The liquid-liquid distribution of mercury(II) has been determined when the organic phase was benzene, hexane containing tributylphosphate(TBP), methylisobutylketone(MIBK), or nitrobenzene, and when the aqueous phase was 0.5M sodium per chlorate containing chloride, bromide, iodide, or thiocyanate ions. The stability constants for the mercury(II) complexes in the aqueous phase and the distribution constants for the extractable complexes were determined by a graphic analysis of the distribution data, which were measured as a function of the ligand concentration. It was concluded that the stability constants determined from the present results agree almost entirely with the previous values and that the only extracted species into benzene and hexane containing TBP is the non-charged complex (HgX2, where X− is the ligand) in all cases, whereas those extracted into MIBK or nitrobenzene include not only the non-charged but also the charged species (HgX3− and sometimes HgX42−) except in the case of the chloride system. The distribution ratio in the hexane-TBP system was further determined by changing the TBP concentration in the hexane phase, and the equilibrium constants for the adduct formation between the HgX2 species and TBP molecules were determined. Finally, some discussion was made of the relation between the distribution behavior of the mercury(II) complexes and the natures of the ligands and the solvents.
The Chemical Society of Japan