Depolymerization of End-of-Life Poly(bisphenol A carbonate) via 4-Dimethylaminopyridine-Catalyzed Methanolysis

Recent Advances in Monomer Design for Recyclable Polymers

“…双酚 A-聚碳酸酯是一类应用极其广泛的工程塑料, 由于单体不具备环张力, 其化学循环只能通过水解、醇 解、酚解、胺解和氢解反应, 得到二醇单体及小分子产 物 [126][127][128][129][130][131] (图 18). 相对于芳香环结构, 线性脂肪族聚碳 酸酯的稳定性差, 更加容易发生化学解聚过程.…”

Closed‐Loop Recycling of Poly(Imine‐Carbonate) Derived from Plastic Waste and Bio‐based Resources

“…Closed‐loop recycling also provides ample opportunities to conserve the vast volume of chemical resources that are imbedded in synthetic macromolecules. To this end, chemical recycling which encompasses the controlled cleaving of chemical bonds in polymers to recover the monomeric species in high yields represents a sustainable method to produce fresh polymers without loss of quality and resources [10–16] . This strategy additionally allows for the generation of value‐added monomers from traditional polymers and thus provides access to upcycled polymeric materials with superior properties [5, 7, 17] …”

Synthesis of Functionalized Cyclic Carbonates through Commodity Polymer Upcycling

“…The chemical recycling of BPA-PC into its starting material, bisphenol A (BPA), has been previously reported using different catalysts through hydrolysis − or hydrogenation, but the procedure implies the carbonate group to be lost. Alcoholysis − and aminolysis , have also been investigated, capturing the otherwise released CO unit, but only to produce organic carbonate and carbamate byproducts with a limited broader use and value. More interestingly, recent studies have also reported the depolymerization of bisphenol A-based polycarbonate (BPA-PC) as a highly interesting carbon source for the preparation of five-membered cyclic carbonates. − …”

“…Several organic catalysts have been successfully employed for the depolymerization of BPA-PC into BPA, specifically organic bases including TBD, DBU, and DMAP, ,, but their limited thermal stability (degradation starting at 100–120 °C) is detrimental if high temperatures are required for the depolymerization (typically >160 °C) or for the reuse of the catalyst for several reactionseven at only 75 °C, TBD starts to degrade after three loops of 2 h . To mitigate this issue, mixtures of organic acids and bases have recently presented enhanced thermal stability .…”

“…By combining cost benefits and waste reduction, the depolymerization of such discarded plastics into high-added-value monomers can thus be considered as an upcycling methodology. 24−26 Several organic catalysts have been successfully employed for the depolymerization of BPA-PC into BPA, specifically organic bases including TBD, DBU, and DMAP, 16,21,27 but their limited thermal stability (degradation starting at 100−120 °C) is detrimental if high temperatures are required for the depolymerization (typically >160 °C) or for the reuse of the catalyst for several reactionseven at only 75 °C, TBD starts to degrade after three loops of 2 h. 21 To mitigate this issue, mixtures of organic acids and bases have recently presented enhanced thermal stability. 28 Among them, TBD:MSA is a protic ionic salt obtained from the mixtures of stoichiometric quantities of triazabicyclodecene (TBD) and methanesulfonic acid (MSA) (Figures S1−S4 and Table S1).…”