阴阳离子双功能化的多金属氧酸盐催化材料的设计合成及其苯羟基化催化性能研究

Polyoxometallates are very good oxidation catalysts because of their stable nature, adjustable structures and the excellent oxidation resistance. Related work often focuse on the modulation of their anions structures to adjust their catalytic activities. The cation parts of polyoxometallates only play a role as the pairing ions in order to change their solubilities and the catalytic microenvironment. Aiming at the hydroxylation of benzene, this project intends to introduced the catalytic activity sites into their cation parts. The metal activity centers coordinate with the nitrogenous ligands and form the catalyst cationic part then via the reaction between anions and cations to form the goal catalytic materials. The center metals that located in the cations and anions of the target materials can be different or not. The active sites of the metals are ordered arranged and monodispersed that will be a great improvement to their activities and selectivities. It is expected to develop collaborative catalytic materilas via introduce different activity centers into the cationic parts that are different from the anionic activity centers. Based on the discussing of the relationship between the catalyst structure and their catalytic properties, the mechanism of this process can be investigated systematicly in order to provide theoretical foundation for the ideal hydroxylation of benzene to phenol.

多金属氧酸盐因其性质稳定，结构可调和好的抗氧化性能而成为一种优良的氧化催化材料。人们常通过调变其阴离子结构来改善其催化活性，多金属氧酸盐化合物的阳离子部分只是作为离子对,来改变其溶解度或者催化的微环境。本项目拟针对苯羟基化反应过程，通过将催化活性位引入阳离子，即将金属活性中心与含氮配体结合，形成催化剂阳离子部分，再与含有金属活性中心的杂多酸阴离子形成阴阳离子对，制备出阴阳离子均含有催化活性中心的目标催化材料。该目标材料可同时含有相同或不同的位于阴阳离子部分的多金属活性中心，有序排列于催化剂阴阳离子中而呈现单分散态的多金属活性位将有可能极大的提高其活性与选择性，而通过在阳离子中引入与阴离子中催化作用不同的活性中心，有望开发具有协同催化作用的苯羟基化催化新材料。同时在研究催化剂结构与其催化苯羟基化性能之间的构效关系基础上，系统研究苯羟基化反应机理，为实现苯直接氧化制苯酚的理想过程提供理论基础。

多金属氧酸盐由于其性质稳定，结构可调和很好的抗氧化性能而成为一种优良的氧化催化材料。长期以来，人们大多通过调变其阴离子结构来改善其催化活性，多金属氧酸盐化合物的阳离子部分只是作为离子对,来改变其溶解度或者催化的微环境。本项目针对苯羟基化反应过程，通过将催化活性位引入阳离子，即将第一金属活性中心与含氮配体结合，形成催化剂阳离子部分，再与含有第二金属活性中心的杂多酸阴离子形成阴阳离子对，制备出含有双金属活性中心的目标催化材料。该目标材料因同时含有相同或不同的位于阴阳离子部分的多金属活性中心，有序排列于催化剂阴阳离子中而呈现单分散态的多金属活性位而极大的提高其活性与选择性。在研究催化剂结构与其催化苯羟基化性能之间的构效关系基础上，系统研究苯羟基化反应机理，为实现苯直接氧化制苯酚的理想过程提供理论基础。