Bromomethane

Structural formula
	Wedge line formula to clarify the geometry
General
Surname	Bromomethane
other names	Methyl bromide; Bromomethyl; Monobromomethane; Methyl bromuer;
Molecular formula	CH 3 Br
Brief description	colorless and odorless gas, smelling sweetish chloroform-like in high concentrations
External identifiers / databases
EC number	200-813-2
ECHA InfoCard	100,000,740
PubChem	6323
Wikidata	Q421758
properties
Molar mass	94.94 g · mol -1
Physical state	gaseous
density	3.97 kg m −3 (0 ° C, 1013 hPa)
Melting point	−93.66 ° C
boiling point	4.0 ° C
Vapor pressure	189 k Pa (20 ° C)
solubility	moderate in water (17.5 g l −1 at 20 ° C); in the liquid state indefinitely soluble in ethanol , diethyl ether and chloroform ;
Dipole moment	1.822 D (6.08 * 10 -30 C * m )
safety instructions
H and P phrases	H: 280-301 + 331-315-319-335-341-373-400-420
	P: 261-273-281-301 + 310-305 + 351 + 338-311
MAK	DFG : 1 ml · m -3 or 3.9 mg · m -3 ; Switzerland: 1 ml · m -3 or ; 3.9 mg · m -3 ;
Toxicological data	214 mg kg −1 ( LD 50 , rat , oral )
Global warming potential	3 (based on 100 years)
Thermodynamic properties
ΔH f 0	−35.4 kJ / mol
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Bromomethane is a haloalkane and the simplest organic bromine compound . The compound is the monosubstituted representative of the series of bromomethanes with bromomethane, dibromomethane , tribromomethane and tetrabromomethane . It should not be confused with bromoethane (CH ₃ CH ₂ Br).

presentation

Industrial production takes place through the reaction of methanol with hydrogen bromide . In the laboratory , haloalkanes are often prepared by reacting alcohols with phosphorus halides such as PCl ₃ , PCl ₅ or PBr ₃ .

properties

Bromomethane is toxic and damages the central nervous system . It belongs to the contact and breath poisons . In the atmosphere, it has a very damaging effect on the ozone layer and increases the greenhouse effect. Therefore, its application was limited in the Montreal Protocol ; the practical implementation is handled very differently internationally. In bromomethane the halogen atom is negatively (δ–) polarized, the carbon atom opposite is polarized positively (δ +):

use

Due to its toxicity, bromomethane is mainly used for pest control , especially for fumigation of containers , for combating animal wood pests e.g. B. used in construction , as well as for disinfestation of soil.

In international trade, it is used to fumigate containers in order to prevent the introduction of animal pests that have nested in vegetable raw materials or in the packaging material. Compared to other methods, fumigation with bromomethane is considered to be one of the most effective. Since January 1, 2008, according to the 33rd amendment to the IMDG Code, labeling has been required for transport containers: "This container has been fumigated." The Federal Office for Consumer Protection and Food Safety (BVL) has banned the use of bromomethane as a fumigant in Germany with effect from September 1, 2006. In the rice-producing countries, methyl bromide continues to be used to control pests in rice , especially for transport and storage protection.

In 2004, according to the authorities there (California Department of Pesticide Regulation), 3500 tons of bromomethane were used as a pesticide on agricultural land in the US state of California alone.

Natural occurrence

Rapeseed fields

Considerable amounts of bromomethane are used as natural defense substances by marine organisms, seaweed , the cruciferous family (Brassicaceae), z. B. cabbage and rapeseed plants , as well as in the combustion of biomass, z. B. in forest fires, released. The amount of bromomethane escaping into the atmosphere is estimated at 10,000 to 50,000 tons annually; the emissions from rapeseed alone are given as 6,600 tons worldwide.

Web links

Commons : Bromomethane - Collection of images, videos and audio files

Gordon W. Gribble: Environmental toxins from the gift table of nature In: Spectrum of Science , June 2005, p. 38ff; (PDF 410 kB).
Karl Sander: Consumer risk from bromomethane in products? , Tüv Rheinland, March 2008 (PDF 670 kB).

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on bromomethane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ Claudia Synowietz (Ed.): Paperback for chemists and physicists . founded by Jean d'Ans, Ellen Lax. 4th edition. Volume II: Organic Compounds . Springer, Berlin 1983, ISBN 3-540-12263-X .
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-64.
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Permittivity (Dielectric Constant) of Gases, pp. 6-188.
↑ Entry on bromomethane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 74-83-9 or bromomethane ), accessed on May 14, 2020.
↑ 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 ).
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-20.
↑ Entry on bromomethane. In: Römpp Online . Georg Thieme Verlag, accessed on January 3, 2016.
^ D. Yoffe, R. From, SD Ukeles, MJ Dagani, HJ Barda, TJ Benya, DC Sanders: Bromine Compounds , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2013; doi : 10.1002 / 14356007.a04_405.pub2 .
↑ S. Hauptmann, J. Graefe, H. Remane: Textbook of Organic Chemistry , Deutscher Verlag für Grundstoffindustrie, Leipzig 1980, p. 275.
↑ ISPM 15 - Ban on bromomethane for fumigation of wooden packaging , October 2009.
↑ Lecture by Karl Sander, TÜV Rheinland Product and Environment GmbH, BfR Consumer Forum Product Safety Berlin 3. – 4. March 2008.
↑ Basmati rice: Every second defective magazine test of Stiftung Warentest 8/ 2010 , p 20-27.
↑ Gordon W. Gribble: Environmental toxins from the gift table of nature . In: Spectrum of Science , June 2005, p. 38ff; PDF .

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on bromomethane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[2] Claudia Synowietz (Ed.): Paperback for chemists and physicists . founded by Jean d'Ans, Ellen Lax. 4th edition. Volume II: Organic Compounds . Springer, Berlin 1983, ISBN 3-540-12263-X .

[CRC90_3_064-3] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-64.

[CRC90_6_188-4] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Permittivity (Dielectric Constant) of Gases, pp. 6-188.

[CLP_100.000.740-5] Entry on bromomethane in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[6] Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 74-83-9 or bromomethane ), accessed on May 14, 2020.

[7] 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 ).

[CRC90_5_20-8] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-20.

[Roempp-9] Entry on bromomethane. In: Römpp Online . Georg Thieme Verlag, accessed on January 3, 2016.

[Ullmann-10] D. Yoffe, R. From, SD Ukeles, MJ Dagani, HJ Barda, TJ Benya, DC Sanders: Bromine Compounds , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2013; doi : 10.1002 / 14356007.a04_405.pub2 .

[11] S. Hauptmann, J. Graefe, H. Remane: Textbook of Organic Chemistry , Deutscher Verlag für Grundstoffindustrie, Leipzig 1980, p. 275.

[12] ISPM 15 - Ban on bromomethane for fumigation of wooden packaging , October 2009.

[13] Lecture by Karl Sander, TÜV Rheinland Product and Environment GmbH, BfR Consumer Forum Product Safety Berlin 3. – 4. March 2008.

[Test-14] Basmati rice: Every second defective magazine test of Stiftung Warentest 8/ 2010 , p 20-27.

[15] Gordon W. Gribble: Environmental toxins from the gift table of nature . In: Spectrum of Science , June 2005, p. 38ff; PDF .