Chloroacetaldehyde

Chloroacetaldehyde
IUPAC name Chloroacetaldehyde
Systematic name Chloroethanal
Identifiers
CAS number	107-20-0 Y, (hydrate: 34789-09-8, 7737-02-2)
ChemSpider	32 Y
UNII	CF069F5D9C Y
Properties
Molecular formula	C2H3Cl
Molar mass	78.50 g mol-1
Appearance	Colourless liquid
Boiling point	85–85.5 °C
Solubility in water	Soluble as hydrate
Hazards
Main hazards	alkylating agent
Related compounds
Related compounds	2-chloroethanol, Chloroacetic acid
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Chloroacetaldehyde is the organic compound with the formula ClCH₂CHO. Like some related compounds, it is highly electrophilic reagent and a potentially dangerous alkylating agent. The compound is not normally encountered in the anhydrous form, but rather as the hydrate (acetal), ClCH₂CH(OH)₂. Chloroacetaldehyde is a useful intermediate in the synthesis, e.g. of 2-aminothiazole or many pharmaceutical compounds. Another use is to facilitate bark removal from tree trunks.

Synthesis and reactions

The hydrate of chloroacetaldehyde is produced by the oxidation of aqueous vinyl chloride using chlorine:

ClCH=CH₂ + Cl₂ + H₂O → ClCH₂CHO + 2 HCl

It can also be prepared from vinyl acetate.^[1]

Being bifunctional, chloroacetaldehyde is a versatile precursor to many heterocyclic compounds. It condenses with thiourea derivatives to give aminothiazoles. This reaction was once important as a precursor to sulfathiazole, one of the first sulfa drugs.^[1]

Environmental aspects

Chloroacetaldehyde is a metabolite in the degradation of 1,2-dichloroethane, which initially converts to chloroethanol. This metabolic pathway is topical since billions of kilograms of 1,2-dichloroethane have been produced as a precursor to vinyl chloride.^[2]

References

1. ^ ^{a b} Reinhard Jira, Erwin Kopp, Blaine C. McKusick, Gerhard Röderer, Axel Bosch, Gerald Fleischmann “Chloroacetaldehydes“ in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a06_527.pub2
2. ^ Janssen, D. B.; van der Ploeg, J. R. and Pries, F., "Genetics and biochemistry of 1,2-dichloroethane degradation", Biodegradation, 1994, 5, 249-57.doi:10.1007/BF00696463