【作者】 张利锋；

【导师】 高国华；

【作者基本信息】 华东师范大学 ， 物理化学， 2011， 博士

【摘要】 离子液体与传统溶剂相比具有蒸汽压低、热稳定性和化学稳定性高、液态温度范围宽、溶解性强等优点,已经在有机合成、电化学、化学分离、聚合物材料等领域得到了广泛的应用。离子液体本身是一种超分子聚集体,其阴阳离子通过氢键、π-π堆积、π-阴离子等非共价键结合形成三维超分子网络结构。离子液体的超分子特性为离子液体高效、绿色地催化有机反应提供了一个契机。其中,离子液体催化毒性小、环保性能优异的碳酸酯类化合物与N-杂环芳香类化合物的有机反应近年来引起了人们极大的关注。本论文主要研究了离子液体催化亲电试剂碳酸酯与苯胺、吲哚等亲核试剂的反应。主要包括：酸碱双功能离子液体协同催化苯胺与碳酸二甲酯反应；离子液体阴阳离子协同催化苯胺与碳酸乙烯酯反应；离子液体阴阳离子协同催化芳香胺与碳酸丙烯酯反应；离子液体催化吲哚与环状碳酸酯的羟烷基化反应。在酸碱双功能离子液体协同催化苯胺与碳酸二甲酯反应中,合成出一种新型酸碱双功能离子液体1-(2-(1’-哌啶)乙基)-3-甲基咪唑氯化铅([PEmim]PbCl3),系统研究了该离子液体催化苯胺与碳酸二甲酯反应合成N-甲基-N-苯基氨基甲酸甲酯的性能。发现具有酸碱双活性位的离子液体[PEmim]PbCl3催化活性明显高于只具有单一活性位的碱性离子液体[PEmim]Cl和酸性金属卤化物PbCl2。离子液体[PEmim]PbCl3的高活性与其同时具有酸性和碱性中心有关,阳离子中的碱性哌啶基团活化苯胺,阴离子中的酸性铅离子活化碳酸二甲酯,阴阳离子的酸碱协同催化使得苯胺与碳酸二甲酯的反应顺利进行。密度泛函理论的研究则模拟了离子液体[PEmim]PbCl3的结构及其与反应底物的相互作用,并分析了它们自然键轨道电荷的分布,发现苯胺的N-H键长和碳酸二甲酯的C=O键长在与[PEmim]PbCl3相互作用之后分别增加了0.0142A和0.0073A,苯胺氮原子增加了0.007的负电荷,碳酸二甲酯羰基碳原子增加了0.044正电荷。与[PEmim]PbCl3相互作用之后,苯胺的亲核性和碳酸二甲酯的亲电性均增强,从而在分子的水平上进一步证实了离子液体酸碱协同作用对该反应的影响。在离子液体阴阳离子协同催化苯胺与碳酸乙烯酯反应中,首先利用离子液体[Bmim]BF4为催化剂,通过系统考察反应时间、反应温度及催化剂用量等反应条件对反应的影响,优化了反应条件,130℃,9 h,催化剂用量为5 mo1%时,产物3-苯基噁唑烷-2-酮的收率达到90%。为了探索离子液体阴阳离子在催化苯胺与碳酸乙烯酯反应合成噁唑烷-2-酮中的作用,详细研究了不同阴阳离子的离子液体对反应的影响,发现离子液体阳离子催化活性顺序为：1-丁基-3-甲基咪唑([Bmim])> 1,2-二甲基-3-丁基咪唑([Bmmim])>1-丁基吡啶([Bpy]),与阳离子提供氢键的能力一致；咪唑型离子液体阴离子的催化活性顺序为Cl> Br> BF4> PF6> C(CN)2COEt≈NTf2>BPh4,与离子液体阴离子接受氢键的能力一致。离子液体可以通过阴阳离子同时活化亲电试剂与亲核试剂,阴阳离子的协同催化显著增强了苯胺与碳酸乙烯酯的反应活性。利用1H NMR、ESI-MS等实验手段对反应机理进行了深入的研究。1H NMR显示出[Bmim]BF4咪唑环2位氢在碳酸乙烯酯的存在下,发生了显著的位移(从69.48移到9.33),证明咪唑环2位氢与碳酸乙烯酯发生了相互作用。ESI-MS实验捕获了一系列[Bmim]BF4与碳酸乙烯酯及苯胺相互作用的超分子聚集体,进一步证实了[Bmim]BF4同时活化反应底物苯胺和碳酸乙烯酯。在离子液体阴阳离子协同催化芳香胺与碳酸丙烯酯反应中,系统研究了离子液体催化芳香胺与碳酸丙烯酯一步合成5-甲基-3-芳基嗯唑烷-2-酮的反应,考察了反应温度、反应时间以及催化剂用量对反应的影响,140℃,7 h,催化剂用量为5 mmo1%时,5-甲基-3-苯基噁唑烷-2-酮的收率达99%。离子液体催化剂可重复使用5次,活性未见明显下降。通过研究不同结构离子液体对该反应的影响,发现离子液体阳离子的催化活性顺序为[Bmim]> [Bmmim]> [Bpy],与阳离子在催化过程中提供氢键的能力一致；与此同时,离子液体阴离子催化活性顺序为OAc>Cl>Br>BPh4,与阴离子在催化过程中接受氢键的能力一致,离子液体阴阳离子对催化芳香胺与碳酸丙烯酯反应具有协同作用。并利用密度泛函理论对离子液体阴阳离子协同催化机理进行了研究。发现离子液体阳离子与碳酸丙烯酯羰基氧之间的作用距离按照[Bmim]< [Bmmim]< [Bpy]的顺序依次递增,[Bmim]的咪唑环2位氢与碳酸丙烯酯羰基氧之间的距离最短,为2.022A,二者之间形成氢键,活化了碳酸丙烯酯；离子液体阴离子与苯胺之间的作用距离按照OAc<Cl<Br<BPh4的顺序依次递增,阴离子与苯胺形成氢键,活化了苯胺。离子液体阴阳离子通过氢键作用可以增强反应底物碳酸丙烯酯的亲电性和苯胺的亲核性。离子液体催化吲哚与碳酸乙烯酯及碳酸丙烯酯羟烷基化反应,简便、绿色地合成了羟乙基吲哚、羟丙基吲哚及其衍生物。在不添加任何有机溶剂的条件下,采用离子液体[Bmim]BF4考察反应温度、时间催化剂用量及反应底物投料比对吲哚与碳酸乙烯酯反应的影响,150℃,9h时,吲哚的转化率达到96%,羟烷基化产品1-(2-羟乙基)吲哚(1a)及其衍生物1-(2-(2-羟基)-乙氧乙基)吲哚(2a)和1-(2-(2-(2-羟基)乙氧乙基)乙氧基)吲哚(3a)总的收率达到90%。不同离子液体催化吲哚与碳酸乙烯酯反应结果显示,咪唑型离子液体催化活性顺序按照BPh4< BF4< Br< Cl< OAc依次增加,与离子液体阴离子在催化过程中接受氢键的能力一致。在吲哚与碳酸丙烯酯的反应中,反应条件为150℃,9h时,吲哚的转化率达到87%,主要产物1-(2-羟丙基)吲哚(1b)的收率达到70%。产物选择性的提高可能是由于碳酸丙烯酯的位阻效应。更多还原

【Abstract】 Ionic liquids have many advantages compared with conventional solvent, such as negligible vapour pressure, high thermal and chemical stability, wide liquid temperature range, non-toxic, strong solubility and catalytic activity. They have been widely used in organic synthesis, electrochemistry, chemical separation and the polymer materials. Ionic liquid is a kind of supramolecular aggregates in itself, the anion and cation of ionic liquid interact each other to form three-dimensional supramolecular network structures through several non-covalent force, such as hydrogen bonds,π-πstacking,π-anion. The supramolecular properties of ionic liquids provide an opportunity for ionic liquids to effectively and greenly catalyze the organic reactions. In recent years, many ionic liquid-catalyzed organic reactions involving carbonates which are considered as low toxically, environmentally benign and green chemical raw material, have been attracted great interest.The ionic liquid-catalyzed organic reactions between electrophile and nucleophile were investigated in this thesis, in which carbonates and aniline, indole were used as reactants. Main content included:experimental and theoretical investigation of reaction of aniline with dimethyl carbonate catalyzed by acid-base bifunctional ionic liquids; Anion-cation cooperative catalysis by ionic liquids on the reaction of aniline and ethylene carbonate; Anion-cation cooperative catalysis by ionic liquids on the reaction of aromatic amines with propylene carbonate; Hydroxyalkylation of indole with cyclic carbonates catalyzed by ionic liquid.In the first section, a novel acid-base bifunctional ionic liquids 1-(2-(1’-piperidinyl) ethyl)-3-methyl imidazolium trichlorolead ([PEmim]PbCl3) was synthesized and applied in the reaction of aniline with dimethyl carbonate for producing methyl-N-methyl-N-phenylcarbamate. The reactivity of [PEmim]PbCl3 which has acid-base dual-active is significantly higher than basic [PEmim]Cl and acidic PbCl2. The studies of reaction mechanism show that the higher reactivity of [PEmim]PbCl3 is accounted for its ability to activate both aniline and dimethyl carbonate by the acidic and basic sites cooperatively. Density functional theory (DFT) calculations simulate the structures and charge properties of [PEmim]PbCl3, complex of [PEmim]PbCl3 and aniline, and complex of [PEmim]PbCl3 and dimethyl carbonate. DFT calculations show that bond length of N-H in aniline and C=O of dimethyl carbonate increases 0.0142 A and 0.0073 A, respectively. NBO charge of N in aniline and carbonyl C of dimethyl carbonate increases 0.007 negative charge and 0.044 positive charge, respectively, when the interaction between reactants and ionic liquid was formed. [PEmim]PbCl3 can increase the electrophilicity of dimethyl carbonate and the nucleophilicity of aniline by its acid and base sites.In the second section, in order to optimize the reaction parameters, the effects of reaction time, temperature and catalyst amount on the reaction of aniline and ethylene carbonate were investigated. Under the optimized conditions(130℃,9 h, amount of catalyst:5 mol%), the yield of 3-phenyloxazolidin-2-one reached 90%. Then we studied the effect of ionic liquids which have different cation and anion on the reaction of aniline and ethylene carbonate. The catalytic activity follows the order of 1-butyl-3-methyl-imidazolium ([Bmim])> 1,2-dimethyl-3-butyl imidazolium ([Bmmim])> 1-butyl-pyridinium ([Bpy]), which is consistent with the order of hydrogen bond donor ability. Simultaneously, the catalytic activity of imidazolium based ionic liquids follows the order Cl> Br> BF4> PF6> C(CN)2COEt≈NTf2> BPh4, which is consistent with the order of the hydrogen bond acceptor ability. The dual activation of nucleophiles and electrophiles by the cations and anions of ionic liquids is crucial to promote the reaction in high yields. Reaction mechanism was also investigated by 1H NMR and ESI-MS. In 1H NMR, the proton in 2-position of imidazolium ring of [Bmim]BF4 shifted fromδ9.48 to 9.33 in the presence of ethylene carbonate, which indicates that the proton in 2-position of imidazolium ring interacts with ethylene carbonate. The interception of supramolecular cationic species involving [Bmim]BF4, aniline and ethylene carbonate further confirm that ionic liquid [Bmim]BF4 simultaneously activate aniline and ethylene carbonate.We studied the reaction of aromatic amines with propylene carbonate for synthesizing 5-methyl-3-aryloxazolidin-2-one catalyzed by ionic liquid. The effects of reaction temperature, time and amount of catalyst were investigated in detail. Under the optimized conditions (140℃,7 h, amount of catalyst:5 mol%), the yield of 5-methyl-3-phenyl-oxazolidin-2-one was 99%. Ionic liquid can be reused five times without any obvious decrease of activity. The effects of cations and anions of ionic liquids were also studied. It was found that the catalytic activity of cation follows the order of 1-butyl-3-methyl-imidazolium ([Bmim])> 1,2-dimethyl-3-butyl imidazolium ([Bmmim])> 1-butyl-pyridinium ([Bpy]), which is consistent with the order of hydrogen bond donor ability. Simultaneously, the catalytic activity of imidazolium based ionic liquids follows the order OAc> Cl> Br> BPh4, which is consistent with the order of the hydrogen bond acceptor ability of anions. The anion-cation cooperative effect of the ionic liquids was also simulated by the density functional theory (DFT). The calculations show that distances of cations of ionic liquids and C=O of propylene carbonate follows the order [Bmim]< [Bmmim]< [Bpy]. The distance of the proton in 2-position of imidazolium ring of [Bmim] and C=O of propylene carbonate is the shortest (2.022 A). [Bmim] activate propylene carbonate throught the hydrogen bond interaction between the proton in 2-position of imidazolium ring and C=O of propylene carbonate. The distances of anions of ionic liquids and N-H in aniline follows the order OAc< Cl< Br< BPh4. Anions of ionic liquids activate aniline throught the hydrogen bond interaction between anions and N-H in aniline. Ionic liquid can simultaneously increase the electrophilicity of propylene carbonate and the nucleophilicity of aniline through the hydrogen bond interactions.We studied the hydroxyalkylation of indole with ethylene carbonate and propylene carbonate catalyzed by ionic liquid. Hydroxyethyl indoles, hydroxypropyl indoles and their derivatives were simply and eco-friendly synthesized. Without any other organic solvent, we systemically studied the effects of reaction temperature, time, amount of catalyst and molar ratio of reactants on the reaction of indole and ethylene carbonate catalyzed by [Bmim]BF4. Under the optimized conditions (150℃,9 h), the conversion of indole reached 96%, the total yield of the hydroxyalkylation products 1-(2-hydroxyethyl)indole (la) and its derivatives 1-(2-(2-hydroxyl)-ethoxyethyl)indole (2a) and 1-(2-(2-(2-hydroxyl)ethoxyethyl)oxyethyl)indole (3a), reached 90%. The catalytic activity of ionic liquid is affected by the anions and follows the order of BPh4< BF4< Br< Cl< OAc, which is consistent with the hydrogen bond acceptor ability of the anions of ionic liquids. In the reaction of indole with propylene carbonate, when the reaction condition was 150℃,9 h, the conversion of indole reached 87%, the yield of main product 1-(2-hydroxypropyl) indole (1b) reached 70%. The selectivity of the main product was improved may be due to steric effects of propylene carbonate.更多还原