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文章编号: 1672-6987(2025)01-0017-07 DOI: 10.16351/j.1672-6987.2025.01.002
王尚, 任柏豪*, 李窈, 吕小兵*(大连理工大学 精细化工国家重点实验室,辽宁 大连 116024)
摘要: SalenCo(Ⅲ)配合物与季铵盐组成的双组分催化体系是催化环氧烷烃与二氧化碳(CO2)共聚反应最有效的催化体系之一。以环氧环己烷与CO2的共聚反应为例,利用密度泛函理论(DFT)计算对该催化体系的反应机理进行研究。链引发环节的计算表明,阴离子(或有机碱)具有两个作用:其中强亲核试剂更容易进行链引发,而较弱的亲核试剂作为平衡离子稳定了Co(Ⅲ)。对链增长环节的计算表明,碳酸根链末端对环氧环己烷的开环是反应的速率控制步骤。SalenCo(Ⅲ)的作用不仅是活化环氧烷烃,还能用于稳定烷氧基链末端,因此反应中聚醚和环状碳酸酯的生成受到了抑制。配合物中水杨醛部分的3-位取代基对反应的手性诱导具有很大的影响,大位阻与小位阻取代基的手性诱导方向相反。
关键词: 二氧化碳; 环氧环己烷; 钴配合物; 不对称共聚; 密度泛函理论计算
中图分类号: O 643.12 文献标志码: A
引用格式: 王尚, 任柏豪, 李窈, 等.手性salenCo(Ⅲ)催化CO2与环氧环己烷不对称共聚反应机理研究[J].青岛科技大学学报(自然科学版), 2025, 46(1): -.
WANG Shang,REN Baihao,LI Yao,et al.Mechanistic study of chiral salenCo(Ⅲ) mediated asymmetric copolymerization of CO2 and cyclohexene oxide[J].Journal of Qingdao University of Science and Technology(Natural Science Edition), 2025, 46(1): -.
Mechanistic Study of Chiral SalenCo(Ⅲ) Mediated Asymmetric Copolymerization of CO2 and Cyclohexene Oxide
WANG Shang, REN Baihao, LI Yao, LYU Xiaobing(State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China)
Abstract: The binary catalytic system composed of salenCo(Ⅲ) complex and quaternary ammonium salt is one of the most efficient catalytic systems for the copolymerization of epoxides and CO2. In this paper, the copolymerization of cyclohexene oxide and CO2 was taken as an example, and the reaction mechanism of the catalytic system was studied by density functional theory (DFT) calculation. Calculations of chain initiation process indicate that the nucleophilic anions or organic bases play two roles: The strong nucleophile is easier to initiate the reaction by attacking the coordinated epoxide, while the weak one is used to stabilize the Co(Ⅲ) ion. The calculation of copolymer chain propagation shows that the ring-opening of cyclohexene oxide by the carbonate chain end is the rate-determining step. SalenCo(Ⅲ) is not only to activate epoxide but also to stabilize the alkoxyl chain end, so the formation of polyether and cyclic carbonate in the reaction is inhibited. The substituents at ortho-positions of the salen ligand of the complex have a significant influence on the chiral induction of the reaction. The opposite chiral induction for copolymerization of CO2 and cyclohexene oxide were observed in the two catalyst systems with different steric hindrance of ortho-position substituents.
Key words: carbon dioxide; cyclohexene oxide; cobalt complex; asymmetric copolymerization; density functional theory calculation
收稿日期: 2023-12-22
基金项目: 国家自然科学基金项目(21920102006).
作者简介: 王尚(1999—),男,硕士研究生. * 通信联系人.