Guanidine Carboxy Zinc Complexes for the Chemical Recycling of Renewable Polyesters. Issue 5 (25th March 2022)

• Record Type: Journal Article
• Authors: Fuchs, Martin; Walbeck, Marcel; Jagla, Eveline; Hoffmann, Alexander; Herres‐Pawlis, Sonja
• Is Part Of: ChemPlusChem. Volume 87:Issue 5(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-25
• Subjects: alcoholysis -- chemical recycling -- circular (bio)economy -- homogeneous catalysis -- poly(lactic acid); Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.202200029
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: Our previously published non‐toxic guanidine carboxy Zn catalysts, suitable for lactide ring opening polymerisation (ROP) under industrially preferred melt conditions, have been tested towards the alcoholysis of renewable polyesters. A structure‐reactivity relationship has been found for the methanolysis of PLA in anhydrous THF, dependent on the substituents introduced at the ligand backbone. Using the unsubstituted "TMGasme" catalyst C2, a polyester conversion of 41 % was reached after 5 h at 60 °C. Introducing an electron density donating ‐NMe2 group at the ligand (C3 ) caused and increase in catalyst activity, resulting in a PLA conversion of 72 %. Hence, C3 was further tested, stressing the industrial applicability of PLA chemical recycling. Catalyst recycling, process scale up as well as solvent free alcoholysis, with full degradation in the PLA melt after 1 h, were demonstrated, allowing for the implementation of a circular (bio)plastics economy promoted by these catalysts. Abstract : Old but gold : Three lactide ROP guanidine carboxy Zn catalysts were resynthesised and tested in the chemical recycling of renewable polyesters towards value added lactates. A tuneable activity, dependent on the ligand backbone has been found. With the fastest catalyst fulfilling industrial requirements these catalysts are well suited to promote a circular (bio)plastics economy.