Dimethyl disulfide
[CAS# 624-92-0]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Thioether perfume
• Name: Dimethyl disulfide
• Synonyms: DMDS; 2,3-Dithiabutane
• Molecular Formula: C₂H₆S₂
• Molecular Weight: 94.19
• CAS Registry Number: 624-92-0
• EC Number: 210-871-0
• FEMA: 3536
• SMILES: CSSC

Properties

• Density: 1.0625
• Melting point: -85 °C
• Boiling point: 109-110 °C
• Refractive index: 1.5243-1.5263
• Flash point: 15 °C
• Water solubility: <0.1 g/100 mL at 20 °C

Safety Data

• Hazard Symbols: GHS02;GHS06;GHS08;GHS09 Danger
• Risk Statements: H225-H331-H301-H336-H370
• Safety Statements: P210-P233-P240-P241-P242-P243-P260-P261-P264-P264+P265-P270-P271-P273-P280-P284-P301+P316-P301+P317-P302+P352-P303+P361+P353-P304+P340-P305+P351+P338-P316-P317-P319-P320-P321-P330-P332+P317-P337+P317-P362+P364-P370+P378-P391-P403+P233-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	2	H330
Flammable liquids	Flam. Liq.	2	H225
Acute toxicity	Acute Tox.	3	H331
Acute toxicity	Acute Tox.	3	H301
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Specific target organ toxicity - single exposure	STOT SE	1	H370
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Specific target organ toxicity - single exposure	STOT SE	3	H336
Skin sensitization	Skin Sens.	1	H317
Skin sensitization	Skin Sens.	1B	H317
Acute toxicity	Acute Tox.	1	H330
Acute toxicity	Acute Tox.	2	H310
Flammable liquids	Flam. Liq.	1	H224
Acute toxicity	Acute Tox.	2	H300
Flammable liquids	Flam. Liq.	3	H226
Acute toxicity	Acute Tox.	4	H332
Reproductive toxicity	Repr.	2	H361
Eye irritation	Eye Irrit.	2A	H319

• Transport Information: UN 2381

Discovery and Applications

Dimethyl disulfide (DMDS) is an organic sulfur compound with the molecular formula CH3SSCH3. It is a volatile liquid characterized by a pungent odor, often associated with its sulfur-containing structure. DMDS occurs naturally in various plants and is released during the decomposition of organic matter. Its discovery and chemical synthesis were driven by a need to understand sulfur compounds' roles in both natural and industrial processes.

Dimethyl disulfide can be synthesized through the reaction of methanethiol with sulfur or by the oxidative coupling of methanethiol. Its structure consists of two methyl groups (CH3) bonded to a central disulfide bridge (S-S), which imparts unique chemical properties, such as its reactivity with metals and other sulfur-containing compounds.

In industry, DMDS has a wide range of applications, primarily due to its sulfur content. One of the most notable uses of dimethyl disulfide is in the petrochemical industry as a sulfiding agent. In this role, it helps to pre-sulfide catalysts used in hydrocracking and hydrotreating processes. These catalysts, typically composed of metals like molybdenum or cobalt, require sulfur to achieve optimal performance in breaking down large hydrocarbon molecules in crude oil into more refined products. DMDS provides a controlled and efficient means of introducing sulfur into these catalytic systems.

Dimethyl disulfide is also utilized as a soil fumigant in agriculture. It serves as an alternative to more toxic fumigants like methyl bromide, providing effective pest control while reducing the environmental impact. When applied to soil, DMDS breaks down into smaller sulfur-containing molecules that inhibit the growth of harmful nematodes, fungi, and weeds, promoting healthier crop yields.

Additionally, DMDS is used as a chemical intermediate in the synthesis of various organic compounds. It can act as a source of sulfur in organic reactions, facilitating the production of pharmaceuticals, agrochemicals, and other specialty chemicals. In the food industry, it is used in trace amounts as a flavoring agent to impart a garlic-like aroma to certain products.

Despite its industrial utility, dimethyl disulfide must be handled with care due to its strong odor and potential health hazards. It is classified as a hazardous substance, and exposure can cause irritation to the skin, eyes, and respiratory system.

Overall, the discovery and development of dimethyl disulfide have had a significant impact on multiple industries. Its versatility as a sulfur donor, catalyst activator, and fumigant make it an essential chemical in applications ranging from petrochemical refining to agriculture.

References

2016. Enhanced deodorization and sludge reduction in situ by a humus soil cooperated anaerobic/anoxic/oxic (A2O) wastewater treatment system. Environmental Science and Pollution Research International, 23(13).
DOI: 10.1007/s11356-016-6771-5

2020. Effect of dimethyl disulfide on the sulfur formation and microbial community composition during the biological H2S removal from sour gas streams. Journal of Hazardous Materials, 386.
DOI: 10.1016/j.jhazmat.2019.121916

2017. Determination of odour concentration by TD-GC×GC-TOF-MS and field olfactometry techniques. Monatshefte für Chemie - Chemical Monthly, 148(10).
DOI: 10.1007/s00706-017-2023-8