Modeling of protonation constants of linear aliphatic dicarboxylates containing -S-groups in aqueous chloride salt solutions, at different ionic strengths, using the SIT and pitzer equations and empirical relationships

Clemente Bretti, Concetta De Stefano, Frank J. Millero, Silvio Sammartano

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

The protonation constants of ethylenedithiodiacetic, dithiodipropionic and dithiodibutyric acids were obtained from potentiometric measurements in NaCl(aq) (I ≤ 5 mol̇L-1) and (CH3)4NCl(aq) (I ≤ 3 mol̇L-1) at t=25∈°C. Their dependences on ionic strength were modeled by the SIT and Pitzer approaches. The activity coefficients of the neutral species were obtained by solubility measurements. The literature values of the protonation constants of (HOOC)-(CH2) n -S-(CH2) n -(COOH) (n=1 to 3) and (HOOC)-(CH2)-S-(CH2) n -S-(CH 2)-(COOH) (n=0 to 5) in NaCl(aq) and KCl(aq) (I ≤ 3 mol̇L -1) at 18∈°C were also analyzed using the above approaches. Both the log∈10 K i H and interaction parameter values follow simple linear trends as a function of certain structural characteristics of the ligands. Examples of modeling these trends are reported.

Original languageEnglish (US)
Pages (from-to)763-784
Number of pages22
JournalJournal of Solution Chemistry
Volume37
Issue number6
DOIs
StatePublished - Jun 1 2008

Keywords

  • Activity coefficients
  • Empirical relationships
  • Protonation constants
  • SIT and Pitzer models
  • Solubility
  • Thioacetates

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Physical and Theoretical Chemistry

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