离子液体合成含溴1，3，4-噻二唑的研究

采用无溶剂一锅法合成了1-丁基-3-甲基咪唑四氟硼酸盐离子液体([bmim]BF4),反应原料N-甲基咪唑、溴代正丁烷和四氟硼酸钾在水浴中搅拌反应3 h,收率为91.8%。然后以1-丁基-3-甲基咪唑四氟硼酸盐离子液体催化合成含溴1,3,4-噻二唑类化合物,反应条件为:反应温度95～100℃,反应时间2 h,收率为58.3%。用减压蒸馏的简单方法将离子液体分离出来。研究结果表明,用离子液体[bmim]BF4合成含溴1,3,4-噻二唑的方法比传统方法即用浓硫酸作催化剂的方法的收率高6.7%。     

1-丁基-3-甲基咪唑四氟硼酸盐的合成研究

以1-溴丁烷和N-甲基咪唑为原料合成了中间体溴化1-丁基-3-甲基咪唑,以中间体与NaBF4进行复分解反应制备了离子液体1-丁基-3-甲基咪唑四氟硼酸盐。探讨了投料比、反应时间、反应温度对中间体和1-丁基-3-甲基咪唑四氟硼酸盐产率的影响,确定了最佳合成条件。在此工艺条件下,1-丁基-3-甲基咪唑四氟硼酸盐产率可达85%以上。     

1-乙基-3-甲基咪唑四氟硼酸盐的合成研究

以溴乙烷和N-甲基咪唑为原料合成了中间体溴化1-乙基-3-甲基咪唑,以中间体与NaBF4进行复分解反应制备了离子液体1-乙基-3-甲基咪唑四氟硼酸盐。探讨了投料比、反应时间、反应温度对中间体和1-乙基-3-甲基咪唑四氟硼酸盐产率的影响,确定了最佳合成条件。在此工艺条件下,1-乙基-3-甲基咪唑四氟硼酸盐产率可达94%以上。     

羟基与酯基官能团化离子液体的合成

以溴代或氯代醇或酯和吡啶为原料合成三个离子液体前体即溴化N-羟乙基吡啶、氯化N-羟己基毗啶和N-甲氧羰乙基吡啶氯代盐;分别将它们与四氟硼酸钠进行复分解反应得到相应的离子液体即N-羟乙基毗啶四氟硼酸盐、N-羟己基毗啶四氟硼酸盐和N-甲氧羰乙基毗啶四氟硼酸盐。利用核磁共振波谱对三个离子液体进行了表征。     

烷基链长对咪唑类离子液体-甲醇体系局部组成的影响

在全浓度范围内测定了3种离子液体-甲醇体系,即1-乙基-3-甲基咪唑四氟硼酸盐-甲醇体系、1-丁基- 3-甲基咪唑四氟硼酸盐-甲醇体系和1-己基-3-甲基咪唑四氟硼酸盐-甲醇体系的核磁共振氢谱（1H NMR）,运用局部组成模型对离子液体和甲醇的化学位移进行关联,得到了表征溶液内部微观环境的局部摩尔分数,分析了烷基链长对咪唑类离子液体-甲醇体系局部组成的影响。结果表明在这3种离子液体-甲醇体系中,离子液体的局部组成与宏观组成差异性非常小,甲醇分子在侧链越长的咪唑类离子液体中越倾向于自身缔合。     

1-乙基-3-甲基咪唑四氟硼酸盐[Emim]BF_4离子液体的制备和表征

以N-甲基咪唑、溴乙烷和四氟硼酸钠为原料,按照两步法制备了离子液体1-乙基-3-甲基咪唑四氟硼酸盐([Emim]BF4),考察了反应时间、温度、溶剂等对中间体[Emim]Br以及离子液体[Emim]BF4产率的影响,结果表明,反应物N-甲基咪唑与溴乙烷的摩尔比1∶1.5,温度70℃,反应8 h,中间体产率为87.4%;中间体中加入等摩尔NaBF4,25℃下反应10 h,离子液体产率为91.1%。     

微波法合成烷基咪唑类离子液体

采用微波辐射方法合成了离子液体溴化1-丁基-3-甲基咪唑、1-丁基-3-甲基咪唑六氟磷酸盐和1-丁基-3-甲基咪唑四氟硼酸盐。与传统方法相比,反应时间极大地缩短。产物结构经核磁共振确证。     

咪唑类离子液体的合成及其对氯苯的吸收-解吸性能研究

以溴代正丁烷、Ⅳ甲基咪唑为原料,合成了咪唑类离子液体1丁基3甲基咪唑六氟磷酸盐([Bmim] PF6)和1-丁基-3-甲基咪唑四氟硼酸盐([Bmim] BF4),通过红外光谱和核磁共振氢谱表征了离子液体结构;以离子液体为吸收剂进行氯苯气体吸收实验,考察了吸收温度、吸收时间、进气氯苯浓度等对离子液体吸收氯苯气体性能的影响...     

离子液体的合成与应用

叙述了离子液体的类型和特点,阐明了离子液体是一种安全绿色环保的液体,是当代化学的研究热点之一。由N-甲基咪唑和溴代正丁烷合成了中间体溴化1-正丁基-3-甲基咪唑,又利用中间体进一步合成了离子液体1-正丁基-3-甲基咪唑四氟硼酸盐和1-正丁基-3甲基六氟磷酸盐,并分别对这三种离子液体做了红外光谱分析。简单绍了离子液体在生物技术中物质的分离和纯化。介绍了离子液体在碱金属和碱土金属、稀土金属和锕系等金属离子萃取方面的应用。表明离子液体有着广阔的发展前景。     

种子溶胀法制备多孔离子液体聚合物

采用种子溶胀法合成了两种多孔离子液体聚合物--1-烯丙基-3-甲基咪唑四氟硼酸盐与丙烯腈单体配比为70:3哄聚物和聚苄乙基三甲基铵四氟硼酸盐,并对离子液体聚合物样品进行了FTIB、SEM和CO2吸附表征.研究了溶胀剂种类和用量对聚合物产率的影响.测定了CO2在多孔聚合物吸附剂上的吸附平衡数据.结果表明:对于多孔咪唑类聚...     

Synthesis and characterization of poly(benzimidazolium) membranes for anion exchange membrane fuel cells

Poly(dimethyl benzimidazolium) iodides were synthesized from polybenzimidazole derivatives by permethylation. They were easily changed to OH^?, CO₃ ^2? and HCO₃ ^? ion conducting electrolytes by immersing in 1 M of KOH, K₂CO₃ and KHCO₃. Properties of polymers were changed by the ion exchange process. The anion conducting membranes showed tough and flexible properties. The water uptake, ion exchange capacity and conductivity varied depending on the counter anions. One of the poly(dimethyl benzimidazolium) carbonate membranes, Me-DAB-OBBA-carbonate showed the highest water uptake (59 %) as well as ion conductivity (33.74 mS/cm at 80 °C), and could be a good candidate for an anion exchange membrane for anion exchange membrane fuel cells.     

苯基丙酮新合成方法的研究

通过苯并咪唑盐与Grignard试剂的加成-水解反应合成了苯基丙酮,并对反应机理进行了探讨。     

两个苯并咪唑羧酸稀土配合物的合成、晶体结构及荧光性质

合成了1,3-二羧甲基苯并咪唑有机配体,并与氯化铕、氯化钐反应得到了两个新的稀土配合物,通过元素分析、X-射线单晶衍射及X-射线粉末衍射对其进行表征。晶体结构表明,两个配合物结构均为两个金属中心被4个配体桥联形成Ln_2O_8型双核次级结构基元,通过(κ~1-κ~1-μ_2)-(κ~1)-μ_3配位模式与配体形成(4,4)拓扑的二维网络结构。同时测定了这两个配合物的热稳定性及Eu配合物的荧光性质。     

New (κ-C,N)-palladacyclic complexes with benzimidazol-2-ylidene ligand: Synthesis, crystal structures and characterization

Reaction of unsymmetrical benzimidazolium bromides (1) with Ag₂O and subsequent transmetallation with chloro-bridged dinuclear palladacycle, [Pd(dmba)(μ-Cl)]₂ (dmba: N,N-dimethylbenzylamine) afforded benzannulated monocarbene complexes [Pd(dmba)(NHC)Cl], 2. The palladacycles (2a–c) were characterized by elemental analysis; NMR spectroscopy and the molecular structure of 2a and 2c were determined by X-ray crystallography.     

Novel Brønsted acidic ionic liquids based on benzimidazolium cation: Synthesis and catalyzed acetalization of aromatic aldehydes with diols

In this article, a new group of Brønsted acidic task-specific ionic liquids based on benzimidazolium cation was synthesized and used as environmentally benign catalysts for acetalization of aromatic aldehydes with diols. Hammett method had been used to determine the acidity order of these ionic liquids, which was consistent with the catalytic activities observed in acetalization reaction. Maximum substrate conversion of 98% and product selectivity of 100% were obtained using [PSebim]HSO₄ as catalyst, which could be reused at least 10 times without obvious loss of catalytic activity.     

An Unexpected Synthesis of Dihydrophenazines en Route to Benzimidazolium Salts

The oxidation of various N,N′‐diarylbenzene‐1,2‐diamines bearing bulky aromatic substituents with sodium periodate on wet silica gel afforded a series of five new dihydrophenazines instead of the expected cyclohexadiene‐1,2‐diimines. The reaction most likely proceeds via a 1,6‐electrocyclic path and provides a convenient access to an important class of nitrogen heterocycles. Subsequent treatment of the mesityl derivative with chloromethyl pivalate and silver triflate led to the corresponding benzimidazolium salt.     

Novel SO<Subscript>3</Subscript>H-Functionalized Ionic Liquids Based on Benzimidazolium Cation: Efficient and Recyclable Catalysts for One-Pot Synthesis of Biscoumarin Derivatives

Abstract  

In this article, a new group of SO₃H-functionalized ionic liquids based on benzimidazolium cation was synthesized and used as environmentally benign catalysts for the one-pot synthesis of biscoumarin derivatives. The ionic liquids showed high catalytic activities and reusabilities with good to excellent yields of the desired products. H ₀ (Hammett function) values and the minimum-energy geometries of SO₃H-functionalized ionic liquids were determined and the results revealed that the acidities and catalytic activities of ionic liquids in the synthesis of biscoumarin derivatives were related to their structures.     

Benzimidazolium salts as small, nonpeptidic and BBB-permeable human prolyl oligopeptidase inhibitors

Prolyl oligopeptidase (POP) is a cytosolic serine peptidase that hydrolyzes proline-containing peptides at the carboxy terminus of proline residues. This peptidase has gained importance as a target for the treatment of cognitive disturbances of patients with neuropsychiatric diseases. Our research addresses the identification of POP inhibitors from a small focused library of polar heterocyclic compounds arising from multicomponent reactions. Two selective POP-specific inhibitors were identified on the basis of their inhibition of dipeptidyl peptidase IV. The most active compounds were evaluated for their in vitro transport through the blood-brain barrier (BBB) using a parallel artificial membrane permeability assay. Our results show for the first time that benzimidazolium salts are new POP-inhibitory scaffolds with properties of solubility, specificity, and lipophilicity that may allow them to cross the BBB by passive diffusion. These findings constitute an excellent starting point to synthesize new POP inhibitors with enhanced properties.     

Elektrochemische Oxidation organischer Verbindungen in Fluorsulfonsäure. VI. Voltammetrische Untersuchungen zur Oxidierbarkeit heterocyclischer Kationen

Electrochemical Oxidation of Organic Compounds in Fluorosulfuric Acid. VI. Voltammetric Investigation about the Oxidability of Heterocyclic Cations The anodic behavior of a series of pyridinium, quinolinium, isoquinolinium, pyrylium, tropylium, pyrazolium and imidazolium cations and of some of their benzoderivatives was investigated by cyclic voltammetry in HSO₃F at −76°C. Because of the available very positive potential region under these conditions almost all cations were oxidized, and in many cases relatively stable dication radicals could be detected. The oxidation potential decreases with decreasing acceptor ability of the heterocyclic ring, increasing extension of the π-electron system and increasing donor effects of substituents. There was no significant difference between the curves obtained from the N-alkylated and the corresponding N-protonated heterocyclic compounds, which showed that the oxidation is not coupled with the N-deprotonation. The voltammograms of phenylsubstituted pyrylium and pyrazolium ions as well as of benzimidazolium ions display typical marks of the anodic aromatic dimerization, which hitherto seemed to have been restricted to donor substituted benzenes and π-excess heterocycles.     

Surface adsorption and anticorrosive behavior of benzimidazolium inhibitor in acid medium for carbon steel corrosion

Corrosion inhibition property of a newly synthesized 3-(4-chlorobenzoylmethyl) benzimidazolium bromide inhibitor against carbon steel corrosion in 1 N hydrochloric acid solution was studied and analyzed utilizing various electrochemical methods. Electrochemical impedance study inferred that the inhibition efficiency increased with increasing inhibitor concentration and give 93.5% at 250 ppm. Potentiodynamic polarization study emphasized that inhibitor acted as a mixed type inhibitor and the adsorption of inhibitor on the metal surface followed Langmuir adsorption isotherm. The noise results were in good correlation with other electrochemical results obtained. The increase of inhibition efficiency with concentrations of inhibitor is attributed to the blocking of the active area by the inhibitor adsorption on the metal surface. The thermodynamic parameter values were calculated and discussed to explain the adsorption mechanism of inhibitor in an acidic medium. The protective surface morphology governed by the inhibited medium was investigated using the scanning electron microscopic technique. The surface roughness of the sample in the absence and presence of inhibitor was obtained using atomic force microscopic study. The effect and reactivity of the inhibitor are further clarified with quantum chemical analysis. Finally, the corrosion protection mechanism is proposed on the ground of experimental and theoretical studies.

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