Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids

Tian, Guoxin; Rao, Linfeng

Title: Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids

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Abstract

The protonation reactions of two ligands that play important roles in the TALSPEAK process for the separation of trivalent actinides from lanthanides, lactic acid and diethylenetrinitropentaacetic acid (DTPA), have been studied at variable temperatures. The protonation constants at 10-70 C were determined by titration potentiometry and the protonation enthalpies were determined at 25 C by titration microcalorimetry. The protonation constants remain essentially unchanged (25-70 C) within the experimental uncertainties, indicating that the effect of temperature on the protonation of lactate is insignificant. In contrast, the protonation constants of DTPA (log {beta}H's) generally decrease as the temperature is increased. Results from this study indicate that the effect of temperature on the protonation of DTPA could alter the speciation of metal ions (actinides and lanthanides) in the TALSPEAK system, since lower values of log{beta}H at higher temperatures suggest that the hydrogen ions would compete less strongly with the metal ions for the complexation of DTPA at higher temperatures.

Authors:: Tian, Guoxin; Rao, Linfeng

Publication Date:: Tue Oct 20 00:00:00 EDT 2009

Research Org.:: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: Chemical Sciences Division

OSTI Identifier:: 1004154

Report Number(s):: LBNL-2766E
Journal ID: ISSN 0149-6395; SSTEDS; TRN: US1100610

DOE Contract Number:: DE-AC02-05CH11231

Resource Type:: Journal Article

Journal Name:: Separation Science and Technology

Additional Journal Information:: Journal Name: Separation Science and Technology; Journal ID: ISSN 0149-6395

Country of Publication:: United States

Language:: English

Subject:: 37; ACTINIDES; HYDROGEN IONS; LACTATES; LACTIC ACID; POTENTIOMETRY; RARE EARTHS; TALSPEAK PROCESS; TITRATION

Citation Formats


                    Tian, Guoxin, and Rao, Linfeng. Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids.  United States: N. p., 2009. 
        Web.

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                    Tian, Guoxin, & Rao, Linfeng. Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids.  United States.

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                    Tian, Guoxin, and Rao, Linfeng. 2009.  
        "Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids".  United States.  https://www.osti.gov/servlets/purl/1004154.

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@article{osti_1004154,

  title        = {Effect of Temperature on the Protonation of the TALSPEAK Ligands: Lactic and Diethylenetrinitropentaacetic Acids},

  author       = {Tian, Guoxin and Rao, Linfeng},

  abstractNote = {The protonation reactions of two ligands that play important roles in the TALSPEAK process for the separation of trivalent actinides from lanthanides, lactic acid and diethylenetrinitropentaacetic acid (DTPA), have been studied at variable temperatures. The protonation constants at 10-70 C were determined by titration potentiometry and the protonation enthalpies were determined at 25 C by titration microcalorimetry. The protonation constants remain essentially unchanged (25-70 C) within the experimental uncertainties, indicating that the effect of temperature on the protonation of lactate is insignificant. In contrast, the protonation constants of DTPA (log {beta}H's) generally decrease as the temperature is increased. Results from this study indicate that the effect of temperature on the protonation of DTPA could alter the speciation of metal ions (actinides and lanthanides) in the TALSPEAK system, since lower values of log{beta}H at higher temperatures suggest that the hydrogen ions would compete less strongly with the metal ions for the complexation of DTPA at higher temperatures.},

  doi          = {},

  url          = {https://www.osti.gov/biblio/1004154},
  journal      = {Separation Science and Technology},

  issn         = {0149-6395},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Tue Oct 20 00:00:00 EDT 2009},

  month        = {Tue Oct 20 00:00:00 EDT 2009}

}

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