离子液体中多元金属氯化物协同催化一锅法转化纤维素制平台化合物4-(5-羟甲基-2-呋喃基)-3-丁烯

The objectives of this project are (1) to design and screen concerted multiple metal catalysts by using in-situ far infrared spectroscopy and high throughput reactor established in my laboratory for one-pot conversion of glucose to 3-buten-2-one, 4-[5-(hydroxymethyl)-2-furanyl] (HMF-Acetone), (2) to study the multiple metal chlorides for their concerted catalytic functions and for the mechanisms of each metal chloride involved in each elemental steps of the over process. One-pot conversion of cellulose contains threes catalytic processes (P1, P2, P3): cellulose hydrolysis to soluble reducing sugars (P1), the conversion of reducing sugars to 5-hydroxymethylfurfural (5-HMF) (P2) and 5-HMF condensation with acetone to obtain HMF-acetone (P3). We will select ionic liquid with high solubility for cellulose as solvent, and screen multiple metal chlorides as concerted catalysts in one pot conversion of cellulose to HMF-Acetone. The selective coordination properties of metal chloride with the active site of substrates in P1, P2, P3 processes will be evaluated and determined by in-situ far-infrared (FIR) spectroscopy and a Freeslate high throughput reactor will be used to screen metal chloride catalysts in the corresponding processes. The coordination structures determined from FIR study and the high throughput catalytic screening results will be correlated to establish catalyst structure and performance relationships. The FIR as a catalyst screening tool based on fundamental understanding of the metal ion preferred coordination structure has produced promising preliminary results for rapidly screening potential effective catalysts. Combined with the power of high throughput reactor, we expect to efficiently screen metal chloride catalysts for optimized one pot conversion of cellulose to HMF-Acetone. FIR and other characterization methods will be used to study the interaction of multiple metal chlorides in ionic liquids and to reveal the synergetic concerted catalytic mechanism of multiple metal chlorides. We will determine the interaction occurring between multiple metal chlorides and the raw materials and products. The results will further guide our catalyst design. The implementation of the project would provide important theoretical basis to accelerate the development of efficient catalytic processes for biomass resources utilizations.

本项目以高效转化纤维素制备重要的平台化合物4-(5-羟甲基-2-呋喃基)-3-丁烯-2-酮（HMF-Acetone）为目标。拟选择有良好纤维素溶解能力的离子液体为溶剂，设计并运用高通量方法优选多元复合金属氯化物催化剂，实现纤维素一锅法转化为HMF-Acetone的技术突破。一锅法转化经过三个催化过程（P1、P2、P3），即首先将纤维素水解为可溶性还原糖，然后还原糖又进一步降解为5-羟甲基糠醛（5-HMF），最后5-HMF与丙酮缩合生成HMF-acetone。结合金属氯化物选择性地与各步反应底物活性部位配位的特性，运用具有原创性的原位远红外光谱方法快速筛选出有效催化P1、P2、P3过程的金属氯化物，再借助高通量反应器进一步快速优化出高效催化纤维素一锅法转化的多元金属氯化物。运用远红外光谱等手段探究多元金属氯化物在离子液体中的相互作用，揭示该多元金属氯化物在催化纤维素一锅法转化过程中的协同机理

生物质是自然界中储量丰富、可再生周期短的资源，其高效转化利用制呋喃类平台化合物是一类重要的反应过程。本项目研究了以生物质及其平台化合物为原料，金属氯化物为催化剂的多个高效催化转化过程，包括纤维素催化转化制单糖类化合物、糖类转化制呋喃类平台化合物5-羟甲基糠醛（5-HMF）、糠醛，以及以上平台化合物与丙酮缩合制生物质燃油前驱体的反应，结合反应动力学、原位远红外光谱分析等手段，研究并建立了金属氯化物（NiCl2、VCl3、MnCl2、ZrCl4等）与生物质基化合物中的多种典型含氧基团（羰基、羟基、醚键等）间定量化的作用强度，据此对其中所涉及的催化反应机理、催化剂的定向设计进行了系统的研究。