Extraction of thorium(IV) and europium(III) by a phosphorylated calix[4]arene in dichloromethane

The extractive properties of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(diphenylphosphinoylmethoxy)calix[4]arene towards thorium(IV) and europium(III) ions are studied. The conventional log-log analysis of the extraction data reveals that the stoichiometry of the extracted species is 1 : 1 metal ion to ligand ratio for the two metals. The effects of ligand concentration, types of diluent and concentration of the salting-out agents are investigated and discussed. The selectivity of the ligand for thorium and europium ions versus Mn2+, Pb2+, Cd2+, Fe2+, Ni2+ and Co2+ is examined.