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chloroacetic acids in general
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|Verifiedfields = changed
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|verifiedrevid = 464362551
|Name = Chloroacetic acid
|ImageFile1 = Chloroacetic acid 2D skeletal. png
|ImageSize1 =
|ImageName1 = Chloroacetic acid
|ImageFile2 = Chloroacetic acid 3D vdW. png
|ImageSize2 = 150px
|ImageName2 = Chloroacetic acid
|PIN = Chloroacetic acid
|SystematicName = Chloroethanoic acid
|OtherNames = 2 Chloroacetic acid2 Chloroethanoic acid
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|Section7=Chembox Hazards
|ExternalSDS = External MSDS
|MainHazards = alkylating agent
|NFPA H = 3
|NFPA F = 1
|NFPA R = 0
|FlashPtC = 126
|AutoignitionPtC = 470
|GHSPictograms =
|GHSSignalWord = Danger
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|LD50 = 76 mg/kg. and in 1857 (in pure form) by the German chemist Reinhold Hoffmann (1831–1919) by refluxing glacial acetic acid in the presence of chlorine and sunlight, and then by the French chemist Charles Adolphe Wurtz by hydrolysis of chloroacetyl chloride (|ClCH2COCl), also in 1857. Chloroacetic acid is prepared industrially by two routes. The predominant method involves chlorination of acetic acid, with acetic anhydride as a catalyst:
|H3C\sCOOH + Cl2 → ClH2C\sCOOH + HCl

This route suffers from the production of dichloroacetic acid and trichloroacetic acid as impurities, which are difficult to separate by distillation:
|H3C\sCOOH + 2 Cl2 → Cl2HC\sCOOH + 2 HCl
|H3C\sCOOH + 3 Cl2 → Cl3C\sCOOH + 3 HCl

The second method entails hydrolysis of trichloroethylene:
|ClHC\dCCl2 + 2 H2O → ClH2C\sCOOH + 2 HCl

The hydrolysis is conducted at 130–140 °C in a concentrated (at least 75%) solution of sulfuric acid. This method produces a highly pure product, unlike the halogenation route. However, the significant quantities of HCl released have led to the increased popularity of the halogenation route. Approximately 420,000 tonnes are produced globally per year.

Most reactions take advantage of the high reactivity of the |C\sCl bond. In its largest scale application, chloroacetic acid is used to prepare the thickening agent carboxymethyl cellulose and carboxymethyl starch. Chloroacetic acid is also used in the production of phenoxy herbicides by etherification with chlorophenols. In this way 2 methyl 4 chlorophenoxyacetic acid (MCPA), 2,4 dichlorophenoxyacetic acid, and 2,4,5 trichlorophenoxyacetic acid (2,4,5 T) are produced. It is the precursor to the herbicide glyphosate and dimethoate. Chloroacetic acid is converted to chloroacetyl chloride, a precursor to adrenaline (epinephrine). Displacement of chloride by sulfide gives thioglycolic acid, which is used as a stabilizer in PVC and a component in some cosmetics.

Like other chloroacetic acids and related halocarbons, chloroacetic acid is a hazardous alkylating agent. The for rats is 76 mg/kg.