Scientists have always been seeking more efficient extractants for rare earths extraction and separation, especially for heavy rare earths. In this paper, a novel extractant (2,4-dimethylheptyl)(2,4,4′-trimethylpentyl)phosphinic acid (USTB-2) was synthesized. The structures of the intermediate and USTB-2 were characterized by P NMR, H NMR, FT-IR and ESI-MS. Its p was 5.62. Its extraction ability was between Cyanex 272 and P507. Its extraction mechanism was cation exchange. Its extraction capacity was larger than that of Cyanex 272 and lower than that of P507. Its solubility in 3 mol/L HCl and deionized water was 11.2 mg/L and 19.0 mg/L, respectively. The Lu(III) loaded in USTB-2 solution can be easily stripped by HCl, HNO and HSO. It has good separation performance for heavy rare earths. Its average separation factor () for adjacent heavy REs from Gd to Lu was 2.18. For some heavy RE couples like Er/Ho, Yb/Tm and Lu/Yb (especially for Lu/Yb), USTB-2 possesses even better separation performance than Cyanex 272. Its extraction efficiency for nonferrous metal ions was in the order Al > Gd > Zn > Nd > La > Co > Cu. The separation factors of Al/Gd, Gd/Zn, Zn/Nd, La/Co by USTB-2 were 2.67, 5.39, 3.35 and 26.67, respectively.

中文翻译：

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用于从氯化物介质中萃取和分离稀土的新型萃取剂(2,4-二甲基庚基)(2,4,4′-三甲基戊基)次膦酸(USTB-2)

科学家们一直在寻找更有效的萃取剂来萃取和分离稀土，特别是重稀土。本文合成了一种新型萃取剂(2,4-二甲基庚基)(2,4,4′-三甲基戊基)次膦酸(USTB-2)。通过P NMR、H NMR、FT-IR和ESI-MS对中间体和USTB-2的结构进行了表征。其 p 为 5.62。其萃取能力介于Cyanex 272和P507之间。其提取机理为阳离子交换。其萃取能力高于Cyanex 272，低于P507。在3 mol/L HCl和去离子水中的溶解度分别为11.2 mg/L和19.0 mg/L。 USTB-2 溶液中负载的 Lu(III) 可以很容易地被 HCl、HNO 和 HSO 剥离。对重稀土具有良好的分离性能。从 Gd 到 Lu 的相邻重稀土的平均分离因子 () 为 2.18。对于一些重稀土对，如 Er/Ho、Yb/Tm 和 Lu/Yb（特别是 Lu/Yb），USTB-2 具有比 Cyanex 272 更好的分离性能。其对有色金属离子的萃取效率依次为 Al > Gd > Zn > Nd > La > Co > Cu。 USTB-2对Al/Gd、Gd/Zn、Zn/Nd、La/Co的分离因子分别为2.67、5.39、3.35和26.67。