甲醇对1-丁基-3-甲基咪唑四氟硼酸离子液体结构与性质影响的模拟研究

采用分子动力学模拟方法研究了298.15 K、0.1 MPa下摩尔分数为0.1-0.9 的甲醇对1-丁基-3-甲基咪唑四氟硼酸盐([BMIM][BF₄])结构与性质的影响. 获得了体系的密度、径向分布函数、配位数、自扩散系数、粘度和电导率, 模拟得到的密度值与实验值符合较好. 结果显示: 体系各组分之间的径向分布函数随甲醇摩尔分数的增加呈规律性变化; 体系内阴阳离子的自扩散系数随着甲醇摩尔分数的增加不断增大; 甲醇的加入削弱了阴阳离子之间的相互作用, 体系粘度随着甲醇摩尔分数的增加逐渐减小, 电导率不断增大. 分析空间分布函数得到体系中各组分的三维空间分布情况.     

离子液体1-仲丁基-3-甲基咪唑六氟磷酸盐的微波辅助合成、晶体结构及热稳定性

以具有支链结构的溴代仲丁烷作为烷基化试剂, 在微波辐射下采用两步法合成了1-仲丁基-3-甲基咪唑六氟磷酸盐([s-bmim][PF₆])离子液体. 在配比为V(水)∶V(乙醇)∶V(甲苯)=0.16∶2.84∶7的混合溶剂体系中, 培养出晶型完整的长约11 mm的离子液体大单晶体. 通过单晶体X衍射研究了[s-bmim][PF₆]的晶体结构. [s-bmim][PF₆]属于三斜立方晶系, 空间群为P2(1)/m, 晶胞参数为a=0.9042(4) nm, b=0.8213(3) nm, c=0.9775(4) nm, γ=116.618°(6), Z=2, V=64.909(4) nm³, D_c=1.454 g/cm³, μ=0.265 mm^-1, F(000)=292. 在[s-bmim][PF₆]晶体结构中, 阴阳离子间的离子键仍然是主要的, 同时还存在氢键和阳离子-阳离子间的非键斥力作用. 研究结果表明, [s-bmim][PF₆]的支化烷基结构对其晶体有效堆积、熔点、液程范围以及热分解温度等性质具有重要影响.     

1-正丁基-3-甲基咪唑溴化物离子液体TGA-FTIR研究

利用TGA-FTIR技术,研究了空气及氮气气氛下1-正丁基-3-甲基咪唑溴化物的热性能.结果表明,在不同的气氛下,在离子液体的沸点附近,存在一定的蒸汽压,随着温度的升高,1-正丁基-3-甲基咪唑溴化物主要以蒸气的形式汽化.在离子液体汽化过程中,未观察到离子液体发生明显的分解现象.在受热过程中,离子液体可能发生碳化作用,在空气气氛中,离子液体可能发生氧化作用,并且,离子液体的碳化速率与氧化速率基本接近.随着温度的升高,离子液体的氧化及碳化产物被进一步深度氧化.     

离子液体1-乙基-3-甲基咪唑三氟甲基磺酸盐与水之间的氢键作用(英文)

通过衰减全反射红外(ATR-IR)光谱、二维红外相关谱结合量子化学计算研究了1-乙基-3-甲基咪唑三氟甲基磺酸盐([emim][OTf])和水之间的氢键作用.结果表明,在[emim][OTf]-水体系中,当水的浓度较低时(0.1x(D2O)0.3),水分子的主要存在形式是包裹在离子液体中的没有缔合的单体.水分子优先填充到[emim][OTf]的空隙中,并且与[emim][OTf]的阴离子形成"[OTf]-…HOH…[OTf]-"结构,水分子与[emim][OTf]的阳离子的相互作用位点是烷基氢而不是芳香氢;当水分子浓度较高时,水分子倾向于自身缔合形成小团簇结构,水分子与[emim][OTf]的阳离子的相互作用位点是芳香氢而不是烷基氢.     

离子液体1-乙基-3-甲基咪唑三氟甲基磺酸盐与水之间的氢键作用

通过衰减全反射红外（ATR-IR）光谱、二维红外相关谱结合量子化学计算研究了1-乙基-3-甲基咪唑三氟甲基磺酸盐（[emim][OTf]）和水之间的氢键作用. 结果表明,在[emim][OTf]^-水体系中,当水的浓度较低时（0.1< x（D₂O）< 0.3）,水分子的主要存在形式是包裹在离子液体中的没有缔合的单体. 水分子优先填充到[emim][OTf]的空隙中,并且与[emim][OTf]的阴离子形成“[OTf]^-…HOH…[OTf]^-”结构,水分子与[emim][OTf]的阳离子的相互作用位点是烷基氢而不是芳香氢;当水分子浓度较高时,水分子倾向于自身缔合形成小团簇结构,水分子与[emim][OTf]的阳离子的相互作用位点是芳香氢而不是烷基氢.     

Electroreduction of Benzoylformic Acid in 1-Ethyl-3-methylimidazolium Bromide Room Temperature Ionic Liquid

The chemical industry is under considerable pressure to replace many volatile organic compounds that are widely used as solvents in organic synthesis. This trend leads to the exploration for novel reaction media. Room temperature ionic liquids as environmentally benign media for organic synthesis and catalytic reactions have been gradually recognized and accepted Owing to their unique chemical and physical properties, ionic liquids become promising candidates as recyclable reaction media for “ Green” applications. These nonvolatile solvents have been used as media or catalysts in dozens of fields, such as organic synthesis, organometallic catalytic reactions, separation and extraction processes.     

1-乙基-3-甲基咪唑丙氨酸离子液体热力学性质的研究

用中和法合成了氨基酸离子液体1-乙基-3-甲基咪唑丙氨酸([C₂mim][Ala]),并利用恒温环境的溶解反应热量计,在(288.15±0.01) K-(308.15±0.01) K温度范围内每隔5 K,测定不同质量摩尔浓度离子液体在水中的溶解焓(Δ_solH_m^θ).根据Archer的方法,通过线性拟合得到了该离子液体的标准摩尔溶解焓(Δ_sol),并计算了其相对表观摩尔溶解焓(^ΦL).在298.15 K下,根据Glasser经验方法得到了格子能U_POT = 566 kJ·mol^-1,并计算了其阴阳离子水化焓值(ΔH⁺ + ΔH^-) = -620 kJ·mol^-1及阴离子水化焓ΔH^-([Ala]^-) = -387 kJ·mol^-1.此外,估算了[C₂mim][Ala]水溶液的热容(C_p(sol))和表观摩尔热容(^ΦC_p).     

离子液体表面活性剂1-丁基-3-甲基咪唑烷基硫酸酯的合成及其在水溶液中的聚集行为

采用离子交换法,由1-丁基-3甲基咪唑氯盐（C4mimCl）和烷基硫酸钠合成了一系列无卤素的阴离子表面活性离子液体—1-丁基-3-甲基咪唑烷基硫酸酯[C4mim][CnH2n 1SO4](n=8,12,16),利用表面张力仪、稳态荧光光谱等手段考察了表面活性离子液体在水溶液表面及体相中的聚集行为,结果表明,与传统无机反离子相比,有机咪唑阳离子[C4mim] 作为反离子的离子液体型表面活性剂具有较高的表面活性,[C4mim] 产生的氢键引起的抑制分子规则排列的作用小于其促进分子有序排列的疏水作用。长烷基链的阴离子是界面膜及胶束的主要组成成分,阴离子疏水烷基碳链的增长虽然可促进胶束的形成,但却在一定程度上抑制[C4mim] 离子参与界面或胶束的形成;阴离子所带烷基链越长,越不利于阳离子[C4mim]＋参与界面膜或胶束的形成,界面膜或胶束中表面活性剂排布越松散,即界面张力越大,体系中胶束聚集数较小。     

嵌段共聚物L64在1-丁基-3-甲基咪唑四氟硼酸盐离子液体中形成的层状液晶

利用偏光显微镜(POM)、小角X射线散射(SAXS)及傅里叶变换红外(FTIR)光谱技术研究了嵌段共聚物PluronicL64(PEO13PPO30PEO13)(PEO:聚氧乙烯;PPO:聚氧丙烯)在室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐[Bmim][BF4]中的聚集行为.绘制了L64/[Bmim][BF4]体系的相图,当L64浓度介于40%-65%(w,质量分数)之间时,L64可与[Bmim][BF4]形成层状液晶.SAXS结果表明,液晶层间距随L64浓度的增加而降低.温度对液晶微结构影响较大,液晶层间距随温度的升高而增大,极性头截面积则减小.并且,在一定温度范围内,升温可使体系的有序性增强.但是,随温度的进一步升高,[Bmim][BF4]与PEO链段之间的氢键被破坏,双折射现象消失,液晶有序性降低.此外,分析了层状液晶的形成机理,[Bmim][BF4]与L64分子间的氢键作用力、静电作用力以及疏溶剂力是液晶形成的驱动力.     

Surfactant-free Ionic Liquid Microemulsions of N,N-dimethylformamide, 1-butyl-3-methylimidazolium hexafluorophosphate,and toluene

The phase diagram of a ternary system consisting of the hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF₆), N, N-dimethylformamide (DMF), and toluene was prepared at 25°C. A single-phase microemulsion and a multiphase region were demonstrated. The systems were nonaqueous IL microemulsions in the absence of traditional surfactants. The single-phase region could be divided into toluene-in-bmimPF₆, bicontinuous, and bmimPF₆-in-toluene subregions by electrical conductivity, similar to the case of surfactant-based IL microemulsions. And by the use of methyl orange as an absorption probe, the polarity of the bmimPF₆-in-toluene microemulsion was probed by UV–vis spectroscopy. The polarity of bmimPF₆ domains increased with increasing bmimPF₆ constant, and a relatively constant polarity was obtained when bmimPF₆ was increased to a certain extent.     

松木屑在AmimCl离子液体中的原位均相乙酰化

不使用任何催化剂, 在离子液体1-烯丙基-3-甲基咪唑氯盐(AmimCl)中实现了松木屑的一步均相乙酰化, 乙酰化松木的质量增重(WPG)范围在-89％～156％之间. 研究表明, 在均相条件下, 可以通过控制乙酰化时间, 乙酰化温度及乙酸酐/OH的摩尔比来控制乙酰化松木的WPG值. 用FTIR, 13C NMR, TGA 和 SEM对乙酰化松木进行表征. 结果表明, 13C NMR和FTIR谱图有明显的乙酰基特征峰, 且乙酰化松木的结构均匀致密, 其热稳定性高达205 ℃, 略低于原生松木.     

Electrodeposition of PdAu Alloy Nanoparticles on Ionic Liquid Functionalized Graphene Film for the Voltammetric Determination of Oxalic Acid

An ionic liquid functionalized graphene film was prepared and PdAu nanoparticles (NPs) were electrodeposited on it. The PdAu NPs were characterized by various methods and they showed the features of alloys. In 0.2 M H₂SO₄ solution, oxalic acid (OA) exhibited a sensitive anodic peak at the resulting electrode at about 1.1 V (vs. SCE), and the peak current was linear to OA concentration in the range of 5–100 µM with a sensitivity of 45.5 µA/mM. The detection limit was 2.7 µM (S/N=3). The electrode was successfully applied to the determination of OA in real sample.     

Nickel Hydroxide and Intercalated Graphene with Ionic Liquid Nanocomposite‐modified Electrode for Sensing of Glucose

A novel non‐enzymatic glucose sensor based on nickel hydroxide and intercalated graphene with ionic liquid (G‐IL) nanocomposite modified glass carbon electrode was fabricated. Scanning electron microscope, Fourier transform infrared spectra and energy dispersive X‐ray spectroscopy of the nanocomposite confirmed the morphology and ingredient of Ni(OH)₂ as well as G‐IL. Moreover, experimental results of cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry indicated the sensing properties of Ni(OH)₂ at Ni(OH)₂/G‐IL modified electrode towards the typical electrocatalytic oxidation process of glucose at 0.43 V in 0.10 M NaOH. The current response was linearly related to glucose concentration in a range from 0.5 to 500 μM with a detection limit of 0.2 μM (S/N = 3) and sensitivity of 647.8 μA mM^?1 cm^?2. The response time of the sensor to glucose was less than 2 s. This work may be expected to develop an excellent electrochemical sensing platform of G‐IL as a catalysis carrier.     

“一锅法”合成离子液体1-乙基-3-甲基咪唑醋酸盐

以1-甲基咪唑,溴乙烷和乙酸铅为原料,采用"一锅法"合成了离子液体1-乙基-3-甲基咪唑醋酸盐,产率87%,其结构经UV,IR和元素分析确证。优化反应条件为:1-甲基咪唑100 mmol,n(溴乙烷):n(1-甲基咪唑):n(乙酸铅)=3.6:2.0:1.0,于60℃反应20 h。     

Ultrasonic‐electrodeposition of Flower‐like Graphene Nanosheets in Ionic Liquid and Its Sensing for Ascorbic Acid

Choline chloride–based ionic liquid Ethaline were employed as the supporting electrolyte, graphene (GE) nanosheet was prepared with ultrasonic wave assisted electrodeposition for the first time. Scanning electron microscope results indicated that flower‐like GE nanosheets were obtained at the electrode surface. Energy dispersive X–ray spectroscopy, Fourier transform infrared spectra and Raman spectra were used to characterize the composition of the flower‐like GE nanosheets. Electrochemical methods showed that the flower‐like GE nanosheets based sensor exhibited high electrocatalytic activity for ascorbic acid (AA) oxidation and can be potentially used for the sensitive amperometric sensing of AA. Amperometric experiments showed that the sensor displayed broad linearity from 0.25 μM to 2.0 mM with a relative low detection limit of 0.1 μM (S/N = 3).     

Solvent-free Synthesis, Crystal Structure and Thermal Stability of Ionic Liquid 1-Hexadecyl-3-methylimidazolium Bromide

Ionic liquid 1-hexadecyl-3-methylimidazolium bromide [C16mim]Br was synthesized by solvent-free alkylation of N-methylimidzole with hexadecyl bromide. A large transparent single crystal of 1-hexadecyl-3-methylimidazolium bromide monohydrate （[C16mim]Br·H2O）, 4 mm in length, was firstly obtained in the water-trichloromethane-toluene growth system （Vwater＇Vtrichloromethane＇Vtoluene = 0.1：1：2）. The crystal structure was determined by single-crystal X-ray diffraction method. It crystallizes in the triclinic system, space group P1, with a = 5.4962（15）, b = 7.839（2）, c = 27.279（8） A, α = 94.375, β = 91.500, γ = 101.999°, Z = 2, V = 1145.2（5） A3, C20H41BrN2O, Mr = 405.46, Dc = 1.176 Mg/m3, μ = 1.804 mm^-1, F（000） = 436, the final R = 0.0523 and wR = 0.1345. The 3D supramolecular structure is constructed through weak interactions between imidazolium cations, Br- anions and lattice water molecules. The long alkyl chain to the imidazolium ring and lattice water molecules play an important role in the self-assembly process. Moreover, it is proposed that [C16mim]Br in water has aggregation behavior and the possible self-assembled structure is the interdigitated pattern. Finally, thermal stability of [C16mim][Br]·H2O was also studied by DSC and TGA analysis.     

1-乙基-3-甲基咪唑四氟硼酸盐离子液体的量子化学研究

The results of the quantum chemistry study of the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM+BF4-) were reported. The ab initio method and density functional theory (B3LYP method) was used to optimize the stable structure of the gas phase ion pair at the level of 6-311++G** basis set, respectively. An IR spectra for EMIM+BF4- were obtained through the vibrational analysis. The changes of atomic charge assignments have been investigated using the Natural Bond Orbital method. The computational results show that there exist hydrogen bonds and other weak interactions between the cation and the anion. Using counterpoise correction method to estimate the basis set superposition error, the interaction energy between the cation and anion is 346.78 kJ/mol.     

Electrocatalytic Oxidation and Determination of Hydrazine at an AuCu Nanoparticles – Graphene – Ionic Liquid Composite Film Coated Glassy Carbon Electrode

Gold‐copper alloy nanoparticles (AuCu NPs) were electrodeposited on a graphene – ionic liquid composite film (EGN‐IL). The AuCu NPs showed high electrocatalysis to the oxidation of hydrazine with a catalytic reaction rate constant of about 5.0×10⁴ mol/Ls. In phosphate buffer solutions (pH 6.8) the oxidation current of hydrazine at 0.15 V (vs. SCE) at the resulting electrode (AuCu? EGN‐IL/GCE) was linear to its concentration in the range of 0.2–110 µM with a sensitivity of 56.7 µA/mM, and the detection limit was 0.1 µM (S/N=3). The electrode was successfully applied to the determination of waste water.     

1-烷基-3-甲基咪唑硫酸氢盐系列离子液体的热力学性质

在293.15~343.15 K温度范围内,用MYX-1密度计测定了系列离子液体 1-丁基-3-甲基咪唑硫酸氢盐[C4mim]HSO4 (1-butyl-3-methylimdazolium hydrosulfate)、1-己基-3-甲基咪唑硫酸氢盐[C6mim]HSO4 (1-hexyl-3-methylimdazolium hydrosulfate)、1-辛基-3-甲基咪唑硫酸氢盐[C8mim]HSO4 (1-octyl-3-methylimdazolium hydrosulfate)、1-癸基-3-甲基咪唑硫酸氢盐[C10mim]HSO4 (1-decyl-3-methylimdazolium hydrosulfate)的密度。利用不同温度下的密度值计算得出了离子液体的热膨胀系数及分子体积。利用Glasser经验方程计算了离子液体的标准熵和晶格能,并进一步对其热力学性质进行了讨论。     

基于离子液体的硫酸根离子选择电极的研究

将离子液体BMIMPF6应用于传感膜中制备硫酸根选择性电极,研究发现离子液体在电极中不仅能够提高传感膜的介电常数和传导速率,还与硫酸根离子发生相互作用,起到载体的功能。利用离子液体和硫脲的协同作用制备的电位传感器,对硫酸根离子在10-5～10-2 mol/L范围内有能斯特响应,同时具有pH干扰小,重复性好,响应时间快等特点,能够用于环境和生物医疗检测。