Chloroacetic acid

Chloroacetic acid

Names
Preferred IUPAC name Chloroacetic acid
Other names 2-Chloroacetic acid
Identifiers
CAS Number	79-11-8 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:27869 Y
ChEMBL	ChEMBL14090 Y
ChemSpider	10772140 Y
ECHA InfoCard	100.001.072
EC Number	201-178-4
KEGG	D07677 Y
PubChem	300
RTECS number	AF8575000
UNII	5GD84Y125G Y
InChI 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
SMILES ClCC(O)=O
Properties
Chemical formula	C2H3ClO2
Molar mass	94.49 g·mol−1
Appearance	Colorless or white crystals
Density	1.58 g·cm−3, solid
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/100mL (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
Magnetic susceptibility (χ)	-48.1·10−6 cm3/mol
Refractive index (nD)	1.4351 (55 °C)
Structure
Crystal structure	monoclinic
Thermochemistry
Specific heat capacity (C)	144.02 J/K mol
Std enthalpy of formation (ΔfHo298)	-490.1 kJ/mol
Hazards
Main hazards	alkylating agent
Safety data sheet	External MSDS
R-phrases	R25 R34 R50
S-phrases	S23 S37 S45 S61
NFPA 704	1 3 0
Flash point	126 °C (259 °F; 399 K)
Autoignition temperature	< 500 °C (932 °F; 773 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	165 mg/kg (mouse, oral)
Related compounds
Related compounds	2-chloropropionic acid sodium chloroacetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
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.

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, 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 reacting chloroacetyl chloride (ClCH₂COCl) with water, also in 1857.

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).

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

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

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.

Illustrative of its usefulness in organic chem. 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, and pesticides). Most reactions take advantage of the high reactivity of the C–Cl bond. It is the precursor to the herbicide glyphosate, and 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.