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

refractive index In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

1.4808. Halon 1011 was invented for use in fire extinguishers in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

during the mid-1940s, 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. It 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 Bromochlorodifluoromethane (BCF), also referred to by the code numbers Halon 1211 and Freon 12B1, is a haloalkane with the chemical formula C F2 Cl Br. It is used for fire suppression, especially for expensive equipment or items that could be d ...

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''. Aircraft A-20 CBM

Bromochloromethane's biodegradation is catalyzed by the

hydrolase Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are este ...

enzyme

alkylhalidase In enzymology, an alkylhalidase () is an enzyme that catalyzes the chemical reaction :bromochloromethane + H2O \rightleftharpoons formaldehyde + bromide + chloride Thus, the two substrates of this enzyme are bromochloromethane and H2O, whereas ...

: :CH₂BrCl + H₂O → CH₂O + HBr + HCl

Preparation

Bromochloromethane is prepared commercially from dichloromethane: :6 CH₂Cl₂ + 3 Br₂ + 2 Al → 6 CH₂BrCl + 2 AlCl₃ :CH₂Cl₂ + HBr → CH₂BrCl + HCl The latter route requires aluminium trichloride as a catalyst. The bromochloromethane is often used as a precursor to

methylene bromide Preparation Dibromomethane is prepared commercially from dichloromethane via bromochloromethane: :6 CH2Cl2 + 3 Br2 + 2 Al → 6 CH2BrCl + 2 AlCl3 :CH2Cl2 + HBr → CH2BrCl + HCl The latter route requires aluminium trichloride as a catal ...

References

External links

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Notice with Respect to n-Propyl Bromide and Bromochloromethane

Data sheet at albemarle.com
{{halomethanes Halomethanes Fire suppression agents Ozone depletion Organobromides Organochlorides