1,2-Dichloroethene

cis-1,2-Dichloroethene (Z) (left) and trans-1,2-Dichloroethene (E) (right)

Names
IUPAC name 1,2-Dichloroethene
Other names 1,2-Dichloroethylene 1,2-DCE sym-Dichloroethylene
Identifiers
CAS Number	156-59-2 (Z) 156-60-5 (E) 540-59-0 (mixture of E and Z)
ChEBI	CHEBI:18882
ChemSpider	10438
Jmol interactive 3D	Image Image
KEGG	C06792
PubChem	643833 (Z) 638186 (E) 10900 (mixture of E and Z)
InChI InChI=1S/C2H2Cl2/c3-1-2-4/h1-2H Key: KFUSEUYYWQURPO-UHFFFAOYSA-N InChI=1/C2H2Cl2/c3-1-2-4/h1-2H/b2-1- Key: KFUSEUYYWQURPO-UPHRSURJBI InChI=1/C2H2Cl2/c3-1-2-4/h1-2H Key: KFUSEUYYWQURPO-UHFFFAOYAW
SMILES Cl[C@H]=CCl ClC=CCl
Properties
Chemical formula	C2H2Cl2
Molar mass	96.95 g/mol
Appearance	clear liquid[1]
Odor	acrid, chloroform-like[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
Dipole moment	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%[1]
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	770 mg/kg (oral, rat) 1275 mg/kg (oral, rat, trans-isomer)[2]
LC50 (Median concentration)	21,273 ppm (mouse, 6 hr, trans-isomer)[2]
LCLo (Lowest published)	16,000 ppm (rat, 6 hr, cis-isomer)[2]
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 200 ppm (790 mg/m^3)[1]
REL (Recommended)	TWA 200 ppm (790 mg/m^3)[1]
IDLH (Immediate danger	1000 ppm[1]
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

1,2-Dichloroethene, commonly called 1,2-dichloroethylene or 1,2-DCE, is an organochloride with the molecular formula C₂H₂Cl₂. It is a highly flammable, colorless liquid with a sharp, harsh 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 few industrial applications,^[3] although they are fundamental given their simple stoichiometries.

Production

cis-DCE, the E isomer, is obtainable by the controlled chlorination of acetylene:

C₂H₂ + Cl₂ → C₂H₂Cl₂

Industrially both isomers arise as byproduct of the production of vinyl chloride, which is produced on a vast scale. Unlike vinyl chloride, the 1,2-dichloroethylene isomers do not polymerize.^[3]

trans-DCE has applications including electronics cleaning, precision cleaning, and certain metal cleaning applications.^[4]

Safety

These compounds have "moderate oral toxicity to rats."^[3]

See also

• 1,1-Dichloroethene
• 1,2-Dichloroethane

References

1. "NIOSH Pocket Guide to Chemical Hazards #0195". National Institute for Occupational Safety and Health (NIOSH).
2. "1,2-Dichloroethylene". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).
3. E.-L. Dreher, T. R. Torkelson, K. K. Beutel (2011). "Chlorethanes and Chloroethylenes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.o06_o01.
4. http://www.axiall.com/Products/Chlorovinyls/Chlorinated-Solvents-and-Feedstock/

External links

• International Chemical Safety Card 0436
• "NIOSH Pocket Guide to Chemical Hazards #0195". National Institute for Occupational Safety and Health (NIOSH).