以甘油氢解制备1，3-丙二醇为导向的MOF催化剂的设计合成及催化机理的研究

Individual design and synthesis of metal-organic frameworks (MOF) catalysts is a new promising alternative way to solve the bottleneck in the field of modern chemical industry. Up to date, the related fundamental studies on in-deep investigation of their catalysis activities as well as illumination of their catalytic mechanism at the molecular level based on the combination of experimental and theoretical methods have never been reported. This project focuses on glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO) reaction, which is heavy energy consumption and low yield, but has high added-value. The adsorption mode of glycerol on the catalyst has an important influence on the selectivity of 1,3-PDO, while the previous works of applicant have demonstrated that artfully designed and implanted defects can regulate the adsorption mode of molecule (JACS, 2014, 136, 9627). On consideration of these two aspects, this project proposes to: 1) improve the selectivity of 1,3-PDO by regulating the adsorption mode of glycerol through the frustrated Lewis pairs (FLP) which are constructed by the artificial defects; 2) enhance the conversion of glycerol through synergistic catalysis of FLP, metal and Brønsted acid (B-acid). This project aims to 1) develop a controllable synthesis technique of FLP-containing MOF (metal@B@ FLP-DEMOF), loading both metal and B-acid; 2) elucidate the reaction mechanism based on the real time tracked intermediate by sophisticated ultra-high-vacuum Fourier transform infrared spectroscopy (UHV-FTIRs) spectra and the results of theoretical calculations. The smooth progress of this project will lay a solid theoretical foundation for design of MOF catalysts for target reactions, and further promote the commercialization of MOF catalysts in chemical industry.

MOF在催化领域已展示了独特优势，然而针对化工领域的瓶颈问题，设计合成MOF催化剂并从分子水平上阐明其催化机理的研究尚未报道。由于甘油在催化剂上的吸附模式对1,3-丙二醇(1,3-PDO)的选择性具有重要影响，同时申请人前期的研究表明缺陷可调控分子吸附模式(JACS, 2014, 136, 9627)，因此本项目拟选择甘油氢解为模板反应,通过缺陷构筑FLP(受阻路易斯酸碱对)调控甘油分子的吸附模式，进而解决1,3-PDO选择性低的问题；利用金属和Brønsted酸(B-酸)与FLP的协同催化的作用提高催化效率。本项目将发展同时负载金属和B-酸的含有FLP的缺陷MOF(metal@B@FLP-DEMOF)的可控制备技术，并利用超高真空红外光谱实时跟踪反应并捕获中间体，结合理论计算阐明反应机理。本项目的开展将为开发以目标反应为导向的MOF催化剂提供理论依据，进而推动MOF催化剂市场化的进程。

MOF在催化领域已展示了独特优势，然而针对化工领域的瓶颈问题，设计合成MOF催化剂并从分子水平上阐明其催化机理的研究尚未报道。据此，项目负责人按照原计划1）设计合成出了一系列新型的MOF材料，例如利用N1,N6-二(吡啶-3-基)己二酰胺柔性配体合成了具有温度响应的荧光性质和超级电容性能的[Cu2(L1)Br2]∞和[CuI2(L1)Cl2]∞，利用4,4′-二苯醚二甲酸配位构筑了{[Ce4(4,4′-二苯醚二甲酸)6(H2O)9]•(H2O)}∞，在此架上引入不同的阳离子，制备出了含阳离子缺陷的单色和多色发光的新型MOFs材料； 2）筛选出符合构筑“受阻路易斯酸碱对”(FLP)的MOF材料，即MIL-100，并在其骨架上植入了FLP，在制备出的FLP-DEMOF材料上分别负载B-酸或金属纳米粒或同时负载二者制备出一系列B@FLP-DEMOF, M@FLP-DEMOF和B@M@FLP-DEMOF催化剂，通过调控DLs的缺陷程度和掺杂的浓度调控MOF骨架上FLP的类型，含量和分布，从而实现B-酸和金属在MOF孔洞中的负载量及其比例、分散度和负载持久性的调控。研究结果表明所制备的复合型催化剂对甘油氢解制1,3-PDO和葡萄糖加氢反应的均具有良好的催化活性。由其是在最优化反应条件下，所有制备出的催化剂对葡萄糖的转化率均高于98%，山梨醇的选择性和产率分别高于85% 和80%，最重要的是Ru@FLP-DEMOFs转频率值约为已报道的Ru负载的聚合物催化剂的10倍。项目负责人制备出了选择性好、转化率高、反应速率快可循环使用的绿色环保低成本的催化剂，通过超高真空原位红外光谱的结构表征和催化性能的研究找出了催化剂结构与催化性能的关系，阐明了目标反应的机理。本项目的开展将为开发以目标反应为导向的MOF催化剂提供理论依据，进而推动MOF催化剂市场化的进程。