卟啉非均相催化剂的设计、合成及其催化性能研究

发布时间：2018-01-06 00:17

本文关键词：卟啉非均相催化剂的设计、合成及其催化性能研究　出处：《江南大学》2017年博士论文　论文类型：学位论文

【摘要】：绿色化学与技术处于当前国际化学的前沿领域,它的研究核心是利用化学原理从根本上消除化学工业对环境的污染。其中,非均相催化为满足人们对绿色化学的需求带来了希望,以其易分离、易回收、能循环使用、处理效果好等优点,成为催化领域中研究开发和实际应用的重点,具有很好的应用前景。卟啉及其衍生物,作为重要的仿生催化剂之一,可以有效的模拟细胞色素酶(P450)的功能,表现出很好的催化效果,但目前卟啉均相催化不稳定、易失活和难循环利用等问题,限制了卟啉仿生催化的进一步发展。近年来,由于框架材料具有可控性好、设计性强和结构稳定等特点,使得它在非均相催化的应用中极具竞争力。因此,制备卟啉框架材料,不仅可以通过高活性密度来增强催化活性,还可以利用框架材料的孔道构建底物的“限域效应”。另外,借助框架材料的表征和分析手段,对卟啉框架催化剂的催化过程进行系统的研究,具有重要的理论意义和应用价值。本论文设计合成了一系列基于卟啉为催化活性中心的金属有机框架催化剂、共价有机框架催化剂(其中包括具有周期性排列单元、以共价键连接的聚合物催化剂),并对其催化精细化学品的合成如不饱和烯烃环氧化、苄胺偶联的催化活性和选择性进行了系统的研究。另外,本工作采用密度泛函理论对卟啉催化剂的制备过程和催化过程进行了几何结构优化和单点能计算,以达到理论与实际相互验证的目的。本论文的主要内容和结果如下:1)金属有机框架(Metal Organic Frameworks,MOFs)材料具有独特的多孔性,以及高的比表面积和尺寸可调的孔道,可以人为的在MOFs的空穴中引入功能性的客体分子。本论文选择类沸石咪唑框架材料(zeolitic imidazolate frameworks,简称ZIFs)作为载体,锰卟啉作为模拟血红蛋白酶的活性中心,构建包裹型卟啉MOFs催化剂(Mn-TAPP@ZIF-8,Mn-TAPP四(4-氨基)苯基锰卟啉)。当使用催化剂材料Mn-TAPP@ZIF-8进行环己烯环氧化,Mn-TAPP@ZIF-8的催化活性明显高于Mn-TAPP的催化活性,说明使用Mn-TAPP@ZIF-8作为烯烃环氧化催化剂是比较好的非均相催化剂。工作还研究了Mn-TAPP与ZIF-8形成的主-客体关系,明确了Mn-TAPP与ZIF-8之间协同效应的机理,发现了ZIF-8内腔上咪唑C-H键与氨基卟啉上的N形成了弱氢键作用,这样的键能结合提高了锰卟啉中高价态锰的含量,进而有利于环氧化的进行。Mn-TAPP@ZIF-8在烯烃环氧化反应中具有广泛的应用价值,对不同烯烃都有很好的催化效果。另外,Mn-TAPP@ZIF-8具有典型的非均相催化的特点,循环利用3次,催化效果几乎没有下降的趋势。2)本章节内容以5,10,15,20-(四羧基苯基)卟啉(H4TCPP)、锰-5,10,15,20-(四羧基苯基)卟啉(Mn-TCPP)为配体,分别与过渡金属Fe和Ni自组装得到两种新型晶态MMPFs材料(Fe-MMPF和Ni-MMPF),通过单晶衍射分析了它们的结构,其中Fe-MMPF包含首次报道的三核铁氧簇和锰卟啉,Ni-MMPF由一维的带状镍氧链与镍卟啉组装而成,根据两种催化剂结构上的特点,通过两个催化体系进行考察,(1))在Fe-MMPF\H2O2\Na HCO3催化体系中,常温下环辛烯的转化率高达99%,没有副产物的生成。催化结果表明,Na HCO3显示出了高效的催化剂助剂作用。催化机理的研究结果明确了氧原子在反应中的转移路径:HCO4-替代H2O2作为新的氧源提供氧原子,氧原子再从HCO4-转移到锰卟啉形成催化活性中间体,活化双键后得到产物。三核铁氧簇对于锰卟啉有一个吸电子的作用,这样吸电子的作用是有利于催化反应的进行,根据这样的现象本工作提出了新的概念,称为“催化有利的电荷移动”。(2))在Ni-MMPF\TBHP催化体系中,根据催化结果明确了共轭烯烃周围电子云密度对环氧化效果的影响。环氧化产率与烯烃本身的立体空间结构效应有联系。另外,苯环和双键上连接供电子基团,有利于双键上电子云密度的增加,双键更容易被卟啉的过氧中间体进攻活化,因此环氧化效果会提高。最后对催化剂进行了5次循环利用实验,发现经过5次循环利用,转化率90%,选择性98%。3)采用具有酰肼基团的卟啉(Mn-HTCPP)为构筑单元,与对苯二甲醛或方酸通过缩合反应成功的合成了一类结构新颖且具有优良环氧化效果的固体催化剂Mn-CPFs。两种框架结构的孔道主要以堆积孔为主,且难溶于常见的极性和非极性有机溶剂。对这两种催化剂进行烯烃环氧化实验测试,结果表明,催化剂Mn-CPF-1具有更加优良的环氧化效果,说明构筑单元Mn-HTCPP与对苯二甲醛的组合有利于提高锰卟啉的催化能力。考察了Mn-CPF-1催化剂对环状烯烃和链状烯烃的催化能力。催化剂循环利用的结果表明Mn-CPF-1稳定性良好,具有很好的可循环利用性。XPS测试表明Mn-CPF-1中锰的电荷分散到共轭有机骨架程度更高,具有更明显的氧化还原能力,因此活性中心的催化性能更强。4)设计合成了具有四个硝基的锰卟啉化合物,在碱性条件下与对苯二胺或联苯二胺进行偶联,得到两种结构不同的微孔有机聚合物催化剂,命名为azo-CMP-1和azo-CMP-2。报道的合成方法简便,制备的azo-CMP-1具有更加优良的环氧化效果。通过SEM分析,发现azo-CMP-1具有对催化有利的片层结构,这与催化剂骨架的构成有关,片层结构不仅能够增强催化剂的疏水性,还有利于产物的释放和降低叔丁醇与活性中心的接触;对催化剂的环氧化机理进行探讨,XPS的结果进一步证实了有机骨架对活性中心的影响:电荷分散到共轭有机骨架中的程度更高,从而使azo-CMP-1中的锰具有更明显的氧化还原能力。对催化剂进行循环利用实验,结果表明azo-CMP-1稳定性良好,具有很好的可循环利用性。5)成功将卟啉和蜜勒胺通过偶氮键连接成为一种具有良好孔道结构的框架催化剂(PMP),基于电子供-受的光催化体系,建立起了空穴氧化、电子转移和能量转移的“三位一体”光催化过程。PMP的高比表面积可以有效地提高底物的传质过程。计算化学和稳态、动态荧光测试的结果表明,PMP可以吸收可见光,能够有效的抑制电子和空穴的复合行为,以此增强电子转移的过程。另外,通过ESR和UV-Vis分析,PMP相对于TNPP能够产生更多单线态氧,说明能量转移过程被增强。上述的双重增强作用说明,PMP是一种在可见光下具有高效光催化活性的非金属催化材料,而且具有很好的可循环利用性。
[Abstract]:Green chemistry and technology in the current international frontiers of chemistry, the essence of the research is to eliminate the environmental pollution of chemical industry fundamentally by chemical principle. The heterogeneous catalytic brings hope to meet the demand for green chemistry, with its easy separation, easy recovery, energy recycling, treatment effect and the like well, become the focus in the field of catalysis and practical application of research and development, has good application prospects. The porphyrin and its derivatives, as one of the most important bionic catalyst, can simulate cytochrome enzyme effective (P450) function, showed good catalytic effect, but the porphyrin homogeneous catalysis is not stable, easy to deactivation and recycling difficult problems, limiting the further development of porphyrin biomimetic catalysis. In recent years, because the frame material has good controllability and stability characteristics of strong in design and structure, making it in the heterogeneous. Very competitive of application. Therefore, the preparation of porphyrin framework material, not only can enhance the catalytic activity by high activity density, "confinement" can also build the substrate utilization frame material channels. In addition, by means of material characterization and analysis framework, the systematic research on the catalytic process of porphyrin catalyst framework that has important theoretical significance and application value. Based on a series of porphyrins in the catalytic center of the metal organic framework catalysts were designed and synthesized in this paper, covalent organic frameworks (including catalyst with periodic unit polymer catalyst covalently bound), and its catalytic synthesis of fine chemicals such as unsaturated olefin the coupling of epoxidation, catalytic activity and selectivity were studied. In addition, by using the density functional theory of porphyrin catalyst preparation The process and catalytic process of geometry optimization and single point calculations, in order to achieve the theory and practice of mutual authentication. The main contents and results of this thesis are as follows: 1) metal organic frameworks (Metal Organic Frameworks, MOFs) has unique porous materials, and the specific surface area and pore size adjustable high the artificially introduced functional guest molecules in the MOFs cavity. This paper selected materials (zeolitic imidazolate zeolitic imidazolate framework frameworks, referred to as ZIFs) as the carrier, as the manganese porphyrin active center simulation hemoglobin enzyme, construction of encapsulated porphyrin MOFs catalyst (Mn-TAPP@ZIF-8, Mn-TAPP four (4- amino phenyl) porphyrin manganese). When using the catalyst material Mn-TAPP@ZIF-8 for the epoxidation of cyclohexene, the catalytic activity of Mn-TAPP@ZIF-8 was significantly higher than that of the catalytic activity of Mn-TAPP, use Mn-TAPP@ZIF-8 as olefin ring Is a good catalyst for oxidation of heterogeneous catalyst was also studied. Mn-TAPP and ZIF-8 formed the main object relation, the mechanism between Mn-TAPP and ZIF-8 synergistic effect, ZIF-8 was found on the inner imidazole C-H bond with amino porphyrin formation of N weak hydrogen bonds, such bonds can high valence manganese content manganese porphyrin increased the binding and.Mn-TAPP@ZIF-8 in olefin epoxidation has wide application value for the epoxidation, have good catalytic effect to different olefins. In addition, Mn-TAPP@ZIF-8 has the typical characteristics of heterogeneous catalysis, 3 recycling, the catalytic effect of almost no downward trend.2) this chapter by 5,10,15,20- (four carboxyl phenyl) porphyrin manganese (H4TCPP), -5,10,15,20- (four carboxy phenyl) porphyrin (Mn-TCPP) as the ligand, respectively with transition metal Fe and Ni self-assembly get two new crystalline MMPFs materials (Fe-MMPF and Ni-MMPF), their structures were analyzed by X-ray diffraction, which contains Fe-MMPF first reported three nuclear iron oxide clusters and manganese porphyrin Ni-MMPF by nickel oxide and nickel porphyrin ribbon chain assembly into one-dimensional, according to the two kinds of catalysts on the structure characteristics, were evaluated by two catalyst system. (1) Fe-MMPFH2O2Na) in the HCO3 catalytic system, room temperature cyclooctene conversion rate as high as 99% generation of by-products. The catalytic results show that Na HCO3 shows the catalyst effect and efficiency. Research results confirm the catalytic mechanism of the transfer path of oxygen atoms in the reaction: HCO4- instead of H2O2 as the source of oxygen the new oxygen atoms, oxygen atoms and then transferred from the HCO4- to the formation of the catalytic activity of manganese porphyrin intermediates, activated double bond product is obtained after three. Nuclear ferrite clusters have a electron withdrawing role for manganese porphyrin, so the electron withdrawing effect is Favorable to the catalytic reaction, according to this phenomenon put forward the new concept of this work, called "charge mobile" favorable catalytic. (2)) in the Ni-MMPFTBHP catalytic system, based on the catalytic results clarified the electron cloud density around the shadow on the epoxidation effect of conjugated olefin ring. With three-dimensional space structure effect epoxidation of olefin yield and itself. In addition, the benzene ring and double bond connected with electron donating group, is conducive to the double bond electron cloud density increases, the double bond is more likely to be peroxy intermediate porphyrin attack activation, so the epoxidation effect will be improved. Finally, the catalyst was 5 cycles using the experiment, found that after 5 times recycling 90%, the conversion rate, selectivity of 98%.3) with hydrazide group porphyrin (Mn-HTCPP) as the construction units, and two of benzene formaldehyde or acid successfully through condensation reaction of synthesis of a novel structure and has the advantages of Solid catalyst Mn-CPFs. Lianghuan oxidation effect of two kinds of frame structure mainly by the accumulation of pore pore, and insoluble in common polar and non-polar organic solvents. For olefin epoxidation test of the two kinds of catalysts showed that Mn-CPF-1 catalyst has excellent epoxidation effect more, that building unit Mn-HTCPP in combination with two of benzene formaldehyde can improve the catalytic ability of manganese porphyrin was studied. The catalytic performance of Mn-CPF-1 catalyst on cyclic olefin and chain olefin catalyst recycling. The results show that Mn-CPF-1 has good stability, good recyclability of.XPS test indicated that the charge of Mn in Mn-CPF-1 dispersed into the conjugated organic skeleton degree higher, with more obvious oxidation reduction ability, so the active center of the catalytic performance of manganese porphyrin compounds with stronger.4) four nitro groups were designed and synthesized in alkali Under the condition of two of benzene and biphenyl amine or two amine coupling by microporous organic polymers catalyst with two different structure, named the synthesis method of azo-CMP-1 and azo-CMP-2. report is prepared by epoxidation of azo-CMP-1 has better results. Through SEM analysis, the azo-CMP-1 has favorable on the catalytic layer structure this, and the catalyst skeleton on the composition, the lamellar structure can not only enhance the hydrophobic catalyst, but also conducive to the product and reduce the release of tert butyl alcohol and active center contact; epoxidation mechanism of catalyst was discussed, the results of XPS further confirmed the effect of organic skeleton on the active center: charge dispersion to conjugated organic in the framework of higher degree, so that the azo-CMP-1 of Mn has more obvious oxidation reduction ability. The catalyst recycling experiment results show that the stability of azo-CMP-1 Good use of.5, has good circulation) successfully porphyrin and melem connected into a framework of the catalyst has good pore structure by azo bond (PMP), the photocatalytic system based on electron donor acceptor, up hole oxidation, electron transfer and energy transfer of "three-in-one" photocatalytic the process of specific surface area of.PMP can effectively improve the mass transfer process of substrate. Computational chemistry and steady-state fluorescence, dynamic test results show that PMP can absorb visible light, the composite can inhibit the behavior of electrons and holes effectively, in order to enhance the electron transfer process. In addition, through the analysis of ESR and UV-Vis, PMP to TNPP can produce more singlet oxygen, energy transfer process is enhanced. The double enhancement shows that PMP is a kind of high efficient photocatalytic activity under visible light non metal catalytic materials, but also has Good recyclability.

【学位授予单位】：江南大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O643.36

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