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).[6] 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.[7]
2-Chloroethanol is produced by treating ethylene with hypochlorous acid:[7]
2-Chloroethanol was once produced on a large scale as a precursor to ethylene oxide:
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.[7] Many of these applications entail its use in installing 2-hydroxyethyl groups.[8] Several dyes are prepared by the alkylation of aniline derivatives with chloroethanol.[9] 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.
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.[10]
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 5 ppm (16 mg/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 1 ppm (3 mg/m3) exposure ceiling.[11]
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.[12][failed verification]
For example, the omission of the locant '1' in 2-chloroethanol, while permissible in general usage, is not allowed in preferred IUPAC names, thus the name 2-chloroethan-1-ol is the PIN.