已经确定,水杨酸异丙酯可以与1,3-二酮类似地用作选择性分离碱金属阳离子的新型高效萃取系统的关键成分。根据水杨酸异丙酯和1,3-二酮与碱金属阳离子(Li,Na+,K+),形成六元金属环,其稳定性沿Li>Na>K系列降低,这导致观察到的增强的对锂的亲和力。水杨酸异丙酯的萃取能力在三辛基氧化膦(TOPO)存在下表现出来。通过FT-IR表征了新获得的水杨酸异丙酯与碱金属阳离子的配合物以及它们与TOPO的混合物中的提取物,拉曼,和NMR光谱。推测了提取的锂络合物的可能结构,并详细研究了TOPO在提取过程中的作用。萃取实验表明,从模型多组分溶液中萃取时,Li/Na和Li/K对的分离系数极高。
It was established that isopropyl salicylate can be used similarly to 1,3-diketones as a key component for a new efficient extraction system for selective separation of alkali metal cations. According to DFT modeling of complexes of isopropyl salicylate and 1,3-diketone with alkali metal cations (Li+, Na+, K+), six-membered metallacycles are formed whose stability decreases along the series Li > Na > K, which results in the observed enhanced affinity to lithium. The extraction ability of isopropyl salicylate is manifested in the presence of trioctylphosphine oxide (TOPO). The newly obtained complexes of isopropyl salicylate with alkali metal cations as well as their extracts in a mixture with TOPO are characterized by means of FT-IR, Raman, and NMR spectroscopy. The probable structure of the extracted lithium complex is presumed and the role of TOPO in the extraction process is investigated in detail. Extraction experiments showed extremely high separation coefficients for Li/Na and Li/K pairs in the extraction from a model multi-component solution.