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Simonnet, M.; 小林 徹; 下条 晃司郎; 横山 啓一; 矢板 毅
Inorganic Chemistry, 60(17), p.13409 - 13418, 2021/09
被引用回数：17 パーセンタイル：88.1(Chemistry, Inorganic & Nuclear)Phenanthroline carboxamide compounds are promising for lanthanide intra-series separation. This paper presents a study on the effect of structure modification of phenanthroline carboxamides onto the extraction of the whole lanthanide series. The study consists in theoretical calculations, extraction experiments of the 14 stable lanthanides and EXAFS analyses of Nd and Dy complexes. The comparison of the tridentate monocarboxamides and the tetradentate dicarboxamides shows different trend in the series extraction, although both preferentially extract the light lanthanides. The amide substituents, although not directly coordinating the metal ions, were also found to impact the distribution ratio, most probably due to a modification in the internal polarity of the molecules. This latter effect, if extrapolated to other nitrogen-based ligands such as pyridines or triazines, can be used to further fine-tune extractants for a process improvement.
Simonnet, M.; 鈴木 伸一; 宮崎 有史*; 小林 徹; 横山 啓一; 矢板 毅
Solvent Extraction and Ion Exchange, 38(4), p.430 - 440, 2020/00
被引用回数：18 パーセンタイル：69.03(Chemistry, Multidisciplinary)Separation of lanthanides is especially challenging because of their chemical similarities. Therefore, improving the separation process is essential. In this work, we present the effect of the counterion nature on the lanthanide extraction by a 1,10-phenanthroline derivative, the 
-octyl--tolyl-1,10-phenanthroline-2-carboxamide. Modification of the counterion yields a drastic change in selectivity, with a shift in the maximum of extraction from the light lanthanides (Pr, Nd, Sm) in nitrate system to the heavy lanthanides (Dy, Ho) in perchlorate system. Other salts (NaCl, NaNO
) showed a gradual increase in extraction along the whole lanthanide series, or no effect (NaSO
). The difference was explained by different coordination in the organic phase. The reversed behaviour depending on the anion is especially interesting because a cycling extraction/back-extraction of light lanthanides in nitrate/chloride media or a cycling extraction/back-extraction of heavy lanthanides in perchlorate/nitrate media can enhance the separation factors of respectively Nd and Dy/Ho.
米澤 仲四郎; 星 三千男; 立川 圓造
Anal. Chem., 57, p.2901 - 2965, 1985/00
被引用回数：69 パーセンタイル：94.52(Chemistry, Analytical)原子炉の放射性腐食生成物(CRVD)中の
Feの放射能とそのFe量を同一の化学操作で簡単に測定できる方法を確立した。Fe-バトフェナントロリン(BPT)錯体を液体シンチレータ(PPO-キシレン)で抽出し、その液体シンチレーション測定によりFeの放射能を求め、吸光度測定によりFe量を求める。Feは過塩素酸イオン存在下でPPO-キシレン中にFe-BPT錯体と過塩素酸イオンとのイオン会合体として、PH=3~8の範囲で定量的に抽出された。抽出液の吸収極大とモル吸光係数(
)は535nmおよび22000であった。本法はFe量30
g/10ml(有機相中)までベールの法則に従った。液体シンチレーション測定により、Feの放射能は最大62%の計数効率で測定出来た。
CoはFeと同様に抽出されるが、PH=6.0のEDTA溶液と振り混ぜる事により逆抽出された。共存する元素および放射性核種の影響を調べ、CRUDの分析に適用した。
and lanthanide series elements亀澤 明憲*; 鈴木 伸一; 小林 徹; 末木 啓介*
no journal, ,
A solvent extraction method is one of the useful technique for the selective separation of minor actinides and lanthanides from high level radioactive waste. Therefore, it is required to advance the performance of an extraction agent. However, extraction mechanisms for the desirable separation ability are still unclear. In the present study, we focused on the certain ligands which contain tridentate coordination site as 2-(1,2,4-triazine-3-yl) 1,10-phenanthroline (TPhen). Partitioning experiments by such ligands were hardly investigated. We synthesized three TPhen ligands having different substituents (methyl group, ethyl group, phenyl group) of each triazine ring at 5,6-position. Three types of ligands were synthesized from 1,10-phenanthroline-2-carboxamidehydrazone with 
-diketone following known procedures. All the ligands were obtained as hydrates identified by NMR and elementary analysis. All the reaction yields were 40 
50 %. The ligand protonation and complexation equilibria were determined by UV-Vis spectroscopic titrations with Eu or H
in acetonitrile solution. The extraction experiments of americium and lanthanide series elements except for promethium were performed with changing the nitric acid concentration, the ligand concentration and the organic phase compositions. And then the distribution ratios of these elements between two phases and separation factors (SF
) were determined.
Simonnet, M.; 小林 徹; 鈴木 伸一; 矢板 毅
no journal, ,
Efficient separation of rare-earth elements has recently been under a renewed interest. One of the most common elemental separation method is liquid-liquid extraction, for which the state of the art is wide due to the similarities with the studies on actinides separation from lanthanides. Therefore, many different extractants can be found in literature, among which 1,10-phenanthroline-based ligands have shown a strong ability for the extraction of trivalent elements. In this study, we focused on 1,10-phenanthroline carboxamide compounds, because they can selectively extract one lanthanide from the series, with the nature of this lanthanide dependent on the extractant structure. Some compounds were tested in different media, and it was found that the nature of the diluent and the composition of the aqueous feed also yield to a maximum shift among the lanthanide series. This study thus aims at emphasizing diluent effect on lanthanide extraction by 1,10-phenanthroline carboxamide ligands.
矢板 毅; 小林 徹; Shuh, D.*; 浅野 永遠*; 森 敦紀*
no journal, ,
We have been new synthesized phenanthroline amide derivatives (phenanthroline amide: PTA) with N and O as donor elements for these purposes. These ligands achieve separation of a special f-element by recognize slight size differences or utilize differences in their interactions with the donor elements. In this talk, the chemical bonding properties of phenanthroline ligands to actinides and lanthanides by XAS/XES and RIXS using soft X-rays, the structural properties of tridentate and tetradentate PTA derivatives by single crystal structural analysis and EXAFS, respectively, will be presented. Taken together, the mechanisms governing ion recognition of PTA derivatives will be reported.
