bromoform

The molecule adopts tetrahedral molecular geometry with C_3v symmetry.

Bromoform was discovered in 1832 by Löwig who distilled a mixture of bromal and potassium hydroxide, as analogous to preparation of chloroform from chloral.George M. Beringer, BROMOFORM (1891) in American Journal of Pharmacy vol 63

[https://archive.org/details/americanjour634211891phil/page/82/mode/1up p. 82]

Bromoform can be prepared by the haloform reaction using acetone and sodium hypobromite, by the electrolysis of potassium bromide in ethanol, or by treating chloroform with aluminium bromide.

Only small quantities of bromoform are currently produced industrially in the United States. In the past, it was used as a solvent, sedative and flame retardant, but now it is mainly used as a laboratory reagent, for example as an extraction solvent.

Bromoform's high density makes it useful for separation of minerals by density. When two samples are mixed with bromoform and then allowed to settle, the top layer will contain minerals less dense than bromoform, and the bottom layer will contain denser minerals. Slightly less dense minerals can be separated in the same way by mixing the bromoform with a small amount of a less dense and miscible solvent.

Bromoform is known as an inhibitor of methanogenesis and is a common component of seaweed. Following research by CSIRO and its spin-off FutureFeed, several companies are now growing seaweed, in particular from the genus Asparagopsis, to use as a feed additive for livestock to reduce methane emissions from ruminants.{{Cite web|title=Is seaweed the solution to agriculture's methane problem?|url=https://phyconomy.net/seaweed/applications/livestock-methane-reduction/|access-date=2020-11-13|website=Phyconomy|language=en-US}}

Bromoform is very commonly made by phytoplankton and seaweeds in the ocean. Bromoform is the most abundant halogenated compound in Asparagopsis.{{cite journal |last1=Ponte |first1=José M. S. |last2=Seca |first2=Ana M. L. |last3=Barreto |first3=Maria Carmo |title=Asparagopsis Genus: What We Really Know About Its Biological Activities and Chemical Composition |journal=Molecules |date=9 March 2022 |volume=27 |issue=6 |pages=1787 |doi=10.3390/molecules27061787|doi-access=free |pmid=35335151 |hdl=10400.3/6452 |hdl-access=free }}

Natural production of bromoform by phytoplankton and seaweeds in the ocean is thought to be its predominant source in the environment.Palmer C J and Reason C J (2009), Relationships of surface bromoform concentrations with mixed layer depth and salinity in the tropical oceans (2009), Global Biogeochemical Cycles, 23, GB2014. However, locally significant amounts of bromoform enter the environment formed as disinfection byproducts known as trihalomethanes when chlorine is added to drinking water to kill bacteria. It is somewhat soluble in water and readily evaporates into the air. Bromoform is the main trihalomethane produced in beachfront salt water swimming pools with concentrations as high as 1.2 ppm (parts per million). Concentrations in freshwater pools are 1000 times lower.Beech AJ et al (1980) Nitrates, Chlorates and Trihalomethanes in Swimming Pool Water. Am J Public Health, 70(1), 79-82 Occupational skin exposure limits are set at 0.5 ppm.[https://www.cdc.gov/niosh/npg/npgd0066.html CDC - NIOSH Pocket Guide to Chemical Hazards]

The substance may be hazardous to the environment, and special attention should be given to aquatic organisms. Its volatility and environmental persistence makes bromoform's release, either as liquid or vapor, strongly inadvisable.

Bromoform can be absorbed into the body by inhalation and through the skin. The substance is irritating to the respiratory tract, the eyes, and the skin, and may cause effects on the central nervous system and liver, resulting in impaired functions. Its LD₅₀ is 7.2 mmol/kg in mice, or 1.8 g/kg. The International Agency for Research on Cancer (IARC) concluded that bromoform is not classifiable as to human carcinogenicity. The EPA classified bromoform as a probable human carcinogen.IARC - https://monographs.iarc.fr/wp-content/uploads/2018/06/mono52-10.pdfATSDR - https://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=712&tid=128

• {{cite journal |author1=Betterton E. A. |author2=Arnold R. G. |author3=Kuhler R. J. |author4=Santo G. A. |date=June 2005 | title = Reductive dehalogenation of bromoform in aqueous solution | journal = Environ. Health Perspect. | volume = 103 |issue=Suppl 5 | pages = 89–91(3) | pmid = 8565919 | doi = 10.2307/3432487| pmc = 1519304 | publisher = Brogan & | jstor = 3432487 }} [http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1519304&blobtype=pdf PDF]
• U.S. Department of Health and Human Services. Toxicological Profile for Bromoform and Dibromochloromethane [https://web.archive.org/web/20080515132119/http://www.atsdr.cdc.gov/toxprofiles/tp130.html]. August 2005.

{{Reflist}}

• {{ICSC|0108|01}}
• {{PGCH|0066}}
• [http://www.chemicalland21.com/industrialchem/solalc/BROMOFORM.htm Entry at chemicalland21.com]
• [https://www.atsdr.cdc.gov/toxprofiles/tp130.pdf Toxicological profile for bromoform and dibromochlormethane]
• [https://web.archive.org/web/20060929185136/http://cira.ornl.gov/documents/BROMOFRM.pdf Toxicity summary]
• IARC Summaries & Evaluations: [http://www.inchem.org/documents/iarc/vol52/05-bromoform.html Vol. 62 (1991)], [http://www.inchem.org/documents/iarc/vol71/069-bromoform.html Vol. 71 (1999)]
• [http://chemsub.online.fr/name/bromoform.html ChemSub Online: Bromoform]

{{Halomethanes}}

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Category:Bromoalkanes

Category:Halomethanes

Category:Halogenated solvents

Category:Flame retardants

Category:IARC Group 3 carcinogens

Category:Halogen-containing natural products

Category:Bromine-containing natural products

Category:Sweet-smelling chemicals

Category:Tribromomethyl compounds