限域多位点离子液体结构调控及其催化羰基化反应过程研究

The synthesis of carbonates from carbonylation of CO2 and high-energy epoxides represents the technical development direction in the field of new energy and high-end materials, which is an important approach for efficient utilization of CO2 into resources. To overcome the disadvantages of existing carbonylation catalysts—uncombined activity and stability, a series of confined multi-site ionic liquids would be constructed by one-step assembly of multi-site ionic liquids with mesoporous material precursors. To begin with, from the point of activating molecules and stabilizing confinement space, 2-3 types of multi-site symmetric imidazole, quaternary ammonium and quaternary phosphine ionic liquids will be designed and synthesized. For the sake of effective mass transfer during reaction, the space will be regulated into ordered mesoporous structure by terminal groups of ionic liquids. Thereafter, the structure-regulation law for confined multi-site ionic liquids, and the structure-activity relationship between confined ionic liquids and carbonylation reaction could be respectively cognized. Finally, combining theoretical calculation and experimental verification, the thermodynamic and kinetic data, as well as transition state information could be obtained, and then the catalytic mechanism of confined multi-site ionic liquids could be revealed from nano- and micro-scale. The study would provide solid scientific basis for efficient and mild conversion of CO2 into carbonates catalyzed by ionic liquids.

替代传统光气法，构建经高能环氧烷烃活化CO2羰基化合成碳酸酯的清洁新路线，是新能源与高端材料领域的技术发展方向，是CO2高效资源化利用的重要途径。针对羰基化反应催化剂活性与稳定性不能兼具的难题，本项目拟设计结构可控的多位点离子液体作为催化中心，结合介孔材料孔道有序且孔径可调的特点，经一步组装定向制备限域多位点离子液体催化材料，开展限域多位点离子液体结构调控及其催化羰基化反应过程研究。基于活化反应分子与构建有序稳定限域空间的考虑，设计合成2~3类多位点对称性咪唑、季铵与季磷离子液体；为保证有效传质，经离子液体端基基团调控形成有序介孔限域空间，探究纳微尺度限域离子液体结构调控机制，阐明限域空间离子液体与反应之间的构效关系；结合理论计算与实验验证，获得反应热/动力学数据与过渡态信息，从纳微层面揭示多位点离子液体催化反应机理，为离子液体催化CO2高效温和转化合成碳酸酯新过程提供科学依据。

针对CO2和环氧烷烃转化合成碳酸酯的羰基化反应过程，设计合成了对称多中心多位点离子液体作为催化中心，采用介孔硅材料前驱体与多位点离子液体一步组装制备了限域多位点离子液体催化材料。分别制备了双中心对称与多中心对称的2类限域离子液体催化材料，通过构效关系研究发现限域前后离子液体的本征性质保持且稳定性提高，所制备的材料均具有较大比表面积的介孔结构；发现了介孔硅骨架稳定离子液体且分散离子液体的作用机制，限域浓度越低越有利于离子液体的充分分散并且活性更高，限域后离子液体催化活性优于等量体相离子液体。揭示了限域多位点离子液体高效温和催化反应相关规律和机理。项目取得的成果对多位点离子液体设计、限域结构调控以及反应规律研究提供了重要的方法和参考，为离子液体催化CO2高效温和转化合成碳酸酯新过程提供科学依据。