固体有机碱及其固载钯催化剂的设计合成及在碳—碳键形成反应中的应用

发布时间：2018-01-02 01:14

本文关键词：固体有机碱及其固载钯催化剂的设计合成及在碳—碳键形成反应中的应用　出处：《南昌大学》2017年博士论文　论文类型：学位论文

【摘要】：碳-碳键的构建是有机化学的基础,已有很多的C-C键的构建方法被报道。几乎所有的C-C键形成反应都需要催化剂的参与,均相有机催化剂或金属催化剂残留一直是难以解决的问题。设计合成出高效、易分离、可循环使用的C-C键形成反应的多相催化剂一直是催化工作者追求的目标。有机碱由于其碱性及富电子位点,能催化一些简单的C-C键形成反应,如Aldol,Henry,Knoevenagel等反应;大部分有机碱含有富电子位点也可以作为配体螯合固载贵金属。本文从易功能化的二维材料氧化石墨烯(GO)及可调控官能团的多孔有机聚合物(POPs)出发,设计合成了一系列固体有机碱及其配位固载贵金属催化剂并通过有机元素分析,傅里叶红外,X射线衍射,X射线能谱,扫描电镜,透射电镜及原子发射光谱等对催化剂进行表征。将其应用于适当的C-C键形成反应中,催化剂表现出高效,高选择性,易分离,可循环的特点。(1)超强有机碱1,1,3,3-四甲基胍(TMG)通过氢键作用固载到氧化石墨烯上得到固体有机碱催化剂TMG/GO,并应用于Aldol反应中,该催化剂具有与均相催化接近的催化活性,并能循环使用多次,活性不降低;更重要的是具有很高的Aldol产物选择性,且能在反应过程中保持该选择性。通过实验结果我们提出了一个TMG/GO催化Aldol反应的可能机理。(2)通过酯化反应调变氧化石墨烯表面的酸性基团共价键负载3-氨丙基三乙氧基硅烷,该能进一步阐述相同反应条件下,碱性基团越多,Aldol反应转化率越高,弱酸性的酚羟基有利于保持Aldol产物不脱水生成烯酮类产物。(3)固体有机碱TMG/GO的氮位点能够螯合固定贵金属Pd,强碱下Pd极易被还原成Pd纳米颗粒。基于该想法,本文通过简单的将Pd(OAc)2与TMG/GO搅拌下合成了Pd@TMG/GO催化剂应用于Heck偶联反应,该催化剂能高效催化Heck偶联反应,并能适用于多种底物,且能多次循环无催化活性降低。(4)均相的邻菲罗啉类催化剂已被报道应用于苯与卤代芳烃的的偶联反应中,而该催化剂不易从反应体系中分离,我们通过傅克反应将邻菲罗啉结构的化合物做成POPs,将该POP应用于苯与碘苯的反应中,产物联苯的收率可达(56%)且适用于碘代芳烃和溴代芳烃与苯的反应(不适用于氯代芳烃),并能循环多次,有助于产物的分离。(5)通过对有机碱咔唑吡啶中的吡啶氮的空间位阻进行调控,发现3,5-咔唑吡啶POP(CNP-2)比2,6-咔唑吡啶POP(CNP-1)更易与Pd(OAc)2形成配合物,固体有机碱载Pd(OAc)2配合物(Pd-CNP-2)在催化卤代芳烃脱卤氰基化过程中无需加入配体和添加剂。且能适用于各类卤代芳烃底物,该催化剂还具有很强的稳定性和可重复使用性能。
[Abstract]:The construction of carbon-carbon bond is the basis of organic chemistry, and many methods of C-C bond construction have been reported. Almost all C-C bond formation reactions require the participation of catalysts. It is difficult to solve the problem of homogeneous organic catalyst or metal catalyst residue. The design and synthesis of high efficiency and easy separation. The multiphase catalyst for the cyclic C-C bond formation reaction has always been the target of the catalysis workers. Organic bases can catalyze some simple C-C bond formation reactions because of their alkaline and electron-rich sites. For example, Aldola Henryn Knoevenagel reaction; Most organic bases containing electron-rich sites can also be used as ligand chelating immobilized precious metals. Let's go. A series of solid organic bases and their coordination supported noble metal catalysts were designed and synthesized. The catalyst was characterized by transmission electron microscope (TEM) and atomic emission spectroscopy. The catalyst was characterized by high efficiency, high selectivity and easy separation when it was applied to the appropriate C-C bond formation reaction. The characteristics of cycle. 1) the ultrastrong organic base (1) 1 / 3 (3) -tetramethylguanidine (TMG) was immobilized on graphene oxide by hydrogen bonding to obtain solid organic base catalyst (TMG/GO). The catalytic activity of the catalyst is close to that of homogeneous catalyst, and it can be reused many times without decreasing its activity. More importantly, it has high selectivity of Aldol products. And the selectivity can be maintained during the reaction. Based on the experimental results, a possible mechanism of Aldol reaction catalyzed by TMG/GO has been proposed. 3-aminopropyl triethoxy silane was loaded on the surface of graphene oxide by adjusting the covalent bond of the acid group on the surface of graphene oxide by esterification reaction. It can be further explained that under the same reaction conditions, the higher the conversion of Aldol is, the more basic groups are. The weakly acidic phenolic hydroxyl group is beneficial to keep the nitrogen site of the solid organic base TMG/GO in the absence of dehydration of the Aldol product to form ketenes. 3) the nitrogen site of the solid organic base TMG/GO can be chelated to immobilize the noble metal PD. PD is easily reduced to PD nanoparticles under strong alkali. In this paper, Pd@TMG/GO catalyst was synthesized by agitating Pd(OAc)2 and TMG/GO in Heck coupling reaction. The catalyst can efficiently catalyze the Heck coupling reaction and is suitable for various substrates. The o-phenanthroline catalysts, which have been used in the coupling reaction between benzene and halogenated aromatics, have been used in the coupling reaction of benzene and halogenated aromatics, and it is difficult to separate the catalyst from the reaction system. The compound with o-phenanthroline structure was made into POPsby Fourier reaction, and the POP was applied to the reaction of benzene with iodobenzene. The yield of biphenyls can reach to 56%) and it is suitable for the reaction of iodide aromatics and brominated aromatics with benzene (not suitable for chlorinated aromatics) and can be recirculated for many times. By regulating the steric resistance of pyridine nitrogen in organic base carbazole pyridine, it was found that the ratio of 3 to 5-carbazole pyridine POPCNP-2) was 2. 6-carbazolpyridine POPP-1) is more likely to form complexes with Pd(OAc)2. Solid organic alkaline-supported Pd(OAc)2 complexes (Pd-CNP-2) do not need to add ligands and additives in the process of catalytic dehalogenation of halogenated aromatics and can be applied to various halogenated aromatics substrates. The catalyst also has strong stability and reusability.
【学位授予单位】：南昌大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O643.36;O621.251

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