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.     

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.     

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].     

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 uranium(VI) in 1-butyl-3-methylimidazolium chloride and thermal characterization of uranium oxide deposit

The electrochemical behavior of uranyl nitrate in 1-butyl-3-methylimidazolium chloride at glassy carbon working electrode has been investigated in the temperature range 343-373 K by transient electrochemical techniques such as cyclic voltammetry, chronopotentiometry and square wave voltammetry. Influence of bulk concentration of uranium and temperature on the electroreduction and transport properties of U(VI) in bmimCl has been examined. Diffusion coefficient (D) and the energy of activation (E_a) of U(VI) in bmimCl has been estimated and is of the order of ∼10⁻⁸ cm²/s and 54 kJ/mol, respectively. Reduction of U(VI) takes place through an irreversible single step two-electron transfer to UO₂ deposit at glassy carbon working electrode. Thermal analysis of the uranium oxide indicated the entrapment of nearly 5% of electrolyte, bmimCl, during electrodeposition, which decomposes in the range 553-653 K.     

Physical and electrochemical properties of 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium iodide,and 1-butyl-3-methylimidazolium tetrafluoroborate

The density, viscosity, refractive index, heat capacity, heat of dilution, ionic conductivity, and electrochemical stability of 1-butyl-3-methylimidazolium bromide ([bmim][Br]), 1-butyl-3-methylimidazolium iodide ([bmim][I]), and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]) were measured at room temperature or over a temperature range of 293.2 to 323.2 K. The density and refractive index values of [bmim][I] appeared to be the highest among three ionic liquids (ILs). However, the experimental viscosity values of [bmim][Br] were higher than those of [bmim][BF₄], while the heat capacities and heats of dilution of [bmim][BF₄] were higher than those of [bmim][Br]. The cyclic voltammogram of [bmim][br] and [bmim][BF₄] indicated electrochemical windows in the stability range from 2.7 V of [bmim][[Br] to 4.7 V of [bmim][BF₄].     

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%。     

室温离子液体1-丁基-3-甲基咪唑六氟磷酸盐的合成研究

由1-甲基咪唑和溴代正丁烷合成了中间体溴化1-丁基-3-甲基咪唑,讨论了温度和反应自身放热对此步反应的影响。中间体再经过阴离子交换,得到了标题化合物,收率为92％。产物的结构经IR和^1HNMR确认。     

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.     

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%。     

High-pressure phase behavior of carbon dioxide in ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Phase equilibrium data of carbon dioxide in the ionic liquid 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf₂N]) are presented at high pressures up to about 30 MPa and at temperatures between 298.15 K and 343.15 K. The solubilities at a given temperature were determined by measuring the bubble point pressure of the ionic liquid solution with carbon dioxide dissolved using the high-pressure equilibrium apparatus equipped with a variable-volume view cell. Solubility results are reported for carbon dioxide concentrations ranging from 0.21 up to 0.80 mole fraction. Carbon dioxide gave very high solubilities in the ionic liquid at lower pressures, while the equilibrium pressure increased very steeply at higher concentrations of carbon dioxide. The solubility of carbon dioxide in the ionic liquid decreased with an increase in temperature.     

氯化1-丁基-3-甲基咪唑（[BMIM]Cl）的合成反应动力学研究

对N-甲基咪唑和氯代正丁烷合成氯化1-丁基-3-甲基咪唑（[BMIM]C1）的季铵化反应进行了动力学研究。通过莫尔法研究温度、投料比与搅拌速率等参数对转化率的影响,探索了不同实验条件对反应平衡的影响。此外,合成反应符合二级反应动力学模型,并且温度、投料比与搅拌速率等参数符合动力学理论规律。反应速率常数随温度的升高而增大,但并不随投料比而改变。搅拌速率在低于600r／min时,反应速率常数随着搅拌速率的提高而增大;搅拌速率高于600r／min时,则不随之而改变。     

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%。     

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。     

微波法合成离子液体1-丁基-3-甲基咪唑四氟硼酸盐的研究

由1-甲基咪唑和溴代正丁烷通过微波法合成了中间体溴化1-丁基-3-甲基咪唑,考察了微波功率和反应时间对此步反应产率的影响。中间体经阴离子交换,得到标题化合物。产物的结构和纯度通过IR1、HNMR和离子选择电极表征。     

Fabrication of cobalt nanowires from mixture of 1-ethyl-3-methylimidazolium chloride ionic liquid and ethylene glycol using porous anodic alumina template

Porous anodic alumina template is synthesized by electrochemical anodization of aluminum and used to grow cobalt nanowires. The cobalt nanowires produced by direct current electrodeposition are characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and physical property measurement system. Test results indicate that the average diameter of cobalt nanowires is about 45 nm, which is generally the same as the pore diameter of porous anodic alumina template, and the cobalt nanowires electrodeposited from mixture of 1-ethyl-3-methylimidazolium chloride ionic liquid and ethylene glycol have a smoother surface and better magnetic properties than cobalt nanowires electrodeposited from aqueous solution, and they show a better squareness. Therefore it can be concluded that the cobalt nanowires electrodeposited from mixture of 1-ethyl-3-methylimidazolium chloride ionic liquid and ethylene glycol using porous anodic alumina template can be used as a perpendicular magnetic recording film.     

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。     

Treatment of tissue paper containing radioactive waste and electrochemical recovery of valuables using ionic liquids

Dissolution of tissue paper waste containing valuable contaminants such as uranium and palladium in 1-butyl-3-methylimidazolium chloride (bmimCl) has been studied. Dissolution of 5-7 wt.% tissue paper in bmimCl is complete within 60 min at 373 K and the time required for dissolution increases with increase of loading. It is difficult to dissolve more than 10 wt.% tissue paper in bmimCl and the limiting solubility of tissue paper is 15-17 wt.% at 373 K. Uranium(VI) and Pd(II) in chloride/nitrate form dissolve in bmimCl along with tissue paper. The electrochemical behaviour of uranium(VI) and palladium(II) in the resultant solution in the presence and absence of a co-solvent, DMSO, has been investigated by transient voltammetric techniques at glassy carbon working electrode and the diffusion coefficients have been determined. Electrolysis of a solution of uranium(VI) and palladium(II) loaded tissue paper in bmimCl results in deposition of uranium oxide (UO₂) and metallic palladium, respectively, which were characterized by X-ray diffraction and scanning electron microscopy. The study established the possibility of dissolving tissue paper and other cellulose based materials containing soluble uranium(VI) and Pd(II) compounds in bmimCl, and their recovery from the resultant solution. Cellulose pulp can be regenerated by adding surplus water after the recovery of valuables and the ionic liquid, bmimCl, can be regenerated for further use by vacuum distillation of DMSO and water.     

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。     

1-乙基-3-甲基咪唑四氟硼酸盐离子液体的合成及溶解性能的研究

以N-甲基咪唑和溴乙烷为原料,合成中间体[Emim]Br,讨论原料配比、溶剂、反应时间和反应温度对[Emim]Br产率的影响,最高产率为94.63%。四氟硼酸钠与中间体[Emim]Br以等摩尔比进行反应,确定最优的合成条件,在最佳合成条件下目标离子液体的转化率为94.45%。浊点法测定溶解度表明甲苯等溶剂在[Emim]BF4离子液体中有较好的溶解性能。