Zhuoxi Li , Yuyu Liang , Xiang Li , Wanjun Mu , Baihua Chen , Jun Tu , Lina Lv , Yanqiu Yang , Xingliang Li
{"title":"钍(IV)与N-甲基乙二胺-N,N′，N′-三乙酸盐配合物在水溶液中的热力学:电位法和微量热法","authors":"Zhuoxi Li , Yuyu Liang , Xiang Li , Wanjun Mu , Baihua Chen , Jun Tu , Lina Lv , Yanqiu Yang , Xingliang Li","doi":"10.1016/j.nucana.2023.100082","DOIUrl":null,"url":null,"abstract":"<div><p>The thermodynamic parameters of the complexes of Th with <em>N</em>-methylethylenediamine-<em>N</em>,<em>Nʹ</em>,<em>N</em>ʹ-triacetic acid (MEDTA; denoted as H<sub>3</sub>L 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<sup>+</sup> and ThL<sub>2</sub><sup>2−</sup> (L<sup>3−</sup> denotes the totally deprotonated MEDTA). Results indicated that both complexation reactions were exothermic and driven by entropic force. The first stepwise reaction (Th<sup>4+</sup> + L<sup>3−</sup> = ThL<sup>+</sup>) was mainly driven by entropy with minimal effect on enthalpy change. The second stepwise reaction (ThL<sup>+</sup> + L<sup>3−</sup> = ThL<sub>2</sub><sup>2−</sup>) was more exothermic and showed less entropic change than the first stepwise reaction. The strong chelation of MEDTA would inhibit the hydrolysis of Th<sup>4+</sup> and increase solubility.</p></div>","PeriodicalId":100965,"journal":{"name":"Nuclear Analysis","volume":"2 3","pages":"Article 100082"},"PeriodicalIF":0.0000,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773183923000368/pdfft?md5=c4327bb66fe3968a08c1c752b7054164&pid=1-s2.0-S2773183923000368-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Thermodynamics of Thorium(IV) complexes with N-methylethylenediamine-N,Nʹ,Nʹ-triacetate in aqueous solutions: Potentiometry and microcalorimetry\",\"authors\":\"Zhuoxi Li , Yuyu Liang , Xiang Li , Wanjun Mu , Baihua Chen , Jun Tu , Lina Lv , Yanqiu Yang , Xingliang Li\",\"doi\":\"10.1016/j.nucana.2023.100082\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The thermodynamic parameters of the complexes of Th with <em>N</em>-methylethylenediamine-<em>N</em>,<em>Nʹ</em>,<em>N</em>ʹ-triacetic acid (MEDTA; denoted as H<sub>3</sub>L 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<sup>+</sup> and ThL<sub>2</sub><sup>2−</sup> (L<sup>3−</sup> denotes the totally deprotonated MEDTA). Results indicated that both complexation reactions were exothermic and driven by entropic force. The first stepwise reaction (Th<sup>4+</sup> + L<sup>3−</sup> = ThL<sup>+</sup>) was mainly driven by entropy with minimal effect on enthalpy change. The second stepwise reaction (ThL<sup>+</sup> + L<sup>3−</sup> = ThL<sub>2</sub><sup>2−</sup>) was more exothermic and showed less entropic change than the first stepwise reaction. The strong chelation of MEDTA would inhibit the hydrolysis of Th<sup>4+</sup> and increase solubility.</p></div>\",\"PeriodicalId\":100965,\"journal\":{\"name\":\"Nuclear Analysis\",\"volume\":\"2 3\",\"pages\":\"Article 100082\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2023-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S2773183923000368/pdfft?md5=c4327bb66fe3968a08c1c752b7054164&pid=1-s2.0-S2773183923000368-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nuclear Analysis\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2773183923000368\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nuclear Analysis","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2773183923000368","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
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 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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