Bromochloromethane

Bromochloromethane
Names
Preferred IUPAC name
Bromochloromethane
Systematic IUPAC name
Bromo(chloro)methane[1]
Other names
  • Borothene
  • Chloromethyl bromide
  • Halon 1011[2]
  • Methylene bromochloride
  • Methyl chlorobromide[2]
  • Monochloromonobromomethane
  • Chlorobromomethane[2]
  • Fluorocarbon 1011[2]
Identifiers
3DMet B00481
Abbreviations
  • BCM
  • CBM[2]
  • UN 1887
1730801
74-97-5 Yes
ChEBI CHEBI:17194 Yes
ChEMBL ChEMBL346918 Yes
ChemSpider 6093 Yes
EC number 200-826-3
25577
Jmol-3D images Image
KEGG C02661 Yes
MeSH bromochloromethane
PubChem 6333
RTECS number PA5250000
UN number 1887
Properties
Molecular formula
 CH2BrCl
Molar mass 129.38 g·mol−1
Appearance Colorless liquid
Odor chloroform-like[2]
Density 1.991 g mL−1
Melting point −88.0 °C; −126.3 °F; 185.2 K
Boiling point 68 °C; 154 °F; 341 K
16.7 g L−1
log P 1.55
Vapor pressure 15.60 kPa (at 20.0 °C)
1.482
Hazards
GHS pictograms
GHS signal word DANGER
H315, H318, H332, H335
P261, P280, P305+351+338
EU classification Xi N
R-phrases R37/38, R41, R59
S-phrases S26, S39
Flash point noncombustible [2]
  • 5 g mol−1 (oral, rat)
  • 20 g kg−1 (dermal, rabbit)
US health exposure limits (NIOSH):
TWA 200 ppm (1050 mg/m3)[2]
TWA 200 ppm (1050 mg/m3)[2]
2000 ppm[2]
Related compounds
Related alkanes
Related compounds
 2-Chloroethanol
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Bromochloromethane or methylene bromochloride and Halon 1011 is a mixed halomethane. It is a heavy low-viscosity liquid with refractive index 1.4808.

It was invented for use in fire extinguishers by the Germans during the mid-40s, in an attempt to create a less-toxic, more effective alternative to carbon tetrachloride. This was a concern in aircraft and tanks as carbon tetrachloride produced highly toxic by-products when discharged onto a fire. CBM was slightly less toxic, and used up until the late 1960s, being officially banned by the NFPA for use in fire extinguishers in 1969, as safer and more effective agents such as halon 1211 and 1301 were developed. Due to its ozone depletion potential its production was banned from January 1, 2002, at the Eleventh Meeting of the Parties for the Montreal Protocol on Substances that Deplete the Ozone Layer.

A 1950s US CBM fire extinguisher.

It can be biologically decomposed using the hydrolase enzyme alkylhalidase by the reaction:

CH2BrCl (l) + H2O (l) → CH2O (l) + Br2 (l) + Cl2 (g)

In fiction

In the Enter the Matrix video game, the player can find a "Chloro-Bromo Methane Gun", which is used as a fire extinguisher. It fires a pressurized cartridge of CBM gas to put out fires. However, due to its chemical properties, firing a cartridge near people causes their lungs to fill with liquid, effectively drowning them.

References

  1. ↑ "bromochloromethane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification. Retrieved 24 June 2012.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 "NIOSH Pocket Guide to Chemical Hazards #0123". National Institute for Occupational Safety and Health (NIOSH).

External links