Benzoic acid

Benzoic acid is an aromatic organic compound and the simplest aromatic acid^[1], with the chemical formula C₇H₆O₂. It was initially obtained from benzoin resin, hence the name benzoic acid. It has a melting point of 122.13°C, a boiling point of 249.2°C, and a relative density (15/4°C) of 1.2659. Its appearance is white needle-like or flaky crystals. It sublimes above 100°C. It is slightly soluble in cold water and hexane, and soluble in hot water, ethanol, benzene, carbon disulfide, and turpentine, among others^[2-4].

Benzoic acid exists widely in nature in the form of free acid, esters, or their derivatives. It is mainly used to produce sodium benzoate preservative, as well as in the synthesis of pharmaceuticals, dyes, and in the production of plasticizers, mordants, fungicides, and fragrances. It can be prepared by direct oxidation of toluene in the presence of manganese dioxide or by decarboxylation of phthalic anhydride using steam.