Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Non-aqueous Binary Mixtures of Protic Ethylene Glycol and Dipolar Aprotic Acetonitrile

Mahali, Kalachand; Roy, Sanϳay; Dolui, Bijoy Krishna

doi:10.1007/s10953-013-0005-y

Cited by 47 publications

(42 citation statements)

References 22 publications

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“…It is of vital importance because such studies give valuable information on protein folding and unfolding process [17,18] and the nature of hydrophobic interaction of amino acids. Thus to explore the solvation mechanisms of various amino acids, several studies were carried out by different groups of researchers in different aquo-organic and non-aqueous solvent systems [25,33,41]. However, it is important to note that though various efforts were made on such studies, only a preliminary study on the measurement of solubility of DL-valine in aqueous electrolyte solutions was done by Khoshkbarchi et al [34] at 298.15 K, which lacks a detailed report on the solvation mechanisms of it in terms of the thermodynamic point of view.…”

Section: Introductionmentioning

confidence: 99%

Solubility and solvation thermodynamics of dl-nor-valine in aqueous solutions of NaCl and KCl

Roy

Guin

Dolui

2015

Journal of Molecular Liquids

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Section: Introductionmentioning

confidence: 99%

Solubility and solvation thermodynamics of dl-nor-valine in aqueous solutions of NaCl and KCl

Roy

Guin

Dolui

2015

Journal of Molecular Liquids

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“…There is less data for α-aminobutanoic acid, but log P values into wet octan-1-ol 2 and wet butan-1-ol are available, 32 and solubilities in water, 45,46,49,50 organic solvents, 41,42,44,45 and water–ethanol 37 mixtures have been determined for dl -α-aminobutanoic acid. Values of log C and derived values of log P are in Table 8, the latter using a value of 0.333 for log C w for water.…”

Section: Resultsmentioning

confidence: 99%

Solvation Descriptors for Zwitterionic α-Aminoacids; Estimation of Water–Solvent Partition Coefficients, Solubilities, and Hydrogen-Bond Acidity and Hydrogen-Bond Basicity

Abraham

Acree

2019

ACS Omega

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The literature data on solubilities and water–solvent partition coefficients have been used to obtain properties or “Absolv descriptors” for zwitterionic α-aminoacids: glycine, α-alanine (α-aminopropanoic acid), α-aminobutanoic acid, norvaline (α-aminopentanoic acid), norleucine (α-aminohexanoic acid), valine (α-amino-3-methylbutanoic acid), leucine (α-amino-4-methylpentanoic acid), and α-phenylalanine. Together with equations that we have previously constructed, these descriptors can be used to estimate further solubilities and partition coefficients in a variety of organic solvents and in water–methanol and water–ethanol mixtures. It is shown that equations for neutral solutes are inadequate for the description of solubilities and partition coefficients for these α-aminoacids, and our equations developed for use with both neutral and ionic solutes must be used. The Absolv descriptors include those for hydrogen-bond acidity, A , and hydrogen-bond basicity, B . We find that both of these descriptors are far smaller in value than those for compounds that contain the corresponding ionic groups. Thus, A for α-alanine is 0.28, but A for the ethylammonium cation is 1.31; B for α-alanine is 0.83, and yet B for the acetate anion is no less than 2.93. The additional descriptors that we developed for equations that involve ions, J + and J – , are very significant for the α-aminoacids, although numerically smaller than for ionic species such as EtNH 3 + and CH 3 CO 2 – .

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“…There are several methods [38][39][40][41][42][43] for the determination of the activity coefficients that involve various theoretical aspects and assumptions. But for simplicity, in many earlier studies the activity coefficient was assumed to be unity [11,12,15,17,[19][20][21][22][23][24]44] during the determination of the Gibbs energy of several amino acids in solution.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, our main concern in the current study is to determine and characterize the total transfer Gibbs energy (DG 0 t ðiÞ) in such binary solvent mixtures; therefore, we also have assumed here that the contribution of activity coefficient is negligible [11,12,15,17,[19][20][21][22][23][24]44]. DG 0 t ðiÞ is also related as DG 0 t ðiÞ ¼ DG 0 s ðiÞ À DG 0 R ðiÞ, where DG 0 t ðiÞ, DG 0 s ðiÞ and DG 0 R ðiÞ are the Gibbs energies of the amino acid solutions in co-solvent (aqueous ME) and reference solvent, water, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…A known mass (of about 0.2-0.3 g) of filtered saturated solution was transferred to a dry conical flask from solution thermostated at all experimental temperatures. The saturated solubility analyses of Gly, Ala, Aba and Val were made by the 'formol titrimetric method' [4,11,12,[19][20][21][22][23] using freshly standardized (0.05 molÁL -1 ) NaOH (GR, E Merck; [99.0 %) solution and 1 % alcoholic phenolphthalein solution as indicator. The solubilities were measured at the natural pHs of the solutions.…”

Section: Methodsmentioning

confidence: 99%

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Chemical Transfer Energetics of a Series of Homologous α-Amino Acids in Quasi-Aprotic 2-Methoxyethanol–Water Mixtures

2016

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The zwitterionic solvation behavior of a series of the homologous a-amino acids glycine (Gly), DL-alanine (Ala), DL-a-amino butyric acids (Aba) and DL-nor-valine (Val), in water and in aqueous mixtures of 2-methoxyethanol, have been studied at equidistant temperature intervals in the range of 288.15-308.15 K, using the solubility method. The solubility data were analyzed according to the 'formol titrimetric' process. Standard Gibbs energies DG 0 t ðiÞ and entropies DS 0 t ðiÞ of transfer were calculated and are discussed. The observed DG 0 t ðiÞ and TDS 0 t ðiÞ versus composition profiles are complicated because of the various interaction effects. The chemical effects of the transfer Gibbs energies DG 0 t;ch ðiÞ and entropies of transfer TDS 0 t;ch ðiÞ have been obtained after elimination of the cavity effect, estimated by the scaled particle theory and dipole-dipole interaction effects, calculated by use of the Keesom orientation expression. The chemical contributions to transfer energetics of homologous a-amino acids are guided by the combined effects of increased dispersion interaction, basicity and decreased acidity, hydrogen bonding effects and hydrophilic hydration of aqueous 2-methoxy ethanol as compared to that of reference solvent, water. In this context the solvating characters of protic ethylene glycol are also referred to for comparison.

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Solvation Thermodynamics of a Series of Homologous α-Amino Acids in Non-aqueous Binary Mixtures of Protic Ethylene Glycol and Dipolar Aprotic Acetonitrile

Cited by 47 publications

References 22 publications

Solubility and solvation thermodynamics of dl-nor-valine in aqueous solutions of NaCl and KCl

Solubility and solvation thermodynamics of dl-nor-valine in aqueous solutions of NaCl and KCl

Solvation Descriptors for Zwitterionic α-Aminoacids; Estimation of Water–Solvent Partition Coefficients, Solubilities, and Hydrogen-Bond Acidity and Hydrogen-Bond Basicity

Chemical Transfer Energetics of a Series of Homologous α-Amino Acids in Quasi-Aprotic 2-Methoxyethanol–Water Mixtures

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