A scalable and continuous access to pure cyclic polymers enabled by quarantined heterogeneous catalysts

06 October 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


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).


Cyclic Polymers
Catalyst Recycling
Synthetic Process
Olefin Metathesis
Polymer Topology

Supplementary materials

Supplementary Information
Supporting Figures and Tables, Experimental Details, Synthetic Procedures, NMR Spectra


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