Abstract: 1-Ethyl-3-methylimidazolium hydrogen sulfate ([EMIM]HSO4) was synthesized with N-methylimidazolium as raw material and characterized by using FT-IR and TG-DTG-DTA and DSC measurements. Some physical properties concerned in aluminum electrolysis, such as density, surface tension, electrical conductivity and viscosity of [EMIM]HSO4, were investigated. The solubility and electrochemical behavior of alumina in [EMIM]HSO4 was studied by using inductively coupled plasma-atomic emission spectrometer (ICP-AES) and cyclic voltammmetry measurements. The results showed that [EMIM]HSO4 was very stable at the temperatures below 270℃, its density and viscosity decreased rapidly with increase of temperature, and molar conductivity reached 2.890 S×cm2/mol at 100℃, demonstrating that [EMIM]HSO4 could be used as electrolyte. The solubility of alumina in [EMIM]HSO4 at 20℃ was 3.81 g/L, suggesting that this system might satisfy the electrolysis of alumina, alumina could be reduced to aluminum at a platinum electrode, with normal deposition at -0.54 V and under potential deposition (UPD) at -0.26 V, and the deposition was a diffusion-controlled process.

Key words: ionic liquids, 1-ethyl-3-methylimidazolium hydrogen sulfate, alumina, solubility, electrochemical deposition

摘要： 以N-甲基咪唑为原料合成了[EMIM]HSO4离子液体，采用红外光谱、核磁氢谱和热分析对产物进行了表征，并测定了与电解相关的物理性质，如密度、表面张力、粘度和电导率等，通过研究Al2O3在[EMIM]HSO4离子液体中的溶解度和电化学行为，探讨了其直接电解的可能性. 结果表明，[EMIM]HSO4在加热至270℃前比较稳定，密度和粘度均随温度升高而减小，在100℃时摩尔电导率为2.890 S×cm2/mol，满足电解质要求. 20℃时测得Al2O3在[EMIM]HSO4中的溶解度为3.81 g/L，满足直接电沉积对溶解度的要求. Al2O3在Pt电极上能发生电沉积，在-0.26 V发生铝的欠电位沉积，-0.54 V发生铝的沉积，电解过程受扩散控制.

关键词: 离子液体, [EMIM]HSO4, 氧化铝, 溶解度, 电沉积