The complexation of Np(V) with aliphatic (oxalic, malonic, succinic, glutaric, and maleic) and aromatic (phthalic, pyromellitic, hemimellitic, trimellitic, and mellitic) polycarboxylic acids was studied by spectrophotometry at 1 M ionic strength (NaClO$\sb4$) and 23$\sp\circ$C. For the aliphatic systems, the stability of the neptunyl complexes was found to decrease as the carbon chain length of the ligand increased which was attributed to an entropy effect. / In polycarboxylate systems, the stability constant decreased in the order hemimellitate $>$ mellitate $>$ pyromellitate $>$ trimellitate, phthalate. With the exception of hemimellitate, this trend follows the order of decreasing basicity of the ligand. After correction of the stability constant for statistical effects, the stability of the mellitate, pyromellitate, trimellitate, and phthalate complexes were approximately the same. / The unexpected strength of hemimellitate complexation was attributed to an increase in electron density at the binding site from the non-chelating carboxylate group through induction. / The complexation of phthalate, trimellitate and hemimellitate and mellitate were studied as a function of pH. Trimellitate and mellitate were found to form MHL as well as ML complexes while for phthalate and hemimellitate only ML species were observed. / The stability constants of the cation-cation complexes Np(V)-U(VI) and Np(V)-Np(V), measured at 6 M ionic strength (HClO$\sb4$) and 25$\sp\circ$C, were found to be 2.45 $\pm$ 0.05 and 1.41 $\pm$ 0.14, respectively. The change in enthalpy for the Np(V)-U(VI) system as determined by the measurement of the stability constant as function of temperature was $-$14.3 $\pm$ 1.6 kJ/mol. / Source: Dissertation Abstracts International, Volume: 50-07, Section: B, page: 2921. / Major Professor: Gregory R. Choppin. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78033 |
| Contributors | Stout, Barbara Elizabeth., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 193 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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