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.

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H2O + acetonitrile) at 25 °C: effect of the solvent

1984 ◽  
Vol 62 (9) ◽  
pp. 1776-1779
Author(s):  
A. L. De ◽  
T. K. De
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Spectrophotometric Study ◽  
Solvent System ◽  
Individual Species ◽  
Aqueous Mixtures ◽  
Gibbs Energies ◽  
Gibbs Energies Of Transfer ◽  
Aqueous Mixture ◽  
The Individual

Thermodynamic dissociation constants (SK) of p-nitroanilinium ion (BH+) have been determined at 25 °C in aqueous solutions containing 20, 40, 60, and 80 wt% acetonitrile (ACN) by spectrophotometric measurements. Standard Gibbs energies of transfer, [Formula: see text] (B) of p-nitroaniline (B) from water to other solvents have been evaluated from the measurement of solubilities at 25 °C. Solvent effect on the dissociation of the acid (BH+), δ(ΔG0) = 2.303RT[p(sK) − p(wK], results in a characteristic minimum with a change in the solvent composition. The result in this protic – dipolar aprotic mixture (H2O + ACN) has been compared with that in aqueous mixture of protic solvent (H2O + ethylene glycol) available from literature. The solvent effect has been discussed in terms of the standard Gibbs energies of transfer [Formula: see text], from water to aqueous mixtures of organic co-solvent of the uncharged base (B), the hydrochloride of the base (BHCl), and hydrochloric acid (HCl) and also in terms of the individual species involved in the dissociation process. The results indicate that solvent effect on dissociation is an involved process, guided by the combined effects of various types of solute–solvent interactions of the Brønsted acid and its conjugate base in addition to the relative solvent basicities.

scholarly journals A review on conductometric studies of electrolytes in mixed solvent systems to understand ion-ion and ion-solvent interactions

2020 ◽  
Vol 10 (3) ◽  
pp. 5355-5360
Keyword(s):  
Mixed Solvent ◽  
Mixed Solvents ◽  
Chemical Properties ◽  
Electrolyte Solutions ◽  
Molar Conductance ◽  
Extensive Literature ◽  
Solvent Interactions ◽  
Physico Chemical ◽  
Wide Range ◽  
Solvent Systems

The study of ion- solvent interaction is of much importance to investigate the nature of different solutions. Measurement of electrical conductivity and evaluation of physico-chemical properties, such as molar conductance, limiting molar conductance, ion-pair association, Walden product etc. shade light on different intermolecular interactions present in electrolyte solutions. Solvation properties can be varied by mixing two or more solvents. An extensive literature survey on conductometric studies has been carried out on different electrolytes dissolved in a wide range of mixed solvent systems. The reported results show that strong solute-solute, solute-solvent and solvent-solvent interactions are responsible for the physico- chemical behavior of a solution in mixed solvents.

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.

Solvent effect on the dissociation of p-nitroanilinium ion in glycerol–water media at 25 °C

1984 ◽  
Vol 62 (11) ◽  
pp. 2245-2248
Author(s):  
Amrita Lal De ◽  
Tapas Kumar De
Keyword(s):  
Solvent Effect ◽  
Dissociation Constants ◽  
Mixed Solvents ◽  
Individual Species ◽  
Aqueous Mixtures ◽  
Free Energies ◽  
Monohydric Alcohol ◽  
Glycerol Water ◽  
Alcohol Water ◽  
The Individual

Thermodynamic dissociation constants (sK) of p-nitroanilinium ion (BH+) have been determined at 25 °C in aqueous mixtures of 10, 30, 50, 70, and 90 wt.% of glycerol (GL) by spectrophotometric measurements. Standard free energies, [Formula: see text], of p-nitroaniline (B) from water to mixed solvents have been evaluated from the measurement of solubilities at 25 °C. p(sK) values decrease with increase in mol% of GL and pass through a minimum and then increase very slowly. The solvent effect on the dissociation, δ(ΔG0) = 2.303RT [p(sK)N – p(wK)N] has been discussed in terms of the standard free energies of transfer [Formula: see text] from water to aqueous mixtures of GL of the uncharged base (B), the hydrochloride of the base (BHCl), hydrochloric acid (HCl), and also in terms of the individual species involved in the dissociation process. The solvent effect in trihydric alcohol – water (GL + H2O) system has been compared with those in dihydric alcohol – water (ethylene glycol + water) and monohydric alcohol – water (ethanol + water) systems available from literature. The much less solvent effect in GL + H2O has been primarily attributed to the contrasting nature of interaction of H+ and of partially charged H atoms of—NH3+ group in BH+ compared to those in other two solvent systems.

Solvent Effect on the Hammett Reaction Constant of Substituted Benzoic Acids

1993 ◽  
Vol 46 (1) ◽  
pp. 31 ◽  
Author(s):  
H Bartnicka ◽  
I Bojanowska ◽  
MK Kalinowski
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Dissociation Constants ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
P Values ◽  
Reaction Constant ◽  
Substituted Benzoic Acids ◽  
Reaction Constants ◽  
Solvent Acidity

Potentiometric titration has been used to measure dissociation constants of 13 monosubstituted benzoic acids in nitromethane, benzonitrile , acetonitrile , propylene carbonate, acetone, N,N-dimethylformamide, dimethyl sulfoxide, methanol and formamide. The reaction constants of the Hammett equation were found to depend on the solvent acidity and basicity expressed by the α and β parameters of Kamlet and Taft. The p values determined earlier in water and ethanol also obey this rule.

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