Yamada Manabu, Rajiv Gandhi Muniyappan, Shibayama Atsushi
Research Center of Advanced Materials for Breakthrough Technology, Graduate School of Engineering Science, Akita University, Akita, 010-8502, Japan.
Graduate School of International Resource Sciences, Akita University, Akita, 010-8502, Japan.
Sci Rep. 2018 Nov 15;8(1):16909. doi: 10.1038/s41598-018-35026-x.
A novel macrocyclic calix[4]arene extractant having a long alkyl chain thioamide, 25,26,27,28-tetrakis(N-n-octylthiocarbamoyl)methoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (1), was synthesized from 25,26,27,28-tetrakis(N-n-octylcarbamoyl)methoxy-5,11,17,23-tetra-tert-butylcalix[4]arene (2) using Lawesson's reagent. Extractant 1 was characterized using H NMR, C NMR, FT-IR spectroscopy, and elemental analysis. The Pd(II) extraction abilities of 1 and 2 were studied in high-boiling-point and environmentally friendly hydrocarbon diluents. Pd(II) extraction experiments were conducted using single-metal Pd(II) solutions, simulated mixed palladium group metal (PGM) solutions, and acid-leached automotive catalyst residue solutions. Different experimental conditions, including the shaking time, HCl/HNO concentration, Pd(II) concentration, extractant concentration, and the organic/aqueous phase ratio, were studied systematically. Extractant 1 showed very selective (> 99.9%) Pd(II) extraction from the mixed PGM/base metal solutions and the acid-leached automotive catalyst residue solution. Conversely, the Pd(II) extraction ability of extractant 2 was found to be negligible. Extractant 1 showed very fast extraction kinetics and a high extraction capacity as compared to those of the commercial extractant di-n-octyl sulfide. Effective stripping of Pd(II) from 1 was performed using HCI, HNO, NH, and HCl-thiourea solutions. Furthermore, 1 was successfully recycled over five extraction/stripping cycles. The Pd(II) extraction mechanism of 1 was studied using FT-IR spectroscopy. Extractant 1 exhibited very selective Pd(II) extraction and high acid stability, demonstrating its industrial applicability for the extraction of Pd(II) from leached automotive catalyst liquors containing PGMs and base metals.
一种具有长烷基链硫代酰胺的新型大环杯[4]芳烃萃取剂，即25,26,27,28-四（N-正辛基硫代甲酰基）甲氧基-5,11,17,23-四叔丁基杯[4]芳烃（1），由25,26,27,28-四（N-正辛基甲酰基）甲氧基-5,11,17,23-四叔丁基杯[4]芳烃（2）使用劳森试剂合成。萃取剂1通过氢核磁共振、碳核磁共振、傅里叶变换红外光谱和元素分析进行表征。在高沸点且环境友好的烃类稀释剂中研究了1和2对钯（II）的萃取能力。使用单金属钯（II）溶液、模拟混合钯族金属（PGM）溶液和酸浸汽车催化剂残渣溶液进行钯（II）萃取实验。系统研究了不同的实验条件，包括振荡时间、盐酸/硝酸浓度、钯（II）浓度、萃取剂浓度以及有机相/水相比例。萃取剂1从混合的PGM/贱金属溶液和酸浸汽车催化剂残渣溶液中对钯（II）的萃取具有很高的选择性（>99.9%）。相反，发现萃取剂2对钯（II）的萃取能力可忽略不计。与市售萃取剂二正辛基硫醚相比，萃取剂1显示出非常快的萃取动力学和高萃取容量。使用盐酸、硝酸、氨水和盐酸-硫脲溶液对1中的钯（II）进行了有效的反萃取。此外，1在五个萃取/反萃取循环中成功实现了循环利用。使用傅里叶变换红外光谱研究了1对钯（II）的萃取机理。萃取剂1表现出非常选择性的钯（II）萃取和高酸稳定性，证明了其在从含PGM和贱金属的浸出汽车催化剂溶液中萃取钯（II）的工业适用性。
