Title: Chloroacetaldehyde
CAS Registry Number: 107-20-0
Additional Names: 2-Chloro-1-ethanal; monochloroacetaldehyde
Molecular Formula: C2H3ClO
Molecular Weight: 78.50
Percent Composition: C 30.60%, H 3.85%, Cl 45.16%, O 20.38%
Line Formula: ClCH2CHO
Literature References: Prepd industrially by carefully controlled chlorination of acetaldehyde: Söll, DE 844595 (1943 to Knapsack-Griesheim); Shawinigan Chem. Ltd., GB 644914 (1947); Guinot, Tabuteau, Compt. Rend. 231, 234 (1950); FR 1012991 (1950 to Comp. des Prod. Chim. et Electrometallurg.).
Properties: Liquid. Acrid, penetrating odor. bp760 85-86°. The anhydr substance polymerizes on standing but reverts to the monomer on distillation.
Boiling point: bp760 85-86°
Derivative Type: Hemihydrate
Properties: Probably ClCH2CH(OH)OCH(OH)CH2Cl, platelets from water, mp 43-50°, bp 85.5° with decompn into water and chloraldehyde. Sol in water, alcohol, ether.
Melting point: mp 43-50°
Boiling point: bp 85.5° with decompn into water and chloraldehyde
CAUTION: Potential symptoms of overexposure are irritation of eyes, skin and mucous membranes; skin burns; eye damage; pulmonary edema; skin, respiratory system sensitization. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 60.
Use: In the manufacture of 2-aminothiazole; to facilitate bark removal from tree trunks.
Chloroacetamide Chloroacetanilide Chloroacetic Acid Chloroacetic Anhydride Chloroacetone

Structural formula Ball-and-stick model
CAS number 107-20-0 YesY, (hydrate: 34789-09-8, 7737-02-2)
PubChem 33
ChemSpider 32 YesY
EC number 203-472-8
Jmol-3D images Image 1
Molecular formula C2H3ClO
Molar mass 78.50 g mol-1
Appearance Colourless liquid
Odor accrid, penetrating
Density 1.117 g/mL
Melting point −16.3 °C; 2.7 °F; 256.8 K
Boiling point 85–85.5 °C
Solubility in water soluble
Solubility soluble in acetone, methanol
Main hazards alkylating agent
Flash point 87.7 °C (189.9 °F) (closed cup)
Related compounds
Related compounds 2-chloroethanol, Chloroacetic acid
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 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.