624-92-0

A colorless oily liquid with a garlic-like odor. Denser than water and slightly soluble in water. Flash point 40°F. Vapors heavier than air. May irritate skin and eyes. Used to make other chemicals.

DIMETHYL DISULFIDE(624-92-0) is a reducing agent. A dangerous fire hazard when exposed to oxidizing materials. Emits toxic fumes of oxides of sulfur when heated to decomposition or on contact with acids [Sax, 9th ed., 1996, p. 1320].

Highly flammable. Slightly soluble in water.

May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Methyl disulfide has a diffuse intense onion odor. It is nonlachrymatory. May be prepared from magnesium methyl iodide and S2C12, or from Na2S2 and sodium methyl sulfate; also from methyl bromide and sodium thiosulfate, after which the resulting sodium methylthiosulfate is heated to yield dimethyl disulfide.

colourless to yellow liquid with a very unpleasant smell, insoluble in water, Soluble in ethanol, ethyl ether and acetic acid. It is a strong odor component irritant which is also included in garlic and has been designated as a specific malodorous substances based on the Offensive Odor Control Law. Its detection threshold shows 0.002 ppm, which senses a low concentration equivalent to Dimethyl sulfide.

Reported found in sour cherry, guava, melon, peach, pineapple, strawberry, cabbage, kohlrabi, onion, garlic, shallot, leek, chive, peas, potato, rutabaga, tomato, parsley, breads, many cheeses, yogurt, milk, egg, fish, meats, hop oil, beer, Scotch whiskey, cognac, grape wines, cocoa, coffee, peanut, peanut butter, pecan, potato chips, oats, soybean, beans, mushrooms, trassi, macadamia nut, mango, cauliflower, broccoli, brussels sprouts, rice, radish, sukiyaki, sake, watercress, malt, wort, krill, southern pea, loquat, sapodilla, shrimp, oyster, crab, crayfish, clam, scallops and squid.

Methyl disulfide is probably best known for its use as a component of flavoring materials. It has an intense onion odor by itself. Ironically, although many find its odor objectionable at high concentrations as noted above, when diluted, its aroma has also been described as pleasant. Methyl disulfide is often used in combination with other flavor compounds in food products, including baked goods, cheese, frozen dairy products, meat products, soups, savory flavors, fruit flavors, soft candy, gelatin, puddings, and both alcoholic and nonalcoholic beverages.
Industrially, methyl disulfide is also used as a sulfiding agent to catalyze reactions in oil refineries and other industries. It has a low flash point of 16 ℃ (61 °F) that presents fire hazards during refinery usage. Due to its strong odor and low flash point, methyl disulfide typically requires storage under nitrogen pressure in closed containers.
Other novel applications are being explored, including inclusion of methyl disulfide in insect trap baiting products to attract biting flies and mosquitos. It is also proposed as an insecticidal fumigant substitute for methyl bromide. Methyl disulfide formed during irradiation of foods also has potential to be used as irradiation detection marker for frozen-stored meats under oxygen-permeable packaging conditions. Among sulfur volatiles, only methyl disulfide was found in meat after 6 months of storage at -40 ℃ (40 °F). Methyl disulfide is also being studied as a signaling molecule in marine ecosystems to study effects of climate change.

ChEBI: An organic disulfide that is methane in which one of the hydrogens has been replaced by a methyldisulfanyl group.

From magnesium methyl iodide and S2Cl2, or from S2S2 and sodium methyl sulfate; also from methyl bromide and sodium thiosulfate, after which the resulting sodium methylthiosulfate is heated to yield dimethyl disulfide.

Detection: 0.16 to 1.2 ppb. Recognition: 90 ppb

Highlyflammable

PrimaryIrritant. This material may be used as an organicintermediate

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.

Naturally occurring methyl disulfide is present in small amounts throughout the natural environment. Accidental releases of larger quantities of methyl sulfide from industrial processes can also potentially enter the environment as liquid or vapor. It is immiscible with water, so it is unlikely to be found in high concentrations in water supplies, but it is miscible with most common organic solvents.
The Hazardous Substances Data Bank (HSDB) provides a good, detailed explanation of environmental fate. When released to air, a vapor pressure of 28.7mmHg at 25 ℃ indicates that methyl disulfide will exist as a vapor in the ambient atmosphere. Vapor-phase methyl disulfide is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals. The half-life for this reaction in air is estimated to be 4 h. Direct photolysis (half-life of 3.2–4.6 h at full sunlight) and reaction with nitrate radicals (half-life of 1.1 h during night-time hours) will also contribute to its atmospheric degradation.
If released to soil, methyl disulfide is expected to have moderate mobility based upon an estimated Koc of 220. In water, methyl disulfide is not expected to adsorb to suspended solids and sediment in water based on its Koc value. In both soil and water, volatilization to the atmosphere is expected to be the major transport process, based on a Henry’s law constant of 1.21× 10–3 atm-m³ mol–1. Estimated volatilization half-lives for a model river and model lake are 3 h and 4 days, respectively. Volatilization from dry soil surfaces is possible given the vapor pressure of this compound. Since methyl disulfide photolyzes readily in sunlight, photodegradation on soil or water surfaces exposed to sunlight could be an important transformation process. Other than photodegradation, because it is such a stable molecule, methyl disulfide is not readily biodegradable by microorganisms and therefore can be relatively persistent in the environment. Although limited biodegradation data suggest that methyl disulfide can biodegrade, insufficient data are available to predict its relative environmental importance in soil or water. An estimated bioconcentration factor (BCF) of 13 suggests the potential for bioconcentration in aquatic organisms is low.

Color Code—Red: Flammability Hazard: Store ina flammable liquid storage area or approved cabinet awayfrom ignition sources and corrosive and reactive materials.Prior to working with Dimethyl disulfide you should betrained on its proper handling and storage. Before enteringconfined space where this chemical may be present, checkto make sure that an explosive concentration does not exist.Store in tightly closed containers in a cool, well-ventilatedarea away from any form of moisture, oxidizers, acids.Metal containers involving the transfer of this chemicalshould be grounded and bonded. Where possible, automatically pump liquid from drums or other storage containers toprocess containers. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. Useonly nonsparking tools and equipment, especially whenopening and closing containers of this chemical. Sources ofignition, such as smoking and open flames, are prohibitedwhere this chemical is used, handled, or stored in a mannerthat could create a potential fire or explosion hazard.Wherever this chemical is used, handled, manufactured, orstored, use explosion-proof electrical equipment andfittings.

This compound requires a shipping label of“FLAMMABLE LIQUID.” It falls in Hazard Class 3 andPacking Group II.

Pass it through neutral alumina before use. [Trost Chem Rev 78 363 1978, Beilstein 1 IV 1281.]

Very little information is available on mechanism of toxicity. Although the authors of one experimental animal study suggested that methyl disulfide toxicity resembles that of hydrogen sulfide, it is not at all clear that cytochrome oxidase inhibition can result from methyl disulfide exposure. Mechanistically hydrogen sulfide is classified as a chemical asphyxiant because of its known ability to disrupt electron transport and oxidative phosphorylation by interaction with the enzyme cytochrome oxidase. Other sources classify methyl disulfide a simple asphyxiant, which means that it is nonreactive with enzymes or other cell components and simply displaces oxygen in the air. Some information indicates that neurotoxicity to insects results when methyl disulfide disrupts calcium-activated potassium channels in insect pacemaker neurons.

Forms explosive mixture with air.Contact with water or acids forms flammable and toxicvapors of hydrogen sulfide. Contact with oxidizing materials or acids can cause a violent reaction.