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Chloroacetic acid

January 01, 1970

For chloroacetic acids in general, see Chloroacetic acids.

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. It is a colorless solid. Related compounds are dichloroacetic acid and trichloroacetic acid.

Chloroacetic acid
Names
Preferred IUPAC name
Chloroacetic acid
Systematic IUPAC name
Chloroethanoic acid
Other names
2-Chloroacetic acid
2-Chloroethanoic acid
Identifiers
  • 79-11-8 Y
3D model (JSmol)
  • Interactive image
3DMet
  • B02139
ChEBI
  • CHEBI:27869 Y
ChEMBL
  • ChEMBL14090 Y
ChemSpider
  • 10772140 Y
ECHA InfoCard 100.001.072
EC Number
  • 201-178-4
KEGG
  • D07677 Y
  • C06755
  • 300
RTECS number
  • AF8575000
UNII
  • 5GD84Y125G Y
  • DTXSID4020901
  • InChI=1S/C2H3ClO2/c3-1-2(4)5/h1H2,(H,4,5) Y
    Key: FOCAUTSVDIKZOP-UHFFFAOYSA-N Y
  • InChI=1/C2H3ClO2/c3-1-2(4)5/h1H2,(H,4,5)
    Key: FOCAUTSVDIKZOP-UHFFFAOYAR
  • ClCC(O)=O
Properties
ClCH2CO2H
Molar mass 94.49 g·mol−1
Appearance Colorless or white crystals
Density 1.58 g/cm3
Melting point 63 °C (145 °F; 336 K)
Boiling point 189.3 °C (372.7 °F; 462.4 K)
85.8 g/(100 mL) (25 °C)
Solubility Soluble in methanol, acetone, diethyl ether, benzene, chloroform, ethanol
log P 0.22
Vapor pressure 0.22 hPa
Acidity (pKa) 2.86[1]
−48.1×10−6 cm3/mol
1.4351 (55 °C)
Structure
Monoclinic
Thermochemistry
144.02 J/(K·mol)
−490.1 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 alkylating agent
GHS labelling:
Danger
H301, H311, H314, H331, H400
P260, P261, P264, P270, P271, P273, P280, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P311, P312, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
Health 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 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
1
0
Flash point 126 °C (259 °F; 399 K)
470 °C (878 °F; 743 K)
Lethal dose or concentration (LD, LC):
76 mg/kg.[2]
Safety data sheet (SDS) External MSDS
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Not to be confused with Acetyl chloride or Chloroacetyl chloride.

Production edit

Chloroacetic acid was first prepared (in impure form) by the French chemist Félix LeBlanc (1813–1886) in 1843 by chlorinating acetic acid in the presence of sunlight,[3] 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,[4] and then by the French chemist Charles Adolphe Wurtz by hydrolysis of chloroacetyl chloride (ClCH2COCl), also in 1857.[5]

Chloroacetic acid is prepared industrially by two routes. The predominant method involves chlorination of acetic acid, with acetic anhydride as a catalyst:

H3C−COOH + Cl2 → ClH2C−COOH + HCl

This route suffers from the production of dichloroacetic acid and trichloroacetic acid as impurities, which are difficult to separate by distillation:

H3C−COOH + 2 Cl2 → Cl2HC−COOH + 2 HCl
H3C−COOH + 3 Cl2 → Cl3C−COOH + 3 HCl

The second method entails hydrolysis of trichloroethylene:

ClHC=CCl2 + 2 H2O → ClH2C−COOH + 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.[2]

Uses and reactions edit

Most reactions take advantage of the high reactivity of the C−Cl 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.[2]

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.[6][7]

Safety edit

 
Chloroacetic acid burns

Like other chloroacetic acids and related halocarbons, chloroacetic acid is a hazardous alkylating agent. The LD50 for rats is 76 mg/kg.[2]

It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[8]

See also edit

References edit

  1. ^ Dippy, J. F. J.; Hughes, S. R. C.; Rozanski, A. (1959). "498. The dissociation constants of some symmetrically disubstituted succinic acids". Journal of the Chemical Society. 1959: 2492–2498. doi:10.1039/JR9590002492.
  2. ^ a b c d Koenig, G.; Lohmar, E.; Rupprich, N. (2005). "Chloroacetic Acids". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_537. ISBN 978-3527306732.
  3. ^ LeBlanc, Félix (1844) "Recherches sur les produits dérivés de l'éther acétique par l'action du chlore, et en particulier sur l'éther acétique perchloruré" (in French), Annales de Chimie et de Physique, 3rd series, 10 : 197–221 ; see especially p. 212.
  4. ^ Hoffmann, Reinhold (1857) "Ueber Monochloressigsäure" (in German) (On mono-chloroacetic acid), Annalen der Chemie und Pharmacie, 102 (1) : 1–20.
  5. ^ Wurtz, Adolphe (1857) "Note sur l'aldéhyde et sur le chlorure d'acétyle" (in French) (Note on aldehyde and on acetyl chloride), Annales de chimie et de physique, 3rd series, 49 : 58–62, see p. 61.
  6. ^ Burgstahler, A. W.; Worden, L. R. (1966). "Coumarone". Organic Syntheses. 46: 28. doi:10.15227/orgsyn.046.0028; Collected Volumes, vol. 5, p. 251..
  7. ^ Inglis, J. K. H. (1928). "Ethyl Cyanoacetate". Organic Syntheses. 8: 74. doi:10.15227/orgsyn.008.0074.
  8. ^ (PDF) (1 July 2008 ed.), Government Printing Office, archived from the original (PDF) on 25 February 2012, retrieved 29 October 2011

External links edit

  • . CABB. Archived from the original on 6 February 2015. Retrieved 6 February 2015.
  • "Monochloroacetic Acid". IPCS Inchem. Retrieved 20 May 2007.

January 01, 1970
chloroacetic, acid, chloroacetic, acids, general, industrially, known, monochloroacetic, acid, organochlorine, compound, with, formula, clch2co2h, this, carboxylic, acid, useful, building, block, organic, synthesis, colorless, solid, related, compounds, dichlo. For chloroacetic acids in general see Chloroacetic acids 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 It is a colorless solid Related compounds are dichloroacetic acid and trichloroacetic acid Chloroacetic acid Names Preferred IUPAC name Chloroacetic acid Systematic IUPAC name Chloroethanoic acid Other names 2 Chloroacetic acid2 Chloroethanoic acid Identifiers CAS Number 79 11 8 Y 3D model JSmol Interactive image 3DMet B02139 ChEBI CHEBI 27869 Y ChEMBL ChEMBL14090 Y ChemSpider 10772140 Y ECHA InfoCard 100 001 072 EC Number 201 178 4 KEGG D07677 YC06755 PubChem CID 300 RTECS number AF8575000 UNII 5GD84Y125G Y CompTox Dashboard EPA DTXSID4020901 InChI InChI 1S C2H3ClO2 c3 1 2 4 5 h1H2 H 4 5 YKey FOCAUTSVDIKZOP UHFFFAOYSA N YInChI 1 C2H3ClO2 c3 1 2 4 5 h1H2 H 4 5 Key FOCAUTSVDIKZOP UHFFFAOYAR SMILES ClCC O O Properties Chemical formula ClCH2CO2H Molar mass 94 49 g mol 1 Appearance Colorless or white crystals Density 1 58 g cm3 Melting point 63 C 145 F 336 K Boiling point 189 3 C 372 7 F 462 4 K Solubility in water 85 8 g 100 mL 25 C Solubility Soluble in methanol acetone diethyl ether benzene chloroform ethanol log P 0 22 Vapor pressure 0 22 hPa Acidity pKa 2 86 1 Magnetic susceptibility x 48 1 10 6 cm3 mol Refractive index nD 1 4351 55 C Structure Crystal structure Monoclinic Thermochemistry Heat capacity C 144 02 J K mol Std enthalpy offormation DfH 298 490 1 kJ mol Hazards Occupational safety and health OHS OSH Main hazards alkylating agent GHS labelling Pictograms Signal word Danger Hazard statements H301 H311 H314 H331 H400 Precautionary statements P260 P261 P264 P270 P271 P273 P280 P301 P310 P301 P330 P331 P302 P352 P303 P361 P353 P304 P340 P305 P351 P338 P310 P311 P312 P321 P322 P330 P361 P363 P391 P403 P233 P405 P501 NFPA 704 fire diamond 310 Flash point 126 C 259 F 399 K Autoignitiontemperature 470 C 878 F 743 K Lethal dose or concentration LD LC LD50 median dose 76 mg kg 2 Safety data sheet SDS External MSDS Related compounds Related compounds Dichloroacetic acidTrichloroacetic acidFluoroacetic acidBromoacetic acidIodoacetic acidAcetic acid2 Chloropropionic acid3 Chloropropanoic acid2 2 Dichloropropionic acidSodium chloroacetate Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Not to be confused with Acetyl chloride or Chloroacetyl chloride Contents 1 Production 2 Uses and reactions 3 Safety 4 See also 5 References 6 External linksProduction editChloroacetic acid was first prepared in impure form by the French chemist Felix LeBlanc 1813 1886 in 1843 by chlorinating acetic acid in the presence of sunlight 3 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 4 and then by the French chemist Charles Adolphe Wurtz by hydrolysis of chloroacetyl chloride ClCH2COCl also in 1857 5 Chloroacetic acid is prepared industrially by two routes The predominant method involves chlorination of acetic acid with acetic anhydride as a catalyst H3C COOH Cl2 ClH2C COOH HCl This route suffers from the production of dichloroacetic acid and trichloroacetic acid as impurities which are difficult to separate by distillation H3C COOH 2 Cl2 Cl2HC COOH 2 HCl H3C COOH 3 Cl2 Cl3C COOH 3 HCl The second method entails hydrolysis of trichloroethylene ClHC CCl2 2 H2O ClH2C COOH 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 2 Uses and reactions editMost reactions take advantage of the high reactivity of the C Cl 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 2 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 6 7 Safety edit nbsp Chloroacetic acid burns Like other chloroacetic acids and related halocarbons chloroacetic acid is a hazardous alkylating agent The LD50 for rats is 76 mg kg 2 It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U S Emergency Planning and Community Right to Know Act 42 U S C 11002 and is subject to strict reporting requirements by facilities which produce store or use it in significant quantities 8 See also editFluoroacetic acidReferences edit Dippy J F J Hughes S R C Rozanski A 1959 498 The dissociation constants of some symmetrically disubstituted succinic acids Journal of the Chemical Society 1959 2492 2498 doi 10 1039 JR9590002492 a b c d Koenig G Lohmar E Rupprich N 2005 Chloroacetic Acids Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a06 537 ISBN 978 3527306732 LeBlanc Felix 1844 Recherches sur les produits derives de l ether acetique par l action du chlore et en particulier sur l ether acetique perchlorure in French Annales de Chimie et de Physique 3rd series 10 197 221 see especially p 212 Hoffmann Reinhold 1857 Ueber Monochloressigsaure in German On mono chloroacetic acid Annalen der Chemie und Pharmacie 102 1 1 20 Wurtz Adolphe 1857 Note sur l aldehyde et sur le chlorure d acetyle in French Note on aldehyde and on acetyl chloride Annales de chimie et de physique 3rd series 49 58 62 see p 61 Burgstahler A W Worden L R 1966 Coumarone Organic Syntheses 46 28 doi 10 15227 orgsyn 046 0028 Collected Volumes vol 5 p 251 Inglis J K H 1928 Ethyl Cyanoacetate Organic Syntheses 8 74 doi 10 15227 orgsyn 008 0074 40 C F R Appendix A to Part 355 The List of Extremely Hazardous Substances and Their Threshold Planning Quantities PDF 1 July 2008 ed Government Printing Office archived from the original PDF on 25 February 2012 retrieved 29 October 2011External links edit Monochloroacetic Acid CABB Archived from the original on 6 February 2015 Retrieved 6 February 2015 Monochloroacetic Acid IPCS Inchem Retrieved 20 May 2007 Retrieved from https en wikipedia org w index php title Chloroacetic acid amp oldid 1219801611, wikipedia, wiki, book, books, library,

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