ABSTRACT

Extraction behavior of Pd(II) and Re(VII) from HNO₃ aqueous solutions (0.1–5.0 M, M = mol∙dm⁻³) to CH₂Cl₂ containing N-cycrohexyl-2-pyrrolidone (NCP, 0.1–2.0 M) as an extractant has been examined. As a result, it was found that distribution ratios (D) of Pd(II) and Re(VII) under [HNO₃] = 3.0 M increase with increasing [NCP] from 0.1 to 2.0 M and that plots of log D vs. log[NCP] show linear relationships with slopes of approximately 2. It was also found that the D values for Pd(II) increase with increasing [HNO₃] up to 3.0 M and decrease in the higher [HNO₃] region (<5.0 M) and those of Re(VII) increase with an increase in [HNO₃] up to 1.0 M and decrease with a further increase in [HNO₃] (<5 M). From these results, it was suggested that the extraction reactions of Pd(II) and Re(VII) take place with two NCP molecules and compete with the extraction of HNO₃. Moreover, it was clarified that IR spectra (1550–1700 cm⁻¹) of CH₂Cl₂ solutions containing extracted Pd(II) and Re(VII) species are consistent with that of trans-Pd(NO₃)₂(NCP)₂ and similar to that of HReO₄(NCP)₂, respectively. From these results, it is proposed that Pd(II) and Re(VII) species in HNO₃ aqueous solutions are extracted to CH₂Cl₂ phase containing NCP as Pd(NO₃)₂(NCP)₂ and HReO₄(NCP)₂.

摘要

从HNO ₃水溶液（0.1–5.0 M，M = mol∙dm ^-3）在含有N-环己基-2-吡咯烷酮（NCP，0.1–2.0 ）的CH ₂ Cl ₂中萃取Pd（II）和Re（VII）的行为M）作为萃取剂已经过检验。其结果是，人们发现，分布比率（d [HNO下的Pd（II）和重（VII）的）₃ ] = 3.0M增加随[NCP]为0.1〜2.0 M和日志的该曲线d VS。日志[NCP]示出了具有约2斜率的线性关系也发现，该d为钯值（II）随[HNO增加₃ ]至多3.0 M和减少在较高[HNO ₃]区域（<5.0 M）和Re（VII）区域随着[HNO ₃ ]的增加而增加，直至1.0 M，而随着[HNO ₃ ]的进一步增加而减小（<5 M）。从这些结果表明，Pd（II）和Re（VII）的萃取反应与两个NCP分子发生，并与HNO ₃的萃取竞争。此外，澄清了含有提取的Pd（II）和Re（VII）物种的CH ₂ Cl ₂溶液的IR光谱（1550–1700 cm ^-1）与反式-Pd（NO ₃）₂（NCP）的光谱一致。₂，与HReO ₄（NCP）₂相似， 分别。根据这些结果，建议将HNO ₃水溶液中的Pd（II）和Re（VII）物种萃取到含有NCP作为Pd（NO ₃）₂（NCP）₂和HReO ₄（NCP）的CH ₂ Cl ₂相中。₂。