N,N′-dimethyl-N,N′-dicyclohexylsuccinamide (DMDCHSA) is investigated as a potential molecule for the liquid-liquid extraction of Pd(II) from chloride solutions for the first time. The effect of several parameters on Pd(II) extraction, such as the contact period between both phases, hydrochloric acid, extractant and hydrogen ion concentrations, is evaluated. Pd(II) extraction equilibrium is very fast (30 s) and the extraction percentage (%E) increases with the HCl concentration in the aqueous phases, being higher than 60% for [HCl] > 5 M. The loading capacity of DMDCHSA for Pd(II) is reasonable (molar ratio extractant/metal higher than 16). Several stripping agents (e.g. distilled water, 1 M HCl, seawater and 20 g/L chloride solution as NaCl) were successfully used to transfer Pd(II) to a new aqueous phase, and data obtained from five successive extraction-stripping cycles suggest a good DMDCHSA stability pattern. Attempts to replace 1,2-dichloroethane (1,2-DCE) by commercial and more environmentally friendly diluents showed much worse %E for Pd(II). Selectivity tests with binary, ternary and more complex metal ion solutions were carried out to evaluate the performance of DMDCHSA towards Pd(II) recovery from 6 M HCl, when in presence of Pt(IV), Fe(III), Zn(II), Al(III) and Ce(III), metal ions usually present in solutions that may result from the hydrometallurgical treatment of spent automobile catalytic converters. It was generally observed that the additional metal ions do not affect the recovery of Pd(II) by DMDCHSA, although Fe(III) and Pt(IV) were co-extracted in a great extent. A solvent extraction (SX) scheme is proposed, based on a previous separation of Fe(III) with tributylphosphate (TBP) and on the selective and sequential stripping of Pt(IV) and Pd(II) from the loaded DMDCHSA with 0.01 M thiourea in 0.5 M HCl and seawater, respectively. The dependence of the Pd(II) distribution ratios on DMDCHSA and acidity, complemented with UV–Visible spectroscopy data, points out to DMDCHSA:Pd(II) extracted species with a 2:1 molar ratio and suggests the occurrence of an outer-sphere ion pair reaction, in which both [PdCl₄]²⁻ and HCl are extracted.

N，N'-二甲基-N，N'-二环己基琥珀酰胺（DMDCHSA）首次被作为潜在分子从氯化物溶液液化萃取Pd（II）。评估了几个参数对Pd（II）萃取的影响，例如两相之间的接触时间，盐酸，萃取剂和氢离子浓度。Pd（II）的萃取平衡非常快（30 s），萃取百分率（％E）随着HCl在水相中的浓度而增加，对于[HCl]> 5 M而言，萃取百分率高于60％。 Pd（II）是合理的（萃取剂/金属的摩尔比大于16）。几种剥离剂（例如蒸馏水，1 M HCl，海水和20 g / L氯化钠（NaCl）溶液已成功用于将Pd（II）转移到新的水相中，从五个连续的萃取-汽提循环获得的数据表明，DMDCHSA的稳定性良好。尝试用商业和更环保的稀释剂代替1,2-二氯乙烷（1,2-DCE）显示Pd（II）的％E差得多。在存在Pt（IV），Fe（III），Zn（II）的情况下，使用二元，三元和更复杂的金属离子溶液进行选择性测试，以评估DMDCHSA对从6 M HCl中回收Pd（II）的性能。 ，Al（III）和Ce（III）等金属离子通常存在于溶液中，这可能是由废汽车催化转化器的湿法冶金处理产生的。通常观察到，尽管在很大程度上共萃取了Fe（III）和Pt（IV），但其他金属离子不会影响DMDCHSA对Pd（II）的回收。提出了一种溶剂萃取（SX）方案，该方案基于先前用磷酸三丁酯（TBP）分离Fe（III）以及从负载的DMDCHSA中用0.01 M硫脲选择性和顺序地汽提Pt（IV）和Pd（II）的方法。分别加入0.5 M HCl和海水。Pd（II）分布比对DMDCHSA和酸度的依赖性，再加上紫外可见光谱数据，指出摩尔比为2：1的DMDCHSA：Pd（II）萃取物，表明存在外球离子对反应，其中[PdCl 基于先前用磷酸三丁酯（TBP）分离Fe（III）以及分别从负载的DMDCHSA中用0.01 M硫脲在0.5 M HCl和海水中选择性和连续地剥离Pt（IV）和Pd（II）进行研究。Pd（II）分布比对DMDCHSA和酸度的依赖性，再加上紫外可见光谱数据，指出摩尔比为2：1的DMDCHSA：Pd（II）萃取物，表明存在外球离子对反应，其中[PdCl 基于先前用磷酸三丁酯（TBP）分离Fe（III）以及分别从负载的DMDCHSA中用0.01 M硫脲在0.5 M HCl和海水中选择性和连续地剥离Pt（IV）和Pd（II）进行研究。Pd（II）分布比对DMDCHSA和酸度的依赖性，再加上紫外可见光谱数据，指出摩尔比为2：1的DMDCHSA：Pd（II）萃取物，表明存在外球离子对反应，其中[PdCl₄ ] ^2-和HCl被萃取。