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Names | |||
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Preferred IUPAC name
1,1-Dichloroethene | |||
Other names
1,1-Dichloroethylene
1,1-DCE Vinylidene chloride Vinylidene dichloride Asymmetrical dichloroethene | |||
Identifiers | |||
3D model (JSmol)
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ChEBI | |||
ChemSpider | |||
ECHA InfoCard | 100.000.786 | ||
KEGG | |||
PubChem CID
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UNII | |||
CompTox Dashboard (EPA)
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Properties | |||
C2H2Cl2 | |||
Molar mass | 96.94 g/mol | ||
Density | 1.213 g/cm3 | ||
Melting point | −122 °C (−188 °F; 151 K) | ||
Boiling point | 32 °C (90 °F; 305 K) | ||
2,240mg/L (25°C) | |||
Vapor pressure | 500 mmHg (20°C)[1] | ||
-49.2·10−6 cm3/mol | |||
1.3 D | |||
Structure | |||
C2v | |||
Planar | |||
Hazards | |||
NFPA 704 (fire diamond) | |||
Flash point | −22.8 °C (−9.0 °F; 250.3 K) | ||
Explosive limits | 6.5–15.5%[1] | ||
Lethal dose or concentration (LD, LC): | |||
LDLo (lowest published)
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1500 mg/kg (rat) 194 mg/kg (mouse)[2] | ||
LCLo (lowest published)
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200 ppm (rat, 4.1 hr) 98 ppm (mouse, 22–23 hr) 1,000 ppm (rat, 2.4 hr)[2] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible)
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none[1] | ||
REL (Recommended)
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Ca[1] | ||
IDLH (Immediate danger)
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Ca [N.D.][1] | ||
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-Dichloroethylene, commonly called vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula CHCl2CH3. 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 clingwrap, Saran, for food, but this application has been phased out.
Production
[edit]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 is a base-catalyzed reaction which uses either NaOH or Ca(OH)2 with temperature ca. 100 °C.[3]
- Cl2CHCH2Cl + NaOH → Cl2C=CH2 + NaCl + H2O
The gas phase reaction, without the base, would be more desirable but is less selective.[4]
Applications
[edit]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
[edit]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 polyethylene.
Safety
[edit]The health effects from exposure to vinylidene chloride are primarily on the central nervous system, including symptoms of sedation, inebriation, convulsions, spasms, and unconsciousness at high concentrations.[5]
International Agency for Research on Cancer has put vinylidene chloride in Class 2B, meaning possibly carcinogenic to humans. National Institute for Occupational Safety and Health considers vinylidene chloride a potential occupational carcinogen.[6]
See also
[edit]References
[edit]- ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0661". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b "Toxicological Review of 1,1-Dichloroethylene" (PDF). United States Environmental Protection Agency. Washington, D.C. June 2002.
- ^ Course CEIC2004 Industrial Chemistry for Engineers. Chemistry Lecture Notes, UNSW
- ^ 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.
- ^ epa.gov
- ^ CDC - NIOSH Pocket Guide to Chemical Hazards