负载型钌取代多酸催化剂的设计合成及其在十四烷氧化中的应用

发布时间：2018-07-20 16:31

【摘要】：多酸为一类纳米尺寸的无机簇状化合物,因兼具酸性和氧化还原性,可作为一种十分高效的双功能催化剂。同时,它还具有尺寸多样、结构可调、组成丰富等特点,对不同的催化反应类型均有较好的适应性。据不完全统计,多酸在催化领域的应用研究成果占据了其所有研究领域中的百分之八十以上,可见多酸是一类值得关注且有应用前景的催化剂以往多酸的研究多集中于均相催化领域,但随着研究的不断深入一些较难克服的缺点凸显,如分散性差、比表面积小、难以回收等。这些缺点在一定程度上制约了多酸在催化领域应用的深入开展,同时也与当前绿色化学的理念相违背。为寻求解决方案,科学家们做了较多的尝试和探索,其中最为行之有效的是将多酸负载到合适的载体上制备非均相催化剂,借助载体的高分散性、高比表面积、易于回收等特点克服弊端,推进多酸绿色催化过程的实现。借助这一思路,我们选择了几种钌取代多酸,借助浸渍法将其负载到不同的载体上制得负载型多酸催化剂,并将其用于十四烷烃的催化氧化实验中。遵循绿色催化理念,实验过程以高纯空气作为氧源,不使用强氧化剂和其他溶剂,力图在较温和的条件下促发反应的进行,重点考察不同的载体结构及其不同反应条件对于催化反应的影响。具体开展了下列三方面工作:1.首先合成含四价钌的取代型多酸Rb_(10)[{Ru_4O_4(OH)_2(H_2O)_4}(γ-GeW_(10)O_(36))_2]·21H_2O(GeW_(10)Ru_2)和NH_4[{Ru_4O_6(H_2O)_9}_2{Fe(H_2O)_2}_2{β-TeW_9O_(33)}_2H]·36H_2O(NH_4-2),并将其负载到不同载体上制备了多相催化剂。选择二氧化硅介孔分子筛SBA-15作为催化剂载体,先期对其进行氨基官能化修饰,后将设计合成的钌取代多酸GeW_(10)Ru_2以浸渍法负载到分子筛上制备负载型多酸催化剂SBA-15-Apts-GeW_(10)Ru_2,并通过多种表征手段证明了该制备方案的可行性。而后选择三种具有不同结构的二氧化硅分子筛SBA-15、KIT-6、FDU-12作为催化剂载体,同样对其进行氨基化修饰后负载钌取代型多酸NH_4-2制得催化剂X-Apts-NH_4-2(X=SBA-15、KIT-6、FDU-12),而后通过多种表征手段对该制备过程中多酸的在不同结构载体上的负载情况作深入探讨。2.负载型催化剂SBA-15-Apts-GeW_(10)Ru_2被用于考察十四烷催化氧化过程研究。一方面,考察了催化剂负载量、反应时间、反应温度、催化剂用量等各种反应条件对催化剂催化效率的影响,找到了催化反应的最佳实验条件即催化剂负载量3.21%,反应时间7 h,反应温度150℃,催化剂用量4 mg,在该条件下正十四烷的转化率可达50.97%;另一方面,通过一系列对照实验推断出十四烷催化氧化反应的机理为自由基引发过程。3.具有不同载体的负载型催化剂X-Apts-NH_4-2(X=SBA-15、KIT-6、FDU-12)被用于十四烷的催化氧化过程研究。一方面,重点考察不同载体在实验中对催化剂的催化活性的影响,并于三者中选出了更适宜作为该反应体系的催化剂载体为FDU-12;另一方面,系统研究了固相催化剂FDU-12-Apts-NH_4-2在不同实验条件下的催化活性,考察了催化剂负载量、反应时间、反应温度、催化剂用量等反应条件对其催化活性的影响,确定了催化反应的最佳实验条件为催化剂负载量2.55%,反应温度150℃,反应时间7 h,催化剂用量4 mg,在此条件下正十四烷的转化率达到了52.84%。
[Abstract]:Polyacid is a kind of nano sized inorganic cluster compound. Because of its acidity and oxidation-reduction, it can be used as a highly efficient dual function catalyst. At the same time, it has the characteristics of wide size, adjustable structure, rich composition and so on. It has good adaptability to different types of catalytic reactions. According to incomplete statistics, polyacid is in the field of catalysis. The results of application research occupy more than eighty percent of all the research fields. It can be seen that polyacid is a kind of valuable and promising catalyst for the previous study of polyacid in the field of homogeneous catalysis. However, with the continuous deepening of the research, some of the more difficult shortcomings, such as poor dispersibility and small specific surface area, are difficult to return. To some extent, these shortcomings restrict the development of the application of polyacid in the field of catalysis. At the same time, it is contrary to the idea of current green chemistry. In order to find a solution, scientists have done more attempts and explorations. The most effective is to load polyacid onto a suitable carrier to prepare heterogeneous catalyst. The high dispersion, high specific surface area and easy recovery of the support carrier overcome the disadvantages and promote the realization of the polyacid green catalytic process. With this idea, we choose several ruthenium to replace polyacid, and use the method of impregnation to produce a loaded polyacid catalyzing agent on different carriers, and use it for the catalytic oxidation experiment of fourteen alkanes. In accordance with the concept of green catalysis, the experimental process uses high pure air as the oxygen source, and does not use strong oxidants and other solvents, trying to promote the reaction under more mild conditions, focusing on the effects of different carrier structures and their different reaction conditions on the catalytic reaction. The following three aspects are carried out in the body: 1. first synthesis of containing compounds Tetravalent Ru Rb_ (10) [{Ru_4O_4 (OH) _2 (H_2O) _4} (H_2O) _4} (10) O_ (36)) _2] 21H_2O (GeW_ (10) Ru_2) and its loaded onto different carriers to prepare polyphase catalysts. It was modified by amino functionalization at the first stage, then the synthesized ruthenium was substituted for polyacid GeW_ (10) Ru_2 to be loaded to the molecular sieve to prepare the supported polyacid catalyst SBA-15-Apts-GeW_ (10) Ru_2 by impregnation method, and the feasibility of the preparation was proved by a variety of characterization methods. And then three kinds of silica molecules with different structures were selected. A catalyst X-Apts-NH_4-2 (X=SBA-15, KIT-6, FDU-12) was prepared by aminated modification of SBA-15, KIT-6 and FDU-12 as a catalyst carrier, and then the loading of polyacid on different structural carriers in the preparation process was investigated by a variety of characterization methods, and the.2. supported catalyst SB was deeply discussed. A-15-Apts-GeW_ (10) Ru_2 was used to investigate the catalytic oxidation of fourteen alkanes. On one hand, the effects of the amount of catalyst load, reaction time, reaction temperature, and the amount of catalyst on the catalytic efficiency of the catalyst were investigated. The optimum experimental conditions for the catalytic reaction were found to be 3.21% of the catalyst load, the reaction time 7 h, and the reaction temperature. At 150 degrees C, the amount of catalyst is 4 mg, and the conversion of fourteen alkanes can reach 50.97% under this condition. On the other hand, a series of controlled experiments have been made to deduce that the mechanism of the catalytic oxidation of fourteen alkanes is the free radical initiation process of the supported catalyst X-Apts-NH_4-2 (X=SBA-15, KIT-6, FDU-12) with different carriers (X=SBA-15, KIT-6, FDU-12) used in the catalytic oxygen of fourteen alkanes. On the one hand, the effect of different carriers on the catalytic activity of the catalyst was investigated, and the catalyst carrier, which was more suitable for the reaction system, was selected in the three of the three, and on the other hand, the catalytic activity of the solid phase catalyst FDU-12-Apts-NH_4-2 under different experimental conditions was studied, and the catalytic activity was investigated. The effect of the amount of agent load, reaction time, reaction temperature, and the amount of catalyst on the catalytic activity of the catalyst has been determined. The best experimental conditions for the catalytic reaction are the catalyst load 2.55%, the reaction temperature 150, the reaction time 7 h and the catalyst amount 4 mg, and the conversion of the positive fourteen alkane has reached 52.84%. under this condition.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

【相似文献】