The Solvent Extraction of Silver Ion by Novel Sulfur-Containing Podans

황을 포함하는 새로운 포단드에 의한 은 이온의 용매추출

  • Received : 1994.05.30
  • Published : 1994.06.25

Abstract

The podands I-VII, acyclic polyethers, expected high extractability for $Ag^+$ against $Pb^{2+}$ were designed and synthesized with high yields. Using podands I-VII as extractants, the %extraction(%Ex) of $Ag^+$ and $Pb^{2+}$ as picrates were determined in water/chloroform systems. The stability constants(log K) for the complexation of $Ag^+$ with podands I-VII were also determined by potentiometry. %Ex($Ag^+$) were proportional to the numbers of substituted sulfur donor atoms. Podand VI(log K : 7.65) having 3 substituted sulfur and podand VII(log K : 9.15) having 4 substituted sulfur, however, exhibited almost 100% of extractability, respectively. In %Ex($Ag^+/Pb^{2+}$, oxygen-sulfur mixed donor podands(IV-VII) showed the higher values. Otherwise, the values of log K and %Ex($Ag^+$) largely depended on the variation of donor-site of sulfur. From the results of NMR experiments, it seems that it is due to the ${\pi}-{\pi}$ stacking interaction between the aromatic end-groups.

Keywords

Podand;solvent extraction;extractant;$Ag^+$ ion;$Pb^{2+}$ ion;%Ex;log K;NMR;donor-site effect;${\pi}-{\pi}$ stacking

Acknowledgement

Supported by : 교육부