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Metal ion extraction by silyl-substituted diphosphonic acids. Part 1. P,P'-Di[3-(trimethylsilyl)-1-propylene] methylene- and ethylene- diphosphonic acids.

Journal Article · · Sep. Sci. Technol.

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 Laboratory (ANL)
Sponsoring Organization:
SC; EM
DOE Contract Number:
AC02-06CH11357
OSTI ID:
943069
Report Number(s):
ANL/CHM/JA-37266
Journal Information:
Sep. Sci. Technol., Journal Name: Sep. Sci. Technol. Journal Issue: 16 ; 2001 Vol. 36; ISSN 0149-6395; ISSN SSTEDS
Country of Publication:
United States
Language:
ENGLISH