Direct Synthesis of Alternating Polycarbonates from CO2 and Diols by Using a Catalyst System of CeO2 and 2-Furonitrile

Yu Gu, Keitaro Matsuda, Akira Nakayama, Masazumi Tamura, Yoshinao Nakagawa, Keiichi Tomishige

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The control technique of polymer molecular weight is required for the synthesis of versatile polymers with various properties. In our previous work, we found that CeO2 + 2-cyanopyridine catalyst system was effective for the direct synthesis of alternating polycarbonates from CO2 and diols, however, the maximum average molecular weight was ∼1000 g mol-1 (degree of polymerization = 7-8). In this study, we succeeded in the synthesis of alternating polycarbonates with higher molecular weight from CO2 and diols by using a catalyst system of CeO2 + 2-furonitrile. The average molecular weight reached up to 5000 g mol-1 and could be controlled by adjusting the amount of diols and 2-furonitrile. Moreover, polycarbonate diols, polycarbonates without capping of OH groups at the ends, were obtained with the average molecular weight of ∼2000 g mol-1. The catalyst system was applicable to the direct polymerization of CO2 and various α,ω-diols, providing the corresponding alternating polymers. Comparison of CeO2 + 2-cyanopyridine and CeO2 + 2-furonitrile catalyst systems based on the kinetics and DFT calculations showed two main causes for the formation of polycarbonates with higher molecular weight in the CeO2 + 2-furonitrile catalyst system: First, the reactivity of 2-furamide, which was formed from 2-furonitrile, with produced polycarbonate diols was lower than that of 2-picolinamide, which was formed from 2-cyanopyridine, leading to decrease of formation of ester-capped polycarbonates. Second, the adsorption of 2-furonitrile on CeO2 was weaker than that of 2-cyanopyridine, leading to low steric hindrance at the active sites of CeO2 and enabling the reaction of longer diols, such as polycarbonate diols with CO2.

Original languageEnglish
Pages (from-to)6304-6315
Number of pages12
JournalACS Sustainable Chemistry and Engineering
Volume7
Issue number6
DOIs
Publication statusPublished - 2019 Mar 18

Keywords

  • Carbon dioxide
  • Cerium oxide
  • Diol
  • Heterogeneous catalyst
  • Polycarbonate

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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