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Methyl bromide
Bromure de methyle
Molecular Formula
MDL Number
Molecular Weight
MOL File

Chemical Properties

colourless gas with a chloroform-like odour
Methyl bromide is a colorless gas with a chloroform-like odor at high concentrations. A liquid below 3.3C. Shipped as a liquefied compressed gas.
−94 °C(lit.)

4 °C(lit.)

3.3 g/mL at 25 °C(lit.)

vapor density 
3.3 (20 °C, vs air)

vapor pressure 
1420 mm Hg ( 20 °C)

refractive index 
-34 °C
storage temp. 
Stable. Incompatible with oxidizing agents, strong acids. This is an ozone-depleting chemical, and its use is restricted in many countries.
Water Solubility 
1.522 g/100 mL
CAS DataBase Reference
74-83-9(CAS DataBase Reference)
NIST Chemistry Reference
Methyl bromide(74-83-9)

Questions And Answer

Methyl bromide (CH3Br) is a halogenated aliphatic hydrocarbon. It is a colorless gas at room temperature and standard pressure.It is 3 times heavier than air. It is odorless except at high concentrations, when it has a burning taste and sweet, chloroformlike smell. Commercially, it is available as a liquefied gas. Some formulations also contain chloropicrin or amyl acetate as a warning agent.
Structure of methyl bromide
Methyl bromide has been used to treat dry packaged foods in mills and warehouses as well as used as a soil fumigant to control nematodes and fungi.
Methyl bromide was used as an anesthetic in the early 1900s, but fatalities halted this practice. Today, methyl bromide is used widely as a fumigant for all types of dry food stuffs, in grain elevators, mills, ships, warehouses, green-houses, and food-processing facilities for the control of nematodes, fungi, and weeds. It is also used as an insecticide, fire extinguisher, and refrigerant, although its domestic use was banned in 1987. Methyl bromide is also used as a methylating chemical in manufacturing and as a low-boiling solvent for extracting oils from nuts, seeds, and flowers. It is termed a structural or commodity fumigant, which is a class term from the Environmental Protection Agency.
Historically, poisonings involving the general public were mainly associated with the methyl bromide used in fire extinguishers. Other poisoning involved unauthorized entry into buildings being fumigated with methyl bromide.
Methyl bromide has a threshold limit value–time weighted average (TLV-TWA) of 5 ppm and the IDLH concentration is 2,000 ppm. The Occupational Safety and Health Administration (OSHA) permissible exposure limit is 20 ppm.
Health Hazard
Methyl bromide is very irritating to the lower respiratory tract. It is thought that the parent compound is responsible for the toxicity of the methyl bromide, with the mechanism of toxicity possibly having to do with its ability to methylate sulfhydryl enzymes. Exposure to high concentrations of methyl bromide can lead to pulmonary edema or hemorrhage, and typically of delayed onset (several hours after exposure). Symptoms of acute intoxication include those consistent with central nervous system depression such as headache, dizziness, throat irritation, nausea, cough visual disturbances, vomiting, and ataxia. Exposures to very high concentrations can lead to unconsciousness. In cases of exposure to fatal levels of methyl bromide, death typically occurs within 4–6h to 1–2 days postexposure, with the cause of death being respiratory or cardiovascular failure resulting from pulmonary edema. Dermal exposure to liquid methyl bromide can cause skin damage in the form of burning, itching, and blistering. Treatment of methyl bromide poisoning is symptomatic and also includes removal of contaminated clothing. The USEPA Office of Pesticide Programs has classified methyl bromide as Not Likely to be Carcinogenic in Humans.
The mode of action of methyl bromide is still not understood. Several mechanisms of toxicity are postulated, including the direct cytotoxic effect of the intact methyl bromide molecule or toxicity due to one of its metabolites.
Methyl bromide is a potent alkylating agent with high affinity for sulfhydryl and amino groups. It reacts in vitro with a number of sulfhydrylcontaining enzymes and causes irreversible inhibition of microsomal metabolism. It binds to amine groups in amino acids, interfering with protein synthesis and function. Also it may methylate many other cellular components such as GSH, proteins, DNA, and RNA.The methanethiol and formaldehyde metabolites may have a role in neurologic and visual changes. The bromide ion concentrations are insufficient to explain methyl bromide toxicity.

Hazard Information

Chemical Properties
Bromomethane is a highly toxic compound and the US EPA has grouped it as a toxicity class I chemical substance. Bromomethane is a colorless gas or volatile liquid that is usually odorless, but has a sweet, chloroform-like odor at high concentrations and is easily miscible with ethanol, ether, aromatic carbon disulfi de, and ketones. It decomposes on heating and, on burning, produces highly toxic and irritating fumes, bromides, carbon oxybromide, carbon dioxide, and monoxide. It is also used as a general purpose fumigant to kill a variety of pests, including rats and insects, and a gas soil fumigant against insects, termites, rodents, weeds, nematodes, and soil-borne diseases. Bromomethane is used for post-harvest fumigation of foods, such as cereals, spices, dried fruits, nuts, fresh fruits, and vegetables. Although bromomethane is on the list of banned ozone-depleting chemical substances of the Montreal Protocol, in 2005 and 2006 it was granted a critical use exemption (under the Montreal Protocol). Bromomethane is an RUP and should be purchased and used only by certifi ed applicators.
Chemical Properties
Methyl bromide (Bromomethane) is an odorless, sweetish, colorless gas that has been used as a soil fumigant and structural fumigant to control pests across a wide range of agricultural sectors. Methyl bromide is soluble in ethanol, benzene, carbon disulfi de, and sparingly in water. During the 1920s, methyl bromide was used as an industrial fi re extinguishing agent. The current uses of methyl bromide include the fumigation of homes and other structures for the control of termites and other pests. Because methyl bromide depletes the stratospheric ozone layer, the amount produced and imported in the United States was reduced incrementally until it was phased out on January 1, 2005, pursuant to our obligations under the Montreal Protocol on Substances that Deplete the Ozone Layer (Protocol) and the Clean Air Act (CAA).
General Description
Colorless highly toxic volatile liquid or a gas. Boiling point 3.56°C (38.41°F). Usually odorless, but has a sweetish chloroform-like odor at high concentrations. Used as an insecticide, a rodenticide, a fumigant, a nematocide, a chemical intermediate and as a fire extinguishing agent.
Reactivity Profile
METHYL BROMIDE(74-83-9) is incompatible with metals, dimethyl sulfoxide, ethylene oxide. [Lewis]. Can give flammable products if mixed with potassium hydroxide, sodium hydroxide and other strong bases. METHYL BROMIDE(74-83-9) in a steel tank reacted with an aluminum tube (part of the level gauge) producing methyl aluminum bromide. When the latter was subsequently exposed to air, enough heat was produced to ignite the METHYL BROMIDE(74-83-9)-compressed air mixture above the liquid layer. The ensuing explosion shattered the tank (also incompatible with zinc, magnesium, and alloys)[Chem. Eng. Pro. 58(8). 1962]. A reaction between METHYL BROMIDE(74-83-9) and dimethyl sulfoxide resulted in an explosion that shattered the apparatus [NFPA 491M. 1991].
Air & Water Reactions
Nonflammable over a wide range of concentrations in air. Slightly soluble in water (about 1.75 g/100 mL of solution at 20° C). Reacts slowly with water to give methyl alcohol and hydrobromic acid. [K-O Vol. 4].
Toxic by ingestion, inhalation, and skin absorption; strong irritant to skin and upper respiratory tract. Questionable carcinogen.
Health Hazard
Exposures to bromomethane in high concentrations cause headaches, burns the skin, itching, redness, blisters, dizziness, nausea, vomiting, and weakness. Prolonged periods of exposure cause mental excitement, muscle tremors, seizures, bronchitis and pneumonia, numbness, tremor, speech defects, damage to the nervous system, lung, nasal mucosa, kidney, convulsions, respiratory paralysis, coma, and death. Human exposure to bromomethane is predominantly occupational, during manufacture and occupational fi eld fumigation.
Health Hazard
Exposures to methyl bromide by inhalation cause injury to the brain, nerves, lungs, and throat. At high doses, breathing methyl bromide causes injury to the kidneys and liver. The symptoms of methyl bromide toxicity and poisoning include, but are not limited to, dizziness, headache, abdominal pain, vomiting, weakness, hallucinations, loss of speech, incoordination, labored breathing, and convulsions. Contact with the skin and eyes can lead to irritation and burns. After serious exposures to methyl bromide, occupational workers suffer with lung and/or nervous system-related problems and permanent brain/ nerve damage. Laboratory study with species of animals indicated that bromomethane does not cause birth defects and does not interfere with normal reproduction except at high exposure levels
Health Hazard
Methyl bromide is a dangerous cumulative poison with delayed symptoms of central nervous system intoxication that may appear as long as several months after exposure. High concentrations can produce fatal pulmonary edema. Chronic exposure can cause central nervous system depression and kidney injury. It may cause severe and permanent brain damage. Severe neurological signs may appear when there is a sudden exposure to high concentrations following continuous slight exposure. Methyl bromide has practically no odor or irritating effects and therefore no warning, even at hazardous concentrations.
Potential Exposure
Methyl bromide is used in fire extinguishers; as a fumigant in pest control and as a methylation agent in industry as an insect fumigant for soil, grain, warehouses, mills, ships, etc. It is also used as a chemical intermediate and a methylating agent; a refrigerant; a herbicide; a low-boiling solvent in aniline dye manufacture; for degreasing wool; for extracting oils from nuts, seeds, and flowers; and in ionization chambers. It is used as an intermediate in the manufacture of many drugs.
Fire Hazard
When heated to decomposition, METHYL BROMIDE emits toxic fumes of bromides. Hazardous polymerization may not occur.
First aid
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
UN1062 Methyl bromide, Hazard Class: 2.3; Labels: 2.3-Poisonous 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
Attacks aluminum to form spontaneously flammable aluminum trimethyl. Incompatible with strong oxidizers, aluminum, dimethylsulfoxide, ethylene oxide; water. Attacks zinc, magnesium, alkali metals and their alloys. Attacks some rubbers and coatings. Methyl bromide reacts with water to generate hydrobromic acid and methanol but the reaction is so slow that it can be disregarded for most practical purposes.
Waste Disposal
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. A poisonous gas. Must be handled by experts: the recommended disposal procedure is to spray the gas into the fire box of an incinerator equipped with an afterburner and scrubber (alkali).

Safety Data

Hazard Codes 
Risk Statements 
R23/25:Toxic by inhalation and if swallowed .
R36/37/38:Irritating to eyes, respiratory system and skin .
R48/20:Harmful: danger of serious damage to health by prolonged exposure through inhalation .
R50:Very Toxic to aquatic organisms.
R59:Dangerous for the ozone layer.
R68:Possible risk of irreversible effects.
R38:Irritating to the skin.
R20/22:Harmful by inhalation and if swallowed .
R11:Highly Flammable.
R67:Vapors may cause drowsiness and dizziness.
R66:Repeated exposure may cause skin dryness or cracking.
R19:May form explosive peroxides.
R12:Extremely Flammable.
Safety Statements 
S15:Keep away from heat .
S27:Take off immediately all contaminated clothing .
S36/39:Wear suitable protective clothing and eye/face protection .
S38:In case of insufficient ventilation, wear suitable respiratory equipment .
S45:In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) .
S59:Refer to manufacturer/supplier for information on recovery/recycling .
S61:Avoid release to the environment. Refer to special instructions safety data sheet .
S36/37:Wear suitable protective clothing and gloves .
S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice .
S24:Avoid contact with skin .
S16:Keep away from sources of ignition-No smoking .
S7:Keep container tightly closed .
UN 1062 2.3

WGK Germany 


HS Code 
Handling and storage of bromomethane cylinders must meet the specifi cations laid down by the regulatory authorities. The cylinders must undergo the required and periodic tests
Methyl bromide (Bromomethane) should be kept stored in sealed containers to keep it from evaporating.
Occupational workers should use appropriate ventilation during production and formulation of bromomethane at the workplace. The ventilation must be suffi cient to maintain the levels of bromomethane below the prescribed OEL. Local exhaust ventilation at source or vapor extraction may also be used. Gloves or rubber boots should not be used as the liquid or concentrated vapor may be trapped inside them
Safety Profile
Suspected carcinogen with experimental carcinogenic data. A human poison by inhalation. Human systemic effects by inhalation: anorexia, nausea or vomiting. Corrosive to skin; can produce severe burns. Human mutation data reported. A powerful fumigant gas that is one of the most toxic of the common organic hahdes. It is hemotoxic and narcotic with delayed action. The effects are cumulative and damaging to nervous system, hdneys, and lung. Central nervous system effects include blurred vision, mental confusion, numbness, tremors, and speech defects. Methyl bromide is reported to be eight times more toxic on inhalation than ethyl bromide. Moreover, because of its greater volatility, it is a much more frequent cause of poisoning. Death following acute poisoning is usually caused by its irritant effect on the lungs. In chronic poisoning, death is due to injury to the central nervous system. Fatal poisoning has always resulted from exposure to relatively high concentrations of methyl bromide vapors (from 8600 to 60,000 ppm). Nonfatal poisoning has resulted from exposure to concentrations as low as 100-500 ppm. In addtion to injury to the lung and central nervous system, the kidneys may be damaged, with development of albuminuria and, in fatal cases, cloudy swelhng and/or tubular degeneration. The liver may be enlarged. There are no characteristic blood changes. Mixtures of 10-1 5 percent with air may be ignited with difficulty. Moderately explosive when exposed to sparks or flame. Forms explosive mixtures with air within narrow limits at atmospheric pressure, with wider limits at higher pressure. The explosive sensitivity of mixtures with air may be increased by the presence of aluminum, magnesium, zinc, or their alloys. Incompatible with metals, dunethyl sulfoxide, ethylene oxide. To fight fire, use foam, water, CO2, dry chemical. When heated to decomposition it emits toxic fumes of Br-. See also BROMIDES
Hazardous Substances Data
74-83-9(Hazardous Substances Data)

Raw materials And Preparation Products

Raw materials
Sodium hydroxide-->Methanol-->Bromine-->Sulfur-->Tetrachlorvinphos-->GLOBULINS, CAT GAMMA
Preparation Products
9-VINYLANTHRACENE-->3-Hydroxy-2-methyl-4H-pyran-4-one-->DMDS-->3-ISOPROPENYL-ALPHA,ALPHA-DIMETHYLBENZYL ISOCYANATE-->4-Methoxy-N,6-dimethyl-1,3,5-triazin-2-amine-->1-[2-(4-CHLOROPHENYL)-1-(1-HYDROXY-1-PHENYLETHYL)ETHYL]-1,2,4-TRIAZOLE-->Metribuzin-->(Aminomethyl)phosphonic acid-->4,4-DIMETHYL-2-PENTANONE-->Antipyrine-->3,3-Diphenyltetrahydrofuran-2-ylidene(dimethyl)ammonium bromide-->1-Methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole-->METHYLMAGNESIUM BROMIDE-->Ozagrel-->Diethyl(acetylamino)((2-((bis(2-hydroxyethyl)amino)methyl)-5-nitrophenyl)methyl)propanedioate-->Pancuronium bromide -->21-Iodo-16-methylpregna-1,4,9(11)-trien-17-ol-3,20-dione-->Camostat-->3-BENZOYLPHENYLACETIC ACID-->Dexamethasone-17-acetate-->BRETYLIUM TOSYLATE-->17,21-dihydroxy-16beta-methylpregna-1,4,9(11)-triene-3,20-dione 21-acetate-->16-Methylpregna-1,4,9(11)-trien-17-ol-3,20-dione-->2-Methyl-2-adamantanol-->Tiotropium bromide-->1-(2-CHLORO-PYRIDIN-4-YL)-ETHANONE-->Propantheline bromide -->9beta,11beta-epoxy-17,21-dihydroxy-16beta-methylpregna-1,4-diene-3,20-dione 21-acetate-->9-Bromo-11,17,21-trihydroxy-16-methylpregna-1,4-diene-3,20-dione-21-acetate-->methyl triC^{9~11^} alkyl ammonium chloride-->Neostigmine bromide -->Methyltriphenylphosphonium bromide-->Octadecy trimethyl ammonium bromide-->16-Methylpregna-4,9(11)-dien-17-ol-3,20-dione-->Vecuronium bromide

Material Safety Data Sheet(MSDS)

Spectrum Detail

Well-known Reagent Company Product Information

Sigma Aldrich