Narita Hirokazu, Maeda Motoki, Tokoro Chiharu, Suzuki Tomoya, Tanaka Mikiya, Motokawa Ryuhei, Shiwaku Hideaki, Yaita Tsuyoshi
Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology (AIST).
Department of Earth Science, Resources and Environmental Engineering, Faculty of Creative Science and Engineering, Waseda University.
Anal Sci. 2017;33(11):1305-1309. doi: 10.2116/analsci.33.1305.
Using N,N,N',N'-tetra-2-ethylhexyl-thiodiglycolamide (TEHTDGA) in n-dodecane as the extractant, we compared the percentages of Pd(II) extracted from HCl and HBr solutions, and analyzed the structures of the Pd(II)-extractant complexes. For comparison, similar experiments were performed with di-n-hexyl sulfide (DHS), a well-known sulfide-type extractant. TEHTDGA extracted Pd(II) from both HCl and HBr solutions much faster than DHS. The Pd(II)/(TEHTDGA or DHS) stoichiometry in the organic phase was 1:2. For TEHTDGA, the extractability of Pd(II) from HBr solution was inferior to that from HCl solution, whereas the opposite was true for DHS. However, FT-IR spectroscopy and EXAFS measurements indicated that the inner-sphere structure of Pd(II) in the TEHTDGA complex was almost the same as that in the DHS system: in both cases, two of the halide ions in the tetrachloro- or tetrabromopalladate(II) ion were replaced by the sulfur atoms of two extractant molecules.
以正十二烷中的N，N，N'，N'-四-2-乙基己基硫代二甘醇酰胺（TEHTDGA）作为萃取剂，我们比较了从HCl和HBr溶液中萃取的Pd（II）的百分比，并分析了Pd（II）-萃取剂配合物的结构。为了进行比较，用二正己基硫醚（DHS）（一种著名的硫化物型萃取剂）进行了类似的实验。TEHTDGA从HCl和HBr溶液中萃取Pd（II）的速度比DHS快得多。有机相中Pd（II）/（TEHTDGA或DHS）的化学计量比为1:2。对于TEHTDGA，从HBr溶液中萃取Pd（II）的能力不如从HCl溶液中，而对于DHS则相反。然而，傅里叶变换红外光谱（FT-IR）和扩展X射线吸收精细结构（EXAFS）测量表明，TEHTDGA配合物中Pd（II）的内球结构与DHS体系中的几乎相同：在两种情况下，四氯钯酸根或四溴钯酸根离子中的两个卤离子都被两个萃取剂分子的硫原子取代。
