Chloroacetic acid

Chloroacetic acid is the chemical compound with the formula ClCH2CO2H. This carboxylic acid is a useful building block in organic synthesis. Like other chloroacetic acids and related halocarbons, it is a potentially dangerous alkylating agent.

Chloroacetic acid is synthesized by chlorinating of acetic acid in the presence of red phosphorus, sulfur, or iodine as a catalyst:
 * CH3CO2H +  Cl2  →  ClCH2CO2H  +  HCl

It also forms by the hydrolysis of trichloroethylene using sulfuric acid as a catalyst.

Illustrative of its usefulness in organic chemistry is the O-alkylation of salicylaldehyde with chloroacetic acid, followed by decarboxylation of the resulting ether, produces benzofuran.