基于聚离子液体固载手性催化剂纳米粒子的合成及其在不对称合成中的应用

发布时间：2018-05-21 04:17

本文选题：手性催化剂 + 聚离子液体　；参考：《河南师范大学》2017年硕士论文

【摘要】：为了得到较纯的手性化合物,人们常常采用手性催化的办法,但是,由于目前市场上的手性催化剂都比较昂贵且当它与反应底物混合时很难分离,导致催化剂难以重复利用,通过催化剂固载的方法可以有效解决催化剂分离回收的问题,但同样面临着非均相体系催化效率低、很难实现在水中绿色催化等问题。本文中,我们提出了一种基于聚离子液体负载手性催化剂纳米粒子的制备方法。首先,通过自由基聚合的方法制备具有-COOH的手性无规共聚物,然后在碱性有机溶剂中与咪唑基聚合物离子液体通过原位离子络合作用生成交联聚离子液体复合物纳米粒子。该纳米粒子作为催化剂能够有效地催化直接不对称Aldol反应,biginelli反应等多组分反应中。同时为了探究聚离子液体在催化反应中所起的作用,我们制备了一系列具有不同表面结构的纳米粒子催化剂,进而研究了催化剂的催化活性、对映选择性以及重复利用性,具体的内容如下:一、具有-COOH的负载L-脯氨酰胺小分子催化剂共聚物的制备我们利用N-对乙烯基苯磺酰基-L-脯氨酰胺、甲基丙烯酸,以二甲基亚砜为溶剂、偶氮二异丁腈作为引发剂采用自由基聚合的方法成功制备了具有-COOH的Poly(MAA-co-Prolinamide)共聚物。然后采用~1HNMR、FT-IR对共聚物的结构进行了表征、采用GPC对共聚物的分子量及其分布进行了表征。二、基于聚离子液体固载L-脯氨酰胺手性催化剂纳米粒子的制备我们制备出了具有不同反离子的聚离子液体,随后将聚离子液体和具有-COOH的无规共聚物溶解在溶剂形成均相溶液,此时共聚物链中的-COOH以非解离的形式大量存在,当它们处在乙醇氨的碱性溶液中时,两者之间通过较强的离子间相互作用立即形成不溶的聚离子液体复合物纳米粒子。通过调控聚离子液体与共聚物之间的比例合成出了一系列具有不同壳层结构的纳米粒子,并通过傅里叶变换红外、静态接触角、透射电镜、光电子能谱、元素分析等对纳米粒子的形貌、表面结构以及元素组成进行了详细的表征。三、聚离子液体复合物纳米粒子在不对称合成反应中的应用为了研究制备的纳米粒子的催化性能,我们将其应用了在三个不对称合成反应中:直接不对称Aldol反应、简单的三组分(Biginelli反应)、复杂的三组分反应:1、对硝基苯甲醛、丙酮作为Aldol反应的主要底物,将上述制备的纳米粒子作为催化剂应用在直接不对称Aldol反应中,研究发现相比于有机小分子催化剂、共聚物,我们所合成的纳米粒子表现出较高的催化特性,尤其是在纯水体系中,催化活性更高,8 h内转化率能达到91%,ee值高达91%。2、脲,苯甲醛,乙酰乙酸乙酯作为Biginelli反应的底物,将上述制备的纳米粒子作为催化剂,应用在Biginelli反应中,研究了催化剂在不同溶剂:THF、CH2Cl2、CH_3CH_2OH、Toluene、H2O中的催化性能。研究发现,相比于其它有机溶剂,在纯水体系中的催化性能尤为突出,转化率达到80%,ee值达到40%,而在其它有机溶剂中的转化率仅仅只有35%,ee值有29%,甚至更低。3、以取代苯甲醛、2-羟基-1,4-萘醌、3-氨基-5-甲基吡唑作为三组分反应的主要底物,将上述制备的纳米粒子作为催化剂分别在不同的溶剂:THF、CH2Cl2、CH_3CH_2OH、Toluene、H2O中进行催化反应,研究发现,相比于其它有机溶剂,在纯水体系中的催化活性更高,其在水中的转化率能达到99%,ee值可达到98%。4、我们将回收的纳米粒子在直接不对称Aldol反应中和三组分反应中,经过5次反复循环催化后,催化剂的催化活性和立体选择性没有明显减弱,且催化剂的回收率可以达到98%以上。
[Abstract]:In order to obtain more pure chiral compounds, chiral catalysis are often used. However, because the chiral catalysts in the market are very expensive and difficult to separate when mixed with the reaction substrates, the catalyst can not be reused. The catalyst separation and recovery can be effectively solved by the method of catalyst immobilization. But also faced with the low catalytic efficiency of heterogeneous systems, it is difficult to realize the problem of green catalysis in water. In this paper, we proposed a preparation method based on the polyionic liquid supported chiral catalyst nanoparticles. First, the chiral random copolymer with -COOH was prepared by free radical polymerization, and then in the alkaline organic solvent. The imidazolic polymer ionic liquid is used to produce crosslinked polyionic Liquid Complex Nanoparticles by in situ ion complexation. As a catalyst, the nanoparticles can catalyze the direct asymmetric Aldol reaction, Biginelli reaction and other multi component reactions, and to explore the role of the polyionic liquid in the catalytic reaction. A series of nanoparticle catalysts with different surface structures were prepared, and the catalytic activity, enantioselectivity and reutilization of the catalyst were studied. Firstly, the preparation of the -COOH prolyl small molecular catalyst copolymer with the load L- was prepared by N- for the vinyl benzensulfonyl -L- prolyl Methacrylic acid, using two methyl sulfoxide as solvent and azo two isobutyl nitrile as initiator, the -COOH Poly (MAA-co-Prolinamide) copolymer was prepared successfully by free radical polymerization. Then ~1HNMR, FT-IR was used to characterize the structure of the copolymer. The molecular weight and distribution of the copolymer were characterized by GPC. Two, Based on the preparation of polyionic liquid supported L- prolyl chiral catalyst nanoparticles, we prepared polyionic liquids with different reverse ions. Then, the polyionic liquids and the random copolymers with -COOH were dissolved in the solvent to form the homogeneous solution. At this time, the -COOH in the copolymer chain existed in the form of non dissociation. In the alkaline solution of ethanol ammonia, the insoluble polyionic liquid composite nanoparticles are formed by the interaction of strong ion INTERIONS. A series of nano particles with different shell structures are synthesized by regulating the proportion between the polymer and the polymer, and the static connection is carried out by Fourier transform infrared (FTIR). Antennae, transmission electron microscopy, photoelectron spectroscopy, element analysis, and so on, the morphology, surface structure and element composition of the nanoparticles were characterized in detail. Three, the application of polyionic liquid composite nanoparticles in the asymmetric synthesis reaction was to study the catalytic properties of the prepared nanoparticles. We applied it to three asymmetric compounds. In the reaction: direct asymmetric Aldol reaction, simple three components (Biginelli reaction), complex three component reactions: 1, nitrobenzaldehyde, acetone as the main substrate for Aldol reaction, the nanoparticles prepared above are used as a catalyst in the direct asymmetric Aldol reaction, and the study found that the copolymerization was compared with the organic small molecular catalyst. The synthesized nanoparticles show high catalytic properties, especially in the pure water system, the catalytic activity is higher, the conversion rate of 8 h can reach 91%, the EE value is up to 91%.2, urea, benzaldehyde, ethyl acetoacetate as the substrate of the Biginelli reaction, and the nanoparticles prepared above are used as the catalyst in the Biginelli reaction. The catalytic performance of the catalyst in different solvents: THF, CH2Cl2, CH_3CH_2OH, Toluene, H2O has been studied. It is found that the catalytic performance in the pure water system is particularly prominent compared with other organic solvents, the conversion rate is 80%, the EE value reaches 40%, while the conversion rate in other organic solvents is only 35%, and the EE value is 29% or even lower.3 to replace benzene. Formaldehyde, 2- hydroxyl -1,4- naphthone and 3- amino -5- methyl pyrazole are the main substrates of the three component reactions. The catalysts prepared above are catalyzed in different solvents: THF, CH2Cl2, CH_3CH_2OH, Toluene, and H2O. The catalytic activity of the prepared nanoparticles in the pure water system is higher than that of other organic solvents, and it is found to be more active in the pure water system. The conversion rate of the water can reach 99% and the EE value can reach 98%.4. The recovered nanoparticles are in the direct asymmetric Aldol reaction and the three component reaction. After 5 repeated cycles, the catalytic activity and the stereoselectivity of the catalyst are not obviously weakened, and the recovery rate of the catalyst can be over 98%.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB383.1

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