Dichloromethane 300295 224354166 2008-07-08T14:05:37Z Smokefoot 698909 rewrite uses, refocused on major uses vs pop culture, rm uncited fumigation use (there is none) {{Chembox new | ImageFileL1 = Methylene_Chloride.PNG | ImageSizeL1 = | ImageFileR1 = Dichloromethane-3D-vdW.png | ImageSizeR1 = 120px | IUPACName = Dichloromethane | OtherNames = Methylene chloride, methylene dichloride, Solmethine, Narkotil, Solaesthin, Di-clo, Freon 30, R-30, DCM, UN 1593, MDC | Section1 = {{Chembox Identifiers | CASNo = 75-09-2 | EINECS = 200-838-9 | PubChem = 6344 | SMILES = C(Cl)Cl | InChI = 1/CH2Cl2/c2-1-3/h1H2 | RTECS = PA8050000 | ChEBI = 15767 | KEGG = C02271 }} | Section2 = {{Chembox Properties | Formula = CH<sub>2</sub>Cl<sub>2</sub> | MolarMass = 84.93 g/mol | Appearance = Colorless liquid | Density = 1.3255 g/cm³, liquid | MeltingPt = -96.7 °C (175.7 K) | BoilingPt = 39 °C (312.8 K) | Solubility = 13 g/l at 20 °C | VaporPressure = 47 kPa at 20 ºC }} | Section3 = {{Chembox Hazards | MainHazards = Harmful ('''Xn'''), [[Carcinogen|Carc. Cat. 2B]] | NFPA-H = 2 | NFPA-F = 0 | NFPA-R = | NFPA-O = | RPhrases = {{R40}} | SPhrases = {{S23}}, {{S24/25}}, {{S36/37}} | FlashPt = None | Autoignition = }} }} [[Image:Dichloromethane near IR spectrum.png|thumb|right|250px|[[near ir spectroscopy|Near IR absorption spectrum]] of dichloromethane showing complicated overlapping [[overtones]] of mid IR absorption features.]] '''Dichloromethane''' ('''DCM''') or '''methylene chloride''' is the [[chemical compound]] with the [[chemical formula|formula]] CH<sub>2</sub>Cl<sub>2</sub>. It is a colorless, volatile liquid with a moderately sweet aroma. It is widely used as a [[solvent]], the general view being that it is one of the less harmful of the [[chlorocarbons]]. Although it is not [[miscible]] with water, it will dissolve in most organic solvents. Approximately 500,000 tons were produced in 1995.<ref name=Ullmann>M. Rossberg et al. “Chlorinated Hydrocarbons” in Ullmann’s Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. {{DOI|10.1002/14356007.a06 233.pub2}}</ref> Dichloromethane was first prepared in 1840 by the [[France|French]] [[chemist]] [[Henri Victor Regnault]], who isolated it from a mixture of [[chloromethane]] and [[chlorine]] that had been exposed to [[sunlight]]. ==Production== Industrially, dichloromethane is produced by [[chemical reaction|reacting]] either methyl chloride or methane with chlorine gas at 400&ndash;500&nbsp;°C. At these temperatures, both methane and methyl chloride undergo a series of reactions producing progressively more chlorinated products.<ref name=Ullmann/> :[[methane|CH<sub>4</sub>]] + [[chlorine|Cl<sub>2</sub>]] → [[methyl chloride|CH<sub>3</sub>Cl]] + [[hydrochloric acid|HCl]] :CH<sub>3</sub>Cl + Cl<sub>2</sub> → '''CH<sub>2</sub>Cl<sub>2</sub>''' + HCl :'''CH<sub>2</sub>Cl<sub>2</sub>''' + Cl<sub>2</sub> → [[chloroform|CHCl<sub>3</sub>]] + HCl :CHCl<sub>3</sub> + Cl<sub>2</sub> → [[carbon tetrachloride|CCl<sub>4</sub>]] + HCl The output of these processes is a mixture of methyl chloride, dichloromethane, chloroform, and carbon tetrachloride. These compounds are separated by [[distillation]]. ==Uses== Dichloromethane's volatility and ability to dissolve a wide range of organic compounds makes it an ideal solvent for many chemical processes. Concerns about its health effects have led to a search for alternatives in many of these applications.<ref name=Ullmann/> It is widely used as a [[paint stripper]] and a [[degreaser]]. In the [[food industry]], it is used to [[decaffeination|decaffeinate]] [[coffee]] and to prepare extracts of [[hops]] and other [[flavoring]]s.<ref>{{cite web | author = Office of Environmental Health Hazard Assessment | publisher = [[California Environmental Protection Agency]] | date = September 2000 | work = Public Health Goals for Chemicals in Drinking Water | title = Dichloromethane | url = http://www.oehha.ca.gov/water/phg/pdf/dcm.pdf}}</ref> Its volatility has led to its use as an [[aerosol spray#Propellant|aerosol spray propellant]] and as a [[blowing agent]] for [[polyurethane]] [[foam]]s. ====Speciallized uses==== Dichloromethane chemically welds certain plastics (for example, it is used to seal the casing of electric meters). Often sold under the brand name of "EMA Plastic Weld" it is also used extensively in the modelmaking industry for joining plastic components together - it is commonly referred to as "Di-clo." Its volatility is exploited in novelty items - [[drinking bird]]s, [[bubble light]]s, and [[jukebox]] displays. ==Toxicity== Dichloromethane is the least [[toxic]] of the simple chlorohydrocarbons, but it is not without its health risks as its high [[Volatility (chemistry)|volatility]] makes it an acute inhalation hazard. Dichloromethane is also metabolised by the body to [[carbon monoxide]] potentially leading to [[carbon monoxide poisoning]].<ref>{{cite journal | author = Fagin J, Bradley J, Williams D | title = Carbon monoxide poisoning secondary to inhaling methylene chloride | journal = Br Med J | volume = 281 | issue = 6253 | pages = 1461 | year = 1980 | pmid = 7437838}}</ref> Prolonged skin contact can result in the dichloromethane dissolving some of the fatty tissues in skin, resulting in skin irritation or chemical burns.<ref>{{cite journal | author = Wells G, Waldron H | title = Methylene chloride burns | journal = Br J Ind Med | volume = 41 | issue = 3 | pages = 420 | year = 1984 | pmid = 6743591}}</ref> It may be [[carcinogen]]ic, as it has been linked to [[cancer]] of the [[lungs]], [[liver]], and [[pancreas]] in laboratory animals.<ref name="USDHHS">{{cite web | author=USDHHS | title=Toxicological Profile for Methylene Chloride | url=http://www.atsdr.cdc.gov/toxprofiles/tp14.pdf | accessdate=2006-09-10}}</ref> Dichloromethane crosses the placenta. [[Fetal]] toxicity in women who are exposed to it during [[pregnancy]] however has not been proven.<ref>{{cite journal | author = Bell B, Franks P, Hildreth N, Melius J | title = Methylene chloride exposure and birthweight in Monroe County, New York | journal = Environ Res | volume = 55 | issue = 1 | pages = 31–9 | year = 1991 | pmid = 1855488 | doi = 10.1016/S0013-9351(05)80138-0}}</ref> In animal experiments it was fetotoxic at doses that were maternally toxic but no [[teratology|teratogenic]] effects were seen.<ref name="USDHHS"/> In many countries products containing dichloromethane must carry labels warning of its health risks. ==See also== * [[Haloalkane]] * [[Halomethane]] ==References== <div class="references-small"> <references /> </div> ==External links== * {{ICSC|0058|00}} * {{PGCH|0414}} * [http://www.npi.gov.au/database/substance-info/profiles/34.html National Pollutant Inventory - Dichloromethane Fact Sheet] * [http://ptcl.chem.ox.ac.uk/MSDS/DI/dichloromethane.html MSDS at Oxford University] * [http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s066dich.pdf Dichloromethane at National Toxicology Program] * [http://www.inchem.org/documents/iarc/vol71/004-dichloromethane.html IARC Summaries & Evaluations Vol. 71 (1999)] [[Category:Organochlorides]] [[Category:Halomethanes]] [[Category:Aerosol propellants]] [[Category:Hazardous air pollutants]] [[Category:Refrigerants]] [[Category:Halogenated solvents]] [[Category:IARC Group 2B carcinogens]] [[bs:Metilen hlorid]] [[cs:Dichlormethan]] [[da:Metylenklorid]] [[de:Dichlormethan]] [[es:Cloruro de metileno]] [[fr:Dichlorométhane]] [[it:Diclorometano]] [[lv:Metilēnhlorīds]] [[nl:Dichloormethaan]] [[ja:ジクロロメタン]] [[pl:Chlorek metylenu]] [[fi:Dikloorimetaani]] [[sv:Diklormetan]] [[vi:Diclomêtan]] [[zh:二氯甲烷]]