中文名称：3,6-二甲基-1,4-二氧杂环己烷-2,5-二酮、DL-丙交酯、内消旋乳酸

英文名称：3,6-Dimethyl-1,4-dioxane-2,5-dione、(+/-)-3,6-Dimethyl-1,4-dioxane-2,5-dione、DL-Lactide

3,6-二甲基-1,4-二氧杂环己烷-2,5-二酮（或 rac-丙交酯），是D和L-丙交酯50:50的外消旋混合物。rac-丙交酯是一种衍生自乳酸的内酯，因其源自丰富的可再生资源而引起了学术界和商业应用的极大兴趣。通过使用各种金属或有机催化剂，rac-丙交酯可以通过开环聚合进行聚合，从而得到聚（D，L-丙交酯）。虽然所得聚合物通常是无定形的，但立体定向催化剂的使用可生成异顺性PLA，其表现出一定程度的结晶度。

3,6-dimethyl-1,4-dioxane-2,5-dione (or RAC lactide) is a racemic mixture of D and L-lactide in the ratio of 50:50. RAC lactide is a lactone derived from lactic acid. It has attracted great interest in academic and commercial applications because of its rich renewable resources. By using various metal or organic catalysts, RAC lactide can be polymerized by ring opening polymerization to obtain poly (D, L-lactide). Although the resulting polymers are usually amorphous, the use of stereotactic catalysts can produce heterocis PLA, which shows a certain degree of crystallinity.