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用反相纸层析技术研究了β-二酮(PMBP、HTTA与HBA)与有机磷酸(P538、P204、P507)组成的体系对稀土的协萃效应。提出两种萃取剂都是以酸性配体形式起作用,协萃效应与两种萃取剂的pKa大小及萃取剂的空间位阻有关。当两种萃取剂的pKa相差较大时,β-二酮的酸式电离被抑制,大大减弱了配位能力,协萃效应很弱。当两种萃取剂的pKa相近,同时空间位阻较小时,协萃效应最为显著。
The paper studied the synergistic effect of β-diketone (PMBP, HTTA and HBA) and organophosphoric acid (P538, P204, P507) on rare earth by reverse phase paper chromatography. It is proposed that both extractants work in the form of acidic ligands and the synergistic effect is related to the pKa of the two extractants and the steric hindrance of the extractant. When the pKa of the two extractants is quite different, the acid ionization of β-diketone is inhibited, greatly reducing the coordination ability and weakening the co-extraction effect. When the two extractants pKa similar, while steric hindrance is small, the strongest synergistic effect.