![]() ![]() īy 1910, most glacial acetic acid was obtained from the pyroligneous liquor, a product of the distillation of wood. This reaction sequence consisted of chlorination of carbon disulfide to carbon tetrachloride, followed by pyrolysis to tetrachloroethylene and aqueous chlorination to trichloroacetic acid, and concluded with electrolytic reduction to acetic acid. In 1845 German chemist Hermann Kolbe synthesised acetic acid from inorganic compounds for the first time. French chemist Pierre Adet proved them identical. The presence of water in vinegar has such a profound effect on acetic acid's properties that for centuries chemists believed that glacial acetic acid and the acid found in vinegar were two different substances. In the 16th-century German alchemist Andreas Libavius described the production of acetone from the dry distillation of lead acetate, ketonic decarboxylation. Sapa that was produced in lead pots was rich in lead acetate, a sweet substance also called sugar of lead or sugar of Saturn, which contributed to lead poisoning among the Roman aristocracy. Ancient Romans boiled soured wine to produce a highly sweet syrup called sapa. The use of acetic acid in alchemy extends into the third century BC, when the Greek philosopher Theophrastus described how vinegar acted on metals to produce pigments useful in art, including white lead ( lead carbonate) and verdigris, a green mixture of copper salts including copper(II) acetate. Vinegar was known early in civilization as the natural result of exposure of beer and wine to air, because acetic acid-producing bacteria are present globally. The name "acetate" can also refer to a salt containing this anion, or an ester of acetic acid. Acetate is the ion resulting from loss of H + from acetic acid. In the context of acid–base reactions, the abbreviation HAc is sometimes used, where Ac in this case is a symbol for acetate (rather than acetyl). To better reflect its structure, acetic acid is often written as CH 3−C(O)OH, CH 3−C(=O)OH, CH 3COOH, and CH 3CO 2H. (The symbol Ac for the acetyl functional group is not to be confused with the symbol Ac for the element actinium context prevents confusion among organic chemists). Ī common symbol for acetic acid is AcOH (or HOAc), where Ac is the pseudoelement symbol representing the acetyl group CH 3−C(=O)− the conjugate base, acetate ( CH 3COO −), is thus represented as AcO −. Acetic acid can never be truly water-free in an atmosphere that contains water, so the presence of 0.1% water in glacial acetic acid lowers its melting point by 0.2 ☌. ![]() Similar to the German name "Eisessig" ("ice vinegar"), the name comes from the solid ice-like crystals that form with agitation, slightly below room temperature at 16.6 ☌ (61.9 ☏). "Glacial acetic acid" is a name for water-free ( anhydrous) acetic acid. The name "acetic acid" derives from the Latin word for vinegar, " acetum", which is related to the word " acid" itself. The systematic name "ethanoic acid", a valid IUPAC name, is constructed according to the substitutive nomenclature. ![]() The trivial name "acetic acid" is the most commonly used and preferred IUPAC name. Its production and subsequent industrial use poses health hazards to workers, including incidental skin damage and chronic respiratory injuries from inhalation. The global demand for acetic acid is about 6.5 million metric tonnes per year (t/a), manufactured from methanol. When bound to coenzyme A, it is central to the metabolism of carbohydrates and fats. In biochemistry, the acetyl group, derived from acetic acid, is fundamental to all forms of life. In the food industry, acetic acid is controlled by the food additive code E260 as an acidity regulator and as a condiment. In households, diluted acetic acid is often used in descaling agents. It is an important chemical reagent and industrial chemical across various fields, used primarily in the production of cellulose acetate for photographic film, polyvinyl acetate for wood glue, and synthetic fibres and fabrics. It has been used, as a component of vinegar, throughout history from at least the third century BC.Īcetic acid is the second simplest carboxylic acid (after formic acid). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Acetic acid / ə ˈ s iː t ɪ k/, systematically named ethanoic acid / ˌ ɛ θ ə ˈ n oʊ ɪ k/, is an acidic, colourless liquid and organic compound with the chemical formula CH 3COOH (also written as CH 3CO 2H, C 2H 4O 2, or HC 2H 3O 2). ![]()
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