A request that this article title be changed to 1,2-Dichloroethylene is under discussion. Please do not move this article until the discussion is closed. |
1,2-Dichloroethene, commonly called 1,2-dichloroethylene or 1,2-DCE, is the name for a pair of organochlorine compounds with the molecular formula C2H2Cl2. They are both colorless liquids with a sweet odor. It can exist as either of two geometric isomers, cis-1,2-dichloroethene or trans-1,2-dichloroethene, but is often used as a mixture of the two. They have modest solubility in water. These compounds have some applications as a degreasing solvent.[1] In contrast to most cis-trans compounds, the Z isomer (cis) is more stable than the E isomer (trans) by 0.4 kcal/mol.[4]
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Names | |||
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Preferred IUPAC name
1,2-Dichloroethene | |||
Other names
1,2-Dichloroethylene
1,2-DCE Acetylene dichloride sym-Dichloroethylene | |||
Identifiers | |||
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3D model (JSmol)
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ChEBI |
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ChemSpider |
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ECHA InfoCard | 100.007.956 | ||
EC Number |
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KEGG |
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PubChem CID
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UNII |
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CompTox Dashboard (EPA)
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Properties | |||
C2H2Cl2 | |||
Molar mass | 96.95 g/mol | ||
Appearance | colorless liquid | ||
Odor | sweet[1] | ||
Density | Z: 1.28 g/cm3 E: 1.26 g/cm3 | ||
Melting point | Z: −81.47 °C E: −49.44 °C | ||
Boiling point | Z: 60.2 °C E: 48.5 °C | ||
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Z: 1.9 D E: 0 D | |||
Hazards | |||
Flash point | 2–4 °C; 36–39 °F; 275–277 K | ||
Explosive limits | 5.6–12.8%[2] | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
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770 mg/kg (oral, rat) 1275 mg/kg (oral, rat, trans-isomer)[3] | ||
LC50 (median concentration)
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21,273 ppm (mouse, 6 hr, trans-isomer)[3] | ||
LCLo (lowest published)
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16,000 ppm (rat, 6 hr, cis-isomer)[3] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible)
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TWA 200 ppm (790 mg/m3)[2] | ||
REL (Recommended)
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TWA 200 ppm (790 mg/m3)[2] | ||
IDLH (Immediate danger)
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1000 ppm[2] | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
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cis-DCE, the Z isomer, is obtainable by the controlled chlorination of acetylene:
Industrially both isomers arise as byproducts of the production of vinyl chloride, which is produced on a vast scale. Unlike 1,1-dichloroethylene, the 1,2-dichloroethylene isomers do not polymerize.[1]
trans-1,2-DCE has applications including electronics cleaning, precision cleaning, and certain metal cleaning applications.[5]
Both isomers participate in Kumada coupling reactions. trans-1,2-Dichloroethylene participates in cycloaddition reactions.[6]
These compounds have "moderate oral toxicity to rats".[1]
The dichloroethylene isomers occur in some polluted waters and soils, as the decomposition products of trichloroethylene. Significant attention has been paid to their further degradation, e.g. by iron particles.[7][8]