2-Chloroethanol
Template:Chembox 2-Chloroethanol (also called ethylene chlorohydrin or glycol chlorohydrin) is an organic chemical compound with the chemical formula HOCH2CH2Cl and the simplest beta-halohydrin (chlorohydrin).[1] This colorless liquid has a pleasant ether-like odor. It is miscible with water. The molecule is bifunctional, consisting of both an alkyl chloride and an alcohol functional group.[2]
Synthesis and applications
2-Chloroethanol is produced by treating ethylene with hypochlorous acid:[2]
2-Chloroethanol was once produced on a large scale as a precursor to ethylene oxide:
- HOCH2CH2Cl + NaOH → C2H4O + NaCl + H2O
This application has been supplanted by the more economic direct oxidation of ethylene. Otherwise chloroethanol is still used in the production of pharmaceuticals, biocides, and plasticizers.[2] Many of these applications entail its use in installing 2-hydroxyethyl groups.[3] Several dyes are prepared by the alkylation of aniline derivatives with chloroethanol.[4] It is also used for manufacture of thiodiglycol.
It is a solvent for cellulose acetate and ethyl cellulose, textile printing dyes, in dewaxing, refining of rosin, extraction of pine lignin, and the cleaning of machines.
Environmental aspects
Chloroethanol is a metabolite in the degradation of 1,2-dichloroethane. The alcohol is then further oxidized via chloroacetaldehyde to chloroacetate. This metabolic pathway is topical since billions of kilograms of 1,2-dichloroethane are processed annually as a precursor to vinyl chloride.[5]
Safety
2-Chloroethanol is toxic with an LD50 of 89 mg/kg in rats. Like most organochlorine compounds, chloroethanol releases hydrochloric acid and phosgene when burned.
In regards to dermal exposure to 2-chloroethanol, the Occupational Safety and Health Administration has set a permissible exposure limit of 5Template:Nbspppm (16Template:Nbspmg/m3) over an eight-hour time-weighted average, while the National Institute for Occupational Safety and Health has a more protective recommended exposure limit of a 1Template:Nbspppm (3Template:Nbspmg/m3) exposure ceiling.[6]
It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[7]Script error: No such module "Unsubst".
References
- ↑ Ethylene chlorohydrin: properties
- ↑ a b c Template:Ullmann
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- ↑ Template:Ullmann
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- ↑ CDC - NIOSH Pocket Guide to Chemical Hazards
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