Terephthalic acid Terephthalic acid Terephthalic acid is an organic compound with formula CH(COH). This white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tonnes are produced annually. The common name is derived from the turpentine-producing tree "Pistacia terebinthus" and phthalic acid. Terephthalic acid was first isolated (from turpentine) by the French chemist Amédée Cailliot (1805–1884) in 1846. Terephthalic acid became industrially important after World War II. Terephthalic acid was produced by oxidation of "p"-xylene with dilute nitric acid. Air oxidation of "p"-xylene gives "p"-toluic acid, which resists
Maleic acid Maleic acid Maleic acid or "cis"-butenedioic acid is an organic compound that is a dicarboxylic acid, a molecule with two carboxyl groups. Its chemical formula is HOCCH=CHCOH. Maleic acid is the "cis"-isomer of butenedioic acid, whereas fumaric acid is the "trans"-isomer. It is mainly used as a precursor to fumaric acid, and relative to its parent maleic anhydride, maleic acid has few applications. Maleic acid is a less stable molecule than fumaric acid. The difference in "heat of combustion" is 22.7 kJ/mole. The heat of combustion is -1355 kJ/mole. Maleic acid is more soluble in water than fumaric acid. The