Showing papers by "Mark L. Dietz published in 2003"
TL;DR: The predominant mode of strontium ion transfer from acidic nitrate media into a series of 1-alkyl-3-methylimidazolium-based room-temperature ionic liquids containing dicyclohexano-18-crown-6 (DCH18C6) shifts from cation exchange to stontium nitratocrown ether complex partitioning as the hydrophobicity of the ionic liquid cation is increased.
245 citations
TL;DR: In this paper, a series of silyl-substituted alkylenediphosphonic acids were shown to be effective solvent extraction reagents for the removal of actinide cations from acidic aqueous solutions into conventional organic solvents.
Abstract: Partially esterified alkylenediphosphonic acids were shown to be effective solvent extraction reagents for the removal of actinide cations from acidic aqueous solutions into conventional organic solvents. As a first step in an effort to design diphosphonic acid extractants that are soluble in supercritical carbon dioxide, we prepared and characterized a novel series of silyl-substituted alkylenediphosphonic acids. The aggregation of these extractants in toluene at 25°C was studied by vapor pressure osmometry. Their solvent extraction chemistry was investigated by employing radiotracers to determine the distribution ratios for selected metal ions between an acidic aqueous phase and an organic phase containing the diphosphonic acid extractant. To determine the effect of incorporating a silicon functionality into diphosphonic acids, the aggregation and solvent extraction properties of the silyl-substituted alkylenediphosphonic acids were compared with those of the conventional alkyl-substituted di(2-ethylhex...
7 citations
TL;DR: In this article, a 20-crown-6 substituent capable of impeding cation/anion access to one face of the crown ether cavity is shown to afford compounds exhibiting good extraction selectivity for potassium ion over both alkaline earth cations (Ca2+, Sr2+) and other alkali metal ions (Na+, Cs+), an apparent result of diminished flexibility of the Crown ether cavity, inhibition of the formation of extractable "sandwich" complexes with large cations, and the destabilizing effect of forcing charge-neutralizing counter anions
Abstract: Incorporation into a 20-crown-6 of a bulky substituent capable of impeding cation/anion access to one face of the crown ether cavity is shown to afford compounds exhibiting good extraction selectivity for potassium ion over both alkaline earth cations (Ca2+, Sr2+) and other alkali metal ions (Na+, Cs+), an apparent result of diminished flexibility of the crown ether cavity, inhibition of the formation of extractable “sandwich” complexes with large cations, and the destabilizing effect of forcing charge-neutralizing counter anions to approach from one face of the crown cavity
1 citations