Nylon‐6 is selectively depolymerized to the parent monomer ϵ‐caprolactam by the readily accessible and commercially available lanthanide trisamido catalysts Ln(N(TMS)2)3(Ln=lanthanide). The depolymerization process is solvent‐free, near quantitative, highly selective, and operates at the lowest Nylon‐6 to ϵ‐caprolactam depolymerization temperature reported to date. The catalytic activity of the different lanthanide trisamides scales with the Ln3+ionic radius, and this process is effective with post‐consumer Nylon‐6 as well as with Nylon‐6+polyethylene, polypropylene or polyethylene terephthalate mixtures. Experimental kinetic data and theoretical (DFT) mechanistic analyses suggest initial deprotonation of a Nylon terminal amido N−H bond, which covalently binds the catalyst to the polymer, followed by a chain‐end back‐biting process in which ϵ‐caprolactam units are sequentially extruded from the chain end.
This content will become publicly available on January 1, 2025
- Award ID(s):
- 2247666
- PAR ID:
- 10522742
- Publisher / Repository:
- Cell Press
- Date Published:
- Journal Name:
- Chem
- Volume:
- 10
- Issue:
- 1
- ISSN:
- 2451-9294
- Page Range / eLocation ID:
- 172 to 189
- Subject(s) / Keyword(s):
- Nylon-6 catalytic deconstruction recycling caprolactam
- Format(s):
- Medium: X Size: 2MB
- Size(s):
- 2MB
- Sponsoring Org:
- National Science Foundation
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Abstract Nylon‐6 is selectively depolymerized to the parent monomer ϵ‐caprolactam by the readily accessible and commercially available lanthanide trisamido catalysts Ln(N(TMS)2)3(Ln=lanthanide). The depolymerization process is solvent‐free, near quantitative, highly selective, and operates at the lowest Nylon‐6 to ϵ‐caprolactam depolymerization temperature reported to date. The catalytic activity of the different lanthanide trisamides scales with the Ln3+ionic radius, and this process is effective with post‐consumer Nylon‐6 as well as with Nylon‐6+polyethylene, polypropylene or polyethylene terephthalate mixtures. Experimental kinetic data and theoretical (DFT) mechanistic analyses suggest initial deprotonation of a Nylon terminal amido N−H bond, which covalently binds the catalyst to the polymer, followed by a chain‐end back‐biting process in which ϵ‐caprolactam units are sequentially extruded from the chain end.
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