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
Orthosilicic acid Orthosilicic acid Orthosilicic acid is the chemical compound with formula . It is assumed to be present in dilute solutions of silicon dioxide (silica) in water. It can be synthesized in non-aqueous solutions. The term "silicic acid" has traditionally been used as a synonym for silicon dioxide, SiO, also known as "silica". Strictly speaking, silica is the anhydride of orthosilicic acid, Si(OH), from which it can be obtained by a dehydration reaction. The solubility of silica in pure water is about 1.5mM, or less, depending on the solid state structure of the compound. Because the concentration of orthosilicic acid is