Record Productivity and Unprecedented Molecular Weight for Ring‐Opening Copolymerization of Epoxides and Cyclic Anhydrides Enabled by Organoboron Catalysts

Abstract

Producing polyesters with high molecular weight (Mn) through ring‐opening copolymerization (ROCOP) of epoxides with cyclic anhydrides remains a major challenge. Herein, we communicate a metal‐free, highly active, and high thermoresistance system for the ROCOP of epoxides with cyclic anhydrides to prepare polyesters (13 examples). The organoboron catalysts can endure a reaction temperature as high as 180 °C for the ROCOP of cyclohexane oxide (CHO) with phthalic anhydride (PA) without the observation of any side reactions. The average Mn of the produced poly(CHO‐alt‐PA) climbed to 94.5 kDa with low polydispersity (Ð=1.19). Furthermore, an unprecedented turnover number of 9900, equivalent to an efficiency of 7.4 kg of polyester/g of catalyst, was achieved at a feed ratio of CHO/PA/catalyst=20000:10000:1 at 150 °C. Kinetic studies, crystal structure analysis, 11B NMR spectra, and DFT calculations provided mechanistic justification for the effectiveness of the catalyst system.

Sequence-Reversible Construction of Oxygen-Rich Block Copolymers from Epoxide Mixtures by Organoboron Catalysts

“…Furthermore, cyclic anhydride, such as phthalic anhydride (PA), can replace CO 2 for the ROCOP with CHO, providing well-defined polyether/ polyester block copolymer. 40 Moreover, an ABCDE polyether/polycarbonate/polyester pentablock copolymer can be synthesized by sequential monomer addition (Figures S23 and S24). Figures S25−S47 provide NMR and DSC characterizations of these block copolymers.…”

Sulfur-containing polymers derived from SO2: synthesis, properties, and applications

“…Homopolymerization of epoxides 148,149 or copolymerizations with other oxa-monomers [150][151][152][153][154] (such as anhydrides or carbon dioxide) in the presence of coordination catalysts proceeded smoothly with high reactivity and polymer selectivity. The improved polymerization behavior could be ascribed to the coordination interaction between the catalysts and the oxygen atom in epoxides that greatly reduces the energy barrier for the ring-opening.…”

Alkali metal carbonate catalyzed copolymerization of anhydrides and epoxides: a simple, efficient and versatile approach to well-defined alternating polyesters

“…[12][13][14][15][16][17] A few phosphazene base derivatives and organic Lewis pairs (LPs) have shown fantastic catalytic performance for ROAC. [18][19][20][21][22][23][24][25][26][27][28][29] However, most existing organo-catalysts also show disadvantages of high cost or a complicated synthetic procedure. The search for greener and simpler catalysts will never be out of date.…”