We have prepared three secondary diamides with 2-ethylhexyl branches and different spacer lengths as extraction reagents to investigate the extraction behavior of Pt(IV) in acid chloride media. Protonation of the carbonyl oxygen atoms of three diamides was investigated by peak observation of NH hydrogen atoms in ¹H NMR spectra at varying HCl concentrations. The pK_a values of the three diamides were determined, and the extraction was carried out at a lower HCl concentration using only NH hydrogen atoms for Pt(IV) extraction, not protonated carbonyl oxygen atom. The short time to reach equilibrium of Pt(IV) extraction indicated that the extraction occurred via outer-sphere coordination. Various spectroscopic data supported the extraction by the NH hydrogen atoms, and the extracted species were [PtCl₆]²⁻. Slope analysis helped elucidate the stoichiometry but not the extraction mechanism, because of the high affinity of diamides and coexisting anions. Extraction reactions with the three diamides were also proposed. For selective extraction of [PtCl₆]²⁻, extraction behavior of various metal ions were also carried out. For practical purpose, kerosene/2-ethylhexanol (80 vol%/20 vol%) was used as diluent, and selective extraction of [PtCl₆]²⁻ was compared using commercially available reagents, TOA, TBP, 2-ethylhexylacetoamide, and three diamido reagents. Furthermore, stripping of [PtCl₆]²⁻ loaded on three diamido reagents was investigated with stripping reagents. The spacer length of the three diamides significantly affected the extraction efficiency of [PtCl₆]²⁻.

我们制备了三种具有 2-乙基己基支链和不同间隔长度的仲二酰胺作为萃取试剂，以研究 Pt(IV) 在酰氯介质中的萃取行为。^{通过在不同 HCl 浓度下1} H NMR 光谱中的NH氢原子的峰值观察来研究三种二酰胺的羰基氧原子的质子化。确定了三种二酰胺的 p K _a值，并在较低的 HCl 浓度下进行萃取，仅使用NH氢原子进行 Pt(IV) 萃取，而不是质子化的羰基氧原子。Pt(IV) 萃取达到平衡的时间短表明萃取是通过外球协调。各种光谱数据支持NH氢原子的提取，提取的物质为[PtCl ₆ ] ^2-。由于二酰胺和共存阴离子的高亲和力，斜率分析有助于阐明化学计量但不能阐明萃取机制。还提出了与这三种二酰胺的萃取反应。对于[PtCl ₆ ] ^2-的选择性萃取，还进行了各种金属离子的萃取行为。出于实际目的，使用煤油/2-乙基己醇（80 vol%/20 vol%）作为稀释剂，选择性萃取 [PtCl ₆ ] ²⁻使用市售试剂 TOA、TBP、2-乙基己基乙酰胺和三种二酰胺试剂进行了比较。此外，用剥离试剂研究了负载在三种二酰氨基试剂上的 [PtCl ₆ ] ^{2-的剥离。}三种二酰胺的间隔长度显着影响[PtCl ₆ ] ^2-的萃取效率。