Chloroacetic acid

Chloroacetic acid
Identifiers
CAS number 79-11-8 YesY
ChemSpider 10772140 YesY
UNII 5GD84Y125G YesY
KEGG D07677 YesY
ChEBI CHEBI:27869 YesY
ChEMBL CHEMBL14090 YesY
RTECS number AF8575000
Jmol-3D images Image 1
Properties
Molecular formula C2H3ClO2
Molar mass 94.5 g mol−1
Appearance Colorless or white crystals
Density 1.58 g cm−3, solid
Melting point

63 °C, 336 K, 145 °F

Boiling point

189.3 °C, 462.5 K, 372.7 °F

Solubility in water 85.8 g/100mL (25 °C)
Acidity (pKa) 2.86[1]
Hazards
MSDS External MSDS
R-phrases R25 R34 R50
S-phrases S23 S37 S45 S61
Main hazards alkylating agent
NFPA 704
NFPA 704.svg
1
3
0
Flash point 126 °C
Related compounds
Related compounds 2-chloropropionic acid
sodium chloroacetate
 YesY acid (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Chloroacetic acid, industrially known as monochloroacetic acid (MCA) is the organochlorine compound with the formula ClCH2CO2H. This carboxylic acid is a useful building-block in organic synthesis.

Contents

Production

The production of chloroacetic acid was 706,000 tonnes/year in 2010,[2] of which over half is produced in China. Other countries with significant production capacity are Germany (105,000), the Netherlands (100,000), India (>65,000), and the United States (55,000). The world's largest producer is Akzo Nobel.[2]

Processes

Chloroacetic acid is prepared industrially via two routes. The predominant method involves chlorination of acetic acid:

CH3CO2H + Cl2ClCH2CO2H + HCl

Acetic anhydride serves as a catalyst for this reaction.

The other main industrial route to chloroacetic acid is hydrolysis of trichloroethylene using sulfuric acid as a catalyst.

CCl2CHCl + 2 H2OClCH2CO2H + 2 HCl

The hydrolysis method produces a highly pure product, which can be important since mono-, di-, and trichloroacetic acids are difficult to separate by distillation. Approximately, 420,000,000 kg/y are produced globally.[3]

Reactivity and uses

Illustrative of its usefulness in organic chemistry is the O-alkylation of salicylaldehyde with chloroacetic acid, followed by decarboxylation of the resulting ether, producing benzofuran.[4]

In industry, chloroacetic acid is used in the production of a wide variety of useful compounds, e.g., drugs, dyes, pesticides.[3] Most reactions taking advantage of the high reactivity of the C–Cl bond. It is the precursor to the herbicide glyphosate. The herbicides MCPA (2-methyl-4-chlorophenoxyacetic acid) and dimethoate are prepared by alkylation with chloroacetic acid. 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.

In its largest-scale application, chloroacetic acid is used to prepare the thickening agent carboxymethyl cellulose and carboxymethyl starch.

Safety

Like other chloroacetic acids and related halocarbons, chloroacetic acid is a potentially dangerous alkylating agent. The LD50 for rats is 76 mg/kg.[3]

Chloroacetic acid easily penetrates skin and mucous membranes and interferes with cellular energy production. Initial dermal exposure to high concentrations (e.g., 80% solution) may not appear very damaging at first, however systemic poisoning may present within hours. Exposure can be fatal if greater than 6% body surface area is exposed to chloroacetic acid. The sodium salt does not penetrate the skin as well as the acid but can be as damaging given a longer duration and greater surface area of exposure.

Upon one's exposure to chloroacetic acid, immediate decontamination should be commenced by rinsing the affected area with water or bicarbonate solution in order to neutralize the acid and prevent further skin absorption.

The antidote of chloroacetic acid poisoning is sodium dichloroacetate (50 mg/kg IV over 10 mins, repeated in 2h; double dosage if hemodialysis is performed).[citation needed]

See also

References

  1. ^ Dippy, J.F.J., Hughes, S.R.C., Rozanski, A., J. Chem Soc., 1959, 2492.
  2. ^ a b M.P. Malveda (july 2011). "CEH Marketing Research Report: MONOCHLOROACETIC ACID". Chemical Economics Handbook. SRI consulting. http://www.sriconsulting.com/CEH/Public/Reports/676.1000/. Retrieved July 2011. 
  3. ^ a b c Günter Koenig, Elmar Lohmar, Norbert Rupprich "Chloroacetic Acids" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a06_537
  4. ^ Burgstahler, A. W.; Worden, L. R. (1966). "Coumarone." Org. Synth. 46: 28.

External links


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Look at other dictionaries:

  • chloroacetic acid — chloracto rūgštis statusas T sritis chemija formulė ClCH₂COOH atitikmenys: angl. chloroacetic acid rus. хлоруксусная кислота ryšiai: sinonimas – chloretano rūgštis …   Chemijos terminų aiškinamasis žodynas

  • chloroacetic acid — An acetic acid in which one or more of the hydrogen atoms are replaced by chlorine. According to the number of atoms so displaced the acid is called monochloroacetic (chloroacetic), dichloroacetic, or trichloroacetic. SYN: chloracetic acid. * * * …   Medical dictionary

  • chloroacetic acid — /ˌklɔroʊəsitɪk ˈæsəd/ (say .klawrohuhseetik asuhd) noun any of three acetic acids monochloroacetic acid, CH2Cl.COOH, which forms rhombic crystals; dichloroacetic acid, CHCl2.COOH, which is a colourless liquid; and trichloroacetic acid, CCl3.COOH …   Australian English dictionary

  • chloroacetic acid — a colorless, crystalline, deliquescent, water soluble powder, C2H3ClO2, usually derived from acetic acid by chlorination: used chiefly in the manufacture of dyes and other organic compounds. Also, chloracetic acid. Also called monochloroacetic… …   Universalium

  • chloroacetic acid — noun The chlorinated derivative of acetic acid CHCl COOH that is used in organic synthesis …   Wiktionary

  • chloroacetic acid — …   Useful english dictionary

  • Chloroacetic acids — In organic chemistry, the chloroacetic acids (systematic name chloroethanoic acids) are three related chlorocarbon carboxylic acids: Chloroacetic acid (chloroethanoic acid ), CH2ClCOOH Dichloroacetic acid (dichloroethanoic acid), CHCl2COOH… …   Wikipedia

  • chloroacetic — /klawr oh euh see tik, euh set ik, klohr /, adj. of or derived from chloroacetic acid. [CHLORO 2 + ACETIC] * * * …   Universalium

  • chloroacetic — /klawr oh euh see tik, euh set ik, klohr /, adj. of or derived from chloroacetic acid. [CHLORO 2 + ACETIC] …   Useful english dictionary

  • Trichloroacetic acid — Chembox new Name = Trichloroacetic acid ImageFileL1 = Trichloroacetic acid 2D skeletal.png ImageSizeL1 =100px ImageFileR1 = Trichloroacetic acid 3D vdW.png ImageSizeR1 =120px ImageFile2 = Trichloroacetic acid elpot.png ImageSize2 =150px IUPACName …   Wikipedia

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