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研究了氯代1-丁基-3-甲基咪唑(BMIC)离子液体中镁置换铜制备镁/铜双金属粉的动力学行为,探讨了搅拌速率、反应温度、铜离子浓度和镁粉颗粒大小等参数对反应速率常数的影响。动力学数据结果表明,在离子液体中镁置换铜的反应符合一级反应速率方程。反应速率常数随着搅拌速率增加、反应温度升高、铜离子浓度降低和镁粉粒径减小而增大。搅拌可使反应速率常数增大1倍左右;Cu(II)离子浓度较小时,反应速率常数随Cu(II)离子浓度的增加而迅速减小,当Cu(II)离子浓度增大到0.25 mol·L-1时,速率常数的减小趋势逐渐变缓;镁粉粒径范围从50~74μm增加到74~100μm,置换反应的速率常数从0.334 h-1减小到0.255 h-1;反应速率常数与反应温度的关系符合阿伦尼乌斯方程,求得置换反应表观活化能为13.6 k J·mol-1,说明置换过程受扩散控制。此外,Evans图研究也表明,置换反应受Cu(II)离子向电极表面扩散过程控制。这一结果与动力学数据的实验结果完全一致。
The kinetic behavior of Mg / Cu bimetallic powders prepared from Mg-substituted copper in 1-butyl-3-methylimidazolium chloride (BMIC) ionic liquid was studied. The effects of stirring rate, reaction temperature, copper ion concentration, Size and other parameters of the reaction rate constant. Kinetic data show that the reaction of magnesium with copper in ionic liquid conforms to the first-order reaction rate equation. The reaction rate constant increases with the stirring rate, the reaction temperature, the concentration of copper ions and the particle size of magnesium powder. When the Cu (II) ion concentration is small, the reaction rate constant decreases rapidly with the increase of Cu (II) ion concentration. When the Cu (II) ion concentration is increased to 0.25 mol · L-1, the decreasing trend of the rate constant becomes slower; the particle size of magnesium powder increases from 50 ~ 74μm to 74 ~ 100μm, the rate constant of displacement reaction decreases from 0.334 h-1 to 0.255 h-1; The relationship between the rate constant and the reaction temperature accords with the Arrhenius equation, and the apparent activation energy of the displacement reaction is 13.6 kJ · mol-1, indicating that the substitution process is controlled by diffusion. In addition, Evans diagram studies also show that the displacement reaction is controlled by the diffusion process of Cu (II) ions toward the electrode surface. This result is in good agreement with the experimental data of kinetic data.