1,2-Dichlorobenzene

Production and uses

1,2-Dichlorobenzene is obtained as a side-product of the production of chlorobenzene: : + → + HCl The reaction also affords the 1,4- and small amounts of the 1,3-isomer. The 1,4- isomer is preferred over the 1,2- isomer due to steric hindrance. The 1,3- isomer is uncommon because it is a meta- compound, while chlorine, like all halogens, is an ortho/para- director in terms of electrophilic aromatic substitution.

It is mainly used as a precursor to 1,2-dichloro-4-nitrobenzene, an intermediate in the synthesis of agrochemicals. In terms of niche applications, 1,2-dichlorobenzene is a versatile, high-boiling solvent. It is a preferred solvent for dissolving and working with fullerenes. It is an insecticide for termites and locust borers, historically used by the United States Forest Service to combat widespread bark beetle outbreaks.

1,2-Dichlorobenzene is also used in softening and removing carbon-based contamination on metal surfaces.

Safety

Data from human exposure to 1,2-dichlorobenzene shows that concentrations of 100 ppm have been reported to cause sporadic irritation of the eyes and respiratory tract. The Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have set occupational exposure limits at a ceiling of 50 ppm, over an eight-hour workday.

References

References

1. ''[[Merck Index]]'', 11th Edition, '''3044'''
2. (September 1998). "Measurements of Saturated Vapor Pressure above the Liquid Phase for Isomeric Dichlorobenzenes and 1,2,4-Trichlorobenzene". Journal of Chemical & Engineering Data.
3. {{PGCH. 0189
4. (4 December 2014). "''o''-Dichlorobenzene". National Institute for Occupational Safety and Health (NIOSH).
5. Gerald Booth (2007). "Nitro Compounds, Aromatic" in ''Ullmann's Encyclopedia of Industrial Chemistry'' Wiley-VCH, Weinheim, 2005.
6. (25 July 2011). "Battle of the Beetles".
7. Technical Order 2J-1-13
8. (16 November 2017). "CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): o-Dichlorobenzene - NIOSH Publications and Products".
9. "CDC - NIOSH Pocket Guide to Chemical Hazards -o-Dichlorobenzene".