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Published on: November 21, 2017
Facile Synthesis of Syndiotactic Polyhydroxyalkanoates Enabled by Stereoselective Copolymerization of Rac-epoxides
Jun Yang1, Jin-Chuang Yang2, Xiao-Bing Lu1
1State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, Dalian University of Technology, 116024 Dalian, China.
Abstract:
Polyhydroxyalkanoates (PHAs) have served as promising alternatives to traditional petroleum-based plastics. Chemical synthesis of stereoregular PHAs via stereoselective copolymerization of racemic-epoxides with carbon monoxide (CO) has not yet been achieved. Here, the design of trimetallic ligand platform featuring various electronic nature and steric demand enables CrIII-catalyzed stereoselective copolymerization of racemic-epoxides with CO, yielding 9 types of functionalized PHA products having 0.70 syndiotacticity. Kinetic study has revealed that trimetallic complex favored the intramolecular chain propagation for the preparation of high molecular weight PHAs with high reactivity and moderate syndiotacticity, while monometallic complex promoted the intermolecular chain propagation toward isotactic-enriched PHAs.
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