2-Chlorobenzoic acid

2-Chlorobenzoic acid is an organic compound with the formula ClC₆H₄CO₂H. It is one of three isomeric chlorobenzoic acids, the one that is the strongest acid. This white solid is used as a precursor to a variety of drugs, food additives, and dyes.^[4]

2-Chlorobenzoic acid

Names
Preferred IUPAC name 2-Chlorobenzoic acid
Other names o-Chlorobenzoic acid
Identifiers
CAS Number	118-91-2 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30793 Y
ChEMBL	ChEMBL115243 Y
ChemSpider	8071 Y
ECHA InfoCard	100.003.897
KEGG	C02357 Y
PubChem CID	8374
UNII	8P0867193V Y
CompTox Dashboard (EPA)	DTXSID4024771
InChI InChI=1S/C7H5ClO2/c8-6-4-2-1-3-5(6)7(9)10/h1-4H,(H,9,10) Y Key: IKCLCGXPQILATA-UHFFFAOYSA-N Y InChI=1/C7H5ClO2/c8-6-4-2-1-3-5(6)7(9)10/h1-4H,(H,9,10) Key: IKCLCGXPQILATA-UHFFFAOYAI
SMILES O=C(O)c1ccccc1Cl
Properties
Chemical formula	C7H5ClO2
Molar mass	156.57 g·mol−1
Appearance	white solid
Melting point	142 °C (288 °F; 415 K)
Boiling point	285 °C (545 °F; 558 K)
log P	2.039 [1]
Acidity (pKa)	2.89 [2] [3]
Magnetic susceptibility (χ)	−83.56·10−6 cm3/mol
Hazards
Safety data sheet (SDS)	Oxford MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Synthesis and reactions

See also: α,α,α-trichlorotoluene

It is prepared by the oxidation of 2-chlorotoluene. The laboratory scale reaction employs potassium permanganate.^[5] Alternatively it arises by the hydrolysis of α,α,α-trichloro-2-toluene.

The chloride is readily replaced by ammonia to 2-aminobenzoic acid. Similarly, the chloride is displaced by diphenylphosphide, leading to 2-diphenylphosphinobenzoic acid.

At elevated temperature it decarboxylates.^[4]