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|Section2= |Section7= }} Lactide is the cyclic di-ester of lactic acid, i.e., 2-hydroxypropionic acid. Lactic acid cannot form a lactone as other hydroxy acids do because the hydroxy group is too close to the carboxylic group. Instead, lactic acid first forms a dimer, which is similar to a 5-hydroxyacid. The dimer contains a hydroxy group at a convenient distance from the carboxylic group for the formation of a lactone. Indeed, the dimer readily forms a six-membered cyclic diester known as lactide. Lactides may be prepared by heating lactic acid in the presence of an acid catalyst. In general, a lactide is the cyclic diester, i.e., the di-lactone of two molecules of any 2-hydroxycarboxylic acid. ==Stereoisomers== Lactic acid is chiral; two enantiomeric forms, (''R'')-lactic acid and (''S'')-lactic acid, may exist. Thus, lactide formed from two equivalents of lactic acid consists of two stereocenters. Three different stereoisomers of lactide are known: 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「lactide」の詳細全文を読む スポンサード リンク
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