Bentseenihapot

Bentseenihapot, or benzoic acids, are a family of aromatic carboxylic acids derived from benzene. They are characterized by one or more carboxyl (CO2H) groups attached to a benzene ring. The simplest member is benzoic acid (C6H5CO2H), a mono‑carboxylic acid used as a food preservative and as a chemical building block.

Beyond benzoic acid, common members include the diacid isomers phthalic acid (ortho‑benzene-1,2-dicarboxylic acid), isophthalic acid (meta‑benzene-1,3-dicarboxylic acid), and terephthalic acid (para‑benzene-1,4-dicarboxylic acid). These diacids differ in the positions of the carboxyl groups on the benzene ring. Terephthalic acid is a key monomer in the production of polyethylene terephthalate (PET) plastics; phthalic acid and its esters are widely used as plasticizers and in various coatings.

Production and properties vary by member. Benzoic acid is typically produced by oxidation of toluene or benzylic feedstocks. Phthalic anhydride, related to phthalic acid, is produced by oxidation of o‑xylene. Terephthalic and isophthalic acids are obtained by oxidation of p‑xylene and m‑xylene, respectively. These acids are generally weak acids and are sparingly soluble in water, with solubility increasing in hot solvents. They can form esters, salts, and higher‑molecular‑weight polymers used in coatings, fibers, and plastics.

Safety and handling considerations include irritation of skin, eyes, and the respiratory tract at high concentrations. They are typically handled under standard chemical‑manufacturing precautions to prevent exposure and environmental release.