Activity Coefficients of NaBr in Aqueous Mixtures with High Relative Permittivity Cosolvent: Ethylene Carbonate + Water at 298.15 K

This article focuses on measuring and modeling activity coefficients and some thermodynamic properties of the quaternary system (NaCl + KCl + N,N-dimethylformamide (DMF) + H 2 O) using a potentiometric technique at (298.15 ± 0.05) K. By employing ion-selective electrodes (Na + -ISE, Cl − -ISE), experimental results were collated for the four series of the mixed electrolyte systems in various ionic strengths for the investigated quaternary system. The electrochemical measurements were carried out over total ionic strengths range from 0.0249 up to about 3.8223 mol•kg −1 in mixed N,N-dimethylformamide + H 2 O solvents, with various solvent mass percents (wt % = 0.0, 0.10, 0.20, and 0.30) at 298.15 ± 0.05 K. Experimental data were modeled on the basis of the Pitzer approach, and the two and three particles mixing ionic interaction parameters (θ NaK and ψ NaKCl ) estimated for the quaternary electrolyte systems under investigation. Finally, using the optimized parameters (θ NaK and ψ NaKCl ), the thermodynamic properties of electrolyte systems, such as activity coefficients of the constituent's electrolyte, osmotic coefficients, and the excess Gibbs free energy, were determined for each mass percent of DMF in water for mixtures of sodium and potassium salts with common anion chloride. The resultant activity coefficients demonstrate a decreasing trend upon decreasing dielectric constants and as the mixed solvent medium growing dense and viscous.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quaternary System Thermodynamic Investigation in a Mixed Solvent: NaCl + KCl + N,N-Dimethylformamide + H₂O

Masumi

Salamat-Ahangari

2021

“…These profiles were observed in many similar systems. 7,23 The averages of the E 0 * obtained by the three models are listed in Table 5. The standard free energy of transference, ΔG t 0 , which can be calculated from the average of E 0 * using the following equation: 24 (9) where "w" and "s" refer to the pure water and the solvent mixture, respectively.…”

Section: As Shown Inmentioning

confidence: 99%

Activity Coefficients for CsBr + MeOH/EtOH + H₂O Ternary Systems Using Potentiometric Measurements at 298.15 K

Tang

et al. 2012

In this paper, the mean activity coefficients for CsBr, as well as the osmotic coefficients, the excess Gibbs free energies, the Gibbs energies of transference, and the primary hydration in different MeOH−water and EtOH−water mixtures at 298.15 K are calculated by potentiometric measurements. The cell used in this work contains two ion selective electrodes (ISEs): Cs-ISE|CsBr(m), ROH(w), H 2 O(1 − w)|Br-ISE (R = Me and Et), and the mass fraction of ROH in the mixture (w) was varied between 0 and 0.3 in 0.1 unit steps. The experimental data were correlated very well by the thermodynamics equations of Pitzer, modified Pitzer, and Debye−Huckel models.

“…In the literature, there are numerous studies of alkali halides in organic–water mixtures by potential difference measurements, for example, KCl and NaCl in ethanol–water, , NaCl/NaF in methanol/ethanol–water, , NaF/NaCl/NaBr in fomamide–water, − NaF/NaBr/NaCl in ethylene carbonate–water, − NaCl/KCl/LiCl in PEG 4000-water. − However, only a few studies are cited in the literature that describe the mean activity coefficients of alkali halides in ternary mixed solvents from potentiometric data …”

Section: Introductionmentioning

confidence: 99%

Activity Coefficients in Quaternary Systems at 298.15 K: RbCl + MeOH + EtOH + H₂O and CsCl + MeOH + EtOH + H₂O Systems

Zhai

et al. 2013

Activity coefficients of RbCl or CsCl in methanol + ethanol + water were determined at 298.15 K by the cells containing ion-selective electrodes (ISEs). The molalities of RbCl and CsCl are up to approximately 1 mol•kg −1 in the mixed solvents, and the mass fractions of five aqueous MeOH/EtOH mixtures studied were (5/5, 10/5, 5/10, 10/10, and 15/15) %. The experimental data were optimized using the extended Debye−Huckel, the Pitzer, and the modified Pitzer equations. The results of the apparent standard electromotive force E 0 * of the three equations are in good agreement. The mean activity coefficients and the standard Gibbs energy of transfer of RbCl or CsCl from pure water to mixed solvents (MeOH + EtOH + water) were also calculated.