Selective extraction of perrehnate anion in nitric acid solution using 2,2′-(methylimino)bis(N,N′-diethylacetamide) as an extractant

In order to examine extraction behavior of ReO(4)(-) from HNO(3) aqueous solution to dichloromethane containing 2,2'-(methylimino)bis(N,N-diethylacetamide) (MIDEA) as an extractant, we have measured distribution ratios (D) by changing [HNO(3)] under constant [MIDEA] (1.064 x 10(-1) M, M = mol dm(-3)) in CH(2)Cl(2) and also by changing [MIDEA] in CH(2)Cl(2) under constant [HNO(3)] (0.1 M) and (0.2 M). As a result, it was found that the D values decrease with an increase in [HNO(3)] and increase with increasing [MIDEA]. The decrease in D values with increasing [HNO(3)] is considered to be due to the effect of acid extraction with MIDEA. A plot of log D values against log [MIDEA] was found to show the linear relationship with slope of ca. 1.1. This result suggests that one MIDEA molecule contributes to the extraction of ReO(4)(-), i.e., 1:1 complex. This is supported by the fact that the ReO(4)(-) species extracted from HNO(3) solution to CH(2)Cl(2) phase containing MIDEA is assigned as [C(13)H(28)O(2)N(3)(+)][ReO(4)(-)] by the single crystal x-ray analysis. (C) 2011 Elsevier Ltd. All rights reserved.