Deuterated malonamide synthesis for fundamental research on solvent extraction systems

Micheau, C.; 上田 祐生; 阿久津 和宏*; Bourgeois, D.*; 元川 竜平

Solvent Extraction and Ion Exchange, 41(2), p.221 - 240, 2023/02

https://doi.org/10.1080/07366299.2023.2166351

Malonamide derivatives, which are among the most extensively investigated extractants in solvent extraction of lanthanoids, actinides, and platinum group metal ions, were deuterated by using Pd/C and Rh/C catalysts with a DO/2-propanol mixture. This method enables to replace the hydrogen atoms by deuterium atoms in the malonamide chemical structure with a controllable deuteration rate. The maximum rate reaches 75 percent approximately, determined by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry. In addition, it has been demonstrated that extraction behavior of the malonamide molecules remains unchanged after the deuteration procedure. Deuterated malonamides should be a powerful tool for fundamental researches on solvent extraction systems, in particular, for structural analysis of the organic phases. The large difference in the neutron scattering cross-section between hydrogen and deuterium leads to a large difference in neutron scattering length density of the malonamide derivatives before and after the deuteration reaction. Therefore, using deuterated malonamides in small-angle neutron scattering and neutron reflectivity studies could give access to the nanoscopic structure of the specific solute species in the bulk organic phase and at the liquid-liquid interface, respectively. This deuteration method could become a general one and be extended to a wide variety of extractant molecules. In this way this work contributes to the development of the fundamental researches in solvent extraction systems.

Structure analysis of a buried interface between organic and porous inorganic layers using spin-contrast-variation neutron reflectivity

熊田 高之; 三浦 大輔*; 阿久津 和宏*; 大石 一城*; 森川 利明*; 河村 幸彦*; 鈴木 淳市*; 奥 隆之; 鳥飼 直也*; 新関 智丈*

Journal of Applied Crystallography, 55(5), p.1147 - 1153, 2022/10

AA2021-0903.pdf:1.06MB

https://doi.org/10.1107/S1600576722007506

スピンコントラスト変調中性子反射率法は一つの試料一つのビームラインから複数の反射率曲線が得られる手法である。我々はその特徴を生かしてメチル化ポリシラザンから作られた多孔質シリカ界面においてアクリルウレタン樹脂は多孔質体内に入り込まないことを見出した。

Spin glass behavior and magnetic boson peak in a structural glass of a magnetic ionic liquid

古府 麻衣子; 綿貫 竜太*; 榊原 俊郎*; 河村 聖子; 中島 健次; 松浦 直人*; 上木 岳士*; 阿久津 和宏*; 山室 修*

Scientific Reports (Internet), 11(1), p.12098_1 - 12098_8, 2021/06

https://doi.org/10.1038/s41598-021-91619-z

Glassy magnetic behavior has been observed in a wide range of crystalline magnetic materials called spin glass. Here, we report spin glass behavior in a structural glass of a magnetic ionic liquid, C4mimFeCl. Magnetization measurements demonstrate that an antiferromagnetic ordering occurs at = 2.3 K in the crystalline state, while a spin glass transition occurs at = 0.4 K in the structural glass state. In addition, localized magnetic excitations were found in the spin glass state by inelastic neutron scattering, in contrast to spin-wave excitations in the ordered phase of the crystalline sample. The localized excitation was scaled by the Bose population factor below and gradually disappeared above . This feature is highly reminiscent of boson peaks commonly observed in structural glasses. We suggest the "magnetic" boson peak to be one of the inherent dynamics of a spin glass state.

Development of spin-contrast-variation neutron reflectometry

熊田 高之; 阿久津 和宏*; 大石 一城*; 森川 利明*; 河村 幸彦*; 佐原 雅恵*; 鈴木 淳市*; 三浦 大輔*; 鳥飼 直也*

J-PARC 20-02; J-PARC MLF Annual Report 2019, p.38 - 40, 2021/00

https://j-parc.jp/researcher/MatLife/ja/publication/files/MLF-AR_2019.pdf

Neutron reflectivity (NR) is used to determine the nanostructure of surfaces and interfaces of thin film samples. NR has an ad-vantage over X-ray reflectivity for measuring deeply-buried interface of materials. However, it is difficult to determine the structure of complex multiple surface and interfaces of the thin film from a single reflectivity curve. To overcome the problem, we developed a new technique called spin-contrast-variation neutron reflectometry (SCV-NR), which utilizes the property that coherent polarized-neutron scattering length of a proton remarkably varies as a function of the proton polarization, PH, against the neutron polarization direction. As PH increases, the scattering length density (SLD) of each layer proportionally increases with the number density of protons, resulting in the variation of NR curves. The structure of multiple surface and interfaces of a thin film can be determined from the multiple curves.

Fine-structure analysis of perhydropolysilazane-derived nano layers in deep-buried condition using polarized neutron reflectometry

阿久津 和宏*; 吉良 弘*; 宮田 登*; 花島 隆泰*; 宮崎 司*; 笠井 聡*; 山崎 大; 曽山 和彦; 青木 裕之

Polymers (Internet), 12(10), p.2180_1 - 2180_10, 2020/10

https://doi.org/10.3390/polym12102180

A large background scattering originating from the sample matrix is a major obstacle for fine-structure analysis of a nanometric layer buried in a bulk material. As polarization analysis can decrease undesired scattering in a neutron reflectivity (NR) profile, we performed NR experiments with polarization analysis on a polypropylene (PP)/perhydropolysilazane-derived SiO (PDS)/Si substrate sample, having a deep-buried layer of SiO to elucidate the fine structure of the nano-PDS layer. This method offers unique possibilities for increasing the amplitude of the Kiessig fringes in the higher scattering vector (Qz) region of the NR profiles in the sample by decreasing the undesired background scattering. Fitting and Fourier transform analysis results of the NR data indicated that the synthesized PDS layer remained between the PP plate and Si substrate with a thickness of approximately 109 ;. Furthermore, the scattering length density of the PDS layer, obtained from the background subtracted data appeared to be more accurate than that obtained from the raw data. Although the density of the PDS layer was lower than that of natural SiO, the PDS thin layer had adequate mechanical strength to maintain a uniform PDS layer in the depth-direction under the deep-buried condition.

Controlled deuterium labelling of imidazolium ionic liquids to probe the fine structure of the electrical double layer using neutron reflectometry

阿久津 和宏*; Cagnes, M.*; 田村 和久; 金谷 利治*; Darwish, T. A.*

Physical Chemistry Chemical Physics, 21(32), p.17512 - 17516, 2019/08

https://doi.org/10.1039/C9CP02479D

本研究で、イオン液体中で形成される電気二重層の構造を決定するための、重水素化技術と中性子反射測定を組み合わせた手法を確立した。そのために、本研究において、選択的に簡素かつ大量に重水素化する方法を開発した。

Development of high-polarization Fe/Ge neutron polarizing supermirror; Possibility of fine-tuning of scattering length density in ion beam sputtering

丸山 龍治; 山崎 大; 阿久津 和宏*; 花島 隆泰*; 宮田 登*; 青木 裕之; 武田 全康; 曽山 和彦

Nuclear Instruments and Methods in Physics Research A, 888, p.70 - 78, 2018/04

https://doi.org/10.1016/j.nima.2018.01.068

イオンビームスパッタ法で成膜されたFe/Si及びFe/Ge多層膜に対して、X線及び偏極中性子反射率、走査型透過電子顕微鏡と組み合わされたエネルギー分散型X線分光分析等のプローブによって層構造や局所元素分析を行った。その結果、Fe/Ge多層膜のGe層に含まれたスパッタリングガスであるArが含まれることにより、Ge層の散乱長密度が減少し、(-)スピンの中性子に対するFeとGeの散乱長密度のコントラストがほぼ消失し偏極中性子反射において高偏極率となることがわかった。Ge層に含まれるArは、成膜時においてAeがGeターゲットで後方散乱することに起因することが知られており、偏極スーパーミラーの高偏極率化に必要な(-)スピン中性子に対する散乱長密度コントラストを微調整する新たな手法となる可能性を示すものである。この結果を基に、Niの5倍の全反射臨界角をもつFe/Ge偏極スーパーミラーを成膜し偏極反射率測定を行った結果、(+)スピン中性子の反射率が0.70以上、偏極率はビームラインの偏極性能が正しく補正されている領域においては0.985以上という高い偏極率を達成した。

A Novel microemulsion phase transition; Toward the elucidation of third-phase formation in spent nuclear fuel reprocessing

Mu, J.*; 元川 竜平; 阿久津 和宏*; 西辻 祥太郎*; Masters, A. J.*

Journal of Physical Chemistry B, 122(4), p.1439 - 1452, 2018/02

https://doi.org/10.1021/acs.jpcb.7b08515

We present evidence that the transition between organic and third phases, which is an unusual transition between two isotropic, bi-continuous micro-emulsion phases. This system contains quaternary; water, n-dodecane, nitric acid, tributyl phosphate (TBP). This quaternary system has been shown to exhibit, under appropriate conditions, three coexisting phases: a light organic phase, an aqueous phase, and the so-called third phase. In this work, we focused on the coexistence of the light organic phase with the third phase using methods of molecular dynamics (MD) simulation and small-angle X-ray scattering (SAXS). Snapshots from the MD simulations as well as a cluster analysis of the organic and third phases revealed structures akin to bi-continuous micro-emulsion phases, with the polar species residing within a mesh, and with the surface of the mesh formed by amphiphilic TBP molecules. The non-polar n-dodecane molecules were observed in these snapshots to be outside this mesh. The only large-scale structural differences observed between the two phases were the dimensions of the mesh. Evidence for the correctness of these structures was provided by the results of SAXS studies, where the profiles obtained for both the organic and third phases agreed well with those calculated from simulation.

Comparative molecular dynamics study on tri--butyl phosphate in organic and aqueous environments and its relevance to nuclear extraction processes

Mu, J.*; 元川 竜平; Williams, C. D.*; 阿久津 和宏*; 西辻 祥太郎*; Masters, A. J.*

Journal of Physical Chemistry B, 120(23), p.5183 - 5193, 2016/06

https://doi.org/10.1021/acs.jpcb.6b00781

A refined model for tri--butyl phosphate (TBP), which uses a new set of partial charges generated from our ab initio density functional theory calculations, has been proposed in this study. Molecular dynamics simulations are conducted to determine the thermodynamic properties, transport properties, and the microscopic structures of liquid TBP, TBP/water mixtures, and TBP/-alkane mixtures. These results are compared with those obtained from four other TBP models, previously described in the literature. We conclude that our refined TBP model appears to be the only TBP model from this set that, with reasonable accuracy, can simultaneously predict the properties of TBP in bulk TBP, in organic diluents, and in aqueous solution. This new TBP model is thus appropriate for the simulation of liquid-liquid extraction systems in the nuclear extraction process, where one needs to simultaneously model TBP in both aqueous and organic phases. It is also promising for the investigation of the microscopic structure of the organic phase in these processes and for the characterization of third-phase formation, where TBP again interacts simultaneously with both polar and nonpolar molecules. Because the proposed TBP model uses OPLS-2005 Lennard-Jones parameters, it may be used with confidence to model mixtures of TBP with other species whose parameters are given by the OPLS-2005 force field.

J-PARCにおけるパルス中性子ビームの利用と展望,1; 中性子ビームの特徴と結晶構造解析

阿久津 和宏*; 大原 高志

ぶんせき, 2014(11), p.617 - 621, 2014/11

http://ci.nii.ac.jp/naid/40020264408

J-PARCのMLFでは現在18本の中性子ビームラインに実験装置が設置され、世界最高強度のパルス中性子ビームを用いた学術研究や産業利用が行われている。本稿では、J-PARCおよびMLFの中性子実験施設の概要、中性子の特徴を紹介するとともに、中性子実験装置の一つである単結晶回折計「千手」の特徴に触れながら中性子結晶構造解析について説明する。