	624-92-0 Y
Abbreviations	DMDS
ChEBI	CHEBI:4608 Y
ChemSpider	11731 Y
Jmol 3D model	Interactive image
PubChem	12232
InChI InChI=1S/C2H6S2/c1-3-4-2/h1-2H3 Y Key: WQOXQRCZOLPYPM-UHFFFAOYSA-N Y InChI=1S/C2H6S2/c1-3-4-2/h1-2H3
SMILES S(SC)C
Properties
Chemical formula	C2H6S2
Molar mass	94.19 g·mol−1
Appearance	Colorless to yellowish liquid
Density	1.06 g/cm3
Melting point	−85 °C (−121 °F; 188 K)
Boiling point	110 °C (230 °F; 383 K)
Solubility in water	2.5 g/L (20 °C)
Vapor pressure	3.8 kPa (at 25 °C) Arkema data sheet
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Dimethyl disulfide (DMDS) is an organic chemical compound with the molecular formula CH₃SSCH₃ which is the simplest disulfide. It is a flammable liquid with an unpleasant, garlic-like odor.

Occurrence

Dimethyl disulfide along with dimethyl sulfide and dimethyl trisulfide have been confirmed as volatile compounds given off by the fly-attracting plant known as dead-horse arum (Helicodiceros muscivorus). These flies are attracted to the odor of fetid meat, they help pollinate this plant.

DMDS can be produced by the oxidation of methanethiol, e.g. with iodine:

2 CH₃SH + I₂ → CH₃SSCH₃ + 2 HI

Chemical reactions

Important reactions include chlorination giving methanesulfenyl chloride (CH₃SCl), methanesulfinyl chloride (CH₃S(O)Cl), and methanesulfonyl chloride (CH₃SO₂Cl) as well as oxidation with hydrogen peroxide or peracetic acid giving the thiosulfinate methyl methanethiosulfinate (CH₃S(O)SCH₃).

Uses

DMDS is used as a food additive in onion, garlic, cheese, meats, soups, savory flavors, and fruit flavors. Industrially, DMDS is used in oil refineries as a sulfiding agent. DMDS is also an effective soil fumigant in agriculture, registered in many states in the U.S. as well as globally. In this capacity, DMDS is an important alternative in replacing methyl bromide, which is being phased out. This pesticide is marketed as "Paladin" by Arkema.

Food use

DMDS is used to alpha substitute 2-methylfuran-acrolein to produce a food stuff used in concentrations from 0.02 ppm up to 50 ppm.

Industrial use

DMDS is a stable pale yellow liquid which works as an effective product in the sulfiding process because of its high sulfur content. It is the sulfiding industry's reagent of choice because it offers more sulfur per pound of reagent when compared to its nearest competitor dimethyl sulfide.

DMDS also works as an effective product for operators in the petrochemicals industry who must protect their steam-cracking coils against the formation of coke and carbon monoxide. DMDS is also used for sulphiding of hydrotreating catalysts.

DMDS is used in the preparation of 4-(methylthio)phenol which is used in the production of various pesticides. DMDS and chlorine are reacted with borontriflouride phenolate to produce 4-(methylthio)phenol. Thiophene and DMDS are blended with combustible hydrocarbon fuel gas to impart a gassy odor to the fuel gas. DMDS is used as a sulfiding reagent to control catalyst activity.