CAS number
- 75-09-2
Molecular formula
- CH2Cl2
Formula weight
- 84.9 g/mol
Family
- Chlorinated aliphatic hydrocarbons (CAH)
Compound properties list|
| Melting/boiling point | -96 °C / -40 °C | Liquid |
| Relative density | 1.33 g/cm3 | Sinks in water |
| Vapour pressure | 375 mm Hg | Very volatile |
| Vapour density | 2.9 | Denser than air |
| Solubility in water | 15,000 mg/L | Very soluble |
| Henry's law constant | 2 x 10-3 atm·m3/mol | Rapid volatilization when dissolved |
| log Koc (Depending on soil or sediment characteristics) | 1.0 - 2.3* | Weak adsorption to organic matter |
At 20 0C, dichloromethane is a liquid denser than water and very volatile. Characterized
as very soluble, it will volatilize rapidly once dissolved and adsorbs weakly to organic matter.
During a spill, the majority of this compound will evaporate but may also enter into the soil or
migrate into a waterway. Once it encounters water (surface or subsurface), dichloromethane will
primarily dissolve or will sink until it reaches an impermeable surface. The liquid dichloromethane
that accumulates in a saturated zone will rapidly dissolve before significant volatilization occurs.
The adsorbed dichloromethane 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.
Dichloromethane should be handled with care as it is toxic.
Dichloromethane is produced industrially by a two step process: methane or methanol is
chlorinated followed by the chlorination of the resulting chloromethane. Production of
dichloromethane grew steadily through the 1970s and early 1980s, but has since declined as more
manufacturers move towards water-based aerosol systems in anticipation of more stringent
regulations. Canada imports, rather than produces, dichloromethane.
Dichloromethane has been widely used as a solvent in paint strippers and varnish removers, as a
propellant in aerosols, as a solvent in the manufacturing of drugs, pharmaceuticals and film
coatings, as a metal cleaning and finishing solvent, in electronics manufacturing, and as an agent
in urethane foam blowing. Aerosol products in which dichloromethane may be found include paints,
automotive products, and insect sprays. Dichloromethane is also approved in Canada for use as a
post-harvest insecticidal fumigant for stored grains. It is also a common by-product of pulp and
paper bleaching.
Agency for Toxic Substances and Disease Registry (ATSDR). 2000. Toxicological
Profile for Methylene Chloride. U.S. Department of Health and Human Services, Public Health
Service, Georgia, USA. (Viewed December 2013)
Canadian Council of Ministers of the Environment, 1999. Canadian Water Quality Guidelines for
the Protection of Aquatic Life: Halogenated Methanes (dichloromethane). 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.
