Pd@MOFs复合材料的制备及其催化铃木反应的尺寸效应研究

发布时间：2018-01-22 14:16

本文关键词： Pd@MOFs复合材料选择性催化 Suzuki-Miyaura cross-coupling反应回收再利用　出处：《辽宁大学》2016年硕士论文　论文类型：学位论文

【摘要】：Suzuki-Miyaura cross-coupling反应是目前在碳-碳偶联反应中一种十分重要的合成反应,其产物联苯化合物由于特殊的物理化学特性目前在除草剂、药物、液晶材料等多个领域中都有着广泛的应用。而对作为催化剂的钯纳米粒子及其载体的研究更是成为最近几年对于Suzuki-Miyaura cross-coupling反应的异相可回收催化剂研究的热点,但是这些负载在载体上的钯纳米粒子复合材料如Pd@Al2O3、Pd@SiO2等都很难在催化过程中体现出选择性,所以研究出对于Suzuki-Miyaura cross-coupling反应具有选择性催化的钯纳米粒子复合材料就变得十分有意义。本论文根据已有的合成方法合成了MOF-5、ZIF-8、MIL-101等一系列MOFs材料,由采用等量浸渍法中的虹吸浸渍法以及液相硼氢化钠的甲醇溶液作为还原剂还原的方法,成功将钯纳米粒子负载到了MOFs的孔洞当中,制备了Pd@MOFs复合材料,利用X-射线粉末衍射(XRD)、透射电镜(TEM)、热重分析(TG)等表征手段,证明了钯纳米粒子成功负载入MOFs的孔洞当中,且MOFs材料的晶体在整个负载过程中结构没有发生改变。从一系列Pd@MOFs复合材料中选择了孔洞窗口尺寸较大的Pd@MIL-101和孔洞窗口尺寸较小Pd@HKUST-1复合材料,用这两种复合材料作为催化剂对铃木进行催化反应,选择出了最佳的实验条件,从两种复合材料对催化反应活性,可以看出在Pd@HKUST-1复合材料对铃木反应催化过程存在尺寸选择效应,这是由于复合材料催化剂的MOFs骨架材料存在空间位阻,对一些产物尺寸较大的底物催化活性较差,对尺寸较小的底物催化活性较好,同时,Pd@MIL-101复合材料由于其孔洞足够大,尺寸选择效应并不明显,对于本实验所涉及的催化反应都有良好的催化活性。相比传统的催化剂三苯基膦钯和钯纳米粒子,本实验所合成的催化剂具有更高的催化活性和更好的选择性,在重复试验中体现出良好的催化活性,使其具备出色的应用前景。
[Abstract]:Suzuki-Miyaura cross-coupling reaction is a very important synthetic reaction in carbon-carbon coupling reaction. Its product biphenyl compounds due to special physical and chemical properties are currently in herbicides, drugs. Liquid crystal materials and other fields have been widely used in many fields, and the study of palladium nanoparticles and their support as catalysts has become the most important research on Suzuki-Miyaura in recent years. The research focus of heterogeneous recyclable catalyst for cross-coupling reaction. However, the PD nanoparticles supported on the support, such as PD @ Al _ 2O _ 3 / PD _ 2O _ 3 / Sio _ 2, are difficult to exhibit selectivity in the catalytic process. So, for Suzuki-Miyaura, Palladium nanoparticles composites with selective catalysis in cross-coupling reaction have become very meaningful. In this thesis, MOF-5 was synthesized according to the existing synthesis methods. A series of MOFs materials, such as ZIF-8, MIL-101 and so on, are reduced by siphon impregnation and liquid phase sodium borohydride methanol solution. Palladium nanoparticles were successfully loaded into the pores of MOFs, and Pd@MOFs composites were prepared by X-ray powder diffraction (XRD), transmission electron microscopy (TEM). Thermogravimetric analysis and other characterization methods proved that PD nanoparticles were successfully loaded into the pores of MOFs. The crystal structure of MOFs material has not changed during the whole loading process. From a series of Pd@MOFs composite materials, Pd@MIL-101 and pore window with larger pore window size are selected from a series of Pd@MOFs composites. Smaller Pd@HKUST-1 composite material. Using these two composite materials as catalyst for the catalytic reaction of Suzuki, the optimum experimental conditions were selected, and the catalytic activity of the two composite materials was obtained. It can be seen that the size selection effect exists in the catalytic process of Suzuki reaction by Pd@HKUST-1 composite material, which is due to the space steric resistance of the MOFs skeleton material of the composite catalyst. The catalytic activity of some substrates with larger product size is poor, and the catalytic activity of substrates with smaller size is better. Meanwhile, the Pd@ MIL-101 composite material is large enough because of its pore size. The size selection effect is not obvious and has good catalytic activity for the catalytic reaction involved in this experiment. Compared with the traditional catalyst triphenylphosphine palladium and palladium nanoparticles. The catalyst synthesized in this experiment has higher catalytic activity and better selectivity, and shows good catalytic activity in repeated experiments, which makes it have a good application prospect.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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