ortho-Dichlorobenzene, o-Dichlorobenzene, odcb
|Molar mass||147.01 g/mol|
|Melting point||−17.03 °C (1.35 °F; 256.12 K)|
|Boiling point||180.5 °C (356.9 °F; 453.6 K)|
|Ingestion hazard||Toxic if swallowed|
|Inhalation hazard||Causes respiratory tract irritation|
|Eye hazard||Causes eye irritation|
|Skin hazard||Causes skin irritation|
|Flash point||66 °C (151 °F; 339 K)|
|US health exposure limits (NIOSH):|
|C 50 ppm (300 mg/m3)|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
1,2-Dichlorobenzene, or orthodichlorobenzene (ODCB), is an organic compound with the formula C6H4Cl2. This colourless liquid is poorly soluble in water but miscible with most organic solvents. It is a derivative of benzene, consisting of two adjacent chlorine centers.
Production and uses
1,2-Dichlorobenzene is obtained as a side-product of the production of chlorobenzene:
5Cl + Cl
2 → C
2 + 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 chlorine, like all halogens, are ortho/para- directors in terms of electrophilic aromatic substitution and the 1,3- isomer is a meta- compound.
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.
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.
- Merck Index, 11th Edition, 3044
- "NIOSH Pocket Guide to Chemical Hazards". National Institute for Occupational Safety and Health (NIOSH). id=0189.
- Gerald Booth (2007). "Nitro Compounds, Aromatic" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2005.
- Technical Order 2J-1-13
- CDC - Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)
- CDC - NIOSH Pocket Guide to Chemical Hazards