CAS number
- 71-55-6
Molecular formula
- C2H3Cl3
Formula weight
- 133.4 g/mol
Family
- Chlorinated aliphatic hydrocarbons (CAH)
Compound properties list|
| Melting/boiling point | -31 °C / 74 °C | Liquid |
| Relative density | 1.33 g/cm3 | Sinks in water |
| Vapour pressure | 115 mm Hg | Very volatile |
| Vapour density | 4.6 | Denser than air |
| Solubility in water | 1,200 mg/L | Moderately soluble |
| Henry's law constant | 2 x 10-2 atm·m3/mol | Rapid volatilization when dissolved |
| log Koc (Depending on soil or sediment characteristics) | 2.0 - 2.8* | Moderate adsorption to organic matter |
At 20 0C, 1,1,1-trichloroethane 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 mostly evaporate but may also enter
into the soil or migrate into a waterway. Once it encounters water (surface or subsurface),
1,1,1-trichloroethane will dissolve or sink until it reaches an impermeable surface. The liquid
1,1,1-trichloroethane that accumulates in a saturated zone will gradually dissolve before partially
volatilizing. The adsorbed 1,1,1-trichloroethane 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.
1,1,1-Trichloroethane should be handled with care as it is toxic.
1,1,1-Trichloroethane is a synthetic chemical that does not occur naturally in the
environment. The most common industrial production method is the reaction of hydrochloric acid with
vinyl chloride to obtain 1,1-dichloroethane, followed by either thermal or photochemical
chlorination. 1,1,1-Trichloroethane was initially developed as a safer solvent to replace other
flammable chlorinated solvents. Because it has been classified as an ozone-depleting chemical, its
production and uses are now limited. Today, the only significant use of 1,1,1-trichloroethane is in
the production of hydrofluorocarbons.
Previously 1,1,1-trichloroethane had many industrial and household uses. It was widely used in the
production of hydrochlorofluorocarbons (HCFC), as a solvent to remove oil or grease from
manufactured materials (such as electrical equipment, motors, electronic components, photographic
film, printed circuit boards, fabrics, etc.), or to dissolve other substances such as glues,
printing inks and paints. 1,1,1-Trichloroethane was also used as a food and grain fumigant. In the
home, it was present in products such as spot cleaners, glues and aerosol sprays.
The production of 1,1,1-trichloroethane in Canada in 1988 was 10,000 tons and an additional 6,000
tons were imported. Most of it was used in metal cleaning, particularly the armatures of electric
motors, generators, and switchgear and electronic equipment. It was also used in adhesives, as a
propellant modifier in aerosols, in several textile finishing operations, as a constituent in
various office supplies, as dry lubricants, and as a laboratory solvent. 1,1,1-Trichloroethane is a
contaminant frequently found in Canadian waters, particularly near industrialized areas.
Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological Profile
for 1,1,1-Trichloroethane. U.S. Department of Health and Human Services, Public Health Service,
Georgia, USA. (Viewed March 2010)
Canadian Council of Ministers of the Environment. 1999. Canadian Water Quality Guidelines for the
Protection of Aquatic Life: Chlorinated Ethanes. In: Canadian Environmental Quality Guidelines.
Canadian Council of Ministers of the Environment, Manitoba, Canada.
(Viewed March 2010)
Montgomery, John H. 2007. Groundwater Chemicals, Desk Reference, Fourth Edition, CRC Press,
Taylor and Francis Group, Florida, USA.
