Bromochlorodifluoromethane

Structural formula
General
Surname	Bromochlorodifluoromethane
other names	Halon 1211 Freon 12B1 R-12B1
Molecular formula	CBrClF 2
Brief description	non-flammable colorless gas with a sweet odor
External identifiers / databases
CAS number 353-59-3 EC number 206-537-9 ECHA InfoCard 100.005.944 PubChem 9625 Wikidata Q419723
properties
Molar mass	165.36 g mol −1
Physical state	gaseous
density	7.6775 kg m −3 (0 ° C, 1013 mbar) 7.1362 kg m −3 (15 ° C, 1 bar)
Melting point	−160.5 ° C
boiling point	−3.3 ° C
Vapor pressure	2.294 bar (20 ° C) 3.3 bar (30 ° C) 5.6 bar (50 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 420-280 P: ?
Global warming potential	2070 (based on 100 years)
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Bromochlorodifluoromethane , also known as Halon 1211 , belongs to the group of halogenated hydrocarbons (halons). This gas was mainly used as an extinguishing agent in extinguishing systems and fire extinguishers. In Germany, however, halon fire extinguishers are no longer permitted for most purposes, as halons have a harmful effect on the ozone layer.

Extraction and presentation

Bromochlorodifluoromethane can be produced in 91% yield by heating silver chlorodifluoroacetate with bromine at 180 to 260 ° C.

${\displaystyle {\ce {CClF2CO2Ag + Br2 -> CBrClF2 + CO2 + AgBr}}}$

The reaction of 1,3-dichloro-1,1,3,3-tetrafluoroacetone with bromine at 580–650 ° C and other reactions also give bromochlorodifluoromethane.

${\displaystyle {\ce {CHClF2 + Br2 + O2 -> CBrClF2 + CBr2F2 + CHClF2}}}$

properties

At temperatures typical for fires, bromine atoms are split off, which intervene anti-catalytically in the radical chain mechanism of a combustion process.

use

The compound was used as an extinguishing agent like other halons. However, only about 10% of the halons were released in fires. Most of the amount released resulted from exercises and tests. In accordance with the regulations of the Montreal Protocol , production in the industrialized countries was stopped on January 1, 1994. In developing countries, production was still possible until 2010. In the EU , handling is regulated by an EC regulation on ozone depletion. Here, import is only permitted for essential applications specified in the Montreal Protocol. In Germany, its manufacture and use as an extinguishing agent has been prohibited since January 1, 1992 in accordance with the Chemicals and Ozone Layer Ordinance.

See also

• Montreal Protocol
• Freon

Individual evidence

1. ↑ ^{a b c d e f g h i} Entry on bromochlorodifluoromethane in the GESTIS substance database of the IFA , accessed on May 19, 2018 (JavaScript required)
2. ↑ G. Myhre, D. Shindell et al .: Climate Change 2013: The Physical Science Basis . Working Group I contribution to the IPCC Fifth Assessment Report. Ed .: Intergovernmental Panel on Climate Change . 2013, Chapter 8: Anthropogenic and Natural Radiative Forcing, pp. 24-39; Table 8.SM.16 ( PDF ).
3. ↑ ^{a b c d e f g} Entry on Halons. In: Römpp Online . Georg Thieme Verlag, accessed on May 19, 2018.
4. ↑ Joachim Buddrus: Fundamentals of organic chemistry . Walter de Gruyter, 2011, ISBN 978-3-11-024640-7 , p. 253 ( limited preview in Google Book search).
5. ↑ Practical manual for operational fire protection . ISBN 978-3-8111-4471-2 ( limited preview in Google Book Search).
6. ^ ^{A b} Alan R. Katritzky, Thomas L. Gilchrist, Otto Meth-Cohn, Charles Wayne Rees: Comprehensive Organic Functional Group Transformations . Elsevier, 1995, ISBN 978-0-08-042704-1 , pp. 223 ( limited preview in Google Book search).