CAS number
- 120-82-1
Molecular formula
- C6H3Cl4
Formula weight
- 181.5 g/mol
Family
- Chlorobenzenes
Compound properties list|
| Melting/boiling point | 17 °C / 213 °C | Liquid or solid |
| Relative density | 1.45 g/cm3 | Sinks in water |
| Vapour pressure | 0.3 mm Hg | Low volatility |
| Vapour density | 6.3 | Much denser than air |
| Solubility in water | 40 mg/L | Low solubility |
| Henry's law constant | 2 x 10-3atm·m3/mol | Rapid volatilization when dissolved |
| log Koc (Depending on soil or sediment characteristics) | 2.8 - 3.9* | Strong adsorption to organic matter |
At 20 0C, 1,2,4-trichlorobenzene can be found as either a liquid or solid. Denser than
water, 1,2,4-trichlorobenzene has low volatility and solubility. Once dissolved, it rapidly
volatilizes and adsorbs strongly to organic matter. As a solid, 1,2,4-trichlorobenzene in soil will
slowly dissolve. In its liquid form, 1,2,4-trichlorobenzene will enter into the soil or drain
towards a waterway before it volatilizes. Liquid 1,2,4-trichlorobenzene that accumulates in the
saturated zone will dissolve slowly before a significant portion volatilizes. Once the source has
been removed, the adsorbed phase will take a long time to disappear, liberating contamination in
either the gaseous or dissolved state. The resulting plumes (gaseous and dissolved) are generally
small in size.
1,2,4-trichlorobenzene should be handled with care, as it is toxic.
1,2,4-trichlorobenzene is the most common trichlorobenzene isomer. Although there are
currently no producers of trichlorobenzenes in Canada, an estimated 40 to 50 tonnes per year were
imported during the mid-1990s. Of this amount, about 30 tonnes were used as solvents in textile
manufacturing, and about 15 tonnes were used as intermediates in the production of other
chemicals.
In the past, trichlorobenzenes were used in combination with polychlorinated biphenyls (PCBs) in
dielectric fluids for transformers and capacitors until 1980 when regulations prohibited new uses of
PCB-containing dielectric fluids. Approximately 2,600,000 tonnes of trichlorobenzenes are present
in transformer dielectric fluids either in use or stored before disposal. In the United States,
trichlorobenzenes are also used as degreasing agents and lubricants.
1,2,4-trichlorobenzene is used industrially as dye carrier, an intermediate in chemical
production (especially herbicides), a degreasing agent, and a lubricant. Trichlorobenzene isomers
have been identified in pulp and paper mill effluents. Effluents from iron and steel manufacturing
contribute to the environmental load of trichlorobenzenes, while petroleum refinery effluents have
been reported to contain trichlorobenzene isomers. The more highly chlorinated benzenes,
particularly hexachlorobenzene, are subject to reductive dechlorination, which may contribute to the
accumulation of the lower chlorinated homologues (example, dichlorobenzenes and trichlorobenzenes) in
buried sediments.
Canadian Council of Ministers of the Environment (CCME). 1999. Canadian water quality
guidelines for the protection of aquatic life: Chlorinated benzenes 1,2,3-Trichlorobenzene. In:
Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment,
Winnipeg. Canada. (Viewed December 2013)
Government of Canada. 1993. Canadian Environmental Protection Act (CEPA). Priority Substances
List Assessment Report: Trichlorobenzenes. Environment Canada and Health Canada Ottawa. (Viewed December 2013)
Environment Canada. 2003. Follow-up report on five PSL1 substances for which there was
insufficient information to conclude whether the substances constitute a danger to the
environment. Government of Canada. (Viewed December 2013)
Montgomery, John H. 2007. Groundwater Chemicals, Desk Reference, Fourth Edition, CRC
Press, Taylor and Francis Group, Florida, U.S.A.
