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
Acetylenedicarboxylic acid separated and the latter is treated with sulfuric acid. Acetylenedicarboxylic acid is used in the synthesis of dimethyl acetylenedicarboxylate, an important laboratory reagent. The acid is commonly traded as a laboratory chemical. It can also be reacted with sulfur tetrafluoride to produce hexafluoro-2-butyne, a powerful dienophile for use in Diels-Alder reactions. Hydrogenacetylenedicarboxylate (often abbreviated as Hadc or HADC) is a monovalent anion of acetylenedicarboxylic acid with the formula CHO or <chem>HO2C-C#C-CO2-</chem>. The anion can be derived from acetylenedicarboxylic acid by removal of a single proton or from the acetylenedicarboxylate dianion by addition of a proton. The name is also used