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| | Dimethyl disulfide Basic information |
| | Dimethyl disulfide Chemical Properties |
| Melting point | -85 °C | | Boiling point | 109 °C(lit.) | | density | 1.0625 | | vapor density | 3.24 (vs air) | | vapor pressure | 22 mm Hg ( 20 °C) | | refractive index | n20/D 1.525(lit.) | | FEMA | 3536 | DIMETHYL DISULFIDE | | Fp | 76 °F | | storage temp. | Flammables area | | solubility | 2.7g/l | | form | Liquid | | Specific Gravity | 1.0647 (20/4℃) | | color | Clear yellow | | Odor | at 0.10 % in propylene glycol. sulfurous vegetable cabbage onion | | Odor Type | sulfurous | | explosive limit | 1.1-16.1%(V) | | Odor Threshold | 0.0022ppm | | Water Solubility | <0.1 g/100 mL at 20 ºC | | JECFA Number | 564 | | BRN | 1730824 | | Exposure limits | ACGIH: TWA 0.5 ppm (Skin) | | Stability: | Stable. Incompatible with strong bases, strong oxidizing agents, strong reducing agents. Flammable. | | InChIKey | WQOXQRCZOLPYPM-UHFFFAOYSA-N | | LogP | 1.91 at 20℃ | | CAS DataBase Reference | 624-92-0(CAS DataBase Reference) | | NIST Chemistry Reference | Disulfide, dimethyl(624-92-0) | | EPA Substance Registry System | Methyl disulfide (624-92-0) |
| | Dimethyl disulfide Usage And Synthesis |
| Description | Dimethyl disulfide has a diffuse intense onion odor. It is nonlachrymatory. Ironically, although many find its odor objectionable at high concentrations as noted above, when diluted, its aroma has also been described as pleasant. Dimethyl 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. | | Chemical Properties | 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. | | Occurrence | 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. | | Uses | Industrially, Dimethyl 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, Dimethyl disulfide typically requires storage under nitrogen pressure in closed containers.
Dimethyl disulfide has a sulfurous odor similar to that of garlic and decaying fish. Because of the distinctive odor of sulfur compounds, similar to DMDS, they are often added to natural gas and propane to warn of leaks and protect people. Therefore, the odor of a DMDS fumigation can be mistaken for a gas leak. DMDS has an odor threshold of approximately 7 ppb, which is about 8 times less than the health‐based level considered by the EPA to be safe (55 ppb). | | Uses | Dimethyl disulfide is used as an intermediate as well as a food additive in onion, garlic, cheese, meats, soups, savory flavors and fruit flavors. It is used in oil refineries as a sulfiding agent. It is used to alfa substitute 2-methylfuran-acrolein to produce food stuff. It is involved in the preparation of 4-(methylthio)phenol. Further, it is used to replace methyl mercaptan as a jet fuel additive. It finds application in artificial flavoring agent and a corrosion inhibitor. In addition to this, it serves as an effective soil fumigant in agriculture. | | Preparation | Dimethyl disulfide can be prepared by the reaction between imethyl sulfate and sodium sulfide. under stirring, sulfur powder was added into sodium sulfide solution. The above reaction system was heated Up to 80-90℃, after reaction for 1 h, cooled to about 30 ℃. Dimethyl sulfate was dropped into the reaction system and the reaction was continued for 2h. Then, distillation, stratification, Separating waste alkali liquor, then through distillation and final products are prepared.
In industry,dimethyl sulfate method is adopted to synthesize dimethyl disulfide.
Na2S+S→Na2S2Na2S2+(CH3)2SO4→CH3SSCH3+Na2SO4
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. | | Definition | ChEBI: Dimethyl disulfide is an organic disulfide that is methane in which one of the hydrogens has been replaced by a methyldisulfanyl group. It has a role as a xenobiotic metabolite. | | Aroma threshold values | Detection: 0.16 to 1.2 ppb. Recognition: 90 ppb | | General Description | 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. | | Air & Water Reactions | Highly flammable. Slightly soluble in water. | | Reactivity Profile | DMDS 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]. | | Health Hazard | 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. | | Fire Hazard | 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. | | Flammability and Explosibility | Highlyflammable | | Safety Profile | Poison by inhalation. A
very dangerous fire hazard when exposed to
heat, flame, or oxidzers. Can react
vigorously with oxiduing materials. See also
SULFIDES. | | Purification Methods | Pass it through neutral alumina before use. [Trost Chem Rev 78 363 1978, Beilstein 1 IV 1281.] | | Toxicity evaluation | 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. |
| | Dimethyl disulfide Preparation Products And Raw materials |
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