环烷酸-酸性磷酸酯-庚烷体系萃取有机相的红外光谱研究

FTIR Investigation of Organic Phase Containing Rare Earth Ion in Naphthenic Acid-Phosphonate Ester-Heptane System

将环烷酸(NA)与2-乙基己基磷酸单2-乙基己基酯(PC88A)混合,以浓KOH溶液皂化,研究了高皂化度(80%)油包水型微乳萃取钕过程的有机相的结构变化。通过红外光谱分析,发现萃取钕过程随着负载率增加,COOH伸缩振动吸收峰、COO-的反对称峰及P O伸缩振动吸收峰的峰位均向低波数移动。结果表明:皂化NA和PC88A的混合体系萃钕过程,NA与PC88A存在相互作用;它们都与Nd3+作用,但PC88A作用较环烷酸完全,萃取有机相中,P—O—H伸缩振动吸收峰消失,还残留部分COOH没有完全转化为COO-;环烷酸、PC88A与钕之间形成的萃合物具有复杂结构。

Naphthenic acid （NA） was mixed with PC88A in heptane, and 10 moL ·L^-1 KOH aqueous solution was used to saponify the solution subsequently. The transparent and clear appearance of the obtained solution indicated the formation of w/o micell and microemusion. In the present study, micell with high saponification percentage （80%） was used to extract neodymiurn. The organic phase structure was characterized using FTIR spectroscopy in the extraction process. IR spectra indicate that the characteristic peaks of v（COOH）, vs （COO^-） and v（ P=O ） shift to lower wavenumbers as the loading of Nd in organic phase increases. The results demonstrated that Nd（ Ⅲ ） are coordinated to P=O and COO^- groups simultaneously, and the supramolecules with self-assembly structure was formed containing PC88A and NA, which were binding with Nd（ Ⅲ ） in the extracted organic phase.