Thermal Transformations of Radicals Derived from Nuclear Waste Separation Ligands Exposed to Radiation.

IF 2.7 2区 化学 Q3 CHEMISTRY, PHYSICAL
The Journal of Physical Chemistry A Pub Date : 2025-07-03 Epub Date: 2025-06-23 DOI:10.1021/acs.jpca.5c01863
Ilya S Sosulin, Aliaksandra Lisouskaya
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引用次数: 0

Abstract

The thermal evolution of electron-beam-induced radicals generated in neat di-n-butyl N,N-diethylcarbamoylphosphonate (DBDECP), N,N-bis(2-ethylhexyl)butanamide (DEHBA), dioctyl phosphate (DOP), tributyl phosphate (TBP), and N,N,N',N'-tetraoctyl diglycolamide (TODGA), and TBP/dodecane extraction system was investigated using electron paramagnetic resonance (EPR) spectroscopy over the temperature range of 108-220 K. Density functional theory (DFT) calculations were employed to support the experimental results, clarifying radical structures and energetics of their thermal transformations. The stability of radicals as temperature increased varied significantly depending on the ligand structure. The diglycol- or amide-centered radicals, such as those found in TODGA and DEHBA, exhibited higher thermal stability than the alkyl radicals. This increased stability is attributed to the greater steric hindrance in the latter species. Calculated energy barriers (∼20 kcal/mol) suggested that thermal evolution predominantly involves conformational rearrangements of the radicals, rather than transformations of the radical structure itself. Additionally, trace amounts of oxygen led to the conversion of carbon-centered radicals into peroxide radicals during thermal annealing. The peroxide radicals formed decomposed more rapidly at elevated temperatures. This study provides important mechanistic insights into the radiolytic degradation of nuclear waste extraction ligands, helping to advance the development of more radiation-resistant solvents for nuclear waste separation processes.

辐照下核废料分离配体自由基的热转化。
采用电子顺磁共振(EPR)技术,在108 ~ 220 K温度范围内研究了纯二正丁基N、N-二乙基氨基膦酸盐(DBDECP)、N,N-二(2-乙基己基)丁酰胺(DEHBA)、磷酸二辛酯(DOP)、磷酸三丁酯(TBP)、N,N,N′,N′-四辛基二甘醇酰胺(TODGA)和TBP/十二烷萃取体系中电子束诱导自由基的热演化过程。采用密度泛函理论(DFT)计算支持实验结果,澄清了自由基结构及其热转化的能量学。随着温度的升高,自由基的稳定性随配体结构的不同而发生显著变化。在TODGA和DEHBA中发现的以二甘醇或酰胺为中心的自由基比烷基自由基表现出更高的热稳定性。这种增加的稳定性归因于后一种中较大的位阻。计算的能垒(~ 20 kcal/mol)表明,热演化主要涉及自由基的构象重排,而不是自由基结构本身的转变。此外,在热处理过程中,微量的氧导致碳中心自由基转化为过氧化物自由基。过氧化氢自由基在高温下分解得更快。该研究为核废料提取配体的放射性降解提供了重要的机理见解,有助于推进核废料分离过程中耐辐射溶剂的开发。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
The Journal of Physical Chemistry A
The Journal of Physical Chemistry A 化学-物理:原子、分子和化学物理
CiteScore
5.20
自引率
10.30%
发文量
922
审稿时长
1.3 months
期刊介绍: The Journal of Physical Chemistry A is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, and chemical physicists.
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