1,2-Dichloroethylene Explained

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.^[1] In contrast to most cis-trans compounds, the Z isomer (cis) is more stable than the E isomer (trans) by 0.4 kcal/mol.^[2]

Production, uses and reactions

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

CH + Cl → CHCl

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

trans-1,2-DCE has applications including electronics cleaning, precision cleaning, and certain metal cleaning applications.^[3]

Both isomers participate in Kumada coupling reactions. trans-1,2-Dichloroethylene participates in cycloaddition reactions.^[4]

Safety and environmental concerns

These compounds have "moderate oral toxicity to rats".^[1]

The dichloroethylene isomers occur in some polluted waters and soils, as the decomposition products of trichloroethylene. Significant attention has been paid to their further degradation, e.g. by iron particles.^{[5] [6]}

See also

• 1,1-Dichloroethene
• 1,2-Dichloroethane, which is also often abbreviated as 1,2-DCE

References

1. Book: E.-L. Dreher . T. R. Torkelson . K. K. Beutel . Chlorethanes and Chloroethylenes . Ullmann's Encyclopedia of Industrial Chemistry . 2011 . Wiley-VCH . Weinheim . 10.1002/14356007.o06_o01. 978-3527306732 .
2. cis- and trans-Dichloroethylenes. The Infrared Spectra from 130–400 Cm. and the Thermodynamic Properties . Kenneth S. . Pitzer . J. L. . Hollenberg . J. Am. Chem. Soc. . 1954 . 76 . 6 . 1493–1496 . 10.1021/ja01635a010 .
3. Web site: Chlorinated Solvents and Feed Stock - Axiall . 2016-03-23 . https://web.archive.org/web/20160408122850/http://www.axiall.com/Products/Chlorovinyls/Chlorinated-Solvents-and-Feedstock/ . 2016-04-08 . dead .
4. 10.1021/jo00078a031. Arene synthesis by extrusion reaction. 16. Coplanar and stable derivatives of 13,14-didehydro-tribenzo[a,c,e]cyclooctene: Synthesis of 5,6-didehydro-1,1,14,14-tetramethyl-10,11-methano-1H-benzo[5,6]cycloocta[1,2,3,4-def]fluorene and 5,6-didehydro-10,11-methano-1H-benzo[5,6]cycloocta[1,2,3,4-def]fluorene-1,14-dione and x-ray crystal structures of 1,1,14,14-tetramethyl-10,11-methano-1H-benzo[5,6-cycloocta[1,2,3,4-def]fluorene and 1,12-dihydro-1,1,12,12-tetramethyldicyclopenta[def,JKL]tetraphenylene |year=1993 |last1=Wang |first1=Xiao Min |last2=Hou |first2=Xuelong |last3=Zhou |first3=Zhongyuan |last4=Mak |first4=Thomas C. W. |last5=Wong |first5=Henry N. C. |journal=The Journal of Organic Chemistry |volume=58 |issue=26 |pages=7498–7506 .
5. 10.1111/j.1574-6976.2010.00210.x. Aerobic biodegradation of the chloroethenes: Pathways, enzymes, ecology, and evolution . 2010 . Mattes . Timothy E. . Alexander . Anne K. . Coleman . Nicholas V. . FEMS Microbiology Reviews . 34 . 4 . 445–475 . 20146755 . free .
6. 10.1021/cm020737i. Hydrodechlorination of Trichloroethylene to Hydrocarbons Using Bimetallic Nickel−Iron Nanoparticles . 2002 . Schrick . Bettina . Blough . Jennifer L. . Jones . A. Daniel . Mallouk . Thomas E. . Chemistry of Materials . 14 . 12 . 5140–5147 .