Trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane (CH4) are replaced by halogen atoms. A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by Mass. Methane is a Chemical compound with the molecular formula. It is the simplest Alkane, and the principal component of Natural gas. Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions Many trihalomethanes find uses in industry as solvents or refrigerants. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. A refrigerant is a compound used in a heat cycle that undergoes a Phase change from a Gas to a Liquid and back THMs are also environmental pollutants, and many are considered carcinogenic. The term carcinogen refers to any substance Radionuclide or radiation that is an agent directly involved in the promotion of Cancer or in the fatation of its propagation Trihalomethanes with all the same halogen atoms are called haloforms.
Contents |
Table of common trihalomethanes
| Molecular
formula |
IUPAC name | Common name | Other names | Molecule |
|---|---|---|---|---|
| CHF3 | trifluoromethane | fluoroform | Freon 23, R-23, HFC-23 |  |
| CHClF2 | chlorodifluoromethane | - | R-22, HCFC-22 |  |
| CHCl3 | trichloromethane | chloroform | methyl trichloride |  |
| CHBrCl2 | bromodichloromethane | - | - |  |
| CHBr2Cl | dibromochloromethane | - | - |  |
| CHBr3 | tribromomethane | bromoform | methyl tribromide |  |
| CHI3 | triiodomethane | iodoform | methyl triiodide |  |
Industrial uses
Refrigerants
Trifluoromethane and chlorodifluoromethane are both used as refrigerants in some applications. The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one The International Union of Pure and Applied Chemistry ( IUPAC) (aɪjuːpæk or ay-yoo-pec) is an international Non-governmental organization Fluoroform is the Chemical compound with the formula CHF3 It is one of the " haloforms " a class of compounds with the formula CHX3 Freon is DuPont 's trade name for its odorless colorless nonflammable and noncorrosive Chlorofluorocarbon and Hydrochlorofluorocarbon Refrigerants Chlorodifluoromethane or difluoromonochloromethane is a Hydrochlorofluorocarbon (HCFC Chloroform, also known as trichloromethane and methyl trichloride, is a Chemical compound with formula C[[Hydrogen H]] Cl Bromoform (CHBr3 is a pale yellowish liquid with a sweet odor similar to chloroform a Halomethane or haloform The term 'iodoform' was also used in World War II to refer to Group keys sent to agents in Europe by the Special Operations Executive this usage is unrelated to the chemical A refrigerant is a compound used in a heat cycle that undergoes a Phase change from a Gas to a Liquid and back Trihalomethanes released to the environment break down faster than chlorofluorocarbons (CFCs), thereby doing much less damage to the ozone layer (if they contain chlorine). The photochemical mechanisms that give rise to the ozone layer were worked out by the British physicist Sidney Chapman in 1930 Chlorodifluoromethane is a refrigerant HCFC, or hydrochlorofluorocarbon, while fluoroform is an HFC, or hydrofluorocarbon. The haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of Chemical compounds consisting of Alkanes such as Methane The haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of Chemical compounds consisting of Alkanes such as Methane Fluoroform is not ozone depleting.
Unfortunately, the breakdown of trihalomethane HCFCs does still result in the creation of some free chlorine radicals in the upper atmosphere and subsequent ozone destruction. Ideally, HCFCs will be phased out entirely in favour of entirely nonchlorinated refrigerants.
Solvents
Chloroform is a very common solvent used in organic chemistry. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. It is a significantly less polar solvent than water, well-suited to dissolving many organic compounds. In physics there are two kinds of dipoles ( Hellènic: di(s- = two- and pòla = pivot hinge An electric dipole is a An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon.
Although still toxic and potentially carcinogenic, chloroform is significantly less harmful than carbon tetrachloride. Carbon tetrachloride, also known by many other names (see Table is the Organic compound with the formula CCl4 Because of the health and regulatory issues associated with the use of carbon tetrachloride, in modern chemistry laboratories chloroform is used as a cheaper, cleaner alternative wherever possible.
Water pollutants
Trihalomethanes are formed as a by-product when chlorine or bromine are used to disinfect water for drinking (commonly known as disinfection by-products). Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Disinfection by-products (DBPs form when organic materials in source water react with chemical treatment agents at the drinking water treatment plant,. They result from the reaction of chlorine and/or bromine with organic matter in the water being treated. The THMs produced may have adverse health effects at high concentrations, and many governments set limits on the amount permissible in drinking water. In the United States, the EPA limits the total concentration of chloroform, bromoform, bromodichloromethane, and dibromochloromethane to 80 parts per billion in treated water. The United States of America —commonly referred to as the This number is called "total trihalomethanes" (TTHM).
Chloroform is also formed in swimming pools which are disinfected with chlorine or hypochlorite in the haloform reaction with organic substances (urine, sweat and skin particles). Chloroform, also known as trichloromethane and methyl trichloride, is a Chemical compound with formula C[[Hydrogen H]] Cl A swimming pool, swimming bath, wading pool, or simply a pool, is an artificially enclosed Body of water intended for Swimming or Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and The hypochlorite Ion is Cl[[Oxygen O]]− A hypochlorite compound is a Chemical compound containing this group with chlorine in Oxidation The haloform reaction is a chemical reaction where a haloform (CHX3 where X is a Halogen) is produced by the exhaustive Halogenation of a methyl Ketone Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. The skin is the outer covering of living tissue of an animal (or plant The reaction to phosgene under the influence of UV is also possible. Phosgene is the Chemical compound with the formula COCl2 This colorless gas gained infamy as a Chemical weapon during World War I Some of the THMs are quite volatile and may easily vaporize into the air. This makes it possible to inhale while showering, for example. The EPA, however, has determined that this exposure is minimal compared to that from consumption.
External links
- National Pollutant Inventory - Chloroform and trichloromethane
- How Ozone Technology
- Testing for Trihalomethanes
- EPA - Trihalomethanes in Drinking Water
Dictionary
trihalomethane
-noun
- (organic chemistry) Any of many halogenated derivatives of methane containing three (not always the same) halogen atoms; many are environmental pollutants
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