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|Section2= |Section3= |Section7= |Section8= }} Glycolic acid (or hydroxyacetic acid); chemical formula C2H4O3 (also written as HOCH2COOH), is the smallest α-hydroxy acid (AHA). This colorless, odorless, and hygroscopic crystalline solid is highly soluble in water. It is used in various skin-care products. Glycolic acid is found in some sugar-crops. A glycolate is a salt or ester of glycolic acid. ==Preparation== There are multiple routes of synthesis of glycolic acid that are practiced today. The majority of the world's supply of glycolic acid is made in a catalyzed reaction of formaldehyde with synthesis gas (carbonylation of formaldehyde), as this is a particularly economical preparative route.〔D.J. Loder, (1939).〕 It is also prepared by the reaction of chloroacetic acid with sodium hydroxide followed by re-acidification. In this way, a few million kilograms are produced annually. Other methods, not apparently in use, include hydrogenation of oxalic acid with nascent hydrogen and the hydrolysis of the cyanohydrin derived from formaldehyde.〔 Some of today's glycolic acids are formic acid-free. Glycolic acid can be isolated from natural sources, such as sugarcane, sugar beets, pineapple, cantaloupe, and unripe grapes.〔(3Dchem: Glycolic acid )〕 Glycolic acid can also be prepared using an enzymatic biochemical process which produces fewer impurities compared to traditional chemical synthesis, requires less energy in production and produces less co-product.〔(Glycolic Acid ) at CrossChem.net〕 Each route can be evaluated for its relative costs and benefits. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Glycolic acid」の詳細全文を読む スポンサード リンク
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