Showing papers by "Mark L. Dietz published in 2001"
TL;DR: The transfer of strontium ion from acidic nitrate media into a series of 1-alkyl-3-methylimidazolium-based room-temperature ionic liquids containing dicyclohexano-18-crown-6 is shown to proceed via cation-exchange, in contrast to conventional solvents such as alkan-1-ols.
330 citations
TL;DR: The ability of the new resin to strongly and selectively retain U(VI) from such a wide range of acid concentrations, along with its favorable physical properties, make it a good candidate for application in the separation and preconcentration of U( VI) from complex environmental, biological, and nuclear waste samples for subsequent determination.
76 citations
TL;DR: In this article, the effect of adding silicon-based functionalities to diphosphonic acids on their aggregation and solvent extraction chemistry was investigated, and two silyl-derivatized diphonic acids, P,P′-di[3-(trimethylsilyl)-1-propylene] methylenediphosphoric acid (H2DTMSP[MDP]) and H2DTLSP[EDP], were prepared and their aggregation, ion extraction and metal ion extraction properties compared to those of the previously studied 2-p′-
Abstract: In conjunction with efforts to develop novel actinide extractants that exhibit solubility in supercritical carbon dioxide (SCCO2), the effect of adding silicon-based functionalities to diphosphonic acids on their aggregation and solvent extraction chemistry was investigated. Two silyl-derivatized diphosphonic acids, P,P′-di[3-(trimethylsilyl)-1-propylene] methylenediphosphonic acid (H2DTMSP[MDP]) and P,P′-di[3-(trimethylsilyl)-1-propylene] ethylenediphosphonic acid (H2DTMSP[EDP]), were prepared and their aggregation and metal ion extraction properties compared to those of the previously studied P,P′-di(2-ethylhexyl) alkylenediphosphonic acids. Vapor pressure osmometry of H2DTMSP[MDP] and H2DTMSP[EDP] in toluene (25°C) indicates that, as is the case for the 2-ethylhexyl-substituted alkylenediphosphonic acid analogs, the compounds are dimeric and (primarily) hexameric, respectively, in the concentration range investigated. Distribution ratio measurements for the alkaline earth cations Ca2+, Sr2+, Ba2+, and ...
22 citations
TL;DR: In this paper, conditions are defined for the efficient preparation of polyethers by direct condensation of ditosylates and alkoxides, and this approach is shown to provide a facile method for the synthesis of the trans-syntrans (C) and trans-anti-trans (D) isomers of DCH18C6.
5 citations
10 May 2001
TL;DR: In this paper, the effect of adding silicon-based functionalities to diphosphonic acids has been investigated, in conjunction with efforts to develop novel actinide extractants exhibiting solubility in supercritical carbon dioxide.
Abstract: In conjunction with efforts to develop novel actinide extractants exhibiting solubility in supercritical carbon dioxide, the effect of adding silicon-based functionalities to diphosphonic acids has been investigated. Specifically, a series of silyl-substituted diphosphonic acids has been prepared and characterized, and their aggregation and metal ion extraction properties compared with alkyl-substituted diphosphonic acids, reagents previously demonstrated to be effective extractants of actinides from acidic aqueous media into various organic solvents. In addition, the influence of the number of methylene groups bridging the phosphorus atoms of the diphosphonic acids on their extraction behavior has been investigated. Variations in the extraction behavior of the compounds arising from differences in the number of bridging methylene groups have been shown to be attributable to a combination of factors, in particular, the aggregation state of the ligand, the size of the chelate rings formed upon complexation, the basicity of the phosphoryl group and the relative acidities of the ligands.
2 citations