Misplaced Pages

Chloroacetic acid

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.

This is an old revision of this page, as edited by CheMoBot (talk | contribs) at 17:59, 5 December 2011 (Updating {{chembox}} (changes to watched fields - updated 'DrugBank_Ref') per Chem/Drugbox validation (report errors or bugs)). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Revision as of 17:59, 5 December 2011 by CheMoBot (talk | contribs) (Updating {{chembox}} (changes to watched fields - updated 'DrugBank_Ref') per Chem/Drugbox validation (report errors or bugs))(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)
Chloroacetic acid
Chloroacetic acid
Chloroacetic acid
Names
IUPAC name Chloroacetic acid
Systematic IUPAC name Chloroethanoic acid
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.001.072 Edit this at Wikidata
KEGG
RTECS number
  • AF8575000
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C2H3ClO2/c3-1-2(4)5/h1H2,(H,4,5)Key: FOCAUTSVDIKZOP-UHFFFAOYSA-N
  • InChI=1/C2H3ClO2/c3-1-2(4)5/h1H2,(H,4,5)Key: FOCAUTSVDIKZOP-UHFFFAOYAR
SMILES
  • ClCC(O)=O
Properties
Chemical formula C2H3ClO2
Molar mass 94.49 g·mol
Appearance Colorless or white crystals
Density 1.58 g·cm, solid
Melting point 63 °C (145 °F; 336 K)
Boiling point 189.3 °C, 462.5 K, 372.7 °F
Solubility in water 85.8 g/100mL (25 °C)
Acidity (pKa) 2.86
Hazards
Occupational safety and health (OHS/OSH):
Main hazards alkylating agent
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability (yellow): no hazard codeSpecial hazards (white): no code
3 1
Flash point 126 °C
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound

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.

Production

The production of chloroacetic acid was 706,000 tonnes/year in 2010, 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.

Processes

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

CH
3CO
2H + Cl
2 → ClCH
2CO
2H + 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.

CCl
2CHCl + 2 H
2O → ClCH
2CO
2H + 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.

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.

In industry, chloroacetic acid is used in the production of a wide variety of useful compounds; e.g., drugs, dyes, pesticides. 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.

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).

See also

References

  1. Dippy, J.F.J., Hughes, S.R.C., Rozanski, A., J. Chem Soc., 1959, 2492.
  2. ^ M.P. Malveda (july 2011). "CEH Marketing Research Report: MONOCHLOROACETIC ACID". Chemical Economics Handbook. SRI consulting. Retrieved July 2011. {{cite web}}: Check date values in: |accessdate= and |date= (help)
  3. ^ 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

Categories: