Abstract:

Among the various acyl groups substituted 1-phenyl, 3-methyl, pyrazolones for the extraction of cerium(Ⅲ), it has been found previously that 4-trifluoroacetyl substituted compound, abbreviated as HAPZ-8113F and denoted as HA in this paper, is most efficient. Combined use of certain sulfoxides can further bring up the extraction coefficient. The order of synergistic effect is as follows: TOPO > DOSO > DN_pSO≈1, 3-DφDSO > l, -2-DφDSO. Through the use of method of normalization in curve plotting, the extracted species in nitric acid medium 13 estimated as a mixtuer of CeA₃ and CeA₃NO₃·S, while in hydrochloric acid medium, it behaves as a mixture of CeA₂Cl·HA and CeA₃Cl·S. The Synergistic extraction equilibrium coefficients are calculated to be lgK₂₁=3, 43 in HNO₃ medium and lgK₂₁=2.86 in HC1 medium respectively, S being di-n-octyl sulfoxide (DOSO) in all cases above, As a comparison, NdA₃·HA and NdA₃·S have been isotated, S being (CH₃)₂SO. The corresponding Ce (Ⅲ) compounds are unstable in air, revealed by change of color from light yellow to dark yellow on standing.