纤维素临水转化成2,5-呋喃二甲酸的多功能协同催化作用

2,5-furandicarboxylic acid, an important biomass-based platform chemical, which may be expected as the best alternatives to fossil resources for the synthesis of biodegradable polymer and other additives. A hight efficient catalytic system for direct conversion of cellulose into 2,5-furandicarboxylic acid is an important basis for technological breakthroughs in the field. This project intends to explore a core-shell magnetite nanocatalyst which Fe3O4 core encapsulated with a nitrogen-containing benzenoid polymer as a shell, then modified by sulfonation and nano-metal or metal oxide also will be loaded onto its surface. The aim is to build a method for the synthesis of the solid catalyst containing multi-active sites for "acid-base" and "oxidation-reduction" catalytic coupling reaction. The synergistic effects of sulfoacid sites, nitrogen sites and variable-valence metal sites in Fe3O4@Polymer for catalytic conversion of cellulose will be investigated. To provide a basis for the regulation of the catalyst structure, to build a dynamics model for catalytic conversion processes in critical water of cellulose, to explore reaction mechanism and the relationship between the rate of each reaction step, and to reveal the synergetic rule of direct conversion of cellulose into 2,5-furandicarboxylic acid with this new material in critical water by multi-series reactions containing hydrolysis, isomerization, dehydration and oxidation. This project will provide a basis for direct conversion of cellulose into 2,5-furandicarboxylic acid by one-pot method and promote technological innovation for the areas of catalytic conversion of biomass into fine chemicals in our country.

2,5-呋喃二甲酸是有望替代石化资源合成可降解高分子及助剂材料等的重要生物质基平台化合物。从纤维素直接转化成2,5-呋喃二甲酸的高效催化体系是该领域技术亟待突破的重要瓶颈。本项目拟探索以纳米Fe3O4为核，苯系含氮聚合物为壳，磺化改性与负载纳米过渡金属或过渡金属氧化物相结合，研究构建具有“酸-碱”催化和“氧化-还原”催化耦合的多功能活性位点固体纳米催化剂的方法；考察聚合物包覆Fe3O4上苯基磺酸位、氮碱位和可变价金属位在催化纤维素转化中的协同作用，为调控催化剂结构提供依据；建立纤维素临水催化转化过程的动力学模型，探索各反应步骤的速率关系及反应机制；揭示该类新材料在纤维素临水转化成2,5-呋喃二甲酸过程中水解、异构化、脱水、氧化等反应串联进行的协同催化规律。为纤维素到2,5-呋喃二甲酸“一锅法”的发展提供基础，促进我国生物质催化精细转化领域的技术创新。

生物质及其平台化合物催化转化制备呋喃基化学品是生物质高值利用的重要途径之一。2,5-呋喃二甲酸（FDCA）是有望替代对苯二甲酸合成绿色可降解高分子材料的一种重要生物质基聚酯原料。本项目以一类含氮高分子聚合物（PDVTA）为载体，通过磺化改性及负载锰、钒、铜等非贵金属氧化物或非贵金属盐等催化活性组分，构建了一类具有“酸-碱”催化和“氧化-还原”催化耦合的多功能活性位点催化剂，实现了生物质及其平台化合物一锅法制备FDCA。通过对多功能活性位点催化剂的设计、制备及结构表征、多功能活性位点催化耦合体系的构建，从而确定了相应的反应机制和产物选择调控规律。项目研究的Cu/MnO2@PDVTA催化剂在温和条件下可实现生物质平台分子5-羟甲基糠醛完全转化，目标产物FDCA的选择性最高可达96.8%。本项目探索了多功能活性位点催化剂在生物质转化中协同催化规律，拓展了非贵金属及其氧化物在生物质催化转化领域的应用，对生物质基聚酯关键单体FDCA的规模化生产具有重要的参考价值。