Metal ion extraction by silyl-substituted diphosphonic acids. Part 1. P,P'-Di[3-(trimethylsilyl)-1-propylene] methylene- and ethylene- diphosphonic acids.
In conjunction with efforts to develop novel actinide extractants that exhibit solubility in supercritical carbon dioxide (SCCO{sub 2}), 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{prime}-di[3-(trimethylsilyl)-1-propylene] methylenediphosphonic acid (H{sub 2}DTMSP[MDP]) and P,P{prime}-di[3-(trimethylsilyl)-1-propylene] ethylenediphosphonic acid (H{sub 2}DTMSP[EDP]), were prepared and their aggregation and metal ion extraction properties compared to those of the previously studied P,P{prime}-di(2-ethylhexyl) alkylenediphosphonic acids. Vapor pressure osmometry of H{sub 2}DTMSP[MDP] and H{sub 2}DTMSP[EDP] in toluene (25{sup o}C) indicates that, as is the case for the 2-ethylhexyl-substituted alkylene diphosphonic acid analogs, the compounds are dimeric and (primarily) hexameric, respectively, in the concentration range investigated. Distribution ratio measurements for the alkaline earth cations Ca{sup 2+}, Sr{sup 2+}, Ba{sup 2+}, and Ra{sup 2+} as well as the representative tri-, tetra-, and hexavalent actinides Am{sup 3+}, Th{sup 4+}, and UO{sup 2+}{sub 2} between solutions of H{sub 2}DTMSP[MDP] and H{sub 2}DTMSP[EDP] in o-xylene and nitric acid indicate that the behavior of these silyl-derivatized compounds closely mimics that of the analogous P,P{prime}-di(2-ethylhexyl) alkylenediphosphonic acids, indicating that incorporation of a silyl functionality has no adverse impact on the metal ion extraction properties of diphosphonic acids.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); EM
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 943069
- Report Number(s):
- ANL/CHM/JA-37266; SSTEDS; TRN: US1000534
- Journal Information:
- Sep. Sci. Technol., Vol. 36, Issue 16 ; 2001; ISSN 0149-6395
- Country of Publication:
- United States
- Language:
- ENGLISH
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