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ID 60102
フルテキストURL
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著者
Deng, Jingyuan Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo
Ratanasak, Manussada Institute for Catalysis, Hokkaido University
Sako, Yuma Graduate School of Natural Science and Technology, Okayama University
Tokuda, Hideki Graduate School of Natural Science and Technology, Okayama University
Maeda, Chihiro Graduate School of Natural Science and Technology, Okayama University Kaken ID researchmap
Hasegawa, Jun-ya Institute for Catalysis, Hokkaido University
Nozaki, Kyoko Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo
Ema, Tadashi Graduate School of Natural Science and Technology, Okayama University ORCID Kaken ID publons researchmap
抄録
Bifunctional AlIII porphyrins with quaternary ammonium halides, 2-Cl and 2-Br, worked as excellent catalysts for the copolymerization of cyclohexene oxide (CHO) and CO2 at 120 °C. Turnover frequency (TOF) and turnover number (TON) reached 10 000 h−1 and 55 000, respectively, and poly(cyclohexene carbonate) (PCHC) with molecular weight of up to 281 000 was obtained with a catalyst loading of 0.001 mol%. In contrast, bifunctional MgII and ZnII counterparts, 3-Cl and 4-Cl, as well as a binary catalyst system, 1-Cl with bis(triphenylphosphine)iminium chloride (PPNCl), showed poor catalytic performances. Kinetic studies revealed that the reaction rate was first-order in [CHO] and [2-Br] and zero-order in [CO2], and the activation parameters were determined: ΔH‡ = 12.4 kcal mol−1, ΔS‡ = −26.1 cal mol−1 K−1, and ΔG‡ = 21.6 kcal mol−1 at 80 °C. Comparative DFT calculations on two model catalysts, AlIII complex 2′ and MgII complex 3′, allowed us to extract key factors in the catalytic behavior of the bifunctional AlIII catalyst. The high polymerization activity and carbonate-linkage selectivity originate from the cooperative actions of the metal center and the quaternary ammonium cation, both of which facilitate the epoxide-ring opening by the carbonate anion to form the carbonate linkage in the key transition state such as TS3b (ΔH‡ = 13.3 kcal mol−1, ΔS‡ = −3.1 cal mol−1 K−1, and ΔG‡ = 14.4 kcal mol−1 at 80 °C).
発行日
2020-05-18
出版物タイトル
Chemical Science
11巻
22号
出版者
Royal Society of Chemistry
開始ページ
5669
終了ページ
5675
ISSN
2041-6520
NCID
AA12555653
資料タイプ
学術雑誌論文
言語
English
著作権者
© The Royal Society of Chemistry
論文のバージョン
publisher
DOI
Web of Science KeyUT
関連URL
isVersionOf https://doi.org/10.1039/D0SC01609H
ライセンス
https://creativecommons.org/licenses/by-nc/3.0/
助成機関名
文部科学省
助成番号
JP15H05796
JP15H05805
JP16H01030