基于“固相氮配体策略”构筑多相钴催化体系用于氢酯基化反应研究

β-Hydroxyesters are important bifunctional compounds and can be generated by alkoxycarbonylation of epoxides. It has been a long-term difficulty that researchers in this field are unable to develop a novel catalyst with all the advantages of stable structure, high efficient performance and facile reusability. To address common issues of possible decomposition and hardly separation of Co2(CO)8 catalyst from products in homogeneous alkoxycarbonylation, we herein propose to start this project by constructing a heterogeneous reaction process. The nitrogen-doped carbons which serve as catalyst supports are prepared with adjustable pores and nitrogen contents. Afterwards, the cobalt precursors are immobilized on supports via the vacuum-assistant impregnation method basing on the complexation between nitrogen and cobalt. As a result, the supported cobalt catalysts with controllable structures are obtained to construct stable and high efficient heterogeneous reaction system for alkoxycarbonylation. The combing principles among the catalyst components are systematically studied. With alkoxycarbonylation of epoxides as probe reaction, the intrinsic structure-performance relationship will be revealed by correlating the textural properties of catalysts, such as pore structure, cobalt size, nitrogen content and distribution, cobalt-nitrogen interaction and so on, with activity, selectivity and reusing abilities. The reaction mechanism will be elucidated by density functional theory calculations. The discoveries from this project will establish the theoretical and technological foundation for the directional design of cobalt catalysts and the development of the heterogeneous alkoxycarbonylation reactions.

β-羟基羧酸酯是重要的双官能团化合物，可通过环氧化合物发生氢酯基化反应合成，开发结构稳定、性能高效且可重复使用的催化剂一直以来是该研究领域的难点。针对当前均相技术的Co2(CO)8催化剂易分解及与重复使用困难这些核心、共性问题，本项目拟从反应的多相化为着眼点，以孔结构和氮含量可调的氮掺杂碳材料为固相载体，基于载体中氮对活性组分钴的络合能力，采用真空辅助浸渍法可控制备负载型钴催化剂，从而构建稳定且高效的多相氢酯基化反应新体系。系统研究该催化剂中各组分之间的结合原理，以环氧化合物氢酯基化为探针反应，考察催化剂的孔结构、钴尺寸、氮物种分布与含量、钴-氮结合效应等因素对反应活性、产物选择性及重复使用性能的影响，揭示反应的构效关系。结合密度泛函理论计算，认识反应机理。本项目的成功实施，将为钴催化剂的定向设计及多相氢酯基化反应的开发提供理论与技术基础。

β-羟基羧酸酯是重要的双官能团化合物，可通过环氧化合物发生氢酯基化反应合成，开发结构稳定、性能高效且可重复使用的催化剂一直以来是该研究领域的难点。针对当前均相技术的Co2(CO)8催化剂易分解和重复使用困难等瓶颈问题，本项目以孔结构和氮含量可调的氮掺杂碳材料为固相载体，基于载体中氮对活性组分钴的络合能力，构建性能稳定且高效的多相氢酯基化反应新体系。通过研究催化剂的孔结构、钴尺寸、氮物种分布与含量、钴-氮结合效应等因素对反应活性、产物选择性及重复使用性能的影响，揭示反应的构效关系。采用空气稳定的Ph3SiCo(CO)4为催化剂前体，通过原位红外表征技术结合密度泛函理论计算，阐明了含氮助剂对催化剂酸碱性调控的机制和反应活性的促进机理。提出并验证进一步提升反应效率的有效途径。