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Published March 29, 2023 | Submitted + Supplemental Material
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A scalable and continuous access to pure cyclic polymers enabled by quarantined heterogeneous catalysts


Cyclic polymers are topologically interesting and envisioned as a lubricant material. However, scalable synthesis of pure cyclic polymers remains elusive. The most straightforward way is to recycle a used catalyst for the synthesis of cyclic polymers. Unfortunately, it is demanding because of the catalyst's vulnerability and inseparability from polymers, which depreciates the practicality of the process. Here, we develop a continuous process streamlined in a circular way that polymerization, polymer separation, and catalyst recovery happen in situ, to dispense a pure cyclic polymer after bulk ring-expansion metathesis polymerization of cyclopentene. It is enabled by introducing silica-supported ruthenium catalysts and a newly-designed glassware. Also, different depolymerization kinetics of the cyclic polymer from its linear analogue is discussed. This process minimizes manual labor, maximizes security of vulnerable catalysts, and guarantees purity of cyclic polymers, thereby showcasing a prototype of a scalable access to cyclic polymers with increased reusability of precious catalysts (≥415,000 turnovers).

Additional Information

The content is available under CC BY NC ND 4.0 License. The authors would like to thank all scientific communities for their cooperative fighting against Covid-19. This work is financially supported by the National Science Foundation (CHE#1807154) and the Creative Research Initiative Grant and the Nano-Material Technology Program through NRF (South Korea). Mr. Nathan Hart at Caltech Glass Shop is gratefully acknowledged for the glass blowing. Dr. Sonjong Hwang is appreciated for the solid-state NMR. Prof. Yan Xu (Peking University), Dr. Jung-Ah Song (Samsung), Ms. Yoon-Jung Jang (Univ. of Minnesota), and Dr. Daryl Allen (Materia) are acknowledged for the helpful discussion and encouragement. Author contributions. R.H.G. and K.-Y.Y. conceived and designed the project. R.H.G. and T.-L.C. directed the project and provided valuable input. K.-Y.Y, Q.G. and J.P.E synthesized the catalysts. K.-Y.Y designed the glassware. K.-Y.Y., J.N. and Q.G. characterized the polymers. J.N. performed depolymerization experiments. R.T. demonstrated the first heterogeneous cyclic polymer process. All authors analyzed the data and discussed the results. K.-Y.Y prepared the initial manuscript and then all authors reviewed and commented on the manuscript. K.-Y.Y., J.N. and Q.G. contributed the project equally. Data availability. All data supporting the findings of this study are available within the Article and its Supplementary Information. The authors declare no competing interests.

Attached Files

Submitted - a-scalable-and-continuous-access-to-pure-cyclic-polymers-enabled-by-quarantined-heterogeneous-catalysts.pdf

Supplemental Material - supplementary-information.pdf



Additional details

August 20, 2023
October 18, 2023