SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2024, Vol. 69 ›› Issue (5): 135-142.DOI: 10.1016/j.cjche.2024.01.007

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Effect of solvent on the initiation mechanism of living anionic polymerization of styrene: A computational study

Shen Li1, Yin-Ning Zhou2, Zhong-Xin Liu1, Zheng-Hong Luo2   

  1. 1. School of Chemical Engineering and Technology, Hainan University, Haikou 570228, China;
    2. Department of Chemical Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China
  • 收稿日期:2023-10-10 修回日期:2024-01-23 出版日期:2024-05-28 发布日期:2024-07-01
  • 通讯作者: Yin-Ning Zhou,E-mail:zhouyn@sjtu.edu.cn;Zhong-Xin Liu,E-mail:liuzhongxin@hainanu.edu.cn;Zheng-Hong Luo,E-mail:luozh@sjtu.edu.cn
  • 基金资助:
    This work was financially supported by the National Natural Science Foundation of China (U21A20313, 22222807). The Center for high-performance Computing at Shanghai Jiao Tong University is also acknowledged.

Effect of solvent on the initiation mechanism of living anionic polymerization of styrene: A computational study

Shen Li1, Yin-Ning Zhou2, Zhong-Xin Liu1, Zheng-Hong Luo2   

  1. 1. School of Chemical Engineering and Technology, Hainan University, Haikou 570228, China;
    2. Department of Chemical Engineering, School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2023-10-10 Revised:2024-01-23 Online:2024-05-28 Published:2024-07-01
  • Contact: Yin-Ning Zhou,E-mail:zhouyn@sjtu.edu.cn;Zhong-Xin Liu,E-mail:liuzhongxin@hainanu.edu.cn;Zheng-Hong Luo,E-mail:luozh@sjtu.edu.cn
  • Supported by:
    This work was financially supported by the National Natural Science Foundation of China (U21A20313, 22222807). The Center for high-performance Computing at Shanghai Jiao Tong University is also acknowledged.

摘要: For living anionic polymerization (LAP), solvent has a great influence on both reaction mechanism and kinetics. In this work, by using the classical butyl lithium-styrene polymerization as a model system, the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory (DFT) calculations and kinetic modeling. In terms of mechanism, it is found that the stronger the solvent polarity, the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent molecules. Furthermore, we also found that the stronger the solvent polarity, the higher the monomer initiation energy barrier and the smaller the initiation rate coefficient. Counterintuitively, initiation is more favorable at lower temperatures based on the calculated results of ∆GTS. Finally, the kinetic characteristics in different solvents were further examined by kinetic modeling. It is found that in benzene and n-pentane, the polymerization rate exhibits first-order kinetics. While, slow initiation and fast propagation were observed in tetrahydrofuran (THF) due to the slow free ion formation rate, leading to a deviation from first-order kinetics.

关键词: Living anionic polymerization, Solvent effect, Reaction kinetics, Computational chemistry, Mathematical modeling, Kinetic modeling

Abstract: For living anionic polymerization (LAP), solvent has a great influence on both reaction mechanism and kinetics. In this work, by using the classical butyl lithium-styrene polymerization as a model system, the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory (DFT) calculations and kinetic modeling. In terms of mechanism, it is found that the stronger the solvent polarity, the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent molecules. Furthermore, we also found that the stronger the solvent polarity, the higher the monomer initiation energy barrier and the smaller the initiation rate coefficient. Counterintuitively, initiation is more favorable at lower temperatures based on the calculated results of ∆GTS. Finally, the kinetic characteristics in different solvents were further examined by kinetic modeling. It is found that in benzene and n-pentane, the polymerization rate exhibits first-order kinetics. While, slow initiation and fast propagation were observed in tetrahydrofuran (THF) due to the slow free ion formation rate, leading to a deviation from first-order kinetics.

Key words: Living anionic polymerization, Solvent effect, Reaction kinetics, Computational chemistry, Mathematical modeling, Kinetic modeling