Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry

The thermodynamic parameters of the complexes of Th with N-methylethylenediamine-N,Nʹ,Nʹ-triacetic acid (MEDTA; denoted as H3L with three dissociable protons) were studied. Potentiometry and microcalorimetry were used to determine formation constants and enthalpies, respectively. Thermodynamic analy...

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Main Authors: Zhuoxi Li, Yuyu Liang, Xiang Li, Wanjun Mu, Baihua Chen, Jun Tu, Lina Lv, Yanqiu Yang, Xingliang Li
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2023-09-01
Series:Nuclear Analysis
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Online Access:http://www.sciencedirect.com/science/article/pii/S2773183923000368
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author Zhuoxi Li
Yuyu Liang
Xiang Li
Wanjun Mu
Baihua Chen
Jun Tu
Lina Lv
Yanqiu Yang
Xingliang Li
author_facet Zhuoxi Li
Yuyu Liang
Xiang Li
Wanjun Mu
Baihua Chen
Jun Tu
Lina Lv
Yanqiu Yang
Xingliang Li
author_sort Zhuoxi Li
collection DOAJ
description The thermodynamic parameters of the complexes of Th with N-methylethylenediamine-N,Nʹ,Nʹ-triacetic acid (MEDTA; denoted as H3L with three dissociable protons) were studied. Potentiometry and microcalorimetry were used to determine formation constants and enthalpies, respectively. Thermodynamic analysis revealed two successively formed complexes, namely, ThL+ and ThL22− (L3− denotes the totally deprotonated MEDTA). Results indicated that both complexation reactions were exothermic and driven by entropic force. The first stepwise reaction (Th4+ ​+ ​L3− = ThL+) was mainly driven by entropy with minimal effect on enthalpy change. The second stepwise reaction (ThL+ ​+ ​L3− = ThL22−) was more exothermic and showed less entropic change than the first stepwise reaction. The strong chelation of MEDTA would inhibit the hydrolysis of Th4+ and increase solubility.
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institution Kabale University
issn 2773-1839
language English
publishDate 2023-09-01
publisher KeAi Communications Co., Ltd.
record_format Article
series Nuclear Analysis
spelling doaj-art-962a3138ac124edca81f902452c76fde2025-08-20T03:42:56ZengKeAi Communications Co., Ltd.Nuclear Analysis2773-18392023-09-012310008210.1016/j.nucana.2023.100082Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetryZhuoxi Li0Yuyu Liang1Xiang Li2Wanjun Mu3Baihua Chen4Jun Tu5Lina Lv6Yanqiu Yang7Xingliang Li8Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Graduate School of China Academy of Engineering Physics, Mianyang, Sichuan, 621999, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Graduate School of China Academy of Engineering Physics, Mianyang, Sichuan, 621999, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Graduate School of China Academy of Engineering Physics, Mianyang, Sichuan, 621999, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Corresponding author.Fundamental Science on Nuclear Wastes and Environment Safety Laboratory, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, ChinaInstitute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621999, China; Corresponding author.The thermodynamic parameters of the complexes of Th with N-methylethylenediamine-N,Nʹ,Nʹ-triacetic acid (MEDTA; denoted as H3L with three dissociable protons) were studied. Potentiometry and microcalorimetry were used to determine formation constants and enthalpies, respectively. Thermodynamic analysis revealed two successively formed complexes, namely, ThL+ and ThL22− (L3− denotes the totally deprotonated MEDTA). Results indicated that both complexation reactions were exothermic and driven by entropic force. The first stepwise reaction (Th4+ ​+ ​L3− = ThL+) was mainly driven by entropy with minimal effect on enthalpy change. The second stepwise reaction (ThL+ ​+ ​L3− = ThL22−) was more exothermic and showed less entropic change than the first stepwise reaction. The strong chelation of MEDTA would inhibit the hydrolysis of Th4+ and increase solubility.http://www.sciencedirect.com/science/article/pii/S2773183923000368ThermodynamicsThoriumN-Methylethylenediamine-N,Nʹ,Nʹ-triacetic acid
spellingShingle Zhuoxi Li
Yuyu Liang
Xiang Li
Wanjun Mu
Baihua Chen
Jun Tu
Lina Lv
Yanqiu Yang
Xingliang Li
Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry
Nuclear Analysis
Thermodynamics
Thorium
N-Methylethylenediamine-N,Nʹ,Nʹ-triacetic acid
title Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry
title_full Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry
title_fullStr Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry
title_full_unstemmed Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry
title_short Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry
title_sort thermodynamics of thorium iv complexes with n methylethylenediamine n n n triacetate in aqueous solutions potentiometry and microcalorimetry
topic Thermodynamics
Thorium
N-Methylethylenediamine-N,Nʹ,Nʹ-triacetic acid
url http://www.sciencedirect.com/science/article/pii/S2773183923000368
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