caa a22 4500 378917692 CHVBK 20180305123557.0 cr unu---uuuuu 161128e20040101xx s 000 0 eng 10.1524/ract.92.1.17.25402 doi (NATIONALLICENCE)gruyter-10.1524/ract.92.1.17.25402 Enhanced extraction of thorium(IV) and uranium(VI) with 1-phenyl-3-methyl-4-pivaloyl-5-pyrazolone in the presence of various neutral organophosphorus extractants [Elektronische Daten] [R. Meera, R. Luxmi Varma, M. L. P. Reddy] This paper describes the results of the investigations carried out on the extraction of thorium(IV) and uranium(VI) from dilute nitric acid solutions into chloroform with 1-phenyl-3-methyl-4-pivaloyl-5-pyrazolone (HPMPP) in the presence and absence of various neutral organophosphorus extractants, tributylphosphate (TBP), octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and trioctylphosphine oxide (TOPO). The results demonstrated that these metal ions were extracted into chloroform as Th(PMPP)4 and UO2(PMPP)2 with HPMPP alone and as Th(PMPP)4·S and UO2(PMPP)2·S in the presence of neutral organophosphorus extractants (S). High selectivity (S.F.=2.8×105) has been observed between thorium(IV) and uranium(VI) when extracted with HPMPP alone. The equilibrium constants of the extracted complexes have been deduced by non-linear regression analysis. The equilibrium constants of the synergistically extracted complexes have been correlated with the donor ability of the phosphoryl oxygen of the neutral organophosphorus extractants in terms of their 31P NMR chemical shifts and basicity values (KH = nitric acid uptake constant). The addition of a neutral organophosphorus extractant to the metal chelate system significantly enhances the extraction efficiency of these metal ions. Thorium(IV) and uranium(VI) complexes of HPMPP and mixtures of HPMPP and neutral organophosphorus extractants were synthesized and characterized by IR spectral data to further clarify the nature of the extracted complexes. © 2004 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Meera R. aut Luxmi Varma R. aut Reddy M. L. P. aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/1/2004(2004-01-01), 17-24 0033-8230 92:1/2004<17 2004 92 ract https://doi.org/10.1524/ract.92.1.17.25402 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.92.1.17.25402 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Meera R. aut NATIONALLICENCE 700 1- Luxmi Varma R. aut NATIONALLICENCE 700 1- Reddy M. L. P. aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/1/2004(2004-01-01), 17-24 0033-8230 92:1/2004<17 2004 92 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter