Fact sheet: 1,1-dichloroethene

From: Public Services and Procurement Canada

Discover a list of a contaminant's important chemical properties, how it will react in the environment, main sources of contamination related, and a brief overview of health and safety issues.

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General information

CAS number

75-35-4

Molecular formula

C2H2Cl2

Formula weight

96.9 g/mol

Family

Chlorinated aliphatic hydrocarbons (CAH)

Properties (at room temperature where applicable)

Compound properties list
ParameterValueComment
Melting/boiling point -122 0C / 32 0CLiquid
Relative density1.2Sinks in water
Vapour pressure550 mm HgVery volatile
Vapour density3.4Denser than air
Solubility in water1,500 mg/LModerately soluble
Henry's law constant2 x 10-2 atm·m3/molRapid volatilization when dissolved
log Koc (Depending on soil or sediment characteristics)1.7 - 2.4*Moderate adsorption to organic matter

Environmental behaviour

At 20 0C, 1,1-dichloroethene is a liquid denser than water and very volatile. Characterized by moderate solubility, it will volatilize rapidly once dissolved and adsorbs moderately to organic matter. During a spill, this compound will primarily evaporate but may also enter into the soil or migrate into a waterway. Once it encounters water (surface or subsurface), the 1,1-dichloroethene will dissolve or sink until it reaches an impermeable surface. The liquid 1,1-dichloroethene that accumulates in a saturated zone will gradually dissolve before volatilization occurs. The adsorbed 1,1-dichloroethene in the vadose and saturated zones will rapidly disappear, liberating contamination in either the gaseous or dissolved state. The resulting plumes (gaseous or dissolved) will be relatively large in size.

Health and safety

1,1-Dichloroethene should be handled with care as it is flammable, toxic and reactive.

Principal resources

1,1-Dichloroethene, also known as vinylidene chloride, is a man-made chemical produced commercially by the dehydrochlorination of 1,1,2-trichloroethane with excess lime or caustic. Although 1,1-dichloroethene is manufactured in large quantities, most of it is used as an intermediate in organic chemical synthesis (vinylidene fluoride and 1,1,1-trichloroethane) and in the production of polyvinylidene chloride copolymers. These polymers, which have been commercially important since their introduction in the early 1940s, are used extensively in many types of flexible packing materials, as flame retardant coatings for fiber and carpet backing, as well as in piping, coating for steel pipes, and adhesive applications. The major application of polyvinylidene chloride copolymers is the production of flexible films for food packaging.

Although 1,1-dichloroethene does not occur naturally, the breakdown of polyvinylidene chloride products is also a source of 1,1-dichloroethene in the environment.

References

Agency for Toxic Substances and Disease Registry (ATSDR), 1994. Toxicological Profile for 1,1-dichloroethene. U.S. Department of Health and Human Services, Public Health Service, Georgia, USA. (Viewed March 2010).

Montgomery, John H. 2007. Groundwater Chemicals, Desk Reference, Fourth Edition, CRC Press, Taylor and Francis Group, Florida, USA.

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