金属有机框架化合物的设计合成及其在交叉偶联反应中的应用

发布时间：2018-06-27 13:43

本文选题：非均相催化剂 + 金属有机框架物　；参考：《浙江大学》2017年硕士论文

【摘要】：钯催化的交叉偶联反应如Suzuki反应和Heck反应是用于形成C-C键的最有力的工具之一,在学术和工业上很有研究价值和应用前景。因为钯既是贵金属又是重金属,所以从经济和环境两方面考虑都必须开发能充分利用每个钯活性位点的钯催化剂,并且具备优异的可回收性能,同时也要抑制钯金属的浸出,以降低催化剂成本和对环境的污染。金属有机框架化合物MOFs具有均一可调的孔径和稳定的骨架结构,有利于反应物分子的扩散,表面易于修饰、比表面积大、热稳定性高、机械性能稳定,是负载型催化剂最有潜力和最理想的载体材料之一。本论文根据交叉偶联反应特点和需求,以及金属有机框架材料在非均相催化方面的独特优势,设计合成了用于交叉偶联反应的金属有机框架钯催化剂。研究内容分为以下两部分:(1)通过后合成修饰的策略设计合成了两个系列的以锆为金属顶点的混合配体金属有机框架化合物MOFs钯催化剂(UiO-66-Mix-PI-Pd和UiO-67-Mix-PI-Pd系列)。先合成的混合配体MOFs(UiO-66-Mix和UiO-67-Mix)性能非常稳定,即使经过后合成修饰其结构完整性也几乎没有损失。非均相 MOFs 钯催化剂 UiO-66-Mix-PI-Pd 和 UiO-67-Mix-PI-Pd 中引入的活性中心的密度是可控的,正是通过调节混合配体MOFs合成过程中混合配体中含有官能团的配体的进料比例来实现的。所得到的非均相UiO-66-Mix-PI-Pd 和 UiO-67-Mix-PI-Pd 催化剂对 Suzuki 和 Heck 交叉偶联反应都显示出优良的催化活性,交叉偶联反应同时受非均相催化剂的金属含量密度和MOFs孔隙率的双重影响,其中具有低的钯含量和高表面积的UiO-67-3-PI-Pd催化剂表现最优,而且UiO-67-3-PI-Pd催化剂在各种各样的不同取代基的反应底物上的成功应用证明了它以非常少的钯的使用量(0.054 mol%Pd)在Suzuki和Heck反应中合成各种不同官能的联苯和苯乙烯衍生物的普遍性。UiO-67-3-PI-Pd催化剂具有许多优点,包括高孔隙率、高活性、高达十倍的可重复使用性、环境友好的溶剂体系中温和的条件下短的反应时间等,所以非均相UiO-67-3-PI-Pd催化剂对于Suzuki和Heck反应是绿色的高效的催化剂。(2)在上一章的优化结论下,进一步选择α二亚胺作为与活性位点结合的混合配体,使用锆作为金属顶点,合成了一种性能更稳定的混合配体MOF(UiO-67-MixDiimine),利用α二亚胺结构和化学性质的特殊性,后合成修饰步骤进一步缩减,后修饰过程中金属有机框架的晶体结构完整性和多孔性得到最大限度的保护,得到性质更加优良的UiO-67-MixDiimine-Pd催化剂。通过调节混合配体MOFs合成过程中混合配体中含有官能团的配体的进料比例,得到一系列不同钯含量密度的UiO-67-MixDiimine-Pd催化剂,通过对比试验,UiO-67-33%MixDiimine-Pd催化剂达到了最优的比表面积和钯密度的协调。进一步将UiO-67-33%MixDiimine-Pd催化剂应用于各类Suzuki和Heck反应中,均得到比UiO-67-3-PI-Pd催化剂更优秀的催化性能。
[Abstract]:Palladium catalyzed cross coupling reactions such as Suzuki reaction and Heck reaction are one of the most powerful tools for C-C bond formation. Because palladium is both a precious metal and a heavy metal, it is necessary to develop palladium catalysts that make full use of each palladium active site in both economic and environmental terms, and have excellent recoverability, and at the same time inhibit the leaching of palladium metals. To reduce catalyst costs and environmental pollution. MOFs have uniform and adjustable pore size and stable skeleton structure, which are beneficial to the diffusion of reactants, easy surface modification, large specific surface area, high thermal stability and stable mechanical properties. It is one of the most potential and ideal carrier materials for supported catalysts. Based on the characteristics and requirements of cross-coupling reaction and the unique advantages of organometallic framework materials in heterogeneous catalysis, a metal-organic frame palladium catalyst for cross-coupling reaction was designed and synthesized in this paper. The research is divided into two parts as follows: (1) two series of mixed ligand metal-organic framework compounds (MOFs) with zirconium as metal vertex were designed and synthesized by post-synthesis modification strategy (UiO-66-Mix-PI-Pd and UiO-67-Mix-PI-Pd series). The properties of the mixed ligand MOFs (UiO-66-Mix and UiO-67-Mix) are very stable. The density of active sites introduced in heterogeneous MOFs palladium catalysts UiO-66-Mix-PI-Pd and UiO-67-Mix-PI-Pd is controllable, which is achieved by adjusting the feed ratio of ligands containing functional groups in the synthesis of mixed ligand MOFs. The heterogeneous UiO-66-Mix-PI-Pd and UiO-67-Mix-PI-Pd catalysts showed excellent catalytic activity for Suzuki and Heck cross-coupling reactions. The cross-coupling reactions were influenced by both the metal content density of the heterogeneous catalysts and the porosity of MOFs. Among them, UiO-67-3-PI-Pd catalysts with low palladium content and high surface area exhibited the best performance. Moreover, the successful application of UiO-67-3-PI-Pd catalyst on various substrates with different substituents proved that it synthesized various functional biphenyls and styrene derivatives in the Suzuki and Heck reactions with a very small amount of palladium (0.054 mol PD). Universal. UiO-67-3-PI-Pd catalysts have many advantages, Including high porosity, high activity, up to ten times reusability, short reaction time under mild conditions in environmentally friendly solvent systems, Therefore, the heterogeneous UiO-67-3-PI-Pd catalyst is a green and efficient catalyst for Suzuki and Heck reactions. (2) under the optimized conclusion in the previous chapter, 伪 -diimide was further selected as the mixed ligand bound to the active site, and zirconium was used as the metal apex. A more stable mixed ligand MOF (UiO-67-Mix Diimine) was synthesized. The crystal structure integrity and porosity of the organometallic frames were protected to the maximum extent during the post-modification process, and UiO-67-MixDiimine-Pd catalysts with better properties were obtained. A series of UiO-67-MixDiimine-PD catalysts with different palladium content densities were obtained by adjusting the feed ratio of ligands containing functional groups in the mixed ligand MOFs. The UiO-67-33 MixDiimine-Pd catalyst has achieved the optimal coordination of specific surface area and palladium density. The UiO-67-33MixDiimine-Pd catalyst was further applied to various Suzuki and Heck reactions, and its catalytic performance was better than that of UiO-67-3-PI-Pd catalyst.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O621.251

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