Bromochlorodifluoromethane

Last updated
Bromochlorodifluoromethane
Halon-1211-2D.png
Halon-1211-3D-vdW.png
Names
Preferred IUPAC name
Bromo(chloro)difluoromethane
Other names
Bromochlorodifluoromethane
Halon 1211
Halon 1211 BCF
BCF
Freon 12B1
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.005.944 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 206-537-9
PubChem CID
UNII
  • InChI=1S/CBrClF2/c2-1(3,4)5 Yes check.svgY
    Key: MEXUFEQDCXZEON-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/CBrClF2/c2-1(3,4)5
  • BrC(Cl)(F)F
Properties
CBrClF2
Molar mass 165.36 g/mol
AppearanceColorless gas
Density 7,1362 kg·m−3 (15 °C, 1 bar)
Melting point −159.5 °C (−255.1 °F; 113.6 K)
Boiling point −3.7 °C (25.3 °F; 269.4 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Bromochlorodifluoromethane (BCF), also referred to by the code numbers Halon 1211 and Freon 12B1, is a haloalkane with the chemical formula C F 2 Cl Br. It is used for fire suppression, especially for expensive equipment or items that could be damaged by the residue from other types of extinguishers. [1] It is stored as a liquid under pressure and vaporizes when discharged to suppress fires. [2] The use of halons, including Halon 1211, has decreased over time due to their adverse impact on the ozone layer. Alternatives have been developed to mitigate environmental concerns while still providing effective fire suppression capabilities.

Contents

Use as a fire extinguishing agent

Brominated haloalkanes were first used during World War II in fire extinguishers for aircraft and tanks. BCF was introduced as an effective gaseous fire suppression agent in the mid-1960s for use around highly valuable materials in places such as museums, mainframe rooms, and telecommunication switching centers. BCFs were also widely used in the maritime industries in the engine rooms of ships and also in the transport industry in vehicles. Its efficiency as a fire extinguishing agent has also led it to be the predominant choice of fire extinguishing agent on commercial aircraft and is typically found in cylindrical hand-held canisters. Its advantages as a fire extinguishing agent are that it has lower toxicity than chemicals such as carbon tetrachloride and that since it is a covalently bonded compound, it does not form conductive ions, therefore being usable on electrical equipment.

BCF is an excellent fire extinguishing agent, as it is a streaming agent with low toxicity, a low pressure, liquefied gas, and effective on all common types of fires, A, B, and C. [3] [4] It is mainly used in portable and wheeled extinguishers, and small spot protection units for aviation and marine engine applications, and was never widely used in fixed systems like Halon 1301 was.

BCF has fairly low toxicity. The lethal concentration for 15 minute exposure is about 32%. [5]

Synthesis

BCF is commercially synthesized in a two-step process from chloroform. Chloroform is fluorinated with hydrogen fluoride. The resulting chlorodifluoromethane is then reacted with elemental bromine at 400-600 °C, with reaction time limited to about 3 seconds. The overall yield is over 90%. [5]

Regulation

The production of BCF and similar chlorofluorocarbons has been banned in most countries since January 1, 1994 as part of the Montreal Protocol on ozone depleting substances. Halon 1211 is also a potent greenhouse gas with a 100-year global warming potential 2,070 times that of carbon dioxide and an atmospheric lifetime of 16.0 years. [6]

Recycling of Halon 1211 allows it to remain in use, [7] [8] although parts availability is limited to a few manufacturers and can be an issue. Halon 1211 is still widely used in the United States, despite its high cost, with the US military being the biggest user. Europe and Australia have banned its use for all but "critical applications" such as aviation, military, and police use. The manufacture of UL Listed halon 1211 extinguishers was supposed to cease on October, 2009. The future listing is still in discussion. Halotron I, the replacement extinguishing agent, requires a larger volume to get the same ratings as 1211.

See also

Related Research Articles

Halon may refer to:

<span class="mw-page-title-main">Chlorofluorocarbon</span> Class of organic compounds commonly used as refrigerants

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.

<span class="mw-page-title-main">Haloalkane</span> Group of chemical compounds derived from alkanes containing one or more halogens

The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.

<span class="mw-page-title-main">Carbon tetrachloride</span> Chemical compound

Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also recognised by the IUPAC) is a chemical compound with the chemical formula CCl4. It is a non-flammable, colourless liquid with a "sweet" chloroform-like smell that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants and as a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal.

Bromotrifluoromethane, commonly known as Halon 1301, R13B1, Halon 13B1 or BTM, is an organic halide with the chemical formula CBrF3. It is used for gaseous fire suppression as a far less toxic alternative to bromochloromethane.

Halomethane compounds are derivatives of methane with one or more of the hydrogen atoms replaced with halogen atoms. Halomethanes are both naturally occurring, especially in marine environments, and human-made, most notably as refrigerants, solvents, propellants, and fumigants. Many, including the chlorofluorocarbons, have attracted wide attention because they become active when exposed to ultraviolet light found at high altitudes and destroy the Earth's protective ozone layer.

<span class="mw-page-title-main">1,1,1,2,3,3,3-Heptafluoropropane</span> Chemical compound

1,1,1,2,3,3,3-Heptafluoropropane, also called heptafluoropropane, HFC-227ea, HFC-227 or FM-200, as well as apaflurane (INN), is a colourless, odourless gaseous halocarbon commonly used as a gaseous fire suppression agent.

Trifluoroiodomethane, also referred to as trifluoromethyl iodide is a halomethane with the formula CF3I. It is an experimental alternative to Halon 1301 (CBrF3) in unoccupied areas. It would be used as a gaseous fire suppression flooding agent for in-flight aircraft and electronic equipment fires.

<span class="mw-page-title-main">Fire suppression system</span> Systems to extinguish or control fires

Fire suppression systems are used to extinguish, control, or in some cases, entirely prevent fires from spreading or occurring. Fire suppression systems have an incredibly large variety of applications, and as such, there are many different types of suppression systems for different applications being used today. Of these, there are some that are still in use but are no longer legal to manufacture and produce.

A fire class is a system of categorizing fire with regard to the type of material and fuel for combustion. Class letters are often assigned to the different types of fire, but these differ between territories; there are separate standards for the United States, Europe, and Australia. The fire class is used to determine the types of extinguishing agents that can be used for that category.

<span class="mw-page-title-main">Bromochloromethane</span> Chemical compound

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

<span class="mw-page-title-main">Dibromodifluoromethane</span> Chemical compound

Dibromodifluoromethane is a mixed halomethane. It is a colorless non-flammable liquid.

PhostrEx is a fire suppression agent developed for use in aviation applications to replace halon, a greenhouse gas (GHG). It was developed by Eclipse Aviation for use aboard their Eclipse 500 very light jets as an engine fire suppression system, and is now being marketed to other aviation manufacturers.

<span class="mw-page-title-main">Fire extinguisher</span> Active fire protection device

A fire extinguisher is a handheld active fire protection device usually filled with a dry or wet chemical used to extinguish or control small fires, often in emergencies. It is not intended for use on an out-of-control fire, such as one which has reached the ceiling, endangers the user, or otherwise requires the equipment, personnel, resources or expertise of a fire brigade. Typically, a fire extinguisher consists of a hand-held cylindrical pressure vessel containing an agent that can be discharged to extinguish a fire. Fire extinguishers manufactured with non-cylindrical pressure vessels also exist but are less common.

<span class="mw-page-title-main">Automatic fire suppression</span> Automatic Emergency Systems

Automatic fire suppression systems control and extinguish fires without human intervention. Examples of automatic systems include fire sprinkler system, gaseous fire suppression, and condensed aerosol fire suppression. When fires are extinguished in the early stages loss of life is minimal since 93% of all fire-related deaths occur once the fire has progressed beyond the early stages.

<span class="mw-page-title-main">Pentafluoroethane</span> Chemical compound

Pentafluoroethane is a fluorocarbon with the formula CF3CHF2. Pentafluoroethane is currently used as a refrigerant (known as R-125) and also used as a fire suppression agent in fire suppression systems.

<span class="mw-page-title-main">Condensed aerosol fire suppression</span> Particle-based form of fire extinction

Condensed aerosol fire suppression is a particle-based method of fire extinction. It is similar to but not identical to dry chemical fire extinction methods, using an innovative pyrogenic, condensed aerosol fire suppressant. It is a highly effective fire suppression method for class A, B, C, E and F. Some aerosol-generating compounds produce a corrosive by-product that may damage electronic equipment, although later generations lower the effect.

<span class="mw-page-title-main">Clean agent FS 49 C2</span> Fire suppression agent

Clean agent FS 49 C2 is an environmentally engineered, human safe, fast acting Clean Agent fire extinguishing gas for gaseous fire suppression installed in a suited fire suppression system. The gas consists of tetrafluoroethane, pentafluoroethane and carbon dioxide.

<span class="mw-page-title-main">Bromofluorocarbon</span>

Bromofluorocarbons (BFCs) are molecules based on carbon, bromine, and fluorine. The most common use has traditionally been in fire suppression systems. The brand name "Halon" is frequently used interchangeably for BFCs. However, not all Halons are technically BFCs.

Halotron I is a fire extinguishing agent based on the raw material HCFC-123 (93%) mixed with tetrafluoromethane and argon as propellants.

References

  1. ↑ Dagani, M. J.; Barda, H. J.; Benya, T. J.; Sanders, D. C. "Bromine Compounds". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_405.
  2. ↑ "The Halon Advantage".
  3. ↑ Tryon, George H.; et al. (others) (1969). Fire Protection Handbook Thirteenth Edition 1969. Boston Massachusetts: National Fire Protection Association. LCCN   62-12655.
  4. ↑ Cote, Arthur E.; et al. (others) (1997). Fire Protection Handbook Eighteenth Edition. Quincy, Massachusetts: National Fire Protection Association. ISBN   0-87765-377-1.
  5. 1 2 Rozen, Shlomo; Hagooly, Aviv (2005). Bromochlorodifluoromethane. doi:10.1002/047084289X.rn00562. ISBN   0471936235.{{cite book}}: |work= ignored (help)
  6. ↑ Hodnebrog, Øivind; Åmås, Borgar; Fuglestvedt, Jan; Marston, George; Myhre, Gunnar; Nielsen, Claus Jørgen; Sandstad, Marit; Shine, Keith P.; Wallington, Tim J. (July 9, 2020). "Updated Global Warming Potentials and Radiative Efficiencies of Halocarbons and Other Weak Atmospheric Absorbers". Reviews of Geophysics. 58 (3).
  7. ↑ "Basic Facts about Halon". H3R Clean Agents. Archived from the original on 2012-01-04.
  8. ↑ "Recycling Halon". H3R Clean Agents. Archived from the original on 2020-08-09.
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