Catalytic chemical recycling of polyamide-based plastics

NU 2022-139

INVENTORS
Yosi Kratish
Tobin Jay Marks*
Lukas Wursthorn

SHORT DESCRIPTION 
Commercially available catalysts efficiently depolymerize Nylon 6 to the parent monomer at 240°C, the lowest temperature ever reported.

ABSTRACT
Northwestern researchers have discovered lanthanide amido catalysts can efficiently catalyze the depolymerization of Nylon-6 to the parent monomer, ε-caprolactam. The readily accessible and commercially available lanthanide amido catalysts enable solvent-free, near quantitative, and highly selective depolymerization of Nylon-6 under mild conditions (240 °C). The reaction is effective for virgin polymer and post-consumer products and is also compatible with admixed plastics such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). With this technology, after the initial sorting process in a recycling facility, one can selectively depolymerize Nylon 6 with high yield.

APPLICATIONS 
Recycling of 

• Pure Nylon-6
• Post-consumer Nylon-6 
• Nylon-6 admixed with PP, PE, and PET 

ADVANTAGES 

• Selective recovery of pure monomers
• Commercially available catalysts
• Solvent free
• High isolated yield (>90%)
• Low operation temperature (~240 °C)
• Effective with post-consumer plastics
• Compatible with different plastics mixtures

PUBLICATION
Wursthorn, L., Beckett, K., Rothbaum, J. O., Cywar, R. M., Lincoln, C., Kratish, Y., & Marks, T. J. (2022), Selective Lanthanide‐Organic Catalyzed Depolymerization of Nylon‐6 to ε‑Caprolactam, Angewandte Chemie International Edition.

IP STATUS
A provisional application has been filed.

Schematic diagram of the catalytic chemical recycling of Nylon-6