Misplaced Pages

Dichloromethane: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 08:32, 14 February 2011 editMichaeloqu (talk | contribs)129 editsm →Toxicity: add many WikiLinks← Previous edit Revision as of 08:35, 14 February 2011 edit undoMichaeloqu (talk | contribs)129 editsm →Toxicity: Missed an obvious wikilink (chlorohydrocarbons).Next edit →
Line 79: Line 79:


==Toxicity== ==Toxicity==
Dichloromethane is the least ] of the simple chlorohydrocarbons, but it is not without its health risks as its high ] makes it an acute inhalation hazard.<ref>{{cite journal|author = Rioux JP, Myers RA|title = Methylene chloride poisoning: a paradigmatic review|journal = J Emerg Med|volume = 6|issue = 3|pages = 227–238|year = 1988|pmid = 3049777|doi = 10.1016/0736-4679(88)90330-7}}</ref> Dichloromethane is also metabolized by the body to ] potentially leading to ].<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|doi = 10.1136/bmj.281.6253.1461|pmc = 1714874}}</ref> Acute exposure by inhalation has resulted in ]<ref>{{cite journal|author = Kobayashi A, Ando A, Tagami N, Kitagawa M, Kawai E, Akioka M, Arai E, Nakatani T, Nakano S, Matsui Y, Matsumura M|title = Severe optic neuropathy caused by dichloromethane inhalation|journal = J Ocul Pharmacol and Ther|volume = 24|issue = 6|pages = 607–612|year = 2008|pmid = 19049266|doi = 10.1089/jop.2007.0100}}</ref> and ].<ref>{{cite journal|author = Cordes DH, Brown WD, Quinn KM|title = Chemically induced hepatitis after inhaling organic solvents|journal = West J Med|volume = 148|issue = 4|pages = 458–460|year = 1988|pmid = 3388849|pmc = 1026148}}</ref> Prolonged skin contact can result in the dichloromethane dissolving some of the ] in skin, resulting in skin irritation or ].<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|pmc = 1009322}}</ref> Dichloromethane is the least ] of the simple ], but it is not without its health risks as its high ] makes it an acute inhalation hazard.<ref>{{cite journal|author = Rioux JP, Myers RA|title = Methylene chloride poisoning: a paradigmatic review|journal = J Emerg Med|volume = 6|issue = 3|pages = 227–238|year = 1988|pmid = 3049777|doi = 10.1016/0736-4679(88)90330-7}}</ref> Dichloromethane is also metabolized by the body to ] potentially leading to ].<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|doi = 10.1136/bmj.281.6253.1461|pmc = 1714874}}</ref> Acute exposure by inhalation has resulted in ]<ref>{{cite journal|author = Kobayashi A, Ando A, Tagami N, Kitagawa M, Kawai E, Akioka M, Arai E, Nakatani T, Nakano S, Matsui Y, Matsumura M|title = Severe optic neuropathy caused by dichloromethane inhalation|journal = J Ocul Pharmacol and Ther|volume = 24|issue = 6|pages = 607–612|year = 2008|pmid = 19049266|doi = 10.1089/jop.2007.0100}}</ref> and ].<ref>{{cite journal|author = Cordes DH, Brown WD, Quinn KM|title = Chemically induced hepatitis after inhaling organic solvents|journal = West J Med|volume = 148|issue = 4|pages = 458–460|year = 1988|pmid = 3388849|pmc = 1026148}}</ref> Prolonged skin contact can result in the dichloromethane dissolving some of the ] in skin, resulting in skin irritation or ].<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|pmc = 1009322}}</ref>


It may be ]ic, as it has been linked to ] of the ], ], and ] 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|format=PDF}}</ref> Dichloromethane crosses the ]. ] toxicity in women who are exposed to it during ], 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 ] at doses that were maternally toxic but no ] effects were seen.<ref name="USDHHS"/> It may be ]ic, as it has been linked to ] of the ], ], and ] 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|format=PDF}}</ref> Dichloromethane crosses the ]. ] toxicity in women who are exposed to it during ], 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 ] at doses that were maternally toxic but no ] effects were seen.<ref name="USDHHS"/>

Revision as of 08:35, 14 February 2011

Dichloromethane
Names
IUPAC name Dichloromethane
Other names Methylene chloride, methylene dichloride, Solmethine, Narkotil, Solaesthin, Di-clo, Freon 30, R-30, DCM, UN 1593, MDC
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.763 Edit this at Wikidata
EC Number
  • 200-838-9
KEGG
PubChem CID
RTECS number
  • PA8050000
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/CH2Cl2/c2-1-3/h1H2Key: YMWUJEATGCHHMB-UHFFFAOYSA-N
  • InChI=1/CH2Cl2/c2-1-3/h1H2Key: YMWUJEATGCHHMB-UHFFFAOYAG
SMILES
  • ClCCl
Properties
Chemical formula CH2Cl2
Molar mass 84.93 g/mol
Appearance Colorless liquid
Density 1.33 g/cm, liquid
Melting point −96.7 °C (−142.1 °F; 176.5 K)
Boiling point 39.6 °C (103.3 °F; 312.8 K)
Solubility in water 13 g/L at 20 °C
Vapor pressure 47 kPa at 20 °C
Hazards
Occupational safety and health (OHS/OSH):
Main hazards Harmful (Xn), Carc. Cat. 2B
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2 1 0
Flash point None
Supplementary data page
Dichloromethane (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound
Near IR absorption spectrum of dichloromethane showing complicated overlapping overtones of mid IR absorption features.

Dichloromethane (DCM or methylene chloride) is an organic compound with the formula CH2Cl2. This colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. More than 500,000 tons were produced in 1991. Although it is not miscible with water, it is miscible with many organic solvents. It was first prepared in 1840 by the French chemist Henri Victor Regnault, who isolated it from a mixture of chloromethane and chlorine that had been exposed to sunlight.

Production

Dichloromethane is produced by treating either methyl chloride or methane with chlorine gas at 400–500 °C. At these temperatures, both methane and methyl chloride undergo a series of reactions producing progressively more chlorinated products.

CH4 + Cl2 → CH3Cl + HCl
CH3Cl + Cl2 → CH2Cl2 + HCl
CH2Cl2 + Cl2 → CHCl3 + HCl
CHCl3 + Cl2 → CCl4 + 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 a useful solvent for many chemical processes. Concerns about its health effects have led to a search for alternatives in many of these applications.

It is widely used as a paint stripper and a degreaser. In the food industry, it has been used to decaffeinate coffee and tea as well as to prepare extracts of hops and other flavorings. Its volatility has led to its use as an aerosol spray propellant and as a blowing agent for polyurethane foams.

Specialized uses

Dichloromethane chemically welds certain plastics; for example, it is used to seal the casing of electric meters. Often sold as a main component of plastic welding adhesives, it is also used extensively by model building hobbyists for joining plastic components together — it is commonly referred to as "Di-clo."

It is also used in the garment printing industry for removal of heat-sealed garment transfers, and its volatility is exploited in novelty items — drinking birds, bubble lights, and jukebox displays.

Dichloromethane is used within the material testing field of civil engineering; specifically it is used during the testing of bituminous materials as a solvent to separate the binder from the aggregate of an asphalt or macadam to allow the testing of the materials.

Toxicity

Dichloromethane is the least toxic of the simple chlorohydrocarbons, but it is not without its health risks as its high volatility makes it an acute inhalation hazard. Dichloromethane is also metabolized by the body to carbon monoxide potentially leading to carbon monoxide poisoning. Acute exposure by inhalation has resulted in optic neuropathy and hepatitis. Prolonged skin contact can result in the dichloromethane dissolving some of the fatty tissues in skin, resulting in skin irritation or chemical burns.

It may be carcinogenic, as it has been linked to cancer of the lungs, liver, and pancreas in laboratory animals. Dichloromethane crosses the placenta. Fetal toxicity in women who are exposed to it during pregnancy, however, has not been proven. In animal experiments, it was fetotoxic at doses that were maternally toxic but no teratogenic effects were seen.

In many countries, products containing dichloromethane must carry labels warning of its health risks.

In the European Union, the European Parliament voted in 2009 to ban the use of dichloromethane in paint-strippers for consumers and many professionals. The ban took effect in December 2010.

References

  1. ^ M. Rossberg et al. “Chlorinated Hydrocarbons” in Ullmann’s Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. doi:10.1002/14356007.a06_233.pub2
  2. Office of Environmental Health Hazard Assessment (2000). "Dichloromethane" (PDF). Public Health Goals for Chemicals in Drinking Water. California Environmental Protection Agency. {{cite web}}: Unknown parameter |month= ignored (help)
  3. Shell Bitumen (2003-09-25). The Shell Bitumen Handbook. ISBN 9780727732200.
  4. Rioux JP, Myers RA (1988). "Methylene chloride poisoning: a paradigmatic review". J Emerg Med. 6 (3): 227–238. doi:10.1016/0736-4679(88)90330-7. PMID 3049777.
  5. Fagin J, Bradley J, Williams D (1980). "Carbon monoxide poisoning secondary to inhaling methylene chloride". Br Med J. 281 (6253): 1461. doi:10.1136/bmj.281.6253.1461. PMC 1714874. PMID 7437838.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. Kobayashi A, Ando A, Tagami N, Kitagawa M, Kawai E, Akioka M, Arai E, Nakatani T, Nakano S, Matsui Y, Matsumura M (2008). "Severe optic neuropathy caused by dichloromethane inhalation". J Ocul Pharmacol and Ther. 24 (6): 607–612. doi:10.1089/jop.2007.0100. PMID 19049266.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. Cordes DH, Brown WD, Quinn KM (1988). "Chemically induced hepatitis after inhaling organic solvents". West J Med. 148 (4): 458–460. PMC 1026148. PMID 3388849.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. Wells G, Waldron H (1984). "Methylene chloride burns". Br J Ind Med. 41 (3): 420. PMC 1009322. PMID 6743591.
  9. ^ USDHHS. "Toxicological Profile for Methylene Chloride" (PDF). Retrieved 2006-09-10.
  10. Bell B, Franks P, Hildreth N, Melius J (1991). "Methylene chloride exposure and birthweight in Monroe County, New York". Environ Res. 55 (1): 31–9. doi:10.1016/S0013-9351(05)80138-0. PMID 1855488.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. "Dichloromethane to be banned in paint-strippers". 2009-01-14. Retrieved 2009-01-15.

External links

Halomethanes
Unsubstituted
Monosubstituted
Disubstituted
Trisubstituted
Tetrasubstituted
* Chiral compound.
Categories: