Gibbs Transfer Energies and Solvent Transport Numbers of Some Copper(II) Salts in Methanol-Dimethylformamide Mixtures

1995 ◽  
Vol 48 (5) ◽  
pp. 987 ◽  
Author(s):  
AV Varghese ◽  
C Kalidas ◽  
P Singh ◽  
G Hefter
Keyword(s):  
Relevant Literature ◽  
Transport Numbers ◽  
Ion Transfer ◽  
Liquid Junction ◽  
Gibbs Energies ◽  
Chemical Theory ◽  
Reference Electrolyte ◽  
Gibbs Transfer Energies ◽  
Junction Potential ◽  
Solvent Transport

Standard Gibbs energies of transfer have been determined for copper(II) iodate, benzoate and formate at 30°C in methanol- dimethylformamide mixtures by solubility measurements. Single-ion transfer energies were obtained by using the negligible liquid junction potential assumption, along with relevant literature data, and are in excellent agreement with values estimated from the reference electrolyte ( tatb ) assumption. The results obtained indicate that all of these salts are heteroselectively solvated in these mixtures, with Cu2+ being preferentially solvated by dmf and the anions by MeOH. This model is consistent with calculations based on the quasi-lattice quasi-chemical theory of Marcus and with solvent transport numbers obtained from e.m.f . measurements.

An Improved Equation for the Liquid Junction Potential at the Interface of Different Solvents

1992 ◽  
Vol 45 (10) ◽  
pp. 1633 ◽  
Author(s):  
A Berne ◽  
C Kahanda ◽  
O Popovych
Keyword(s):  
Mixed Solvent ◽  
Electrolyte Solutions ◽  
Transport Numbers ◽  
Liquid Junction Potential ◽  
Aqueous Methanol ◽  
Liquid Junction ◽  
Chemical Potentials ◽  
Solvent Dependence ◽  
New Equation ◽  
Junction Potential

The component of the liquid-junction potential due to the diffusion of ions across an interface of electrolyte solutions in different solvents was formulated by taking into account the solvent dependence of the transport numbers, t, and of the chemical potentials of ions in the interphase region as determined from experimental data on their variation in the mixed-solvent compositions. The new equation was applied to NaCl/NaCl and HCl/HCl junctions between water and methanol-water solvents over the entire solvent range. Significant differences between the results obtained with the new equation and the old formulation, which treated the transport numbers as solvent-independent, were observed only for the HCl junctions involving 90-100 wt % aqueous methanol, where tH exhibits a sharp minimum as a function of the solvent composition.

Evaluation of Ionic and Solvent Components of the Liquid-Junction Potential Between Aqueous and Several Aquo-Organic Solutions

1994 ◽  
Vol 47 (5) ◽  
pp. 921 ◽  
Author(s):  
C Kahanda ◽  
O Popovych
Keyword(s):  
Mixed Solvent ◽  
Approximate Equation ◽  
Transport Numbers ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Solvated Ions ◽  
A Cell ◽  
Solvent Component ◽  
Organic Solutions ◽  
Junction Potential

Values of Ej,ion, the ionic component of the liquid-junction potential Ej, were calculated for the HCl,H2O |HCl,S2 and KCl,H2O | KCl,S2 junctions, where S2 was EtOH-H2O, HCONMe2- H2O and Me2SO-H2O solvents, and for the AgNO3,H2O | AgNO3,MeCN-H2O junction, over the entire mixed-solvent ranges. Both the old approximate equation for Ej,ion and our improved equation, which accounts for the variation of the ionic transport numbers t and chemical potentials Go in the interphase region, were used. Significant differences between the two equations were observed for systems where the t and ΔtG° functions dnisplayed extrema against the mixed-solvent composition. The highest Ej,ion value was 395 mV, for the HCl,H2O | HCl,Me2SO junction. Values of Ej,s,the solvent component of Ej, were calculated by subtracting the corresponding Ej,ion values from the total Ej, which was evaluated in each case from the e.m.f , of a cell with the liquid junction of interest and the transfer activity coefficient of the electroactive ion, estimated by the tetraphenylborate assumption. The magnitude of Ej,s was significant for the junctions between H2O and most of the solvents, and was particularly large for those involving dipolar aprotic solvents and highly solvated ions. The maximum Ej,s value was -201 mV, observed for the junction HCl,H2O|HCl,100% Me2SO.

Solubility and Thermodynamic Transfer Functions of Cesium Dianilinetetraisothiocyanatochromate(III)

1998 ◽  
Vol 63 (3) ◽  
pp. 293-298
Author(s):  
Vladislav Holba
Keyword(s):  
Experimental Data ◽  
Isopropyl Alcohol ◽  
Transfer Functions ◽  
Butyl Alcohol ◽  
Aqueous Methanol ◽  
Gibbs Energies ◽  
Gibbs Energy Of Transfer ◽  
Energy Of Transfer ◽  
The Given ◽  
Reference Electrolyte

The solubilities of cesium dianilinetetraisothiocyanatochromate(III) in water as well as in aqueous methanol, isopropyl alcohol, tert-butyl alcohol and acetonitrile were measured as a function of temperature and solvent composition. The Gibbs energies, enthalpies and entropies of transfer of the salt from water to the given solvents have been evaluated from experimental data. The contribution of [Cr(C6H5NH2)2(NCS)4]- ion to the Gibbs energy of transfer of the investigated salt has been calculated using the tetraphenylarsonium tetraphenylborate (TATB) reference electrolyte assumption.

scholarly journals Investigating the Proton and Ion Transfer Properties of Supported Ionic Liquid Membranes Prepared for Bioelectrochemical Applications Using Hydrophobic Imidazolium-Type Ionic Liquids

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 359
Author(s):  
László Koók ◽  
Piroska Lajtai-Szabó ◽  
Péter Bakonyi ◽  
Katalin Bélafi-Bakó ◽  
Nándor Nemestóthy
Keyword(s):  
Mass Transfer ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Microbial Fuel Cells ◽  
Transport Numbers ◽  
Liquid Membranes ◽  
Ion Transfer ◽  
Supported Ionic Liquid ◽  
Supported Ionic Liquid Membranes ◽  
Transfer Properties

Hydrophobic ionic liquids (IL) may offer a special electrolyte in the form of supported ionic liquid membranes (SILM) for microbial fuel cells (MFC) due to their advantageous mass transfer characteristics. In this work, the proton and ion transfer properties of SILMs made with IL containing imidazolium cation and [PF6]− and [NTf2]− anions were studied and compared to Nafion. It resulted that both ILs show better proton mass transfer and diffusion coefficient than Nafion. The data implied the presence of water microclusters permeating through [hmim][PF6]-SILM to assist the proton transfer. This mechanism could not be assumed in the case of [NTf2]− containing IL. Ion transport numbers of K+, Na+, and H+ showed that the IL with [PF6]− anion could be beneficial in terms of reducing ion transfer losses in MFCs. Moreover, the conductivity of [bmim][PF6]-SILM at low electrolyte concentration (such as in MFCs) was comparable to Nafion.

scholarly journals Electrodiffusion Phenomena in Neuroscience and the Nernst–Planck–Poisson Equations

Electrochem ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 197-215
Author(s):  
Jerzy J. Jasielec
Keyword(s):  
Electrical Potential ◽  
Signal Propagation ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Patch Clamp Technique ◽  
Poisson Equations ◽  
Cellular Environment ◽  
Electrochemical Transport ◽  
Insight Into ◽  
Junction Potential

This work is aimed to give an electrochemical insight into the ionic transport phenomena in the cellular environment of organized brain tissue. The Nernst–Planck–Poisson (NPP) model is presented, and its applications in the description of electrodiffusion phenomena relevant in nanoscale neurophysiology are reviewed. These phenomena include: the signal propagation in neurons, the liquid junction potential in extracellular space, electrochemical transport in ion channels, the electrical potential distortions invisible to patch-clamp technique, and calcium transport through mitochondrial membrane. The limitations, as well as the extensions of the NPP model that allow us to overcome these limitations, are also discussed.

Use of a Sodium Chloride—Phosphate Buffer for pH Standardization in a New Blood-Gas Analyzer with an Isotonic Sodium Chloride Bridge

1973 ◽  
Vol 19 (11) ◽  
pp. 1243-1247 ◽  
Author(s):  
P A Drinker ◽  
D C Noonan ◽  
N Ramanaiah ◽  
J R Tole
Keyword(s):  
Sodium Chloride ◽  
Blood Gas ◽  
Gas Analyzer ◽  
Liquid Junction ◽  
Isotonic Sodium Chloride ◽  
Salt Depletion ◽  
The Stability ◽  
Conventional Scheme ◽  
Blood Gas Analyzer ◽  
Junction Potential

Abstract Two different blood-gas analyzers were tested to determine the effects on blood pH measurement of changing the reference bridge solution from saturated KCl to normal saline (0.16 mol of NaCl per liter). This change, which necessitated the preparation of modified buffers equimolal in NaCl with respect to blood, virtually eliminated salt depletion of the bridge solution and improved the stability of the liquid-junction potential between the bridge solution and the sample. The instruments we used were the Corning 165 pH Blood Gas Analyzer and the Radiometer E5021 pH Electrode with PHM72 Acid Base Analyzer. Comparison of results on clinical blood samples indicates that performance with the modified bufferbridge system is the same as that obtained with the conventional scheme. Analytical performances of the Corning and Radiometer instruments for PO2 and PCO2, as well as for pH, were comparable.

The real and chemical Gibbs energies of silver ion transfer from water to some organic solvents

1985 ◽  
Vol 193 (1-2) ◽  
pp. 113-122 ◽  
Author(s):  
Zbigniew Koczorowski ◽  
Irwina Zagórska
Keyword(s):  
Organic Solvents ◽  
Silver Ion ◽  
Ion Transfer ◽  
The Real ◽  
Gibbs Energies

scholarly journals DETERMINATION OF ALKALINITY AND DISSOCIATION CONSTANTS OF HIGH SALINITY WATERS: USE OF F5BC TITRATION FUNCTION

2018 ◽  
Vol 35 (2) ◽  
pp. 79
Author(s):  
Bernadete F. Cavalcanti ◽  
Lourdes Cristina Lucena Agostinho ◽  
Luciano Nascimento
Keyword(s):  
Natural Waters ◽  
Dissociation Constants ◽  
A Priori ◽  
Linear Regression Analysis ◽  
Liquid Junction ◽  
Carbonate System ◽  
Ph Measurements ◽  
Apparent Dissociation Constant ◽  
Junction Potential

Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline watersfrom Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing “a priori” the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.

scholarly journals Liquid Junction Potential in Potentiometric Titrations. 5. Deduction of the Potential Functions for E.M.F. Cells with Complex Formation and with Liquid Junctions of the Type AY|AY+ BYz(B) + HY + AyL.

1999 ◽  
Vol 53 ◽  
pp. 314-319 ◽  
Author(s):  
Erzsébet Néher-Neumann ◽  
G. Voyiatzis ◽  
T. Østvold ◽  
Tapani A. Pakkanen ◽  
Markku Ahlgrén ◽  
...  
Keyword(s):  
Complex Formation ◽  
Potential Functions ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Potentiometric Titrations ◽  
Junction Potential
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