Publisher: American Chemical Society (ACS)

Issue: 3

License:

Publication date(s): 2021/02/05 (print) 2021/01/15 (online)

Pages: 1563-1569

Volume: 11 Issue: 3

Journal: ACS Catalysis

Link: [{"URL"=>"https://pubs.acs.org/doi/pdf/10.1021/acscatal.0c04858", "content-type"=>"unspecified", "content-version"=>"vor", "intended-application"=>"similarity-checking"}]

URL: http://dx.doi.org/10.1021/acscatal.0c04858

Cyclic polyesters could improve the properties of degradable plastics, but routes to them that provide a product with faster rates, higher molar mass, and greater selectivity for cyclic vs linear polymer are needed. Here, homogeneous Ce(III)–N-heterocyclic carbene (NHC) catalysts show outstanding activities (turn-over-frequency (TOF) > 864 000 h–1), excellent control, and selectivity for cyclic polylactide (PLA) topology (>95%), yielding high molar mass PLA (60 < Mn < 250 kg mol–1). They efficiently produce cyclic PLA from rac-lactide or l-lactide and aliphatic cyclic polyesters from ε-caprolactone or β-butyrolactone. The enhanced performances are only achievable from combining cooperative Lewis acidic cerium(III) and hemilabile N-heterocyclic carbene functionalities.