甲酸辅助的光催化甲醇C-C偶联合成乙二醇的机理研究

开发新的经济的乙二醇合成路线，降低我国乙二醇对外依存度，具有重要的理论和现实意义。光催化甲醇脱氢直接偶联合成乙二醇的反应条件温和，为乙二醇的合成提供了新途径，但其应用受制于催化剂较差的稳定性和较低的反应效率。我们前期的研究结果表明TiO2光催化剂能够高效催化多种一元醇偶联合成邻位二醇，且在甲醇体系中甲酸的引入能够促进乙二醇的生成效率，但其作用机理还缺乏理论认识。本项目拟以含甲酸的甲醇光催化体系为研究对象，以通过反应条件的调变控制反应过程及甲酸分解途径、光催化乙二醇生成性能评价和同位素标记确定反应机理等相结合的方法为手段，开展甲酸存在下光催化甲醇反应的过程和机理研究，获得相关动力学反应条件对光催化乙二醇生成体系的影响规律，揭示甲酸参与的光催化甲醇合成乙二醇的自由基反应机理，阐明甲酸分解途径的控制对反应过程的作用规律及内在实质，为进一步的高效甲醇直接合成乙二醇体系的认识提供基础理论和技术支持。

Developing new synthetic route of ethylene glycol and reducing our dependence on foreign ethylene glycol has important theoretical and practical significance. Direct photocatalytic dehydrodimerization of methanol into ethylene glycol, which happens at mild reaction conditions, provides a new way for the synthesis of ethylene glycol. But the catalyst so far reported is very unstable and has low efficiency. TiO2 photocatalysts we developed could efficiently catalyze the dehydrodimerization of monobasic alcohol into ortho-diols, and we also found the introduction of formic acid can promote production efficiency of ethylene glycol from methanol, but its mechanism is not yet clear. The project intends to choose the formic acid contained photocatalytic-methanol-into-ethylene-glycol system as the research object, by modulating the reaction conditions to control the reaction process and formic acid decomposition pathways, and combining the evaluation of ethylene glycol photocatalytic performance and isotope labeling method to determine the reaction mechanism, to carry out the photocatalytic process and mechanism of methanol dehydrodimerization into ethylene glycol with formic acid in the presence, to get the influence of reaction kinetics conditions on the photocatalytic ethylene glycol synthesis system, to investigate and reveal the reaction mechanism of formic acid assisted catalytic conversion of methanol into ethylene glycol, to clarify the action law and inherent essence of controlled formic acid decomposition pathways for the reaction process, and finally to provide basic theoretical and technical support for the further understanding of high efficiency and high selectivity direct synthesis of methanol into ethylene glycol systems.