Bromomethane

Bromomethane

Names
IUPAC name Bromomethane
Identifiers
CAS Number	74-83-9 Y
3D model (Jmol)	Interactive image
Beilstein Reference	1209223
ChEBI	CHEBI:39275 Y
ChEMBL	ChEMBL48339 Y
ChemSpider	6083 Y
ECHA InfoCard	100.000.740
EC Number	200-813-2
Gmelin Reference	916
KEGG	C18447 Y
MeSH	methyl+bromide
PubChem	6323
RTECS number	PA4900000
InChI InChI=1S/CH3Br/c1-2/h1H3 Y Key: GZUXJHMPEANEGY-UHFFFAOYSA-N Y
SMILES CBr
Properties
Chemical formula	CH3Br
Molar mass	94.94 g·mol−1
Appearance	Colorless gas
Odor	Chloroform-like
Density	3.97 kg/m3 (gas, 0 °C) 1.72 g/mL (liquid, 4 °C)
Melting point	−93.66 °C (−136.59 °F; 179.49 K)
Boiling point	4.0 °C (39.2 °F; 277.1 K)
Solubility in water	17.5 g L−1
log P	1.3
Vapor pressure	190 kPa (at 20 °C (68 °F))
Magnetic susceptibility (χ)	-42.8·10−6 cm3/mol
Thermochemistry
Std enthalpy of formation (ΔfHo298)	−35.1–−33.5 kJ mol−1
Hazards
EU classification (DSD)	T N
R-phrases	R23/25, R36/37/38, R48/20, R50, R59, R68
S-phrases	(S1/2), S15, S27, S36/39, S38, S45, S59, S61
NFPA 704	1 3 0
Flash point	194 °C (381 °F; 467 K)
Autoignition temperature	535 °C (995 °F; 808 K)
Explosive limits	10%-16%
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	1200 ppm (mouse, 1 hr) 7316 ppm (rabbit, 30 min) 2833 ppm (rat, 1 hr) 302 ppm (rat, 8 hr) 390 ppm (mouse, 9 hr)
LCLo (lowest published)	300 ppm (guinea pig, 9 hr)
US health exposure limits (NIOSH):
PEL (Permissible)	C 20 ppm (80 mg/m3) [skin]
REL (Recommended)	Ca
IDLH (Immediate danger)	Ca [250 ppm]
Related compounds
Related alkanes	Bromoiodomethane Bromoethane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula CH₃Br. This colorless, odorless, nonflammable gas is produced both industrially and particularly biologically. It has a tetrahedral shape and it is a recognized ozone-depleting chemical. It was used extensively as a pesticide until being phased out by most countries in the early 2000s.

Bromomethane originates from both natural and human sources. In the ocean, marine organisms are estimated to produce 56,000 tonnes annually. It is also produced in small quantities by certain terrestrial plants, such as members of the Brassicaceae family. It is manufactured for agricultural and industrial use by reacting methanol with hydrogen bromide:

In 1999, an estimated 71,500 tonnes of synthetic methyl bromide were used annually worldwide. 97% of this estimate is used for fumigation purposes, whilst 3% is used for the manufacture of other products. Moreover, 75% of the consumption takes place in developed nations, led by the U.S. (43%) and Europe (24%). Asia and the Middle East combine to use 24% whereas Latin America and Africa have the lowest consumption rates at 9%.

Until its production and use was curtailed by the , bromomethane was widely applied as a soil sterilant, mainly for production of seed but also for some crops such as strawberries and almonds. In commercial large-scale monoculture seed production, unlike crop production, it is of vital importance to avoid contaminating the crop with off-type seed of the same species. Therefore, selective herbicides cannot be used. Whereas bromomethane is dangerous, it is considerably safer and more effective than some other soil sterilants. Its loss to the seed industry has resulted in changes to cultural practices, with increased reliance on soil steam sterilization, mechanical rogueing, and fallow seasons. Bromomethane was also used as a general-purpose fumigant to kill a variety of pests including rats and insects. Bromomethane has poor fungicidal properties. Bromomethane is the only fumigant allowed (heat treatment is only other option) under ISPM 15 regulations when exporting solid wood packaging (forklift pallets, crates, bracing) to ISPM 15 compliant countries. Bromomethane is used to prepare golf courses, particularly to control Bermuda grass. The Montreal Protocol stipulates that bromomethane use be phased out.