一步法合成丙交酯

One-Step Synthesis of Lactide

摘要:

聚乳酸（PLA）是最有前途的可生物降解聚合物之一。国家“禁塑令”的颁布，使得PLA产量和应用领域得到史无前例的扩大。丙交酯（LD）作为生物塑料PLA的关键中间体，其化学纯度、光学纯度和生产成本直接决定PLA的质量和经济价值。目前工业上常见的是两步法合成技术，预聚?解聚的方法可保证乳酸的转化率，但是难以避免LD外消旋化反应，选择性低，能源成本高。一步法作为一种替代策略，很好地克服了两步法合成LD的一些缺点。因此，文中重点介绍一步法合成LD，并对不同的方法进行了介绍和技术比较。

Abstract:

Polylactic acid （PLA） is widely considered to be one of the most promising biodegradable polymers. The promulgation of the national “banning plastic bags” has led to an unprecedented expansion of PLA production and application areas. The chemical purity， optical purity， and production cost of lactide （LD）， a key intermediate of bioplastic PLA， directly determine the quality and economic value of PLA. The two-step synthesis technology is standard in the industry nowadays， and the pre-polymerization-depolymerization approach ensures the conversion rate of lactic acid. Still， its main problems are LD racemization， low selectivity， and high energy cost. The one-step method as an alternative strategy is well suited to overcome some disadvantages of the two-step LD synthesis. Therefore， this review focuses on the one-step synthesis of LD and describes and compares the different methods technically.