INVESTIGATION ON DEVELOPMENT AND MOLECULAR DESIGN OF HIGH-PERFORMANCE SOLVENT EXTRACTION REAGENTS FOR RARE EARTHS

合成了3种含羧酸、异羟肟酸和膦酸功能基的化学修饰杯芳烃，考察了它们对3价稀土的萃取性能。通过在杯[4或6]芳烃的下缘引入羧酸和异羟肟酸官能团，合成了羧酸酯型和异羟肟酸酯型杯芳烃。还合成了羧酸酯的单体和线性三聚体类似物，以比较它们与羧酸酯杯芳烃的萃取行为。结果表明，杯芳烃羧酸酯衍生物对稀土元素的相互分离具有更高的萃取性和选择性，但杯芳烃环的大小对萃取选择性没有影响。杯芳烃异羟肟酸衍生物通过阳离子交换机理萃取金属离子，对三价铟和镓有很高的选择性 关于我们 特别是与相应的羧酸酯衍生物相比。在杯[4]芳烃的酸性膦酸酯衍生物的合成初期，虽然有人试图在杯[4]芳烃的下边缘引入功能基团，但由于功能基团的庞大性，发现这是不可能的，这也被计算机模拟所证实。因此，在除去叔丁基基团之后，它们被引入到对叔丁基杯[4] -芳烃的上边缘;通过取代酚羟基的氢原子来将烷基基团如丙基和辛基基团引入到下边缘。合成了杯芳烃衍生物的单体类似物，并与杯芳烃衍生物的萃取性能进行了比较。这三种化合物对稀土离子的选择性没有差异，这是由于在杯芳烃环上引入膦酸酯官能团，使杯芳烃环失去了对离子半径的尺寸识别能力所致，计算机模拟也证实了这一点.预计在较低边缘中引入大体积烷基基团如2-乙基己基将提高选择性。少

Three types of chemically modified calixarenes containing functional groupes of carboxylic acid, hydrxamic acid and phosphonic acid were synthesized to be examined on their solvent extraction behaviors for trivalent rare earths. Carboxylate and hydroxamate types of calixarenes were synthesized by introducing functional groups of carboxylic acid and hydroxamic acid into lower rim of calix [4 or 6] arenes. Monomeric and linear trimeric analogues of carboxylates were also synthesized to compare their extraction behavior with carboxylate calixarenes. It was found that the carboxylate derivatives of calixarenes have much higher extability and selectivity for mutual separation of rare earth elements compared with the monomeric and linear trimeric analogues ; but, the ring size of the calixarene derivatives does not affect the selectivity. The hydroxamate derivatives of calixarene was found to extract metal ions by cation-exchange mechanism and have high selectivity to trivalent indium and ga … More llium in particular compared with the corresponding carboxylate derivatives. At the initial stage of the synthesis of acidic phosphonate derivatives of calix [4] arene, although it was attempted to introduce the functional groups into the lower rim of the calixarene, it was found impossible owing to the bulkiness of the functional groups, which was confirmed also by the computer simulation. Consequently, they were introduced into the upper rim of the p-tert-butylcalix [4] -arene after removal of the tert-butyl groups ; alkyl groups such as propyl and octyl groups were introduced into the lower rim by substituting the hydrogen atoms of phenolyc hydroxy groups for the alkyl groups. Monomeric analogue was also synthesized to compare the extraction behavior with the calixarene derivatives. No differences of the selectivity to rare earths were found among these three kinds of compounds, which was attributed to the loss of the size recognition for ionic radii by calixarene ring caused by the introduction of the phosphonate functional groupes into upper rim, which was also confirmed by the computer simulation. It was expected that the introduction of bulky alkyl groups such as 2-ethylhexyl group into the lower rim would enhance the selectivity. Less