Aliphatic polyesters are an important class of plastics that are biocompatible and biodegradable, making them attractive as replacements for nondegradable plastics. The perfectly alternating copolymerization of epoxides and cyclic anhydrides is a promising method for the synthesis of polyesters with an impressive range of chemical and physical properties. Current catalytic methods have centered around the design of catalysts with salen- and porphyrin-like ligands with metals such as Al, Cr, and Mg. Although ligand modifications can improve the rate and control of the polymerization, high molecular weights are still unachievable by many catalysts and catalyst structure often needs to be optimized for each monomer pair. Herein, the use of simple rare earth metal salts as efficient and controlled catalysts for the synthesis of aliphatic polyesters is presented. These salts, in the presence of a cocatalyst, can catalyze an array of substituted epoxides and cyclic anhydrides with great efficiency and control without the need of a supporting ligand framework. High molecular weight polymers can also be synthesized without evidence of catalyst deactivation. Furthermore, when these salts are applied as a benchtop catalyst exposed to moisture and oxygen, surprisingly effective catalysis for numerous monomers is observed. Trends of the different rare earth metal salts and selectivity towards a variety of monomer pairs in addition to characterization of high molecular weight polymers will be discussed.

Simple salts as efficient and controlled catalysts for the synthesis of sustainable polymers

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.