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铝在路易斯酸性1-烯丙基-3甲基米唑氯铝酸离子液体中的低温电沉积(英文) 总被引:1,自引:0,他引:1
Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising elec-trolytes in the low-temperature electrodeposition of aluminium.Systematic studies on deposition process have been performed by cyclic voltammetry and chronoamperometry.The surface morphology and X-ray diffraction(XRD) patterns of deposits prepared at different experimental conditions were also investigated.It was shown that the nu-cleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited.The crys-tallographic orientation of deposits was mainly influenced by temperature and current density.Smooth,dense and well adherent aluminium coatings were obtained on copper substrates at 10-25 mA?cm?2 and 313.2-353.2 K.More-over,the current efficiency of deposition and purity of aluminium have been significantly improved,demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium. 相似文献
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The electrochemistry and electrodeposition of antimony were investigated on glassy carbon and nickel electrodes in a basic 1-ethyl-3-methylimidazolium chloride-tetrafluoroborate room temperature ionic liquid. Cyclic voltammetry results show that Sb(III) may be either oxidized to Sb(V) via a quasi-reversible charge-transfer process or reduced to Sb metal. Diffusion coefficients for both Sb(III) and Sb(V) species were calculated from rotating disc voltammetric data. Analysis of chronoamperometric current–time transients indicates that the electrodeposition of Sb on glassy carbon proceeded via progressive three-dimensional nucleation with diffusion-controlled growth of the nuclei. Raising the deposition temperature results in decreased average radius of the individual nuclei. Dense deposits can be obtained within a deposition temperature range between 30 to 120 °C. Scanning electron microscopy revealed dramatic changes in the surface morphology of antimony electrodeposits as a function of deposition temperature; deposits obtained at 30 °C had a nodular appearance whereas those obtained at 80 and 120 °C consisted of evenly distributed fine polygonal crystals. 相似文献
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以1-甲基-3丁基咪唑氯离子液体为溶剂直接溶解氯化铜,硫化钠水溶液作为沉淀剂快速制得片状硫化铜纳米颗粒.对比实验揭示,离子液体对于片状硫化铜纳米结构的形成具有决定性的影响.UV-Vis光谱检测显示其在240到600 nm处有较宽的吸收峰. 相似文献
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Shu-I Hsiu 《Electrochimica acta》2006,51(13):2607-2613
Voltammetry at a glassy carbon electrode was used to study the electrochemical co-deposition of Pd-In from a chloride-rich 1-ethyl-3-methylimidazolium chloride/tetrafluoroborate air-stable room temperature ionic liquid at 120 °C. Deposition of Pd alone occurs prior to the overpotential deposition (OPD) of bulk In. However, underpotential deposition (UPD) of In on the deposited Pd was observed at the potential same as the deposition of Pd. The UPD of In on Pd was, however, limited by a slow charge transfer rate. Samples of Pd-In alloy coatings were prepared on nickel substrates and characterized by energy dispersive spectroscope (EDS), scanning electron microscope (SEM) and X-ray powder diffraction (XRD). The electrodeposited alloy composition was relatively independent on the deposition potential within the In UPD range. At more negative potentials where the OPD of Pd-In has reached mass-transport limited region, the alloy composition corresponds to the Pd(II)/In(III) composition in the plating bath. The Pd-In alloy coatings obtained by direct deposition of Pd and UPD of In on the deposited Pd appeared to be superior to the Pd-In alloys that were obtained via the co-deposition of Pd and bulk In at OPD potentials. 相似文献
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Vapor pressure values of binary systems water + ethanol, water + ionic liquid 1-propyl-3- methylimidazolium bromide ([PMIM] [Br]), ethanol + [PMIM] [Br] and ternary system water + ethanol + [PMIM] [Br] at different temperatures were measured by using a modified boiling point method in various concentrations of (16.66%, 33.7%), (17.4%, 33.9%) and (16.5%, 32%) mass percent of ionic liquid, respectively. The experimental vapor pressures of solvent were well correlated by the Antoine-type equation, and the overall average absolute deviation (AAD) was found to be 0.39%. The experimental results for mixtures containing ionic liquid indicate that the vapor pressure of the solvents can be decreased noticeably to different extent due to the affinity difference between ionic liquid and solvent, which is similar to the salt effect of common inorganic salts. As a result, ionic liquid may find industrial applications in extractive distillations for the system with a low separation factor or even for an azeotropic mixture. 相似文献
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Determination of Vapor Pressures for Binary and Ternary Mixtures Containing Ionic Liquid 1-propyl-3-methylimidazolium Bromide 总被引:1,自引:0,他引:1 下载免费PDF全文
Vapor pressure values of binary systems water + ethanol, water + ionic liquid 1-propyl-3-methylimidazolium bromide ([PMIM][Br]), ethanol + [PMIM][Br] and ternary system water + ethanol + [PMIM][Br] at different temperatures were measured by using a modified boiling point method in various concentrations of (16.66%, 33.7%), (17.4%, 33.9%) and (16.5%, 32%) mass percent of ionic liquid, respectively. The experimental vapor pressures of solvent were well correlated by the Antoine-type equation, and the overall average absolute deviation (AAD) was found to be 0.39%. The experimental results for mixtures containing ionic liquid indicate that the vapor pressure of the solvents can be decreased noticeably to different extent due to the affinity difference between ionic liquid and solvent, which is similar to the salt effect of common inorganic salts. As a result, ionic liquid may find industrial applications in extractive distillations for the system with a low separation factor or even for an azeotropic mixture. 相似文献
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Conductivities of AlCl3/Ionic Liquid Systems and Their Application in Electrodeposition of Aluminium
Solubilities and conductivities of anhydrous AlCl3 in six kinds of ionic liquids (ILs) were measured. Among the six kinds of ILs [bmim]Cl, [bmim]Br, [bmim]BF4, [bmim]PF6, [emim][EtSO4] and [bmim][HSO4], anhydrous AlCl3 could be dissolved in the first five kinds but was hardly dissolved in [bmim][HSO4]. The results showed that the nominal solubilities of AlCl3 in ILs increased in the order of [bmim][HSO4] < [bmim]PF6 < [emim][EtSO4] < [bmim]BF4 < [bmim]Cl < [bmim]Br. Conductivities of the AlCl3/ILs systems depended apparently on the nominal molar ratio of AlCl3 to ILs. The conductivities of AlCl3/[bmim]Cl, AlCl3/[bmim]Br and AlCl3/[bmim]PF6 systems had a similar tendency as a function of the nominal molar ratio, that is, as the molar ratio was increased, conductivities increased first and then decreased, with the maximum conductivity obtained at approximately 0.9:1, 1.0:1 and 0.5:1, respectively. Conductivities of the AlCl3/[bmim]BF4 exhibited a dentate change and decreased with the molar ratio of AlCl3 to [bmim]BF4 increasing in general. With the increasing of the anhydrous AlCl3 amount in [emim][EtSO4], conductivity of AlCl3/[emim][EtSO4] monotonically decreased. AlCl3/[bmim]Cl system was chosen as the electrolyte for the electrodeposition of Al. Preliminary experimental results showed that dense, adherent and homogeneous Al coatings could be electrodeposited on stainless steel by means of constant potential technique and the surface coverage was quite satisfactory. 相似文献
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A high performance liquid chromatography (HPLC) method was proposed to monitor the synthesis and purification of the 1-alkyl-3-methylimidazolium ionic liquid precursors from alkylation of 1-methylimidazole with alkyl halides and determine the purity of final products. The results showed that separation of 1-methylimidazole from the precursors could be obtained under the HPLC performance conditions such as cation exchange column, acetonitrile/KH2PO4 aqueous solution and 209 nm wavelength. The content of unreacted 1-methylimidazole in the precursors could be easily calculated from their corresponding HPLC peak areas with the calibration curve of 1-methylimidazole. The retention times of the 1-alkyl-3-methylimidazolium ionic liquid precursors decreased with their increasing alkyls, and the ionic liquids with the same cation and different anions had almost the same retention times. 相似文献
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考察了碱性离子液体1-乙基-3-甲基咪唑磷酸二乙酯盐{[Em im]+[(EtO)2(PO)O]-}催化一系列醛与活性亚甲基类化合物的Knoevenagel反应,比较了该离子液体在有溶剂存在及无溶剂条件下的催化性能。结果表明,该离子液体在乙醇作溶剂条件下对芳香醛的反应具有较高的催化活性,采用摩尔分数为20%的离子液体来催化该反应,于室温反应即可顺利完成,产率达73.2%~97%,生成相应的取代烯烃化合物。在无溶剂条件下采取机械研磨的方法进行反应,该离子液体表现出更高的催化活性,采用摩尔分数为10%的离子液体进行反应,在1~10 m in即可使产率达90%以上,所得产物均为E式构型。而且在无溶剂条件下,不仅可催化芳香醛的反应,亦可催化脂肪醛的反应。所用离子液体可重复使用,第5次使用时产率仍能达到85.9%。 相似文献
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Shi-Ping Gou 《Electrochimica acta》2008,53(5):2538-2544
The electrodeposition of nickel and nickel-zinc alloys was investigated at polycrystalline tungsten electrode in the zinc chloride-1-ethyl-3-methylimidazolium chloride molten salt. Although nickel(II) chloride dissolved easily into the pure chloride-rich 1-ethyl-3-methylimidazolium chloride ionic melt, metallic nickel could not be obtained by electrochemical reduction of this solution. The addition of zinc chloride to this solution shifted the reduction of nickel(II) to more positive potential making the electrodeposition of nickel possible. The electrodeposition of nickel, however, requires an overpotential driven nucleation process. Dense and compact nickel deposits with good adherence could be prepared by controlling the deposition potential. X-ray powder diffraction measurements indicated the presence of crystalline nickel deposits. Non-anomalous electrodeposition of nickel-zinc alloys was achieved through the underpotential deposition of zinc on the deposited nickel at a potential more negative than that of the deposition of nickel. X-ray powder diffraction and energy-dispersive spectrometry measurements of the electrodeposits indicated that the composition and the phase types of the nickel-zinc alloys are dependent on the deposition potential. For the Ni-Zn alloy deposits prepared by underpotential deposition of Zn on Ni, the Zn content in the Ni-Zn was always less than 50 atom%. 相似文献
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采用超声波辅助加热回流的方法合成了氯代1–烯丙基–3–甲基咪唑离子液体([AMIM]Cl),并对其进行了紫外光谱(UV)和傅利叶红外光谱(FT–IR)表征。考察了反应物摩尔比、反应时间和超声波功率对离子液体的收率和纯度的影响,探讨了超声波对合成反应的强化效应。实验结果表明超声波能强化[AMIM]Cl的合成,明显缩短合成时间,且其强化效应受反应物摩尔比的影响较小,而与超声波功率紧密相关。[AMIM]Cl适宜的合成条件为反应温度50℃、反应时间2h、氯丙烯与1–甲基咪唑的摩尔比1.4、超声波功率100W,此时离子液体的收率和纯度分别为94.4%和99.2%。 相似文献
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The electrodeposition of palladium–silver alloys was investigated in a basic 1-ethyl-3-methylimidazolium chloride/tetrafluoroborate ionic liquid containing Pd(II) and Ag(I). Cyclic voltammetry experiments showed that the reduction of Ag(I) occurs prior to the reduction Pd(II). Both electrodeposition processes require nucleation overpotential. Energy-dispersive spectroscopy data indicated that the composition of the Pd–Ag alloys could be varied by deposition potential and concentrations of Pd(II) and Ag(I) in the solution. The Pd content in the deposited Pd–Ag alloy increased with decreasing deposition potential and the Pd mole fraction in the plating bath. At potentials where the deposition of both Pd and Ag was mass-transport limited, the Pd/Ag ratio in the electrodeposited alloys was slightly less than the Pd(II)/Ag(I) ratio in the ionic liquid due to the smaller diffusion coefficient of Pd(II). Scanning electron micrographs of the electrodeposits showed that in general, the Pd–Ag alloys were nodular and become more compact upon increasing the temperature up to 120 °C. 相似文献
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In this study, Al was electrodeposited on a platinum substrate at room temperature from an ionic liquid bath of EMIC containing AlCl3 using potentiostatic polarization (PP), galvanostatic polarization (GP), monopolar current pulse polarization (MCP) and bipolar current pulse polarization (BCP). Transition of current or potential during galvanostatic or pulse polarization revealed that the initial stage of the deposition process was controlled by a nucleation process depending on the polarization condition. For example, the average size of Al deposits decreased with increasing current density in the case of GP. FE-SEM observation showed that dense and compact Al deposits with a smooth surface were obtained by the current pulse method. Roughness factor evaluated from electrochemical impedance measurement confirmed the smooth surface of these deposits. Adhesion strength of Al deposits was greatly improved using BCP in which an anodic pulse was combined with a cathodic pulse for electrodeposition. In this study, the optimal parameters for BCP were found to be IC = −16.0 mA cm−2, IA = 1.0 mA cm−2, rC (duty ratio) = 0.5, and f = 2 Hz. The mechanisms of electrodeposition by these three methods are discussed. 相似文献
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N-乙基-N-丁基吗啉离子液体的合成及性能 总被引:2,自引:0,他引:2
以吗啉、溴乙烷、溴代正丁烷为原料三步法合成了N-乙基-N-丁基吗啉四氟硼酸盐离子液体,中间体(a)产率94.1%,(b)产率90.7%,离子液体产率87.6%。这种具有吗啉阳离子的离子液体用质谱、红外光谱、元素分析、核磁共振和热重分析等手段进行了表征,并对产物的溶解性及形成双水相体系条件进行了考察,结果表明:产物在极性溶剂里具有较好的溶解性,当离子液体的质量浓度为345~440 g/L、KH2PO4质量浓度85~95 g/L、溶液酸度4.5~6.0时,形成上下相体积比接近1的双水相体系,性质稳定。 相似文献