双盐离子液体中木质素氧化降解的作用机制研究

氧化降解是木质素高值化利用的重要途径，构建功能化溶剂体系是高效转化木质素的先决条件之一。我们前期工作证实，木质素氧化降解过程中“双盐离子液体” (DSILs)具有协同效应。基于此，本项目拟构建功能化DSILs溶剂体系，实现定向氧化降解木质素制芳香醛。通过研究DSILs的化学构成–反应性的关系，宏观上探讨离子协同效应；考虑氢键、聚集体和团簇等因素影响，考察DSILs的功能基团（离子）与木质素活性基团之间相互作用，多尺度研究离子对木质素典型化学键的协同活化或稳定机制；考察DSILs中离子协同活化分子O2或H2O2的可行性，研究离子单独或协同活化及断裂木质素主要联接键的作用，在分子水平上揭示DSILs中木质素氧化降解反应机理。通过本项目研究，可揭示氧化降解木质素过程中DSILs的离子协同作用机制，为发展木质素高值化利用新技术提供科学依据。

Oxidation depolymerisation is an important method to lignin valorization. Constructing the functional solvent system with lignin dissolution is one of the essential prerequisites to efficient conversion. Our previous work presented that the synergistic effects of “Double salt ionic liquids” (DSILs) exists in oxidation depolymerisation of lignin. Thus, based on DSILs’ properties being “fine-tuned”, this project aimed to develop the oriented oxidation depolymerisation of lignin for producing aromatic aldehyde. Synergistic effects of ions are studied macroscopically through investigating the relationship between the chemical structure of DSILs and the reactivity. Especially considering the influences of hydrogen-bonds, aggregates and clusters in DSILs, mechanisms of cooperative activation or stabilization of ions for the typical bonds of lignin are investigated in multi-scale through studying the interactions between DSILs’ functional groups (ions) and the active groups in lignin. The effects of sole- or cooperative ions on activating and destructing the main association bonds of lignin are also investigated through studying the availability of cooperative activating molecular O2 or H2O2 by ions in DSILs, which reveals mechanisms of oxidation depolymerisation of lignin in DSILs in molecular scale. These above researches will reveal the cooperative action mechanisms of ions in DSILs during lignin oxidation depolymerisation and provide the scientific evidences for developing the novel process of lignin valorization.