Efficient catalyst removal and recycling in copolymerization of epoxides with carbon dioxide via simple liquid–liquid phase separation

Abstract

A simple and efficient catalyst removal system has been developed in the cobalt-salen-catalyzed copolymerization of propylene oxide with carbon dioxide. The present system requires no prior modification of the catalyst, and the removal is achieved by simple addition of myristic acid, followed by organic liquid-liquid phase separation.

Carbon dioxide copolymers: Emerging sustainable materials for versatile applications

“…91 In another example, Nozaki and coworkers reported a universal catalyst removal method with the Co residue down to 1.9 ppm. 92 To prevent soil from accumulation of heavy metal, it is natural to develop low toxic metal catalyst with high efficiency. Many efforts have been given to efficiently prepare PPC with nontoxic Al centered catalyst.…”

“…The catalysts of Lee and coworkers can be filtered off by silica gel due to the existence of four appended quaternary ammonium salts, keeping Co residue in the range of 1‐2 ppm 91 . In another example, Nozaki and coworkers reported a universal catalyst removal method with the Co residue down to 1.9 ppm 92 …”

Catalysts for CO 2 /epoxide ring-opening copolymerization

“…Finally, the polymerization catalysts should ideally be colourless, odourless, inexpensive and have low toxicity, as they may contaminate the polymer product. In this context, there have been a number of reports of strategies to remove and recycle homogeneous catalysts [33][34][35].…”

Metal-Free Approach for a One-Pot Construction of Biodegradable Block Copolymers from Epoxides, Phthalic Anhydride, and CO2

“…11,12 Removing the residual metals trapped in the resultant polymers, including heavy metals and even benign Zn (Fe), is necessary for their applications in food packaging and biomedical materials. 13,14 In sharp contrast, organocatalytic polymerization is greener and more economical in that it not only avoids undesired metal residuals but also reduces the consumption of metal resources. 15,16 Until 2016, a significant breakthrough in metal-free catalyst system was intelligently achieved by Feng's group in the anionic copolymerization of epoxides and CO 2 , combining triethyl borane (TEB) as an activator and quaternary ammonium salt as an initiator.…”