Open Loop Recycling – Guanidine Iron(II) Polymerization Catalyst for the Depolymerization of Polylactide

A previously reported non‐toxic guanidine‐iron catalyst active in the ring opening polymerization (ROP) of polylactide (PLA) under industrially relevant conditions was evaluated for its activity in the alcoholysis and aminolysis of PLA under mild conditions. Kinetic and thermodynamic parameters were determined for the methanolysis of PLA with [FeCl2(TMG5NMe2asme)] (C1) using 1H NMR spectroscopy. A comparison with the Zn analog of C1 showed that the metal center has a large impact on the activity for the alcoholysis. Further, the influence of different nucleophiles was tested broadening the scope of products from PLA waste. C1 is the first discrete metal catalyst reported to be active in the selective aminolysis of PLA. Catalyst recycling, scale‐up experiments and solvent‐free alcoholysis were conducted successfully strengthening the industrial relevance and highlighting aspects of green chemistry. Moreover, the selective depolymerization of PLA in polymer blends was successful. C1 is a promising catalyst for a circular (bio)plastics economy. Versatile Allrounder: We report the first iron catalyst active in the selective alcoholysis and aminolysis of PLA using different nucleophiles. Having the increasing plastic waste problem and the acute danger imposed by climate change in mind solvent‐free alcoholysis and catalyst recycling were investigated. Further, the successful selective methanolysis of PLA could facilitate the downstream separation of mixed plastic waste.