Bromochloromethane

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

Bromochloromethane

Stereo, skeletal formula of bromochloromethane with all explicit hydrogens added
Spacefill model of bromochloromethane
Names
Preferred IUPAC name Bromo(chloro)methane
Other names Bromochloromethane Borothene[citation needed] Chloromethyl bromide Halon 1011[1] Methylene bromochloride Methyl chlorobromide[1] Monochloromonobromomethane Chlorobromomethane[1] Fluorocarbon 1011[1]
Identifiers
CAS Number	74-97-5 Y
3D model (JSmol)	Interactive image
Abbreviations	BCM[citation needed] CBM[1] UN 1887
Beilstein Reference	1730801
ChEBI	CHEBI:17194 Y
ChEMBL	ChEMBL346918 Y
ChemSpider	6093 Y
ECHA InfoCard	100.000.752
EC Number	200-826-3
Gmelin Reference	25577
KEGG	C02661 Y
MeSH	bromochloromethane
PubChem CID	6333
RTECS number	PA5250000
UNII	45WX84110G Y
UN number	1887
CompTox Dashboard (EPA)	DTXSID4021503
InChI InChI=1S/CH2BrCl/c2-1-3/h1H2 Y Key: JPOXNPPZZKNXOV-UHFFFAOYSA-N Y
SMILES ClCBr
Properties
Chemical formula	CH2BrCl
Molar mass	129.38 g·mol−1
Appearance	Colorless liquid
Odor	Chloroform-like[1]
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
Solubility in water	16.7 g·L−1
log P	1.55
Vapor pressure	15.60 kPa (at 20.0 °C)
Magnetic susceptibility (χ)	−86.88·10−6·cm3/mol
Refractive index (nD)	1.482
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H315, H318, H332, H335
Precautionary statements	P261, P280, P305+P351+P338
Flash point	Non-combustible[1]
Lethal dose or concentration (LD, LC):
LD50 (median dose)	5 g·mol−1 (oral, rat) 20 g·kg−1 (dermal, rabbit) 4300 mg·kg−1 (oral, mouse)[2]
LC50 (median concentration)	3000 ppm (mouse, 7 hr)[2]
LCLo (lowest published)	28,800 ppm (rat, 15 min) 29,000 ppm (rat, 15 min) 27,000 ppm (mouse, 15 min)[2]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 200 ppm (1050 mg/m3)[1]
REL (Recommended)	TWA 200 ppm (1050 mg/m3)[1]
IDLH (Immediate danger)	2000 ppm[1]
Related compounds
Related alkanes	Chloromethane Chloroiodomethane Dibromochloromethane
Related compounds	2-Chloroethanol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

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

Pyrene 1qt. pump-type chlorobromomethane (CB or CBM), 1960s, UK

Bromochloromethane's biodegradation is catalyzed by the hydrolase enzyme alkylhalidase:

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.^[3]