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 CHCl. They are both colorless liquids with a sweet odor. It can exist as either of two

geometric isomers Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...

, ''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 and use

''cis''-DCE, the ''Z'' isomer, is obtainable by the controlled

chlorination Chlorination may refer to: * Chlorination reaction In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transform ...

of acetylene: :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. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC ...

, which is produced on a vast scale. Unlike vinyl chloride, the 1,2-dichloroethylene isomers do not polymerize. ''trans''-DCE has applications including electronics cleaning, precision cleaning, and certain metal cleaning applications.

Reactions

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 reactions.

Safety

These compounds have "moderate oral toxicity to rats".

Environmental aspects

The dichloroethylene isomers occur in some polluted waters and soils. Significant attention has been paid to their further degradation, e.g. by iron particles.

References

External links