木质素临氢催化转化多产单环芳烃催化剂及工艺的基础研究

Lignin is the only large-volume renewable source of aromatic chemicals in nature. Monocyclic aromatics are not only very important basic organic raw materials and solvents in chemical industry, but also a necessary blending in jet fuels. Therefore, the production of monocyclic aromatic hydrocarbons from lignin has great significance. Recently, researchers have succeeded in producing monocyclic aromatic hydrocarbons from lignin by hydrodeoxygenation. Almost all of monomers combined with C-O-C bond in lignin converts to monocyclic aromatic hydrocarbons in this process. However, only few monomers combined with C-C bond converts to monocyclic aromatic hydrocarbons. The strategy would be adopted in this project is to design and prepare a new Ru/Nb-based suport catalyst with the multifunctions of hydrogenation, adsorption/activation of C-O and C-C bonds. Combining the catalyst characterization, reaction pathway study and model molecules verification experiments, propose the mechanism of producing monocyclic aromatic hydrocarbons from lignin by catalytic process. According to the mechanism, optimize the catalyst and reaction process. This novel strategy is expected to realize the efficient conversion of monomers combined with C-O-C bonds or C-C bonds to monocyclic aromatic hydrocarbons so as to achieve the goal of maximum production of monocyclic aromatic hydrocarbons from lignin by hydrodeoxygenation.

木质素是自然界芳香化合物的唯一一个大容量可再生来源，而单环芳烃既是重要的基本有机化工原料和溶剂，又是喷气燃料的重要组成部分。因此，将木质素转化为单环芳烃具有重大的意义。目前已有研究实现了木质素中通过C-O-C键连接的基本结构单元临氢催化转化为单环芳烃，但是木质素中仍有大量通过C-C键连接的基本结构单元尚未转化成单环芳烃。本项目针对上述问题，拟设计、制备具有对C-O和C-C键吸附活化及加氢等多功能的新型金属Ru/Nb基载体催化剂。通过反应路径和模型化合物验证研究，结合催化剂表征分析研究，揭示金属Ru/Nb基载体催化剂上木质素临氢催化转化制单环芳烃的反应机理。在反应机理的指导下，再进行催化剂和工艺条件的优化，保证高效催化木质素中C-O-C键连接的基本结构单元转化为单环芳烃的前提下，同时催化C-C键连接的基本结构单元转化为单环芳烃，从而达到木质素临氢催化转化多产单环芳烃的目的。

木质素是自然界芳香化合物的唯一一个大容量可再生来源，而单环芳烃既是重要的基本有机化工原料和溶剂，又是喷气燃料的重要组成部分。因此，将木质素转化为单环芳烃具有重大的意义。目前已有研究实现了木质素中通过C-O-C键连接的基本结构单元临氢催化转化为单环芳烃，但是木质素中仍有大量通过C-C键连接的基本结构单元尚未转化成单环芳烃。本项目针对上述问题，设计、制备了层状Ru/Nb2O5、Ru/NbOPO4等多功能催化剂，可以同时活化木质素中C-O、C-C键，实现木质素临氢催化转化多产单环芳烃。项目以木质素模型化合物为研究对象，结合原位表征，揭示了该系列催化剂上C-O和C-C键的作用机制，即NbOx通过对苯环的独特吸附活化C-O和C-C键，B酸中心促进了碳正离子的形成利于Caroma-C键的断裂，金属则提供氢气活化中心。在深入了解催化作用机理的基础上，进一步指导催化剂的制备，最终实现了木质素临氢催化转化高效产单环芳烃。