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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 C2H2Cl2. They are both 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.[4]

Production, uses and reactions

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

C2H2 + Cl2 → C2H2Cl2

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.[5]

Both isomers participate in Kumada coupling reactions. trans-1,2-Dichloroethylene participates in cycloaddition reactions.[6]

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.[7][8]

See also

References

  1. ^ a b c d 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.
  2. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0195". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ a b c "1,2-Dichloroethylene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^ 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.
  5. ^ "Chlorinated Solvents and Feed Stock - Axiall". Archived from the original on 2016-04-08. Retrieved 2016-03-23.
  6. ^ Wang, Xiao Min; Hou, Xuelong; Zhou, Zhongyuan; Mak, Thomas C. W.; Wong, Henry N. C. (1993). "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". The Journal of Organic Chemistry. 58 (26): 7498–7506. doi:10.1021/jo00078a031.
  7. ^ Mattes, Timothy E.; Alexander, Anne K.; Coleman, Nicholas V. (2010). "Aerobic biodegradation of the chloroethenes: Pathways, enzymes, ecology, and evolution". FEMS Microbiology Reviews. 34 (4): 445–475. doi:10.1111/j.1574-6976.2010.00210.x. PMID 20146755.
  8. ^ Schrick, Bettina; Blough, Jennifer L.; Jones, A. Daniel; Mallouk, Thomas E. (2002). "Hydrodechlorination of Trichloroethylene to Hydrocarbons Using Bimetallic Nickel−Iron Nanoparticles". Chemistry of Materials. 14 (12): 5140–5147. doi:10.1021/cm020737i.

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