A Raman Spectrographic and Potentiometric Study of Aqueous Lithium and Potassium Acetate Complexation at Temperatures from 20 to 200 ∘C

Fournier, Patricia; Gout, Robert; Oelkers, Eric H.

doi:10.1007/s10953-005-6251-x

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…3 d , would suggest that only solvent-separated ion pairs exist in potassium acetate solutions and that neither contact-shared (CIP) nor solvent-shared (SIP) occur (CIP, the two ions are in direct contact; SIP, the ions share one hydration layer; and solvent-separated, each ion retains its first hydration layer). The absence of CIPs disagrees with potentiometric measurements, which indicate that K + and CH 3 COO − associate–albeit weakly–to form neutral complexes ( 61 , 62 ) best understood as pairs of ions in direct contact ( 63 ).…”

Section: Resultsmentioning

confidence: 71%

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Daronkola

Verde

2021

Biophysical Journal

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Proteins of halophilic organisms, which accumulate molar concentrations of KCl in their cytoplasm, have a much higher content in acidic amino acids than proteins of mesophilic organisms. It has been proposed that this excess is necessary to maintain proteins hydrated in an environment with low water activity, either via direct interactions between water and the carboxylate groups of acidic amino acids or via cooperative interactions between acidic amino acids and hydrated cations. Our simulation study of five halophilic proteins and five mesophilic counterparts does not support either possibility. The simulations use the AMBER ff14SB force field with newly optimized Lennard-Jones parameters for the interactions between carboxylate groups and potassium ions. We find that proteins with a larger fraction of acidic amino acids indeed have higher hydration levels, as measured by the concentration of water in their hydration shell and the number of water/protein hydrogen bonds. However, the hydration level of each protein is identical at low (b KCl ¼ 0.15 mol/kg) and high (b KCl ¼ 2 mol/kg) KCl concentrations; excess acidic amino acids are clearly not necessary to maintain proteins hydrated at high salt concentration. It has also been proposed that cooperative interactions between acidic amino acids in halophilic proteins and hydrated cations stabilize the folded protein structure and would lead to slower dynamics of the solvation shell. We find that the translational dynamics of the solvation shell is barely distinguishable between halophilic and mesophilic proteins; if such a cooperative effect exists, it does not have that entropic signature.

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Section: Resultsmentioning

confidence: 71%

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Daronkola

Verde

2021

Biophysical Journal

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“…Ions can come into direct contact to form contact ion pairs, or the ion pairs are solvent-separated such as for aqueous sulfate solutions containing Mg 2+ , Cd 2+ , Co 2+ , Ni 2+ , Zn 2+ , or Cu 2+ , respectively, as found by Barthel’s group. , The probability of ion pairing increases with increasing electrolyte concentration, reducing the number of free water molecules available for hydration, such as in NaClO 4 or CdCl 2 solutions, ,, and this might occur even at low concentrations. Also, effects such as “local hydrolysis” for systems containing derivatives of weak acids cause ion pairing (e.g., acetate salts in water , and hydroxides, fluorides, and formates − ).…”

Section: Theory Developmentmentioning

confidence: 99%

“…49,50 The probability of ion pairing increases with increasing electrolyte concentration, reducing the number of free water molecules available for hydration, such as in NaClO 4 or CdCl 2 solutions, 49,51,52 and this might occur even at low concentrations. Also, effects such as "local hydrolysis" 53 for systems containing derivatives of weak acids cause ion pairing 54 (e.g., acetate salts in water 23,55 and hydroxides, fluorides, and formates 56−58 ).…”

Section: ■ Theory Developmentmentioning

confidence: 99%

Thermodynamic g^E Models and Equations of State for Electrolytes in a Water-Poor Medium: A Review

Held

2020

J. Chem. Eng. Data

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Research on the thermodynamics of electrolytes is timeless, and modeling an electrolyte solution might be considered to be a golden oldie, which was, is, and will be important in the design of processes and new materials in the future. The reason is that electrolytes play important roles in different scientific disciplines, such as material development, technical processes (chemical industry, biotechnology, and pharma and food industries), and most recently the energy sector. Closely connected is the further development of advanced thermodynamic models. The age of digitalization requires robust physical models as the basis for static and dynamic process modeling, and that will provide the basis for surrogate approaches in future machine learning developments. This all brings thermodynamic modeling to a consideration of its most important feature. There are many thermodynamic approaches which have been developed to correlate, model, and predict the properties and phase behavior of electrolytes. Usually, this has been very successful for aqueous electrolyte solutions. However, for solutions with poor water content, electrolyte modeling is challenging. This mini-review summarizes the recent advance of thermodynamic models for electrolyte solutions in a water-poor medium and suggests the required theoretical framework.

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“…From a molecular level, there should be a structural continuity from the complexes in dilution to concentrated, and to The acetate ion (CH 3 COO -) occurs widely in nature, being produced by microorganisms and by decomposition of humic acids [2,3]. Many metal-acetate salts have been studied extensively [4][5][6][7][8]. Magnesium ion (Mg 2+ ) is a major cation and is present at moderate concentrations in seawater [9], which will be levitated in the air by the action of wind on the surface of seawater.…”

Section: Introductionmentioning

confidence: 99%

The structural evolution of magnesium acetate complex in aerosols by FTIR–ATR spectra

Pang

Zhang

et al. 2015

Journal of Molecular Structure

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A Raman Spectrographic and Potentiometric Study of Aqueous Lithium and Potassium Acetate Complexation at Temperatures from 20 to 200 ∘C

Cited by 7 publications

References 28 publications

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Thermodynamic g^E Models and Equations of State for Electrolytes in a Water-Poor Medium: A Review

The structural evolution of magnesium acetate complex in aerosols by FTIR–ATR spectra

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A Raman Spectrographic and Potentiometric Study of Aqueous Lithium and Potassium Acetate Complexation at Temperatures from 20 to 200 ∘C

Cited by 7 publications

References 28 publications

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Proteins maintain hydration at high [KCl] concentration regardless of content in acidic amino acids

Thermodynamic gE Models and Equations of State for Electrolytes in a Water-Poor Medium: A Review

The structural evolution of magnesium acetate complex in aerosols by FTIR–ATR spectra

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Product

Resources

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Thermodynamic g^E Models and Equations of State for Electrolytes in a Water-Poor Medium: A Review