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METHYL MERCAPTAN is a reducing agent--can react vigorously with oxidizing agents. Dangerous fire or explosion hazard when exposed to heat, flame, sparks or strong oxidizing agents (e.g., calcium hypochlorite). When heating to decomposition emits highly toxic fumes of oxides of sulfur [Lewis, 3rd ed., 1993, p. 862]. Violent reaction with mercury(II) oxide [Klason P., Ber., 1887, 20, p. 3410].

Highly flammable. Reacts with water, steam or acids to produce toxic, flammable vapors [Lewis].

Flammable, dangerous fire risk. Explosive limits in air 3.9–21.8%. Strong irritant. Liver damage.

Can cause death by respiratory paralysis. It is an eye and respiratory tract irritant. Exposure results in pulmonary edema and hepatic and renal damage.

Methyl mercaptan is used in methionine synthesis, and widely as an intermediate in pesticide manufacture. A foul-smelling odorant usually added to chemicals, including pesticides.

Combustion produces irritating sulfur dioxide. Flash back along vapor track may occur. Very dangerous when exposed to heat, flame, or oxidizers. On decomposition METHYL MERCAPTAN emits highly toxic fumes of sulfur oxides. METHYL MERCAPTAN will react with water, steam or acids to produce toxic and flammable vapors; and can react vigorously with oxidizing materials. Irritating sulfur dioxide is produced upon combustion. When heated to decomposition, METHYL MERCAPTAN emits highly toxic fumes and flammable vapors. Incompatible with mercuric oxide and oxidizing materials. Avoid direct sunlight, and areas of high fire hazards. Hazardous polymerization may not occur.

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. Medical observation is recommended for 24 to 48 hours after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a drug or other inhalation therapy. If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water.

UN1064 Methyl mercaptan, Hazard Class: 2.3; Labels: 2.3-Poisonous gas, 2.1-Flammable gas, Inhalation Hazard Zone C. Cylinders must be transported in a secure upright position, in a well-ventilated truck. Protect cylinder and labels from physical damage. The owner of the compressed gas cylinder is the only entity allowed by federal law (49CFR) to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without the express written permission of the owner.

Violent reaction with strong oxidizers, bleaches, copper, nickel and their alloys; aluminum. Reacts with acids producing flammable and toxic hydrogen sulfide

Methanethiol (also known as methyl mercaptan) is a colorless gas with a smell like rotten cabbage. It is a natural substance found in the blood and brain of humans and other animals as well as plant tissues. It is disposed of through animal feces. It occurs naturally in certain foods, such as some nuts and cheese. It is also one of the main chemicals responsible for bad breath and the smell of flatus. The chemical formula for methanethiol is CH₃SH; it is classified as a thiol. It is sometimes abbreviated as MeSH. It is very flammable.

colourless gas with a garlic-like or rotten cabbage-like smell

Methyl mercaptan has an objectionable odor of decomposing cabbage or garlic

Methyl mercaptan has an objectionable odor of decomposing cabbage. May be prepared by heating an aqueous solution of potassium methyl sulfate and KHS; from sodium methyl sulfate and potassium sulfhydrate; also from methanol and hydrogen sulfide in the presence of a catalyst.

Methyl mercaptan is a colorless gas or white liquid with a disagreeable odor like garlic or rotten cabbage. Shipped as a liquefied compressed gas. The odor threshold is 0.002 ppm.

Return refillable compressed gas cylinders to supplier. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform to EPA regulations governing storage, transportation, treatment, and waste disposal. Incineration followed by effective scrubbing of the effluent gas.

Colorless gas with a garlic-like or rotten cabbage odor. An experimentally determined odor threshold concentration of 2.1 ppb_v was reported by Leonardos et al. (1969). A detection odor threshold concentration of 81 μg/m³ (41 ppb_v) was determined by Katz and Talbert (1930).

Methanethiol is released from decaying organic matter in marshes and is present in the natural gas of certain regions, in coal tar, and in some crude oils.
In surface seawater, methanethiol is the primary breakdown product of the algal metabolite dimethylsulfoniopropionate (DMSP). Marine bacteria appear to obtain most of their protein sulfur by the breakdown of DMSP and incorporation of methanethiol, despite the fact that methanethiol is present in seawater at much lower concentrations than sulfate (～0.3 nM vs. 28 mM). Bacteria in oxic and anoxic environments can also convert methanethiol to dimethyl sulfide (DMS), although most DMS in surface seawater is produced by a separate pathway. Both DMS and methanethiol can be used by certain microbes as substrates for methanogenesis in some anaerobic soils.
Methanethiol is a weak acid, with a pKa of ～10.4. This acidic property makes it reactive with dissolved metals in aqueous solutions. The environmental chemistry of these interactions in seawater or fresh water environments such as lakes has yet to be fully investigated.
A material safety data sheet (MSDS) lists methanethiol as a colorless, flammable gas with an extremely strong and repulsive smell. At very high concentrations it is highly toxic and affects the central nervous system. Its penetrating odor provides warning at dangerous concentrations. An odor threshold of 1 ppb has been reported. The United States OSHA Ceiling Limit is listed as 10 ppm.

ChEBI: Methanethiol is an alkanethiol. It has a role as a human metabolite and a Saccharomyces cerevisiae metabolite.

Methanethiol is prepared commercially by the reaction of methanol with hydrogen sulfide gas over an acidic solid catalyst, such as alumina. It can be prepared by the reaction of methyl iodide with thiourea.

Detection: 0.02 to 4 ppb. Aroma characteristics at 1.0%: vegetable oil, alliaceous, eggy, creamy with savory nuances

Taste characteristics at 1 ppm: sulfurous, alliaceous, creamy with a surface-ripened cheese top note and a clean, savory, meaty depth

By heating an aqueous solution of potassium methyl sulfate and KHS; from sodium methyl sulfate and potassium sulfhydrate; also from methanol and hydrogen sulfide in the presence of a catalyst

Occurs naturally in kohlrabi stems (Brassica oleracea var. gongylodes) and potato plants (Duke, 1992)

Biological. After 20 d, methyl mercaptan started to degrade in anaerobic sediments and sludges producing stoichiometric amounts of methane. Complete degradation was achieved after 20 d. Under anaerobic freshwater conditions, methyl mercaptan were degraded by methanogenic archea (van Leerdam et al., 2006).
Photolytic. Sunlight irradiation of a methyl mercaptan-nitrogen oxide mixture in an outdoor chamber yielded formaldehyde, sulfur dioxide, nitric acid, methyl nitrate, methanesulfonic acid, and an inorganic sulfate (Grosjean, 1984a).
Chemical/Physical. In the presence of nitric oxide, gaseous methyl mercaptan reacted with OH radicals forming methyl sulfenic acid and methyl thionitrite. The rate constant for this reaction is 2.1 x 10^-11 cm³/molecule?sec at 20 °C (MacLeod et al., 1984). Forms a crystalline hydrate with water (Patnaik, 1992).

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 this chemical you should be trainedon its proper handling and storage. Before entering confinedspace where this chemical may be present, check to makesure that an explosive concentration does not exist. Methylmercaptan must be stored to avoid contact with water,steam, or strong acids (such as hydrochloric, sulfuric, andnitric) because toxic flammable vapors will be released. Itshould not contact oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates) since violentreactions occur. Store in tightly closed containers in a cool,well-ventilated area away from heat or sparks. Sources ofignition, such as smoking and open flames, are prohibitedwhere methyl mercaptan is handled, used, or stored. Metalcontainers involving the transfer of 5 gallons or more ofmethyl mercaptan should be grounded and bonded. Drumsmust be equipped with self-closing valves, pressure vacuumbungs, and flame arresters. Use only nonsparking tools andequipment, especially when opening and closing containersof methyl mercaptan. Procedures for the handling, use, andstorage of cylinders should be in compliance with OSHA1910.101 and 1910.169, as with the recommendations ofthe Compressed Gas Association.

Methanethiol is a byproduct produced by the metabolism of asparagus. The ability to produce methanethiol in urine after eating asparagus was once thought to be a genetic trait. However recent research suggests that the peculiar odor is in fact produced by all humans after consuming asparagus, while the ability to detect it (methanethiol being one of many components in "asparagus pee") is in fact the genetic trait. The chemical components responsible for the change in the odor of urine show as soon as 15 minutes after eating asparagus.