Complexation of Uranium(VI) with Thiodiacetic Acid in Solution at 10–85 °C

Abstract

The protonation of thiodiacetate and its complexation with uranium(VI) in 1.05 mol kg -1 NaClO 4 are studied at variable temperatures (10-85°C). Three U VI complexes (UO 2 L, UO 2 HL + , and UO 2 HL 2 -, where L is thiodiacetate) are identified in this temperature range. The formation constants and the enthalpies of complexation are determined by potentiometry and calorimetry. The complexation of uranium(VI) with thiodiacetate becomes more endothermic at higher temperatures. However, the complexes become stronger due to increasingly more positive entropies of complexation at

Spectrophotometric and calorimetric studies of U(VI) complexation with sulfate at (25 to 70)°C

“…The increase of entropy with the temperature could be the consequence of a more disordered bulk water structure at higher temperatures due to the perturbation by thermal movements. In the process of complexation, the solvating water molecules are released to an already expanded and more disordered bulk solvent [27]. As a result, the net gain in the complexation entropy is larger at higher temperatures.…”

Thermodynamic study of the complexation of uranium(VI) with nitrate at variable temperatures

“…At each temperature, the spectra of UO 2þ 2 were slightly red-shifted as the concentration of nitrate was increased. Analysis by the Hyperquad program indicated that there are two absorbing species of U(VI) and the spectra were best-fitted with the formation of a 1:1 complex, UO 2 …”

“…The SIT (specific ion interaction) approach originated from the Brønsted-Guggenheim-Scatchard model [33 -35] has been used to calculate the equilibrium constants at zero ionic strength. For reaction (2), the equilibrium constant at the standard state (lg K m in molality) are calculated by:…”

“…Complexation of actinides with inorganic and organic ligands at elevated temperatures has been a subject of study [1][2][3][4][5] in recent years because there is an urgent need for such data in the management of nuclear wastes and the development of advanced nuclear energy systems. Currently, the majority of thermodynamic data on the complexation of actinides are determined at or near 25°C [6,7].…”

Hydrogen-bonded assemblies in the molecular crystals of 2,2′-thiodiacetic acid with ethylenediamine ando-phenylenediamine

“…Tda is a versatile ligand that has been widely explored employing its multidendate and chelating coordination abilities with many metals. It forms complexes with different metal ions, such as lanthanides (Zhang et al, 2002), cobalt (Grairrane, Pastor, Alvrez, Mealli et al, 2005), magnesium , zinc (Grairrane et al, 2006;Wyrzykowski et al, 2013), copper (Alarcon-Payer et al, 2005;Baggio et al, 1999), vanadium (Alvarez et al, 2010), lead (Gabriel et al, 2013;Wu et al, 2013), tin (Sandhu & Sharma, 1996), calcium and strontium (Grairrane et al, 2007), uranium(VI) (Kirishima & Sato, 2014;Di Bernardo et al, 2006), ruthenium (Zangl et al, 2009) and manganese (Grairrane et al, 2003(Grairrane et al, , 2011. Multidentate macrocyclic ligands have been synthesized using Tda and triazine (Aghatabay et al, 2009;Steenland et al, 1999).…”