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1,1-Dichloroethylene

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This is an old revision of this page, as edited by 128.220.5.53 (talk) at 19:33, 7 October 2010 (Provided correct dipole moment: 1.3 D. (replaced incorrect dipole moment, ie 2.3 D)). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

1,1-Dichloroethene
Structural formula
Structural formula
Ball-and-stick model
Ball-and-stick model
Names
IUPAC name
1,1-Dichloroethene
Other names
1,1-Dichloroethylene
1,1-DCE
vinylidene chloride
vinylidene dichloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.786 Edit this at Wikidata
  • ClC(Cl)=C
Properties
C2H2Cl2
Molar mass 96.94 g/mol
Density 1.213 g/cm³
Melting point -122 °C
Boiling point 32 °C
1.3 D
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
2
4
2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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1,1-Dichloroethene, commonly called 1,1-dichloroethylene or 1,1-DCE, is an organochloride with the molecular formula C2H2Cl2. It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water, but soluble in organic solvents. 1,1-DCE was the precursor to the original cling-wrap for food, but this application has been phased out.

Production

1,1-DCE is produced by dehydrochlorination of 1,1,2-trichloroethane, a relatively unwanted byproduct in the production of 1,1,1-trichloroethane and 1,2-dichloroethane. The conversion involves a base-catalyzed reaction:

Cl2CHCH2Cl + NaOH → Cl2C=CH2 + NaCl + H2O

The gas phase reaction, without the base, would be more desirable but is less selective.[1]

Applications

1,1-DCE is mainly used as a comonomer in the polymerization of vinyl chloride, acrylonitrile, and acrylates. It is also used in semiconductor device fabrication for growing high purity silicon dioxide (SiO2) films.

Polyvinylidene chloride

Main article: polyvinylidene chloride

As with many other alkenes, 1,1-DCE can be polymerised to form polyvinylidene chloride. A very widely used product, cling wrap, or Saran was made from this polymer. During the 1990s research suggested that, in common with many chlorinated carbon compounds, Saran posed a possible danger to health by leaching, especially on exposure to food in microwave ovens. Since 2004, therefore cling wrap's formulation has changed to a form of polythene.

Safety

The health effects from exposure to 1,1-DCE are primarily on the central nervous system, including symptoms of sedation, inebriation, convulsions, spasms, and unconsciousness at high concentrations.[2]

See also

References

  1. ^ Manfred Rossberg, Wilhelm Lendle, Gerhard Pfleiderer, Adolf Tögel, Eberhard-Ludwig Dreher, Ernst Langer, Heinz Rassaerts, Peter Kleinschmidt, Heinz Strack, Richard Cook, Uwe Beck, Karl-August Lipper, Theodore R. Torkelson, Eckhard Löser, Klaus K. Beutel, Trevor Mann “Chlorinated Hydrocarbons” in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. doi:10.1002/14356007.a06_233.pub2.
  2. ^ epa.gov
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