1990 Fiscal Year Final Research Report Summary
Mechanism of the Substitution Reaction of Technetium Bata-Diketone Complexes.
| Project/Area Number |
01470045
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機・錯塩・放射化学
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| Research Institution | Tohoku Univeristy |
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Principal Investigator |
OMORI Takashi Tohoku Univ., Faculty of Science, Associate Professor, 理学部, 助教授 (80004349)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Technetium (III) Complexes / Acetylacetone Complexes / Acetonitrile / Thiourea Complexes / EDTA Complexes / Base Hydrolysis Reaction / Solvent Extraction With TBP / Extraction From Perchloric Acid |
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| Research Abstract |
Technetiumu complexes have been interested in the field of the coordination chemistry and radiopharmaceuticals. Since no stable isotopes exist in technetium, the serious problem that radioactive technetium is recovered from waste solution should be solved as an urgent project. The present studies have been carried out from these view points.
1. Tris (acetylacetonato) technetium (III) which is substituion-inert is base-hydrolyzed in an alkaline solution even at room temperature. The reaction mechanism of base-hydrolysis has been established.
2. A preliminary research showed that a ligand molecule in tris (acetylacetonato) technetium (III) is replaced by acetonitrile in the presence of a strong acid. The solvent substitution reaction gives bis (acetonitrile) bis (acetylacetonato) technetium (III) with a rate of 8.86 x10^<-4> s^<-1> at 30^ﾟC. The complex was isolated as perchlorate, of which identification was done by means of IR spectroscopy and elemental analysis.
3. The mechanism of the formation reaction of technetium (III) -EDTA complex was clarified by the ligand substitution reaction of hexakis (thioureato) technetium (III) ion with EDTA.
4. The concentration and separation of technetium from the radioactive waste solution containing other metal ions was established on an anion-exchange column. Furthermore, the concentration process of pertechnetate ion eluted with a perchloric acid solution from the column was examined by means of solvent extraction using TBP. Dependence of the concentration of acid and TBP on the distribution ratio of pertechnetate was studied using carbon tetrachloride or cyclohexane as a diluent.
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