2-Chlorobenzoic acid is an organic compound with the formula ClC<sub>6</sub>H<sub>4</sub>CO<sub>2</sub>H. 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.
It is prepared by the oxidation of 2-chlorotoluene. The laboratory scale reaction employs potassium permanganate. Alternatively it arises by the hydrolysis of ñ,ñ,ñ-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.