Upcycling of Polylactic acid to 2-Bromopropionates and Lactates

Abstract

Abstract The valorization and recycling of bioderived polylactic acid (PLA) have garnered significant attentions. In this study, a pioneering approach using hydrogen bromide (HBr) catalysis for the degradation of PLA to 2-bromopropionates and lactates is presented. Both HBr solution and HBr-HAc (acetic acid) solution were found to be efficient for the process. Notably, the HBr solution predominantly yields lactic acid (LA) with an exceptional yield of ≥ 99 mol% at temperatures ranging from 80 to 110 oC. Conversely, the HBr-HAc solution yields both 2-bromopropionic acid (2BA) and LA, with 2BA yield achieving a remarkable yield of 55.2 mol% at 100 oC. Subsequently, esterification of the PLA derived 2BA and LA was conducted, and a serious of 2-bromopropionates and lactates were synthetized. Furthermore, the impact of reaction factors was investigated via multivariate analysis methods.