Bioplastics such as poly(lactic acid) (PLA), which are derived from renewable sources, promoted as biodegradable and implemented for numerous functions, offer a promising alternative to the enduring synthetic plastics abundant in society. However, the degradation of PLA is slow under natural environmental conditions. A chemical recycling route is thus required to couple mitigation of plastic persistence repercussions with circular economy adherence. In the present work, the production of ethyl lactate by the catalysed transesterification of post-consumer PLA was investigated. The catalyst employed was a propylendiamine Zn(II) complex. The PLA samples investigated consisted of a phone case, an infant’s toy, a film, a cup and 3D printing material. Degradation reactions were studied at 50 °C and 90 °C and the concentrations measured at two different time intervals, 1 h and 3 h. The results revealed that greater activity of the catalyst was observed at 50 °C for two PLA samples (cup, 3D print). PLA film achieved the greatest lactate yield (71%) of all samples after 3 h at 50 °C. It is concluded that the propylenediamine Zn(II) catalyst can be used to produce green solvent ethyl lactate at mild temperatures from post-consumer PLA, even in the presence of unknown additives.

源自可再生资源的生物塑料，例如聚乳酸（PLA），被推广为可生物降解的，并实现了多种功能，为社会上持久的合成塑料提供了有希望的替代方法。但是，在自然环境条件下，PLA的降解缓慢。因此，需要化学回收途径来将塑料持久性影响的减轻与循环经济的坚持结合起来。在本工作中，研究了消费后PLA的催化酯交换反应生产乳酸乙酯。所用的催化剂是丙二胺锌（Ⅱ）配合物。被调查的PLA样品包括手机壳，婴儿玩具，薄膜，杯子和3D打印材料。在50°C和90°C下研究了降解反应，并在两个不同的时间间隔（1小时和3小时）中测量了浓度。结果表明，对于两个PLA样品（杯，3D打印），在50°C下观察到了更高的催化剂活性。在50°C下放置3 h后，PLA膜的所有样品的乳酸产量最高（71％）。结论是，即使在存在未知添加剂的情况下，丙二胺Zn（II）催化剂也可以在温和的温度下从消费后的PLA生产绿色溶剂乳酸乙酯。