The Hydrolysis of Hydroxamic Acid Complexants in the Presence of Non-Oxidizing Metal Ions 2: Neptunium (IV) Ions
The Hydrolysis of Hydroxamic Acid Complexants in the Presence of Non-Oxidizing Metal Ions 2: Neptunium (IV) Ions
复制标题
非氧化性金属离子存在下异羟肟酸络合剂的水解 2：镎 (IV) 离子
DOI：
10.1007/s10953-007-9225-3
复制
发表时间：
2008
影响因子：
1.2
通讯作者：
R. Taylor
中科院分区：
文献类型：
--
作者：
Fabrice P. L. Andrieux;C. Boxall;I. May;R. Taylor
摘要
异羟肟酸是一种不含盐的有机化合物，对Fe 3+、Np 4+和Pu 4+等阳离子具有亲和力，已被确定为先进核燃料后处理中控制Pu和Np的合适试剂。使用形态图对甲氧肟酸和乙酰氧肟酸（FHA、AHA）与Np（IV）离子之间形成的1：1和2：1复合物进行紫外可见、近红外分光光度研究的结果进行解释，以识别不同pH值和配体与金属比下存在的物质。动力学模型描述了由于异羟肟酸部分的水解导致的络合物的不稳定性，该动力学模型先前针对Fe（III）-AHA络合物开发（Andrieux et al. 36：1201-1217，[2007]），在此针对实验Np（IV）-FHA数据进行测试。因此，在硝酸中形成1：1 Np（IV）-FHA络合物的络合常数估计为K1=2715，表明络合作用可保护配体在0.1>pH>−0.1时不被水解。
Abstract
Hydroxamic acids are salt free, organic compounds with affinities for cations such as Fe3+, Np4+ and Pu4+, and have been identified as suitable reagents for the control of Pu and Np in advanced nuclear fuel reprocessing. The results of a UV-visible, near-IR spectrophotometric study of the 1:1 and 2:1 complexes formed between formo- and aceto-hydroxamic acids (FHA, AHA) and Np(IV) ions are interpreted using speciation diagrams for the identification of the species present at different pH and ligand to metal ratios. A kinetic model that describes the instability of the complex due to hydrolysis of the hydroxamate moiety, previously developed for the Fe(III)-AHA complexes (Andrieux et al. in J. Solution Chem. 36:1201–1217, [2007]), is tested here against experimental Np(IV)-FHA data. Consequently, the complexation constant for formation of the 1:1 Np(IV)-FHA complex in nitric acid is estimated at K1=2715 and indications are that complexation protects the ligand against hydrolysis at 0.1>pH>−0.1.