Dichloroethene

Dichloroethene refers to the chemical compound family with the formula C2H2Cl2, consisting of two carbon atoms bearing two chlorine substituents. It exists as distinct isomers that differ in the arrangement of the chlorine atoms around the carbon–carbon double bond.

The 1,1-dichloroethene isomer, also known as vinylidene chloride, has the formula CH2=CCl2. It is not subject to geometric isomerism because both chlorine atoms are attached to the same carbon. The 1,2-dichloroethene isomer has chlorine atoms on opposite carbons and exists as two geometric isomers: cis-1,2-dichloroethene and trans-1,2-dichloroethene. These isomers can exhibit different physical properties and reactivities due to their spatial arrangement.

Production and uses are typically industrial. Dichloroethenes can be formed as byproducts in chlorinated hydrocarbon processes or produced by dehydrohalogenation or dechlorination steps in the manufacture of other chlorinated compounds. They are used as solvents and as chemical intermediates in the synthesis of vinyl chloride monomer and related materials, as well as in older degreasing applications. Today, many applications are governed by safety, environmental, and regulatory considerations, with a focus on minimizing emissions and exposure.

Safety and environmental aspects are important for dichloroethenes. They are generally volatile and can be irritants to the eyes, skin, and respiratory system; exposure should be controlled to avoid acute and long-term effects. They are flammable and may form hazardous vapors in air. Proper storage, handling, and disposal in accordance with regulatory guidelines are essential to limit environmental release and human health risks.