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DOE OSTI · 1901932

Selective Lanthanide-Organic Catalyzed Depolymerization of Nylon-6 to ϵ-Caprolactam

Wursthorn, Lukas·Beckett, Kristen·Rothbaum, Jacob O.·Cywar, Robin M.·Lincoln, Clarissa·Kratish, Yosi·Marks, Tobin Jay
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Abstract

We report 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 ..epsilon..-caprolactam depolymerization temperature reported to date. The catalytic activity of the different lanthanide trisamides scales with the Ln 3+ 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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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYcatalysisdepolymerizationlanthanidesnylonplastic recycling

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BibTeXRIS

Wursthorn, Lukas, Beckett, Kristen, Rothbaum, Jacob O., Cywar, Robin M., Lincoln, Clarissa, Kratish, Yosi, Marks, Tobin Jay. 2022-11-28. Selective Lanthanide-Organic Catalyzed Depolymerization of Nylon-6 to ϵ-Caprolactam. https://doi.org/10.1002/anie.202212543

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