1,1-Dichloroethylene

1,1-Dichloroethylene
Structural formula	Ball-and-stick model
Names
	Preferred IUPAC name 1,1-Dichloroethene
	Other names 1,1-Dichloroethylene; 1,1-DCE; Vinylidene chloride; Vinylidene dichloride; Asymmetrical dichloroethene
Identifiers
CAS Number	75-35-4 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:34031 ;
ChemSpider	6126 ;
ECHA InfoCard	100.000.786
KEGG	C14039 ;
PubChem CID	6366;
UNII	21SK105J9D ;
CompTox Dashboard (EPA)	DTXSID8021438 ;
	InChI InChI=1S/C2H2Cl2/c1-2(3)4/h1H2 Key: LGXVIGDEPROXKC-UHFFFAOYSA-N ;
	SMILES ClC(Cl)=C;
Properties
Chemical formula	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)
Solubility in water	2,240mg/L (25°C)
Vapor pressure	500 mmHg (20°C)
Magnetic susceptibility (χ)	-49.2·10−6 cm3/mol
Dipole moment	1.3 D
Structure
Point group	C2v
Molecular shape	Planar
Hazards
NFPA 704 (fire diamond)	2 4 2
Flash point	−22.8 °C (−9.0 °F; 250.3 K)
Explosive limits	6.5–15.5%
	Lethal dose or concentration (LD, LC):
LDLo (lowest published)	1500 mg/kg (rat); 194 mg/kg (mouse)
LCLo (lowest published)	200 ppm (rat, 4.1 hr); 98 ppm (mouse, 22–23 hr); 1,000 ppm (rat, 2.4 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	Ca
IDLH (Immediate danger)	Ca [N.D.]
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

1,1-Dichloroethylene, commonly called vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula CCl₂CH₂. 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

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

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

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. Accordingly, Saran changed their formulation in 2004 to a form of polyethylene.^[5]

Safety

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.^[6]

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.^[7]

References

^ ^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.
^ Burke, Michael (2015-04-25). "CEO explains why SC Johnson hobbled Saran Wrap". Journal Times. Retrieved 2024-09-18.
^ epa.gov
^ CDC - NIOSH Pocket Guide to Chemical Hazards

External links

Agency for Toxic Substances and Disease Registry: 1,1-Dichloroethene

[PGCH-1] NIOSH Pocket Guide to Chemical Hazards. "#0661". National Institute for Occupational Safety and Health (NIOSH).

[toxicology-2] "Toxicological Review of 1,1-Dichloroethylene" (PDF). United States Environmental Protection Agency. Washington, D.C. June 2002.

[3] Course CEIC2004 Industrial Chemistry for Engineers. Chemistry Lecture Notes, UNSW

[4] 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.

[5] Burke, Michael (2015-04-25). "CEO explains why SC Johnson hobbled Saran Wrap". Journal Times. Retrieved 2024-09-18.

[6] .gov

[7] CDC - NIOSH Pocket Guide to Chemical Hazards

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