Temperature dependence of activity coefficients and Gibbs energies of transfer of LiBr in acetonitrile, dimethyl sulfoxide, and N,N-dimethylacetamide from EMF measurements

1997 ◽  
Vol 75 (11) ◽  
pp. 1500-1507 ◽  
Author(s):  
J. Barthel ◽  
R. Neueder ◽  
A. Schröder
Keyword(s):  
Dimethyl Sulfoxide ◽  
Activity Coefficients ◽  
Redox Reaction ◽  
Electromotive Force ◽  
Association Constants ◽  
Aprotic Solvents ◽  
Temperature Dependent ◽  
Emf Measurements ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer

Electromotive force (EMF) measurements based on the redox reaction[Formula: see text]are reported for solutions of LiBr at concentrations 0.005 < cLiBr/(mol dm−3) < 0.1 in acetonitrile (AN), dimethyl sulfoxide (DMSO), and N.N-dimethylacetamide (DMA) in the temperature range 278.15 < T/K < 308.15. Gibbs energies of transfer and activity coefficients are estimated. The association constants of LiBr in AN, DMSO, and DMA from EMF measurements and the enthalpy of transfer AN → DMSO are compared to those from other methods of determination. Keywords: temperature-dependent EMF measurements, aprotic solvents, LiBr, TlBr(s) | TlxHg(l) electrode, activity coefficients, transfer quantities.

Activity Coefficients and Gibbs Energies of Transfer of Tetraalkylammonium Dianilinetetraisothiocyanatochromates(III)

1994 ◽  
Vol 59 (8) ◽  
pp. 1738-1744
Author(s):  
Vladislav Holba
Keyword(s):  
Activity Coefficients ◽  
Transfer Functions ◽  
Butyl Alcohol ◽  
Methyl Ethyl ◽  
Tetraalkylammonium Ions ◽  
Ionic Transfer ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Acetonitrile Solutions ◽  
Mixed Systems

The solubilities of tetraalkylammonium dianilinetetraisothiocyanatochromates(III) (alkyl = methyl, ethyl, 1-propyl, and 1-butyl) in water, water - methanol, water - tert-butyl alcohol and water - acetonitrile solutions were measured at 25 °C. The results were used to evaluate the activity coefficients and Gibbs energies of transfer of the saturating salts from water to the mixed systems. The Gibbs energies of transfer of the [Cr(C6H5NH2)2(NCS)4]- ion were obtained by means of known ionic transfer functions for the tetraalkylammonium ions based on the TATB assumption.

Gibbs energies of transfer of individual ions from water to acetone + water solvents

1989 ◽  
Vol 67 (8) ◽  
pp. 1268-1273 ◽  
Author(s):  
Mahmoud Mohamad Elsemongy ◽  
Ahmed Ahmed Abdel-Khalek
Keyword(s):  
Glass Electrode ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Emf Measurements ◽  
Gibbs Energies ◽  
Electrode Potentials ◽  
Gibbs Energies Of Transfer ◽  
Acetone Water ◽  
Alkali Metal Halides ◽  
Dipolar Aprotic Solvents

The standard absolute potentials of hydrogen, Ag–AgX (X = Cl, Br, and I) and M/M+ (M = Li, Na, K, Rb, and Cs) electrodes in nine different acetone + water solvents containing up to 80 wt. % acetone were determined from the emf data at 25 °C of the cells: glass electrode/HCl (m), solvent/AgCl–Ag and glass electrode (M)/MX (m), solvent/AgX–Ag. The standard Gibbs free energies of a transfer of halogen acids and alkali metal halides as well as their constituent individual ions from water to the respective solvents were computed. The observed increases in [Formula: see text] values of all ions with increasing acetone content of the solvent and their relative order in each solvent were interpreted and discussed. A comparison of the present results with those obtained earlier in the dimethyl sulphoxide (DMSO) + water solvents shows the different nature of the two dipolar aprotic solvents, acetone and DMSO, in their aqueous mixtures. Keywords: acetone + water solvents, electrode potentials, emf measurements, individual ions, transfer free energies.

Solute–solvent effects in the dissociation of thymolsulfonephthalein (an uncharged acid) in aqueous mixtures of acetonitrile (ACN), urea, and dimethyl sulfoxide (DMSO)

1986 ◽  
Vol 64 (8) ◽  
pp. 1521-1526 ◽  
Author(s):  
A. L. De ◽  
A. K. Atta
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Solvent Effects ◽  
Mixed Solvent ◽  
Dissociation Constants ◽  
Aqueous Mixtures ◽  
Solvent Interactions ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Solvent Systems

The thermodynamic first dissociation constants, [Formula: see text] of thymolsulfonephthalein (H2A), an uncharged acid, have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 80 wt% acetonitrile (ACN), 11.52, 20.31, 29.64, and 36.83 wt% urea, 20, 40, 60, and 80 wt% dimethyl sulfoxide (DMSO) by spectrophotometric measurements. The solvent effect represented by ∂(ΔG0) = 2.303RT[p(sK)N − p(wK)N] is found to increase in ACN + H2O system as mol% ACN increases in the solvent. In contrast, the corresponding values in urea + H2O as well as DMSO + H2O solvent systems decrease with increase in proportion of organic component in the solvent, the decrease being sharp in urea + H2O. The results have been discussed in terms of the standard Gibbs energies of transfer of H+ from water to the mixed solvent, [Formula: see text] and the relative values of the standard Gibbs energies of transfer of HA−, [Formula: see text] and of [Formula: see text] in all the solvent systems. The overall dissociation behaviour of the acid (H2A) is found to be dictated by the specific solute-solvent interactions of the species participating in the dissociation equilibria.

Transfer activity coefficients between some dipolar aprotic solvents and alcohols of salts composed of various anions and potassium complexed with Bis(4,4'(5')-t-butylbenzo)-18-crown-6

1983 ◽  
Vol 36 (9) ◽  
pp. 1753 ◽  
Author(s):  
Jr MK Chantooni ◽  
IM Kolthoff ◽  
G Roland
Keyword(s):  
Dimethyl Sulfoxide ◽  
Stability Constants ◽  
Propylene Carbonate ◽  
Activity Coefficients ◽  
Isopropyl Alcohol ◽  
The Other ◽  
Aprotic Solvents ◽  
Transfer Activity ◽  
Dipolar Aprotic Solvents

Stability constants, Kf(LK+) and Kf(LKX) = [LKX]/[L][KX] at 25� in the dipolar aprotic solvents acetone (Me2CO), acetonitrile (MeCN), propylene carbonate (pc), N,N-dimethylformamide (HCONMe2), dimethyl sulfoxide (Me2SO), as well as in the alcohols, methanol (MeOH), isopropyl alcohol (Pr1OH), and butan -1-ol (BuOH) have been determined, L being bis(4,4'(5')-t-buty1benzo)-18- crown-6 (di(BuBo)-18-cr-6). This crown is considerably more lipophylic than is dibenzo-18-crown-6. Values of Kf(LKX) have been found from values of Kf(LK+), KA(KX) and KA(LKX). Transfer activity coefficients, Me2COγS, have been calculated (based on the Parker proposal that γ(Ph4As+) = γ(BPh4-) between acetone and the various solvents used of K+, Br-, ClO4-, P1- (picrate), LK+, KX, and LKX. It is found that K+ is more strongly solvated in Me2CO than in the other aprotic solvents of low donicity. The reverse is true between Me2CO and HCONMe2 or Me2SO (even after correcting for the Born effect).

Solubility of Tris(ethylenediamine)chromium(III) and Hexaureachromium(III) Hexacyanoferrates(III) in Water and Mixed Water-Organic Solvents

1995 ◽  
Vol 60 (4) ◽  
pp. 537-544 ◽  
Author(s):  
Vladislav Holba ◽  
Marcela Hanková
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Binary Mixtures ◽  
Organic Solvents ◽  
Activity Coefficients ◽  
Butyl Alcohol ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Mixed Water

The solubilities of tris(ethylenediamine)chromium(III) and hexa(urea)chromium(III) hexacyanoferrates(III) in aqueous solutions of different supporting electrolytes as well as in binary mixtures of water with methanol, tert-butyl alcohol and acetonitrile were measured at 25 °C. The experimental data have been used to evaluate the activity coefficients of the saturating salts in water and their Gibbs energies of transfer from water into the binary mixtures investigated.

Transfer of 1,1'-dialkyl-4,4'-bipyridinium dication (viologen) across the water-dichloroethane and water-nitrobenzene interfaces

1987 ◽  
Vol 52 (4) ◽  
pp. 830-837 ◽  
Author(s):  
Josef Hanzlík ◽  
Zdeněk Samec
Keyword(s):  
Cyclic Voltammetry ◽  
Charge Transfer ◽  
Ion Association ◽  
Association Constants ◽  
Methyl Ethyl ◽  
Considerable Influence ◽  
Conductivity Measurements ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Voltammetric Measurements

Transfer of viologen dications R2V2+ (R = methyl, ethyl, propyl, butyl, pentyl, heptyl or benzyl) across the water-1,2-dichloroethane and water-nitrobenzene interfaces has been studied by cyclic voltammetry. Effects of the changes in the viologen structure and in the composition of solutions of both phases on the voltammetric behaviour have been inspected. Ion association, in particular that occuring in the organic phase, has a considerable influence on the viologen dication transfer and plays the key role in the proposed charge transfer mechanism. From the conductivity measurements the association constants for viologen tetraphenylborates in nitrobenzene have been evaluated. From the voltammetric measurements the Gibbs energies of transfer of viologen dications across the water-nitrobenzene interface have been determined.

scholarly journals Activities of dilute NiO in Na2O•2SiO2 by electromotive force measurements

1994 ◽  
Vol 72 (4) ◽  
pp. 1080-1082 ◽  
Author(s):  
P.J. Tumidajski
Keyword(s):  
Thermodynamic Properties ◽  
Activity Coefficients ◽  
Electromotive Force ◽  
Electrochemical Cell ◽  
Dilute Solution ◽  
Force Measurements ◽  
Standard State ◽  
Emf Measurements ◽  
Temperature Range ◽  
Electromotive Force Measurements

The thermodynamic properties of dilute NiO in Na2O•2SiO2 for XNiO < 0.0125 have been investigated in the temperature range 1073–1173 K by emf measurements using the electrochemical cell[Formula: see text]where NiO denotes a solution with Na2O•2SiO2. It was found that for XNiO < 0.003 the solutions obey Henry's law. The Henrian activity coefficients and the related dilute solution thermodynamic properties based on the solid NiO standard state are reported.

scholarly journals The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1314
Author(s):  
Mykola Moroz ◽  
Fiseha Tesfaye ◽  
Pavlo Demchenko ◽  
Myroslava Prokhorenko ◽  
Nataliya Yarema ◽  
...  
Keyword(s):  
Electromotive Force ◽  
Equilibrium Phase ◽  
Stoichiometric Composition ◽  
Negative Electrode ◽  
Electrochemical Cells ◽  
Thermodynamic Quantities ◽  
Positive Electrodes ◽  
Gibbs Energies ◽  
Buffer Region ◽  
First Time

Equilibrium phase formations below 600 K in the parts Ag2Te–FeTe2–F1.12Te–Ag2Te and Ag8GeTe6–GeTe–FeTe2–AgFeTe2–Ag8GeTe6 of the Fe–Ag–Ge–Te system were established by the electromotive force (EMF) method. The positions of 3- and 4-phase regions relative to the composition of silver were applied to express the potential reactions involving the AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 compounds. The equilibrium synthesis of the set of phases was performed inside positive electrodes (PE) of the electrochemical cells: (−)Graphite ‖LE‖ Fast Ag+ conducting solid-electrolyte ‖R[Ag+]‖PE‖ Graphite(+), where LE is the left (negative) electrode, and R[Ag+] is the buffer region for the diffusion of Ag+ ions into the PE. From the observed results, thermodynamic quantities of AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 were experimentally determined for the first time. The reliability of the division of the Ag2Te–FeTe2–F1.12Te–Ag2Te and Ag8GeTe6–GeTe–FeTe2–AgFeTe2–Ag8GeTe6 phase regions was confirmed by the calculated thermodynamic quantities of AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 in equilibrium with phases in the adjacent phase regions. Particularly, the calculated Gibbs energies of Ag2FeGeTe4 in two different adjacent 4-phase regions are consistent, which also indicates that it has stoichiometric composition.

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