Depolymerization of End-of-Life Poly(lactide) to Lactide via Zinc-Catalysis

Abstract

The chemical recycling of poly(lactide) (PLA), especially the initial depolymerization step was studied. High molecular weight PLA was depolymerized in the presence of zinc catalyst to lactide, the industrial relevant chemical for the synthesis of high molecular weight PLA; therefore, an efficient recycling is feasible without the need for depolymerization reagents. An excellent performance was observed for zinc(II) acetate with turnover frequencies of up to ∼260 h−1 at 200–210 °C. Noteworthy, the lactide was isolated in high purity by reactive distillation. Furthermore, the zinc(II) acetate catalyst was recycled up to five times.