Solvent Effect on Deprotonation Equilibria of Acids of Various Charge Types in Non-aqueous Isodielectric Mixtures of Protic Ethylene Glycol and Dipolar Aprotic N,N-Dimethylformamide at 298.15 K

Dolui, Bijoy Krishna; Bhattacharya, S.; Kundu, Kiron K.

doi:10.1007/s10953-008-9281-3

Cited by 17 publications

(10 citation statements)

References 23 publications

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“…All the three dipolar aprotic cosolvents may participate in self-association (i.e., dimerization, Schemes , a, and b , ) at a higher concentration.…”

Section: Resultsmentioning

confidence: 99%

“…Homologous α-amino acids such as glycine (> 99.0 % E Merck) and dl -alanine (> 99.0 %, E-Merck), dl -α-amino butyric acid (> 99.0 %, E-Merck) and dl -nor-valine (> 99.0 %, E-Merck) were used after being dried in a vacuum desiccator without further purification . Ethylene glycol (> 99.0 %, LR, BDH) was purified ,, by refluxing with 2 % to 3 % NaOH (> 97.0 % E-Merck) for 3 h to 4 h followed by distillation. The distilled ethylene glycol was then dried over freshly baked anhydrous Na 2 SO 4 (> 98.0 %, E-Merck) for 4 to 5 days then decanted off and fractionally distilled through a 2 / 3 m long vigreux column, rejecting the head and tail portions.…”

Section: Methodsmentioning

confidence: 99%

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Solubility and Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Nonaqueous Binary Mixtures of Ethylene Glycol and Dimethyl Sulfoxide

2015

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In this article the standard free energies (ΔG t 0 (i)) and entropies (ΔS t 0 (i)) of transfer of four homologous α-amino acids including glycine (Gly), DL-alanine (DL-Ala), DLα-amino butyric acid (DL-Aba.) and DL-nor-valine (DL-n-Val) from ethylene glycol (EG) to nonaqueous mixtures of ethylene glycol and dimethyl sulfoxide (DMSO) at 298.15 K are reported. The Gibbs energies of solutions have been determined from solubility measurements of each amino acid at different temperatures, that is, from 288.15 to 308.15 K by "formol titrimetry". The chemical parts of free energies (ΔG t,ch 0 (i)) and entropies (TΔS t,ch 0 (i)) of transfer of the homologous α-amino acids have been computed by subtracting the cavity effects and dipole−dipole interaction effects from the total transfer energies. The characteristics of the solvation thermodynamics of α-amino acids in EG-DMF and EG-ACN mixed solvent systems studied earlier are also discussed here for comparison.

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“…All the three dipolar aprotic cosolvents may participate in self-association (i.e., dimerization, Schemes , a, and b , ) at a higher concentration.…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Solubility and Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Nonaqueous Binary Mixtures of Ethylene Glycol and Dimethyl Sulfoxide

2015

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“…The 'short-range' primary solvating effect as dictated by the chemical nature of the solvents is hardly noticeable [8,9]. It makes the understanding of the solvent effect inadequate, as is evident from recent studies [10][11][12]. In view of these inconclusive investigations and in continuation of the earlier studies of the solvent effect on ion-solvent transfer equilibrium in aqueous co-solvents [8,9], we have extended the same to some iso-dielectric solvent systems.…”

Section: Introductionmentioning

confidence: 97%

“…Consequently, one of the essential prerequisite for understanding the solvent effect on reaction equilibrium is the evaluation of solvation energies or at least the transfer Gibbs free energies, DG tr , of the involved ionic and non-ionic species from the selected reference solvent to the concerned mixed solvents. However, this is in view of the fact that the long range ''secondary solvating" effect, as guided by 'Born-type' electrostatic effects [6,7], is due to the different dielectric constants of the solvents. These are fairly uncertain because of the uncertainty of the 'effective radius' factor and the 'local' dielectric constant in the vicinity of the ions in solution.…”

Section: Introductionmentioning

confidence: 99%

“…Also (methanol + NMP) possess strong solvent-solvent interactions. Dolui et al [7] studied the solvent effect on deprotonation equilibria of acids of various charge types in non-aqueous iso-dielectric mixtures of protic ethylene glycol and dipolar aprotic N,N-dimethylformamide. They concluded that a true understanding of the solvent effect on the overall deprotonation equilibria of acids and bases becomes relatively easier, if it is possible to understand the behavior of the species involved in a particular solvent system of systematically varying physico-chemical nature of different compositions.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic determination of solvation potentials of divalent metal chlorides (MCl2) in iso–dielectric media by EMF measurements

Spah

Song

et al. 2009

The Journal of Chemical Thermodynamics

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Solvation Chemistry of DL‐Nor‐Valine in Aqueous Mixture of Dipolar Aprotic N,N‐Dimethyl Formamide

Mahali

Roy

Dolui

2014

J Chinese Chemical Soc

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In this article, we reported the solubilities of the amino acid DL-nor-valine (VAL) at five equidistant temperatures i.e. from 15 to 35°C in aqueous mixtures of N,N-dimethyl formamide (DMF). The Standard free energies (DG t 0 ( ) i ) and entropies (DS t 0 ( ) i ) of transfer of VAL from water to aqueous mixture of cationophilic dipolar aprotic DMF have been evaluated at 25°C. The transfer of Gibbs energies (DG t ch , 0 ( ) i ) and entropies (TDS t ch , 0 ( ) i ) due to the chemical effects have been obtained after elimination of cavity effect, estimated by the scaled particle theory and dipole-dipole interaction effects, computed by the used of Keesom-orientation expression. The chemical contribution of transfer energetics of DL-nor-valine (VAL) are mainly guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMF mixtures as compared to that of reference solvent, water.

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Solvent Effect on Deprotonation Equilibria of Acids of Various Charge Types in Non-aqueous Isodielectric Mixtures of Protic Ethylene Glycol and Dipolar Aprotic N,N-Dimethylformamide at 298.15 K

Cited by 17 publications

References 23 publications

Solubility and Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Nonaqueous Binary Mixtures of Ethylene Glycol and Dimethyl Sulfoxide

Solubility and Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Nonaqueous Binary Mixtures of Ethylene Glycol and Dimethyl Sulfoxide

Thermodynamic determination of solvation potentials of divalent metal chlorides (MCl2) in iso–dielectric media by EMF measurements

Solvation Chemistry of DL‐Nor‐Valine in Aqueous Mixture of Dipolar Aprotic N,N‐Dimethyl Formamide

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