Organochloride 1271805 221712508 2008-06-25T19:18:27Z SpBot 7016748 robot Modifying: [[de:Chlororganische Verbindungen]] {| class="toccolours" border="1" style="float: right; clear: right; margin: 0 0 1em 1em; border-collapse: collapse;" | align="center" bgcolor="#ffffff" | [[Image:Chloroform2.svg|100px]]<br><br>[[Image:Chloroform-3D-vdW.png|100px]] |- | Two representations<br>of the organochloride<br>[[chloroform]]. |- |} An '''organochloride''', '''organochlorine''', '''chlorocarbon''', or '''chlorinated solvent''' is an [[organic compound]] containing at least one [[covalent bond|covalently bonded]] [[chlorine]] atom. Their wide structural variety and divergent chemical properties lead to a broad range of uses. These chemicals are typically [[nonaqueous]] and are usually denser than [[water]] due to the presence of heavy chlorine atoms. ==Applications== The simplest form of organochlorides are chlorinated [[hydrocarbon]]s. These consist of simple [[hydrocarbon]]s in which one or more hydrogen atoms have been replaced with chlorine. Most low molecular weight chlorinated hydrocarbons such as [[chloroform]], [[dichloromethane]], [[dichloroethene]], and [[trichloroethane]] are useful as solvents. These solvents tend to be relatively [[chemical polarity|non-polar]]; they are therefore immiscible with water and effective in cleaning applications such as [[degreasing]] and [[dry cleaning]]. Many organochlorides have significant biological activities, and some can be toxic. For example, many powerful and effective [[insecticide]]s are organochlorides. Common examples include [[DDT]], [[dicofol]], [[heptachlor]], [[endosulfan]], [[chlordane]], [[mirex]], and [[pentachlorophenol]]. These can be either [[hydrophilic]] or [[hydrophobic]]. [[Polychlorinated biphenyl]]s (PCBs) were once commonly used electrical insulators and heat transfer agents. Their use has generally been phased out due to health concerns. Chlorinated [[alkene]]s are useful monomers used in the preparation of a variety of materials. For example, [[vinyl chloride]] is [[polymerization|polymerized]] to form the plastic [[polyvinyl chloride]] (PVC). ==Natural presence== Although halogenated organic compounds are relatively rare in nature compared to non-halogenated organic compounds, many organochlorides have been isolated from natural sources ranging from bacteria to humans.<ref name="Gribble">{{cite journal | title = Naturally Occurring Organohalogen Compounds | author = Gordon W. Gribble | journal = [[Acc. Chem. Res.]] | volume = 31 | issue = 3 | pages = 141–152 | year = 1998 | url = | doi = 10.1021/ar9701777}}</ref><ref name="Gribble99">{{cite journal | title = The diversity of naturally occurring organobromine compounds | author = Gordon W. Gribble | journal = [[Chemical Society Reviews]] | volume = 28 | issue = 5 | pages = 335| year = 1999 | url = | doi = 10.1039/a900201d}}</ref> There are examples of natural chlorine-containing compounds found in nearly every class of biomolecules including [[alkaloid]]s, [[terpene]]s, [[amino acid]]s, [[flavonoid]]s, [[steroid]]s, and [[fatty acid]]s.<ref name="Gribble"/><ref>Kjeld C. Engvild, "Chlorine-Containing Natural Compounds in Higher Plants", ''Phytochemistry'', Vol. 25, No. 4, 7891-791, 1986.</ref> Organochlorides, including [[dioxin]]s, are produced in the high temperature environment of forest fires, and dioxins have been found in the preserved ashes of lightning-ignited fires that predate synthetic dioxins.<ref>{{cite journal|author=Gribble, G.W.|year=1994|title=The Natural production of chlorinated compounds|journal=Environmental Science and Technology|volume=28|pages=310A–319A|doi=10.1021/es00056a001}}</ref> In addition, a variety of a simple chlorinated hydrocarbons including dichloromethane, chloroform, and [[carbon tetrachloride]] have been isolated from marine algae.<ref> Gribble, G. W. , "Naturally occurring organohalogen compounds - A comprehensive survey", ''Progress in the Chemistry of Organic Natural Products'' (1996), 68, 1-423.</ref> A majority of the [[chloromethane]] in the environement is produced naturally by biological decomposition, forest fires, and volcanoes.<ref>[http://www.atsdr.cdc.gov/toxprofiles/tp106-c1-b.pdf Public Health Statement - Chloromethane], [[Centers for Disease Control]], Agency for Toxic Substances and Disease Registry</ref> The natural organochloride [[epibatidine]], an alkaloid isolated from tree frogs, has potent [[analgesic]] effects and has stimulated research into new pain medication. ==Toxicity== Some types of organochlorides have significant toxicity to plants or animals, including humans. Dioxins, produced when organic matter is burned in the presence of chlorine, and some insecticides such as DDT are [[persistent organic pollutant]]s which pose dangers to the environment. For example, mid-twentieth century overuse of DDT, which accumulates in animals because the body is unable to break down or dispose of them, resulted in the severe decline of some bird populations. In addition, chlorinated solvents, when not handled and disposed of properly, present problems with groundwater pollution because they break down very slowly in the environment. Some highly reactive organochlorides such as [[phosgene]] have even been used as [[chemical warfare agent]]s. However, the presence of chlorine in an organic compound does not in any way ensure toxicity. Many organochlorides are safe enough for consumption in foods and medicines. For example, peas and broad beans contain the natural chlorinated plant hormone [[4-chloroindole-3-acetic acid]] (4-Cl-IAA);<ref>{{cite journal|author=Pless, Tanja; Boettger, Michael; Hedden, Peter; Graebe, Jan|title=Occurrence of 4-Cl-indoleacetic acid in broad beans and correlation of its levels with seed development|journal=Plant Physiology|year=1984|volume=74|issue=2|pages=320–3}}</ref><ref>{{cite journal|author=Magnus, Volker; Ozga, Jocelyn A.; Reinecke, Dennis M.; Pierson, Gerald L.; Larue, Thomas A.; Cohen, Jerry D.; Brenner, Mark L.|title=4-chloroindole-3-acetic and indole-3-acetic acids in Pisum sativum|journal=Phytochemistry|year=1997|volume=46|issue=4|pages=675–681|doi=10.1016/S0031-9422(97)00229-X}}</ref> and the sweetener [[sucralose]] (Splenda) is widely used in diet products. As of 2004, there were at least 165 organochlorides approved worldwide for use as pharmaceutical drugs, including the antihistamine [[loratadine]] (Claritin), the antidepressant [[sertraline]] (Zoloft), the anti-epileptic [[lamotrigine]] (Lamictal), and the inhalation anesthetic [[isoflurane]].<ref>MDL Drug Data Report (MDDR), Elsevier MDL, version 2004.2</ref> With her influential 1962 book ''[[Silent Spring]]'', [[Rachel Carson]] brought the issue of organochloride toxicity to public awareness. While many countries have phased out the use of some types of organochlorides (such as the US ban on DDT as a result of Carson's work), persistent organochlorides continue to be observed in humans and mammals across the planet at potentially dangerous levels many years after production and use have been limited. In [[Arctic]] areas, particularly high levels are found in [[marine mammal]]s. These chemicals especially impact mammals, and are even found in human breast milk. Males typically have far higher levels, as females reduce their concentration by transfer to their offspring through breast feeding.<ref>''Marine Mammal Medicine'', 2001, Dierauf & Gulland</ref> == See also == * [[Haloalkane]] * [[Organic halide]] == References == <references/> ==External links== *[http://www-ssrl.slac.stanford.edu/research/highlights_archive/organo-Cl_compounds.html "Formation of Chlorinated Hydrocarbons in Weathering Plant Material" article at SLAC website] *[http://www.chem.cmu.edu/groups/collins/about/members/colin_horwitz/hydro.html "The oxidation of chlorinated hydrocarbons" article from The Institute for Green Oxidation Chemistry at the Carnegie Mellon University website] [[Category:Organochlorides| ]] [[de:Chlororganische Verbindungen]] [[es:Organoclorado]] [[eo:Klorkarbonhidrogeno]] [[fr:Composé organochloré]] [[pt:Organoclorados]]