Solvent‐Free Heterogeneous Catalytic Hydrogenation of Polyesters to Diols

Abstract

The utilization of carbon resources stored in plastic polymers through chemical recycling and upcycling is a promising approach for mitigating plastic waste. However, most current methods for upcycling suffer from limited selectivity towards a specific valuable product, particularly when attempting full conversion of the plastic. We present a highly selective reaction route for transforming polylactic acid (PLA) into 1,2‐propanediol utilizing a Zn‐modified Cu catalyst. This reaction exhibits excellent reactivity (0.65 g gcat−1 h−1) and selectivity (99.5 %) towards 1,2‐propanediol, and most importantly, can be performed in a solvent‐free mode. Significantly, the overall solvent‐free reaction is an atom‐economical reaction with all the atoms in reactants (PLA and H2) fixed into the final product (1,2‐propanediol), eliminating the need for a separation process. This method provides an innovative and economically viable solution for upgrading polyesters to produce high‐purity products under mild conditions with optimal atom utilization.

Amination of polylactic acid to alanine using a Ru–Co bimetallic catalyst

“…The use of carbon resources stored in PLA through chemical recovery is the upcycling of waste PLA. 5–8 At present, the chemical recovery methods of PLA mainly include hydrolysis, alcoholysis and pyrolysis. Hydrolysis is the degradation of PLA to produce lactic acid, and lactic acid can be used as a raw material to transform into a variety of valuable chemicals, such as acetaldehyde, acetic acid, propionic acid, acrylic acid and ketone.…”