# Open‐ and Closed‐Loop Recycling of Polyesters and Post‐Consumer Waste Under Industrially Relevant Conditions Using Bisguanidine Organocatalysts

## TL;DR

This paper introduces a new catalyst that efficiently recycles various plastics, including PLA, PET, and PCL, under mild conditions, making it a promising tool for a sustainable circular plastics economy.

## Contribution

The study presents a highly active and robust bisguanidine organocatalyst for the chemical recycling of multiple polyesters and post-consumer waste.

## Key findings

- Bisguanidine TMG2e completely depolymerizes PLA via alcoholysis within minutes under mild conditions.
- The catalyst effectively handles binary and ternary plastic mixes and is robust against impurities in post-consumer waste.
- TMG2e shows excellent activity for methanolysis and ethanolysis of PLA and can process post-consumer PET waste.

## Abstract

With the increasing demand for sustainable plastic materials, the implementation of a circular plastics economy starting from designing environmentally friendly polymers and including effective recycling strategies is of the utmost importance. The biobased and biodegradable polyester polylactide (PLA) is a promising candidate for a sustainable, circular plastics economy. Polyesters can be chemically recycled to obtain monomers or value‐added chemicals following either a closed‐ or open‐loop recycling approach. However, the requirements for catalysts applicable in post‐consumer waste recycling are high: Besides a high activity, robustness and scalability of the catalyst are important factors. We studied highly active, robust bisguanidine organocatalysts for the depolymerization of the polyesters polycaprolactone, polyethylene terephthalate, and PLA. Focusing on PLA, we investigated the structure–reactivity relationship of the length of the aliphatic linker between the guanidine functionalities to identify the most active catalyst: Bis(N,N,N′,N′‐tetramethylguanidino)ethane (TMG2e) depolymerizes PLA completely via alcoholysis within minutes under mild reaction conditions. The bisguanidine shows excellent activity for the alcoholysis of the investigated polymers, the ability to depolymerize binary and ternary plastic mixes, and robustness against additives, plasticizers, and other impurities in different post‐consumer waste samples. Thus, TMG2e has promising properties to be an asset for the implementation of a sustainable, circular plastics economy.

The chemical recycling of polylactide (PLA), polyethylene terephthalate (PET), and polycaprolactone (PCL) is performed using bisguanidine organocatalysts. Intensive kinetic studies of the methanolysis and ethanolysis of PLA were performed. The most active organocatalyst was successfully applied in the depolymerization of ternary plastic mixes of PLA, PCL, and PET as well as in the depolymerization of post‐consumer PET waste.© 2026 WILEY‐VCH GmbH