Abstract
In order to make recycling a viable strategy for post-consumer plastics, economically feasible revalorization processes must be developed. The ammonolysis of polyamides can be such a cutting-edge recycling technology; however, due to the rigid structure of these polyamide plastics, operating conditions of current ammonolysis processes are harsh, including high temperatures (>300 degrees C) and high NH3 pressures. Here, we report a very green and elegant ammonolysis process of the widely abundant polyamide 66 by using a hard Lewis acid catalyst and 1 bar of NH3 in a simple glycol solvent at 200 degrees C. Computational studies revealed that especially the vicinal diol moiety of these glycol solvents plays a key role in activation of the ammonia nucleophile, with glycerol being the most effective solvent, reaching the depolymerization equilibrium after 20 h even without a catalyst. To our delight, a biosourced glycerol (obtained from the saponification of triglycerides) could also directly serve as a suitable solvent, even outperforming the ammonolysis process in highly purified glycerol.
Original language | English |
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Pages (from-to) | 6923-6930 |
Number of pages | 8 |
Journal | Green Chemistry |
Volume | 24 |
Issue number | 18 |
DOIs | |
Publication status | Published - 20 Sept 2022 |
Keywords
- DEGRADATION
- DEPOLYMERIZATION
- DECOMPOSITION
- HYDROGENATION
- TOXICITY
- POLYMERS
- NYLON-6
- AMIDES