季銨功能化金屬有機框架材料的合成及其催化性質(zhì)
發(fā)布時間：2018-10-16 09:07
【摘要】：CO_2的轉(zhuǎn)化利用是當(dāng)今綠色化學(xué)的研究熱點,CO_2的轉(zhuǎn)化反應(yīng)也多種多樣,其中CO_2與環(huán)氧化物的環(huán)加成反應(yīng)以其條件溫和、原子經(jīng)濟性和無毒無害等優(yōu)點成為最重要的一類轉(zhuǎn)化方式。很多多孔催化劑都被用于該轉(zhuǎn)化反應(yīng)。金屬有機框架材料(Metal-OrganicFrameworks,MOFs)作為一種具有高孔隙率、高比表面積、孔道有序且可調(diào)、可通過預(yù)修飾和后修飾引入特定功能位點等優(yōu)點的多孔功能材料,近年來在包括非均相催化的各領(lǐng)域內(nèi)被廣泛使用。在MOFs的催化應(yīng)用中最受關(guān)注的反應(yīng)之一當(dāng)屬CO_2與環(huán)氧化物的環(huán)加成反應(yīng)(cycloaddition of carbon dioxide to epoxides,CCE)。該反應(yīng)通常需要一種促使環(huán)氧化物開環(huán)并在碳酸酯閉環(huán)步驟中離去的親核陰離子(一般為鹵素離子)。然而絕大多數(shù)MOFs材料的框架結(jié)構(gòu)呈電中性,不含親核陰離子。為了提升MOFs催化劑對CCE反應(yīng)的催化效果,一般需要外加均相的離子化合物(如四丁基溴化銨)以引入親核陰離子。這種含有均相助催化劑的催化系統(tǒng)并不是完全的環(huán)境友好型非同相系統(tǒng)。解決這一問題的有效途徑是將MOFs離子化:在框架上引入陽離子基團,獲得正電性框架結(jié)構(gòu),從而將抗衡陰離子包封在孔道內(nèi),實現(xiàn)MOFs和親核陰離子的一體化。本文利用2-甲�；鶎Ρ蕉姿崤潴w在酰胺溶劑熱反應(yīng)條件下可發(fā)生Leuckart-Wallach甲�；�原胺化反應(yīng)的性質(zhì),發(fā)展了 MOFs材料的原位叔胺基修飾方法。再通過對叔胺基的N-甲基化后修飾和離子交換,合成了一系列以不同鹵素離子為抗衡陰離子的季銨功能化MOFs催化劑。催化實驗結(jié)果表明,這種MOFs催化劑在CCE反應(yīng)中表現(xiàn)出很好的催化活性并而無需外加助催化劑。本論文內(nèi)容包括以下三個部分:1.利用甲�；晦D(zhuǎn)化反應(yīng)合成叔胺功能化MOFs利用2-甲�；鶎Ρ蕉姿崤潴w在DMF溶劑熱合成MOFs過程中的原位Leuckart-Wallach還原胺化反應(yīng),合成了叔胺功能化的MOFs材料UiO-66-CH_2-N(CH_3)_2;利用BDC和BDC-CHO混合配體合成了混配型叔胺功能化UiO-66-CH_2-N(CH_3)_2-MLx。此外,我們還將這種原位轉(zhuǎn)化策略擴展,通過改變酰胺溶劑合成了叔胺基種類不同的叔胺功能化UiO-66,通過改變金屬離子獲得叔胺基功能化的MIL-101材料,從而發(fā)展了利用配體原位轉(zhuǎn)化制備功能化MOFs的方法。利用X射線衍射儀、熱重分析儀和核磁共振儀等手段對合成的MOFs材料的骨架結(jié)構(gòu)、熱穩(wěn)定性和修飾比例進行了表征。2.季按離子功能化UiO-66的制備及其對CCE反應(yīng)的催化性質(zhì)通過N-甲基化修飾及陰離子交換對前一部分得到的叔胺功能化UiO-66進行后合成修飾,合成了含有不同種類鹵素抗衡陰離子的季銨離子化MOFs催化劑;研究了其對CCE反應(yīng)的催化性能,考察了混合配體比例、抗衡陰離子種類和催化劑用量、反應(yīng)溫度、壓力以及時間等反應(yīng)條件的影響。實驗表明,混合配體的UiO-66-CH_2-N~+(CH_3)_3Br~--ML0.72材料因其適中的孔道尺寸及后修飾比例作為催化劑更具優(yōu)勢;最適宜的反應(yīng)條件為:底物14.29mmol、溫度100℃、壓力1 MPa、時間4 h、催化劑100 mg。此外,我們還擴展了反應(yīng)底物的種類,用氧化苯乙烯、環(huán)氧氯丙烷、環(huán)氧丁烷和環(huán)氧環(huán)己烷等物質(zhì)作為反應(yīng)底物。結(jié)果表明反應(yīng)均能不同程度的發(fā)生,并且催化產(chǎn)率與底物分子尺寸和取代基種類有關(guān)。3.溴甲基化功能化MOFs的合成嘗試溴甲基功能化MOFs材料可作為離子型MOFs的前體。這一部分我們分別嘗試了兩種路線來合成溴甲基化的MIL-101-CH_2Br材料。在后合成鹵化路線中,成功合成了 MIL-101-CH_3,但是接下來的溴代后修飾反應(yīng)不能發(fā)生;而在配體預(yù)修飾路線的研究中,我們發(fā)現(xiàn)2-溴甲基對苯二甲酸甲酯的水解反應(yīng)并不生成希望的2-溴甲基對苯二甲酸配體而是生成了 4-羧基苯酞,以此為原料未能得到MIL-101類型的MOFs產(chǎn)物。上述嘗試性研究盡管未得到目標(biāo)MOFs產(chǎn)物,但也獲得了有用的化學(xué)信息。
[Abstract]:The conversion and utilization of CO _ 2 is a hot spot of green chemistry today. CO _ 2 conversion is also varied, and the cycloaddition reaction of CO _ 2 and epoxide is the most important type of transformation in terms of its mild condition, atom economy and non-toxic and harmless. Many porous catalysts are used for this conversion reaction. Metal organic framework materials (MOFs), as a porous functional material with high porosity, high specific surface area, orderly and adjustable pore channel, can introduce specific functional sites through pre-modification and post-modification, have been widely used in various fields including heterogeneous catalysis. One of the most important reactions in the catalytic application of MOFs is the cycloaddition of CO _ 2 and epoxide (CCE). This reaction generally requires a nucleophilic anion (typically a halogen ion) that causes the epoxide to ring open and leave in the carbonate closed loop step. However, the framework structure of most MOFs materials is neutral and does not contain nucleophilic anions. In order to improve the catalytic effect of the MOFs catalyst on CCE reaction, it is generally necessary to add homogeneous ionic compounds (such as tetraisobutyl bromide) to introduce nucleophilic anions. This catalytic system containing both the aid catalysts is not a complete environmentally friendly non-phase system. The effective way to solve this problem is to ionize the MOFs: the cation groups are introduced into the frame to obtain the positive electrical framework structure, so that the counter anion is encapsulated in the pore canal, and the integration of the MOFs and the nuclear anions is realized. In this paper, the properties of the reductive amination reaction of Leuckart-Wallach A with 2-methylterephthalic acid ligand can take place under the thermal reaction conditions, and the in-situ tertiary amine modification method of MOFs material has been developed. After N-methylation modification and ion exchange on tertiary amine groups, a series of quaternary amine functional MOFs catalysts with different halogen ions as counter anions were synthesized. The results of catalytic experiments show that this kind of MOFs catalyst shows good catalytic activity in CCE reaction without addition of cocatalyst. The contents of this thesis include the following three parts: 1. In this paper, the functional MOFs of the tertiary amine functionalized MOFs were synthesized by the in-situ LeBuckart-Wallach reduction amination reaction in DMF solvent thermal synthesis by the in situ conversion reaction of toluidine, and a tertiary amine functionalized MOFs material UiO-66-CH _ 2-N (CH _ 3) _ 2 was synthesized. Mixed-type tertiary amine functionalized UiO-66-CH _ 2-N (CH _ 3) _ 2-MLx was synthesized by using the mixed ligand of hydrogen bromide and poly-CHO-CHO. In addition, we extended the in-situ conversion strategy, and synthesized a tertiary amine functionalized UiO-66 with different tertiary amine groups by changing the diethylamine solvent, and by changing the metal ions to obtain the tertiary amine-functionalized MIL-101 material, the method for preparing the functional MOFs by in-situ conversion of the ligand is developed. The skeleton structure, thermal stability and modification ratio of synthetic MOFs were characterized by Xray diffractometer, thermogravimeter and nuclear magnetic resonance instrument. According to the preparation of the ion functionalized UiO-66 and the catalytic properties of the CCE reaction, the tertiary amine functionalized UiO-66 obtained from the previous part is synthesized and modified through N-methylation modification and anion exchange, and a quaternary ammonium salt ionized MOFs catalyst containing different kinds of halogen counter anions is synthesized; The catalytic performance of the CCE reaction was studied, and the effects of the ratio of the mixed ligand, the type of counter anion and the amount of catalyst, reaction temperature, pressure and time on the reaction conditions were investigated. The experiments show that the UiO-66-CH _ 2-N ~ + (CH _ 3) _ 3Br ~-ML0.072 material of the mixed ligand has the advantages of moderate pore size and post-modification ratio as the catalyst; the most suitable reaction conditions are: substrate 14.29mmol, temperature 100 鈩，
本文編號：2273886
[Abstract]:The conversion and utilization of CO _ 2 is a hot spot of green chemistry today. CO _ 2 conversion is also varied, and the cycloaddition reaction of CO _ 2 and epoxide is the most important type of transformation in terms of its mild condition, atom economy and non-toxic and harmless. Many porous catalysts are used for this conversion reaction. Metal organic framework materials (MOFs), as a porous functional material with high porosity, high specific surface area, orderly and adjustable pore channel, can introduce specific functional sites through pre-modification and post-modification, have been widely used in various fields including heterogeneous catalysis. One of the most important reactions in the catalytic application of MOFs is the cycloaddition of CO _ 2 and epoxide (CCE). This reaction generally requires a nucleophilic anion (typically a halogen ion) that causes the epoxide to ring open and leave in the carbonate closed loop step. However, the framework structure of most MOFs materials is neutral and does not contain nucleophilic anions. In order to improve the catalytic effect of the MOFs catalyst on CCE reaction, it is generally necessary to add homogeneous ionic compounds (such as tetraisobutyl bromide) to introduce nucleophilic anions. This catalytic system containing both the aid catalysts is not a complete environmentally friendly non-phase system. The effective way to solve this problem is to ionize the MOFs: the cation groups are introduced into the frame to obtain the positive electrical framework structure, so that the counter anion is encapsulated in the pore canal, and the integration of the MOFs and the nuclear anions is realized. In this paper, the properties of the reductive amination reaction of Leuckart-Wallach A with 2-methylterephthalic acid ligand can take place under the thermal reaction conditions, and the in-situ tertiary amine modification method of MOFs material has been developed. After N-methylation modification and ion exchange on tertiary amine groups, a series of quaternary amine functional MOFs catalysts with different halogen ions as counter anions were synthesized. The results of catalytic experiments show that this kind of MOFs catalyst shows good catalytic activity in CCE reaction without addition of cocatalyst. The contents of this thesis include the following three parts: 1. In this paper, the functional MOFs of the tertiary amine functionalized MOFs were synthesized by the in-situ LeBuckart-Wallach reduction amination reaction in DMF solvent thermal synthesis by the in situ conversion reaction of toluidine, and a tertiary amine functionalized MOFs material UiO-66-CH _ 2-N (CH _ 3) _ 2 was synthesized. Mixed-type tertiary amine functionalized UiO-66-CH _ 2-N (CH _ 3) _ 2-MLx was synthesized by using the mixed ligand of hydrogen bromide and poly-CHO-CHO. In addition, we extended the in-situ conversion strategy, and synthesized a tertiary amine functionalized UiO-66 with different tertiary amine groups by changing the diethylamine solvent, and by changing the metal ions to obtain the tertiary amine-functionalized MIL-101 material, the method for preparing the functional MOFs by in-situ conversion of the ligand is developed. The skeleton structure, thermal stability and modification ratio of synthetic MOFs were characterized by Xray diffractometer, thermogravimeter and nuclear magnetic resonance instrument. According to the preparation of the ion functionalized UiO-66 and the catalytic properties of the CCE reaction, the tertiary amine functionalized UiO-66 obtained from the previous part is synthesized and modified through N-methylation modification and anion exchange, and a quaternary ammonium salt ionized MOFs catalyst containing different kinds of halogen counter anions is synthesized; The catalytic performance of the CCE reaction was studied, and the effects of the ratio of the mixed ligand, the type of counter anion and the amount of catalyst, reaction temperature, pressure and time on the reaction conditions were investigated. The experiments show that the UiO-66-CH _ 2-N ~ + (CH _ 3) _ 3Br ~-ML0.072 material of the mixed ligand has the advantages of moderate pore size and post-modification ratio as the catalyst; the most suitable reaction conditions are: substrate 14.29mmol, temperature 100 鈩，
本文編號：2273886
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