Premium
Chemical Recycling of End‐of‐Life Polyamide 6 via Ring Closing Depolymerization
Author(s) -
Alberti Christoph,
Figueira Ruben,
Hofmann Melanie,
Koschke Svetlana,
Enthaler Stephan
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201903970
Subject(s) - depolymerization , caprolactam , polyamide , monomer , nylon 6 , polymer chemistry , acetic anhydride , polymerization , polymer , chemistry , materials science , organic chemistry , catalysis
Abstract The chemical recycling of end‐of‐life polymers, a sequence of depolymerization and polymerization reactions, enables the conserving of fossil resources and can add some value to the circular economy. In this study, a process for the depolymerization of end‐of‐life Nylon 6 via ring‐closing reactions to produce as building block N ‐acetylcaprolactam have been set up. In detail, a combination of acetic anhydride as depolymerization reagent and catalytic amounts of 4‐dimethylaminopyridine allows under microwave irradiation and within short times (15 min) the conversion of end‐of‐life Nylon 6 to N ‐acetylcaprolactam under solvent‐less conditions. Applying optimized conditions a sequence of Nylon 6 goods was transformed in good yields. The product N ‐acetylcaprolactam was converted to ϵ‐caprolactam by transfer of the acetyl functionality to 2‐aminoethanol to give N ‐(hydroxyethyl)acetamide a precursor for poly( N ‐vinylacetamide). The generated ϵ‐caprolactam can be used as monomer for the synthesis of new Nylon 6, therefore a chemical recycling of the monomeric unit of Nylon 6 is feasible.