Preparation of Novel Functionalized Ammonium Salts that Effectively Catalyze Depolymerization of Nylon-6 in Ionic Liquids

Abstract

A new type of ammonium salt containing DMAP in the cation was prepared and applied for the depolymerization of nylon-6 giving monomeric caprolactam in high yield through direct distillation. The ionic liquids could be used at least five times.

Chemical Recycling of End‐of‐Life Polyamide 6 via Ring Closing Depolymerization

“…Purification of the product was carried out by extraction or distillation to isolate the monomer 3 and to recover the ionic liquid. However, under these conditions the ionic liquid tends to decompose, which hampers the overall atom economy of this procedure …”

“…However, under these conditions the ionic liquid tends to decompose, which hampers the overall atom economy of this procedure. [40][41][42][43] Recently, we have demonstrated the application of acetic anhydride as depolymerization reagent in the depolymerization of poly(bisphenol A carbonate) in the presence of DMAP as catalyst. [44] As major product diacetylated bisphenol A was obtained.…”

Organocatalysis for depolymerisation

“…Finally, the same research group depolymerised PA-6 in these quaternary ammonium-based ILs using DMAP salts prepared with iodine and imidazolium as counter anions. 54 This system catalysed the reaction several times, reaching up to 79% of monomer recovery; however, since their performances in terms of catalytic activity and selectivity were poorer than the ones displayed in previous experiments using DMAP alone, this catalyst was not further investigated.…”

Preparation of SRN1-Type Coupling Adducts from Aliphatic gem-Dinitro Compounds in Ionic Liquids

“…Recently ionic liquids have attracted significant interest in organic synthesis because of their unique properties such as wide redox windows, high polarities and high solubilities [23,24,25,26,27,28]. During the course of our investigation on ionic liquid chemistry [29,30,31], it occurred to us that ionic liquids could become a new solvent system for a reaction via electron transfer such as S RN 1 reaction. To our best of knowledge, there have been no reports that employ ionic liquids for such reactions.…”