Methyl bromide

  • Bromomethane
  • Monobromomethane
Formula
CH3Br
Structure
Description
A colorless odorless gas at room temperature and pressure. Sweet odor.
Uses
Fungicide, herbicide, insecticide, nematicide.

Registry Numbers and Inventories.
CAS
74-83-9
EC (EINECS/ELINCS)
200-813-2
EC Index Number
602-002-00-2
EC Class
Mutagenic Category 3; Toxic; Harmful; Irritant; Dangerous for the Environment; Dangerous for the Environment
RTECS
PA4900000
RTECS class
Agricultural Chemical and Pesticide; Tumorigen; Mutagen; Reproductive Effector; Human Data
UN (DOT)
1062
Merck
12,6108
Beilstein/Gmelin
1209223
Beilstein Reference
4-01-00-00068
RCRA
U029
EPA OPP
53201
Swiss Giftliste 1
G-2062
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed

Properties.
Formula
CH3Br
Formula mass
94.94
Melting point, °C
-92.8
Boiling point, °C
4.5
Vapor pressure, mmHg
1400 (20 C)
Vapor density (air=1)
3.3
Odor Threshold Odor threshold 80 mg/m3
Critical temperature
194
Critical pressure
66.2
Density
1.737 g/cm3 (20 C)
Solubility in water
17 f/L (20 C)
Viscosity
0.397 cp @ 0C
Surface tension
24.5 g/s2
Refractive index
1.4432 (20 C)
Dipole moment
1.78 D
Dielectric constant
9.97 (0 C)
Partition coefficient, pKow
1.19
Heat of fusion
6.0 kJ/mol
Heat of vaporization
23.9 kJ/mol
Heat of combustion
-7733 kJ/mol

Hazards and Protection.
Storage
Protect from heat. Storage area should be dry, ventilated, and cool. Vents should have calcium chloride traps. Keep away from sunlight. Keep constantly below 40 C. Protect against physical damage.
A D1A D2B E
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Wear appropriate chemical protective clothing.
Respirators
At any detectable concentration - Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode. Any supplied-air respirator with full facepiece and operated in a pressure-demand or other positive-pressure mode in combination with a separate escape supply. Escape - Any air-purifying respirator with a full facepiece and an organic vapor canister. Any appropriate escape-type self-contained breathing apparatus. For Unknown Concentrations or Immediately Dangerous to Life or Health - Any supplied-air respirator with full facepiece and operated in a pressure-demand or other positive-pressure mode in combination with a separate escape supply. Any self-contained breathing apparatus with a full facepiece.
Small spills/leaks
Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors.
Stability
Stable. Forms aluminum alkyls in presence of aluminum. These are spontaneously ignitable.
Incompatibilities
Incompatible with metals, dimethyl sulfoxide, ethylene oxide If mixed with potassium hydroxide, sodium hydroxide and other strong bases Incompatible with zinc, magnesium, and alloys)[Chem.
Decomposition
Thermal decomposition products: oxides of carbon, acid halides, halides.

Fire.
Flash Point,°C
-44
Autoignition, °C
537
Upper exp. limit, %
16
Lower exp. limit, %
10
Fire fighting
Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Use foam, dry chemical, or carbon dioxide.
Fire potential
May burn but does not ignite readily.
Hazards
Vapors from liquefied gas are initially heavier than air and spread along ground. Containers may explode when heated. Ruptured cylinders may rocket.
Combustion products
Toxic gases and vapors (such as hydrogen bromide and carbon monoxide) may be released in a fire involving methyl bromide.
Health
3
 
Flammability
1
 
 
Reactivity
0
 

Health.
Exposure limit(s)
TLV: 5 ppm; 20 mg/m3 (ACGIH 1993-1993). OSHA PEL: C 20 ppm (80 mg/m3) skin NIOSH REL: Ca See Appendix A NIOSH IDLH: Potential occupational carcinogen 250 ppm
Poison_Class
1*
Exposure effects
Dizziness, headache, confusion, lethargy, seizures, and coma may be noted. Late sequelae include organic brain syndrome and extrapyramidal effects. Methyl bromide was not teratogenic in rats; severe neurotoxicity and mortality have been noted in rabbits. In rats, a transient decrease in plasma testosterone and testicular nonprotein sulfhydryl concentrations have been noted.
   Ingestion
Anorexia, nausea, vomiting, diarrhea and gastric hemorrhage have been reported.
   Inhalation
Symptons associated with short term exposure include nausea, vomiting, stomach pain, chest pain, difficulty breathing headache, symptoms of drunkenness, hyperactivity or drowsiness tingling sensation, visual disturbances, bluish skin color paralysis, convulsions, coma
   Skin
Methyl bromide and related agents are intense vesicants and can result in severe dermal burns.
   Eyes
Vapor exposure may result in upper respiratory tract irritation and a burning sensation of the nose and oropharynx. Transient blurred vision may occur. Corneal burns may occur. Possible permanent effects on hearing may also occur.

First aid
 
   Ingestion
This compound is a gas, therefore inhalation is the first route of exposure.
   Inhalation
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used.
   Skin
CAUTION: Exposure of skin to compressed gases may result in freezing of the skin. Treatment for frostbite may be necessary. Remove the victim from the source of contamination. IMMEDIATELY wash affected areas gently with COLD water (and soap, if necessary) while removing and isolating all contaminated clothing. Dry carefully with clean, soft towels. Call a hospital or poison control center IMMEDIATELY even if no symptoms (such as inflammation or irritation) develop. Be prepared to transport the victim to a hospital for treatment after washing the affected area if advised to do so by a physician.
   Eyes
First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

Transport.
UN number
1062
Response guide
Hazard class
2.3
PRTC
T
USCG CHRIS Code
MTB
 
36 Halogenated hydrocarbons
Std. Transport #
4920518
 
IMO Gas Code
N