Complexing Properties of α-Isosaccharinate: Stability Constants, Enthalpies and Entropies of Th-complexation with Uncertainty Analysis

Journal article, 2006

The complexation of Th-alpha-isosaccharinate has been examined using liquid-liquidextraction technique. An organic phase consisting of 0.025 M acetylacetone in toluene was used with a 1.0 M NaClO4 aqueous phase kept at pH 8 in a thermostated AKUFVE unit. Two temperatures, 15 degrees C and 35 degrees C, were investigated and the stability constants for the complexation reaction Th4+ + pISA <-> Th(ISA(-))(p)((4-p)+) were determined by curve fitting of a distribution ratio equation to experimental data employing a chi(2) method to estimate the standard deviation. By incorporating data from a previous study at 25 degrees C, Delta H degrees and AS' for the reaction were also obtained, using randomly generated, binomially distributed, data points around the stability constant values with one standard deviation in two dimensions. Three alpha-isosaccharinate ligands were found to be involved in the complexation with thorium.