Fact sheet: 1,2-dichlorobenzene

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


Molecular formula


Formula weight

147 g/mol



Properties (at room temperature where applicable)

Compound properties list
Melting/boiling point -16 °C / 180 °CLiquid
Relative density1.3 g/cm3Sinks in water
Vapour pressure2 mm HgModerately volatile
Vapour density5.1Much denser than air
Solubility in water135 mg/LLow solubility
Henry's law constant2 x 10-3atm·m3/molRapid volatilization when dissolved
log Koc (Depending on soil or sediment characteristics)2.5 - 3.0*Moderate adsorption to organic matter

Environmental behaviour

At 20 0C, 1,2-dichlorobenzene is a liquid denser than water and moderately volatile. Characterized by low solubility, it will volatilize rapidly once dissolved and adsorbs moderately to organic matter. During a spill, this compound will evaporate in part but may also enter into the soil or drain into a waterway. Once it encounters water (surface or subsurface), 1,2-dichlorobenzene will dissolve or sink until it reaches an impermeable surface. As a liquid, 1,2-dichlorobenzene that accumulates in a saturated zone will slowly dissolve before volatilization occurs. The adsorbed 1,2-dichlorobenzene in the vadose and saturated zones will take a long time to disappear, liberating contamination in either the gaseous or dissolved state. The resulting plumes (gaseous or dissolved) will be relatively small in size.

Health and safety

1,2-dichlorobenzene should be handled with care as it is flammable and toxic.

Principal resources

1,2-dichlorobenzene does not occur naturally. Chlorinated benzenes are typically produced by reacting liquid benzene with gaseous chlorine in the presence of a catalyst at moderate temperatures and atmospheric pressures. This reaction yields a mixture of chlorobenzene isomers with varying degrees of chlorination.

1,2-dichlorobenzene is used primarily as a precursor to 3,4-dichloroaniline herbicides. Other industrial uses of 1,2-dichlorobenzene include solvents and carbon removal, particularly in metallurgy. It is also used as an intermediate in the synthesis of dyes and other herbicides, degreasers, as a dye carrier, as an odor control product and as a fungicide. 1,2-dichlorobenzene is one of the more common chlorobenzene congeners found in the environment, because of its various commercial applications, dissipative use patterns, and long environmental persistence.


Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological profile for dichlorobenzenes. U.S. Department of Health and Human Services, Public Health Service. Georgia, U.S.A. (Viewed December 2013)

Canadian Council of Ministers of the Environment. 1999. Canadian water quality guidelines for the protection of aquatic life: Chlorinated benzenes-1,2-Dichlorobenzene. In: Canadian environmental quality guidelines, 1999. Canadian Council of Ministers of the Environment, Winnipeg. Canada. (Viewed December 2013)

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