Selective extraction of perrhenate anion in nitric acid solution using 2,2鈥?(imino)bis(N,N鈥?dioctylacetamide) as an extractant

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• 作者：Mohammad C. Ali^a ; Tomoya Suzuki^a ; Yu Tachibana^a ; Yuji Sasaki^b ; Yasuhisa Ikeda^a ; ^{yikeda@nr.titech.ac.jp}
• 关键词：Amide compound ; Extraction ; Perrhenate ; Selectivity ; Mechanism
• 刊名：Separation and Purification Technology
• 出版年：2012
• 期刊代码：78_13835866
• 类别：ce
• 出版时间：18 May, 2012
• 卷：92
• 期：Complete
• 页码：77-82
• 文件大小：987 K

摘要

In order to examine extraction behavior of from HNO₃ aqueous solution to dodecane containing 2,2鈥?(imino)bis(N,N鈥?dioctylacetamide) (IDOA) as an extractant, we have measured distribution ratios (D) by changing [HNO₃] under constant [IDOA] (5.00 脳 10^鈭? M, M = mol dm^鈭?) in dodecane and also by changing [IDOA] in dodecane under constant [HNO₃] 0.1, 1.0, and 2.0 M. It was found that the D values decrease with an increase in [HNO₃] and increase with increasing [IDOA]. The decrease in D values with increasing [HNO₃] is considered to be due to effect of the protonation of IDOA in aqueous phase and also competitive extraction of with from aqueous to organic phase. A plot of log D values against log [IDOA] gave the linear relationship with slope of ca. 1.03 卤 0.01 ([HNO₃] = 0.1 M), 1.02 卤 0.01 ([HNO₃] = 1.0 M) and 0.94 卤 0.01 ([HNO₃] = 2.0 M). These results suggest that one IDOA molecule contributes to the extraction of . Effects of diluents (dodecane, toluene, dichloromethane) on the extraction of with IDOA showed that IDOA exhibits higher extraction efficiencies into dodecane than toluene and dichloromethane. Furthermore, the influences of HNO₃, H₂SO₄ and HCl on the extraction of into dodecane were examined by changing their concentrations from 0.1 to 2.0 M at [IDOA] = (5.00 脳 10^鈭?M). The results showed that the highest D values of were observed in the H₂SO₄ system. The effects of the concentrations of the various salts ((NH₄)₂SO₄, NH₄Cl, and NH₄NO₃) on the extraction of into dodecane were also examined under constant [IDOA] (3.00 脳 10^鈭? M) and [acid] (0.1 M). It was found that the D values of decrease with an increase in the concentrations of salts in the aqueous phase. These results suggest that anionic species (, Cl^{鈭?/sup>, ) are extracted with from aqueous to organic phase. This is confirmed by the extraction experiments of (NH₄)₂SO₄, NH₄Cl, and NH₄NO₃ in the absence of using IDOA into dodecane. Hence, it was proposed that the decrease of D values with an increase in acid concentrations is due to the competitive extraction of anionic species (, Cl鈭?/sup>, ).}