1,2-Dichloroethene

1,2-Dichloroethene
cis-1,2-Dichloroethene (Z)	trans-1,2-Dichloroethene (E)
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 (E/Z) ;
3D model (JSmol)	Interactive image; Interactive image;
ChEBI	CHEBI:18882 ;
ChemSpider	10438 ;
ECHA InfoCard	100.007.956
KEGG	C06792 ;
PubChem CID	643833 (Z); 638186 (E); 10900 (E/Z);
UNII	FYO9G15JYD (Z) ; 41799BI61U (E) ; XU9RUA6YUT (E/Z) ;
CompTox Dashboard (EPA)	DTXSID8024991 ;
	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
Odor	acrid, chloroform-like
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
Magnetic susceptibility (χ)	−51.0·10−6 cm3/mol (cis); −48.9·10−6 cm3/mol (trans);
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%
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	770 mg/kg (oral, rat); 1275 mg/kg (oral, rat, trans-isomer)
LC50 (median concentration)	21,273 ppm (mouse, 6 hr, trans-isomer)
LCLo (lowest published)	16,000 ppm (rat, 6 hr, cis-isomer)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 200 ppm (790 mg/m3)
REL (Recommended)	TWA 200 ppm (790 mg/m3)
IDLH (Immediate danger)	1000 ppm
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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 Z 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]

E-Z relative stability

In contrast to most cis-trans compounds, the Z isomer (cis) is more stable than the E isomer (trans) by 0.4 kcal/mol.^[5]

Safety

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

References

^ ^a ^b ^c ^d ^e ^f ^g NIOSH Pocket Guide to Chemical Hazards. "#0195". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b ^c "1,2-Dichloroethylene". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b ^c 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. ISBN 978-3527306732.
^ "Chlorinated Solvents and Feed Stock - Axiall". Archived from the original on 2016-04-08. Retrieved 2016-03-23.
^ Pitzer, Kenneth S.; Hollenberg, J. L. (1954). "cis- and trans-Dichloroethylenes. The Infrared Spectra from 130–400 Cm.^–1 and the Thermodynamic Properties". J. Am. Chem. Soc. 76 (6): 1493–1496. doi:10.1021/ja01635a010.

External links

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

[NIOSH-1] ^ ^a ^b ^c ^d ^e ^f ^g NIOSH Pocket Guide to Chemical Hazards. "#0195". National Institute for Occupational Safety and Health (NIOSH).

[IDLH-2] "1,2-Dichloroethylene". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[Ullmann-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. ISBN 978-3527306732.

[4] "Chlorinated Solvents and Feed Stock - Axiall". Archived from the original on 2016-04-08. Retrieved 2016-03-23.

[5] Pitzer, Kenneth S.; Hollenberg, J. L. (1954). "cis- and trans-Dichloroethylenes. The Infrared Spectra from 130–400 Cm.^–1 and the Thermodynamic Properties". J. Am. Chem. Soc. 76 (6): 1493–1496. doi:10.1021/ja01635a010.

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