1,2-Dichloroethylene or 1,2-DCE is the name for a pair of
organochlorine compounds with the molecular formula . The two compounds are isomers, each being 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.
In contrast to most
''cis-trans'' compounds, the ''Z'' isomer (''cis'') is more stable than the ''E'' isomer (''trans'') by 0.4 kcal/mol.
Production, uses and reactions
''cis''-DCE, the ''Z'' isomer, is obtainable by the controlled
chlorination of
acetylene
Acetylene (Chemical nomenclature, systematic name: ethyne) is a chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is u ...
:
:CH + Cl → CHCl
Industrially both isomers arise as byproducts of the production of
vinyl chloride
Vinyl chloride is an organochloride with the formula H2C =CHCl. It is also called vinyl chloride monomer (VCM) or chloroethene. It is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC). Vinyl chloride is a ...
, which is produced on a vast scale. Unlike
1,1-dichloroethylene
1,1-Dichloroethylene, commonly called vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula . It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water but soluble in organic solv ...
, the 1,2-dichloroethylene isomers do not polymerize.
[
''trans''-1,2-DCE has applications including electronics cleaning, precision cleaning, and certain metal cleaning applications.
Both isomers participate in ]Kumada coupling
In organic chemistry, the Kumada coupling is a type of cross coupling reaction, useful for generating carbon–carbon bonds by the reaction of a Grignard reagent and an organic halide. The procedure uses transition metal catalysts, typically ...
reactions. ''trans''-1,2-Dichloroethylene participates in cycloaddition reaction
In organic chemistry, a cycloaddition is a chemical reaction in which "two or more unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity". T ...
s.
Safety and environmental concerns
These compounds have "moderate oral toxicity to rats".[
The dichloroethylene isomers occur in some polluted waters and soils, as the decomposition products of ]trichloroethylene
Trichloroethylene (TCE) is an organochloride with the formula C2HCl3, commonly used as an industrial metal-degreasing solvent. It is a clear, colourless, non-flammable, volatile liquid with a chloroform-like pleasant mild smell and sweet taste. . Significant attention has been paid to their further degradation, e.g. by iron particles.
See also
* 1,1-Dichloroethene
1,1-Dichloroethylene, commonly called vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula . It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water but soluble in organic solv ...
* 1,2-Dichloroethane
The chemical compound 1,2-dichloroethane, commonly known as ethylene dichloride (EDC), is a chlorinated hydrocarbon. It is a colourless liquid with a chloroform-like odour. The most common use of 1,2-dichloroethane is in the production of vinyl ...
, which is also often abbreviated as 1,2-DCE
References
External links
*
*
{{DEFAULTSORT:Dichloroethene, 1, 2-
Chloroalkenes
Halogenated solvents