Abstract Novel macrocyclic extractants were synthesized and employed in liquid–liquid extraction (LLE) for palladium/platinum (Pd/Pt) separation in aqueous feed source. Dioxadithia-benzo-crown ether diols (BCES2O2) 2g–2i were prepared through bis-epoxide cyclization with aqueous 1,2-benzenedithiol under mild basic conditions. For improved miscibility and stability in the organic diluent (i.e. toluene), 2g–2i were alkylated to afford dimethoxy-BCES2O2 3g–3i. LLE experiments reveal their high stability, extraction efficiency, and separation performance ( β Pd 2 + / Pt 2 + = 10 4 − 10 5 ) in highly acidic feed solutions (∼6 M HCl). The most suitable extractant 3i followed a 1:1 3i-Pd2+ complex with stability constant Kex ∼ 105. Density functional theory calculations reveal that the rigid cavity size (1.58–1.65 A) of 3i is ideal for Pd2+ (1.56 A) in forming S4 coordination geometry. The Pd2+ can be repeatedly extracted by 3i [in toluene] and stripped by 1 M HCl + 0.15 M thiourea solution without performance deterioration. Each cycle can be accomplished

中文翻译：

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使用新型烷基化二氧杂-二噻冠醚衍生物从废汽车催化剂酸浸出液中高选择性提取钯

摘要 合成了新型大环萃取剂，并将其用于液-液萃取 (LLE)，以在水性进料源中分离钯/铂 (Pd/Pt)。Dioxadithia-benzo-crown ether diols (BCES2O2) 2g-2i 是通过双环氧化物环化与 1,2-苯二硫醇水溶液在温和的碱性条件下制备的。为了提高在有机稀释剂（即甲苯）中的混溶性和稳定性，2g-2i 被烷基化得到二甲氧基-BCES2O2 3g-3i。LLE 实验揭示了它们在高酸性进料溶液（~6 M HCl）中的高稳定性、萃取效率和分离性能（β Pd 2 + / Pt 2 + = 10 4 - 10 5 ）。最合适的萃取剂 3i 遵循 1:1 3i-Pd2+ 配合物，稳定性常数 Kex ∼ 105。密度泛函理论计算表明，3i 的刚性腔尺寸 (1.58–1.65 A) 是 Pd2+ (1. 56 A) 在形成 S4 协调几何。Pd2+ 可以用 3i [在甲苯中] 反复萃取，用 1 M HCl + 0.15 M 硫脲溶液汽提，性能不会下降。每个周期都可以完成