Electrochemical behavior of fission palladium in 1-butyl-3-methylimidazolium chloride

Electrochemical behavior of palladium (II) chloride in 1-butyl-3-methylimidazolium chloride has been investigated by various electrochemical transient techniques using glassy carbon working electrode at different temperatures (343-373 K). Cyclic voltammogram consisted of a prominent reduction wave at −0.61 V (vs. Pd) due to the reduction of Pd(II) to Pd, and two oxidation waves at −0.26 and 0.31 V. A nucleation loop is observed at −0.53 V. The diffusion coefficient of palladium (II) in bmimCl (∼10⁻⁷ cm²/s) was determined and the energy of activation (63 kJ/mol) was deduced from the cyclic voltammograms at various temperatures. Nucleation and growth of palladium on glassy carbon working electrode has been investigated by chronoamperometry and chronopotentiometry. The growth and decay of chronocurrents measured for palladium deposition has been found to follow the instantaneous nucleation model with three-dimensional growth of nuclei. The surface morphology of the deposit obtained at various applied potentials revealed the formation of dendrites immediately after nucleation and spread in all the directions with time.     

Electrochemical behavior of rhodium(III) in 1-butyl-3-methylimidazolium chloride ionic liquid

Electrochemical behavior of rhodium(III) chloride in 1-butyl-3-methylimidazolium chloride was investigated by various electrochemical transient techniques at glassy carbon working electrode at different temperatures (343-373 K). Cyclic voltammogram of rhodium(III) in bmimCl consisted of a surge in reduction current occurring at a potential of −0.48 V (vs. Pd) is due to the reduction of Rh(III) to metallic rhodium and a very small oxidation wave occurring at −0.1 V. Increase of scan rate increases the peak current and remarkably shifts the cathodic peak potential () in negative direction indicating the irreversibility of electroreduction of rhodium(III). The diffusion coefficient of rhodium(III) in bmimCl (∼10⁻⁹ cm²/s) was determined and the energy of activation (∼25 kJ/mol) was deduced from cyclic voltammograms at various temperatures. The cathodic (τ_r) and anodic (τ_o) transition times were measured from chronopotential transients and the ratio τ_o/τ_r was found to be 1:7. Electrowinning of rhodium from bmimCl medium results in a deposition of metallic rhodium with lower (20-25%) Faradaic efficiency. A separation factor of rhodium from co-existing noble metal fission product palladium in bmimCl was determined during electrodeposition.     

Electrochemical behavior of ruthenium (III), rhodium (III) and palladium (II) in 1-butyl-3-methylimidazolium chloride ionic liquid

Electrochemical behavior of ruthenium (III), rhodium (III) and palladium (II) in 1-butyl-3-methylimidazolium chloride (bmimCl) and their ternary and binary solutions in bmimCl was studied at various working electrodes at 373 K by cyclic voltammetry and chronoamperometry. Ruthenium (III) chloride forms a stable solution with bmimCl and the cyclic voltammogram of ruthenium (III) in bmimCl recorded at glassy carbon electrode consisted of several redox waves due to the complex nature of ruthenium to exist in several oxidation states. Electrolysis of ruthenium (III) chloride in bmimCl at the cathodic limit of bmimCl (−1.8 V (vs. Pd)) did not result in ruthenium metal deposition. However, it was deposited from bmimPF₆ and bmimNTf₂ room temperature ionic liquids at −0.8 V (vs. Pd). The electrochemical behavior of ruthenium (III) in bmimCl in the presence of palladium (II) and rhodium (III) was studied by cyclic voltammetry. The presence of palladium (II) in bmimCl favors underpotential deposition of ruthenium metal. The nuclear loop at −0.5 V (vs. Pd) was observed in all solutions when palladium (II) co-existed with other two metal ions. Nucleation and growth of the metal on glassy carbon working electrode was investigated by chronoamperometry. The growth and decay of chronocurrents has been found to follow the instantaneous nucleation model with three-dimensional growth of nuclei.     

Investigation on the electro-oxidation of iodide in the room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate at platinum electrode

The oxidation behavior of iodide has been investigated by linear sweep voltammetry and cyclic voltammetry at a platinum electrode in the room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([C₄mim][BF₄]). The experimental results showed that iodide yielded two oxidation peaks P_a1 and P_a2 in [C₄mim][BF₄], and both of P_a1 and P_a2 are diffusion-controlled. P_a1 yielded from iodide to triiodide at +0.58 V is a two-electron oxidation wave, and P_a2 yielded from triiodide to iodine at +1.00 V is one-electron oxidation wave. Linear relationships between I_pa1 and the concentration of iodide can be established from 0.45 to 7.2 mmol L⁻¹ with a detect limit of 0.3 mmol L⁻¹ by linear sweep voltammetry, and from 0.30 to 7.8 mmol L⁻¹ with a detect limit of 0.2 mmol L⁻¹ by differential pulse voltammetry. These methods can be used for simple, rapid determination of iodide in the crude [C₄mim][BF₄].     

Effects of 1-butyl-3-methylimidazolium tetrafluoroborate on the oxidation of glucose catalyzed by glucose oxidase

The effects of room temperature ionic liquids (ILs) on the conformation and electrocatalytic activity of enzymes were studied using glucose oxidase (GOx) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF₄) as models. UV-vis and circular dichroic (CD) spectra indicated that [bmim]BF₄ did not affect the conformation of the enzyme, and the secondary structure of GOx in [bmim]BF₄-PBS mixtures (the content of the IL is from 0 to 20 vol%) was essentially the same as that of the native one. The Raman spectra showed that no interaction existed between glucose and [bmim]BF₄. The oxidation of glucose catalyzed by GOx was investigated under a substrate-saturated condition in [bmim]BF₄-PBS mixtures using ferroceneacetic acid (FcA) as a mediator. The voltammetric results showed that electrocatalytic current (i_cat) decreased with the increase of the content of [bmim]BF₄ in the mixtures. The reason causing the decrease of i_cat was analyzed. The reduction in the diffusion rate of FcA due to the increase of the viscosity after the addition of the IL was a key factor of causing the decrease of i_cat. The results presented here will be useful for the designing of the related biosensor used in ILs-containing system.     

Electrochemical aspects of black chromium electrodeposition from 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

The electrochemical behaviour of trivalent chromium (Cr³⁺) in 1-butyl-3-methylimidazolium tetrafluoroborate [BMIm][BF₄] ionic liquid solutions was studied by cyclic voltammetry and chronoamperometry. The reduction of Cr³⁺ occurs in two steps, Cr³⁺ to Cr²⁺ and Cr²⁺ to Cr⁰, respectively. The first step is quasi-reversible with a diffusion coefficient of Cr³⁺ in solution of 3.13 × 10⁻⁸ cm² s⁻¹ at 303 K and 25.8 × 10⁻⁸ cm² s⁻¹ at 358 K, estimated from cyclic voltammetry data.Black chromium films were electrodeposited on copper, stainless steel and carbon steel substrates at a constant potential of −1.5 V vs Pt quasi-reference electrode. The films consist of aggregates of nanosized particles. The coatings in the as-deposited condition present an amorphous structure but after annealing for 4 h, a nanocrystalline Cr₂O₃ phase is formed, with an average crystallite size of 17 nm.     

Synthesis of phosphinic acid resin using acidic 1-butyl-3-methylimidazolium chloroaluminate ionic liquid as catalyst

The resin is functionalized by the introduction of phosphinic acid moieties by Friedel–Crafts phosphination reaction using acidic 1-butyl-3-methylimidazolium chloroaluminate ionic liquid as catalyst. The phosphorous and hydroxyl capacities of the resin are compared with those obtained by using conventional aluminium chloride catalysis. Extraction of uranium(VI) from nitric acid medium by the resins has been studied, and it was found that the distribution coefficient (K_d, mL/g) of uranium(VI) initially decreases with the increase in the concentration of nitric acid, and reaches a minimum value at 1.5 M in nitric acid followed by the increase in K_d values. A maximum distribution coefficient has been obtained when the concentration of nitric acid was 4.0–5.0 M. The extraction data have been fitted in to a Langmuir adsorption model for obtaining the apparent experimental capacity.     

1-丁基-3-甲基咪唑表面活性离子液体的界面膨胀流变行为研究

研究了1-丁基-3-甲基咪唑十二烷基硫酸盐([bmim][DS])和1-丁基-3-甲基咪唑二(2-乙基己基)磺基琥珀酸酯盐([bmin][AOT]两种表面活性离子液体在正庚烷/水界面的动态界面张力和膨胀特性。比较了[bmim][DS]或[bmin][AOT]和传统表面活性剂十二烷基硫酸钠(SDS)或二(2-乙基己基)磺基琥珀酸酯钠(Na[AOT])之间的膨胀弹性,并且考察了1-丁基-3-甲基咪唑阳离子之间静电相互作用对界面膜特性的影响。另外,通过对比[bmim][DS]和[bmim][AOT]在不同浓度下的膨胀弹性,验证了烷基链数量的改变对界面膨胀流变行为的影响。     

Electrochemical behavior of europium (III) in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide

N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyNTf₂) was synthesized and characterized by CHNS elemental analysis, ¹H and ¹³C NMR and IR spectroscopy. Europium tris[bis(trifluoromethylsulfonyl)imide] (Eu(NTf₂)₃) was prepared and studied for the electrochemical behavior of Eu(III) in BMPyNTf₂ at glassy carbon and stainless steel working electrodes at 298-373 K by cyclic voltammetry, chronopotentiometry and chronoamperometry. Cyclic voltammogram of Eu(III) in BMPyNTf₂ consisted of a quasi-reversible cathodic wave at −0.45 V (vs. Fc/Fc⁺, 373 K), which could be attributed to the reduction of Eu(III) to Eu(II) and an irreversible wave at −2.79 V (vs. Fc/Fc⁺) due to reduction of Eu(II) to Eu(0). The diffusion coefficient of Eu(III) in BMPyNTf₂ was determined to be in the range of ∼10⁻⁷ cm² s⁻¹ by various electrochemical methods and the charge transfer rate constant was determined to be ∼10⁻⁵ cm s⁻¹ by cyclic voltammetry.     

Vapor pressure measurement and correlation of acetonitrile+1-butyl-3-methylimidazolium chloride,+1-butyl-3-methylimidazolium tetrafluoroborate,and+1-hexyl-3-methylimidazolium chloride

Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride ([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and+1-hexyl-3-methylimidazolium chloride ...     

乙腈+[C4mim][Cl]、乙腈+[C4mim][BF4]、乙腈+[C6mim][Cl]的气液平衡测定与关联（英文）

Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride ([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and+1-hexyl-3-methylimidazolium chloride ([C6mim][Cl]) at temperatures of 313 to 353 K by a quasi-static method. The experimental data for the binary sys-tems were correlated by the non-random two liquid (NRTL) equation with an average absolute relative deviation (AARD) of within 1.84%. The results indicate that the three ionic liquids (ILs) can result in a negative deviation from the Raoult's law for the binary solutions containing acetonitrile, and the affinity between ILs and acetonitrile mole-cules fol ows the order [C4mim][BF4]+acetonitrile N [C4mim][Cl]+acetonitrile N [C6mim][Cl]+acetonitrile.     

离子液体［BMIM］Br的水溶液VLE与扩散系数的分子模拟

在Linux操作系统下采用Towhee软件和NPT-Gibbs系综Monte-Carlo方法（GEMC）,模拟了不同温度、不同压力下二元体系［BMIM］Br+H₂O的汽液相平衡性质。提出了一种修正介电常数的方法来计算长程力,所得结果与非极化模型、极化模型及实验结果进行了比较。结果表明：相比于极化模型和非极化模型,修正介电常数的计算结果更接近实验值。此外,采用DL_POLY软件和分子动力学模拟的方法对［BMIM］Br水溶液的扩散系数进行了计算。结果表明：随着溶液中水含量的增多,ILs阴阳离子以及水分子的扩散系数得到了明显的改善。     

1-丁基-3-甲基咪唑六氟磷酸盐离子液体合成

按照两步法合成了离子液体1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6),探讨了时间、温度、溶剂、反应物配比等对中间体1-丁基-3-甲基咪唑溴盐([Bmim]Br)以及离子液体[Bmim]PF6产率的影响。结果表明,反应物配比为(1∶1.1)~(1∶2),温度70℃,反应30 h,中间体产率为95.91%;中间体中加入等摩尔KPF6,25℃下反应10 h后,离子液体产率为97.26%。     

1-丁基-3-甲基咪唑四氟硼酸盐离子液体的合成与表征

以N-甲基咪唑和1-溴代正丁烷为原料,两步合成法制备了离子液体[bmim]BF4。考察了反应时间、反应温度、原料配比对中间体1-丁基-3-甲基咪唑溴盐[bmim]Br收率的影响和离子交换时间和离子交换温度对目标产物[bmim]BF4产率的影响。结果表明:①合成中间体[bmim]Br的最佳条件为:反应温度65℃,反应时间16 h,N-甲基咪唑与1-溴代正丁烷的摩尔比为1∶1.1,产品收率可达94.8%;②合成离子液体的最佳条件为:反应温度65℃,反应时间24 h。     

纤维二糖在离子液体1-丁基-3-甲基咪唑氯盐中的结构动力学特性

开展分子动力学模拟探索不同压力条件下纤维素的基本结构单元--纤维二糖在离子液体1-丁基-3-甲基咪唑氯盐（[C₄mim]Cl）中的结构动力学特征。研究结果表明,高压环境使二糖分子内氢键网络结构瓦解,二糖与阴阳离子间相互作用增强,形成溶质-溶剂间氢键。借助空间分布函数得到常压及高压环境下二糖分子周围溶剂层分布特征,并通过径向分布函数定量考察了纤维二糖/离子液体体系分子间与分子内的氢键特征,为在化学键水平上认识纤维素在离子液体中溶解机制提供必要的理论基础。     

Anodic behavior of gold in 1-butyl-3-methylimidazolium methanesulfonate ionic liquid with chloride anion

The anodic behavior of gold has been investigated in presence of chloride and/or water in 1-butyl-3-methylimidazolium methanesulfonate (BMI CH₃SO₃) ionic liquid (IL). The cyclic voltammetry (CVs) in presence of chloride ions shows two waves attributed to the oxidation of the gold electrode which occurs under two steps: the first one is attributed to the electrochemical dissolution of gold into to gold(I), while the second one is attributed to an overlap of the chloride oxidation step as well as the oxidation of Au(I) to Au(III). Furthermore the determination of water and chloride content in IL allowed observing that the passive layer induced by water could be removed under chloride. Thanks to those results we were able to clarify the conditions of gold recovering in this kind of electrolyte.     

Charging/discharging kinetics of poly(3,4-ethylenedioxythiophene) in 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide ionic liquid under galvanostatic conditions

The constant current charging/discharging experiments of poly(3,4-ethylenedioxythiophene) (PEDOT), modified electrodes in room temperature ionic liquid, for instance 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide, were performed for two types of cell configurations, three and two-electrode cells. In each case, a linear variation of the voltage with respect to time was observed. The electrochemical responses were analyzed in term of a series combination of a resistance R and a capacitor C. Accordingly, the capacitance of the modified electrodes was determined. One observed a linear variation of the capacitance as a function of the amount of PEDOT. This capacitance described the chemical capacitance of PEDOT that reflected the capability of the system to accept or release additional charge carriers on a given variation of the chemical potential. Also, the electrochemical response during constant current charging/discharging experiments for two-electrode cell in which the same amount of PEDOT was deposited on each electrode showed a type I electrochemical supercapacitor response. This kind of an electrochemical chain allowed us to mimic and to analyze the electrical responses of an electrochemical actuator based on an interpenetrating polymer networks containing PEDOT that was able to work in air.     

室温离子液体1-丁基-3-甲基咪唑磷酸二丁酯的电导率研究

利用磷酸三丁酯与N-甲基咪唑在恒温150℃下一步合成了离子液体1-丁基-3-甲基咪唑磷酸二丁酯,考察了其在丙酮,水,DMF,乙酸溶剂中的电导率及摩尔电导率。实验发现该离子液体在不同溶剂中的电导率(κ)相差很大,其顺序为κa(水)>κb(DMF)>κc(丙酮)>κd(乙酸)。在相同温度下,电导率及摩尔电导率随浓度的增大而增大;在相同浓度下,电导率及摩尔电导率随温度的升高而增大。     

Diffusion coefficient of ferrocene in 1-butyl-3-methylimidazolium tetrafluoroborate - concentration dependence and solvent purity

The ionic liquid l-butyl-3-methylimidazolium tetrafluoroborate is used as electrolyte in the electrochemical determination of the diffusion coefficient of ferrocene as a function of concentration by cyclic voltammetry and chronoamperometry. An improved synthesis of the room temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate is described, which yields a product of high purity suitable for electrochemical purposes. A qualitative color test is discussed which allows the simple detection of silver ion contaminations. The diffusion coefficient of ferrocene appears to be concentration dependent in the solvent chosen.     

微波辐射下一步法合成1-丁基-3-甲基咪唑六氟磷酸离子液体

采用微波辐射法一步合成1-丁基-3-甲基咪唑六氟磷酸([Bmim]PF6)离子液体,产物结构经过IR和1H NMR验证。通过考察各种影响因素对产物的影响得出最佳的反应条件:n(溴代正丁烷)∶n(1-甲基咪唑)∶n(六氟磷酸钾)=1.1∶1∶1.6(摩尔比),70℃以及250 W的微波功率下照射15 min,收率可达到92.7%。