Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 4. Symmetrical 2:2, 3:3 and Unsymmetrical 2:1, 3:1 and 1:3 Type Electrolytes in Pure Organic Solvents

Conductivities of symmetrical and unsymmetrical electrolytes of 2:2, 3:3, 2:1, 3:1 and 1:3 charge types in pure organic solvents (methanol, ethanol, 1-propanol, dimethyl sulfoxide, acetonitrile, formamide, N-methylformamide, N,N-dimethylformamide, N-methylacetamide and N,N-dimethylacetamide) were analyzed using the Quint-Viallard conductivity equation and taking into account the ion association effect. The molar limiting conductances and the ion association constants were determined for various multivalent electrolytes in these solvents using the literature conductivities. In many cases, for the first time, it was possible to obtain consistent values of the limiting ionic conductances in organic solvents.     

Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 2. Symmetrical 3:3 Type Electrolytes. Dilute Aqueous Solutions of Rare Earth Hexacyanoferrates(III) and Hexacyanocobaltates(III)

Literature values of the electrical conductivities of dilute aqueous solutions of trivalent rare earth hexacyanoferrates(III) (La, Pr, Nd, Sm, Gd) and of rare earth hexacyanocobaltates(III) (La, Nd, Sm, Y) were reexamined within the framework of the Quint-Viallard conductivity equation in order to obtain a uniform representation of their conductivities. It was observed that the limiting conductances of electrolytes at infinite dilution depend weakly on the applied conductivity equation, whereas the derived ion association equilibrium constants vary considerably and therefore should be treated rather as fitting parameters.     

Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 1. Symmetrical 2:2 Type Electrolytes. Dilute Aqueous Solutions of Alkaline Earth Metal Sulfates and Transition Metal Sulfates

Literature values of the electrical conductivities of dilute aqueous solutions of alkaline metal sulfates (BeSO₄, MgSO₄, CaSO₄, SrSO₄) and of transition metal sulfates (MnSO₄, FeSO₄, CoSO₄, NiSO₄, CuSO₄, ZnSO₄, CdSO₄) were reexamined within the framework of the Quint-Viallard conductivity equations in order to obtain a uniform representation of conductivities. It was observed that the limiting conductances of electrolytes at infinite dilution are very similar irrespective of the applied conductivity equation, whereas the derived ion association equilibrium constants vary considerably. The ion association equilibrium constants are therefore of doubtful physical value and should be treated rather as just fitting parameters.     

Limiting conductances of electrolytes and the walden product in mixed solvents in a phenomenological approach

The applicability of the Quint-Viallard conductivity equation to the representation of electrical conductivities in mixed solvents is examined. The concept of the modified Walden product is introduced, and the benefits compared with the ordinary Walden product are discussed. The universal curve of limiting conductances for all electrolytes (or for all ions) in a given pair of solvents is introduced and examined in a number of mixtures which include methanol, ethanol, 1-propanol, tert-butyl alcohol, 1,4-dioxane, N, N-dimethylformamide, sulfolane, tetrahydrofuran, and ethylene carbonate with water. Also examined are nonaqueous mixtures of acetone-ethanol, acetone-1-propanol, dimethyl sulfoxide-propylene carbonate, acetonitrile-methanol, acetonitrile-carbon tetrachloride, and acetonitrile-propylene carbonate. Many electrolytes were involved in the evaluation of the universal curves, but the majority are alkali-metal halides, tetraalkylammonium halides, tetraalkylammonium tetraphenylborides, and potassium xanthates (inorganic and organic acids are treated separately). If in a given mixed solvent system the limiting conductance of electrolyte is unknown, the universal curve permits estimating its value and gives an indication about the quality of performed conductivity measurements. The existence of universal curves of limiting conductances indicates that the properties of electrolytes in pure solvents are, to a great extent, preserved also in the mixture of solvents due to the simple dilution effect.     

混合电解质的电导测定

电导测定为研究离子与离子之间的缔合效应、离子与溶剂的相互作用及溶剂结构提供了一个有效手段 .目前 ,电解质水溶液、电解质非水溶剂体系的电导数据却很缺乏 ,而混合电解质体系的电导测定在理论及应用方面都很重要 .作为全面系统地考察金属氯化物的混合电解质的电导性质变化规律 ,前文已测定了 Na Cl- KCl- H2 O体系 [1] 、 Na Cl- Rb Cl- H2 O体系及 KCl- Rb Cl- H2 O体系的电导值 [2 ] ,本文用自行设计的电导池测定了 Ca Cl2 - H2 O,Ca Cl2 - Na Cl- H2 O,Ca Cl2 - KCl- H2 O体系在 2 98.1 5 K时的低浓度电导数据 ,探讨了…     

The Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint-Viallard Conductivity Equation. Part 3. Unsymmetrical 3:1, 1:3, 3:2, 4:1, 1:4, 4:2, 2:4, 1:5 1:6 and 6:1 Type Electrolytes. Dilute Aqueous Solutions of Rare Earth Salts, Various Cyanides and other Salts

Electrical conductivities of dilute aqueous solutions for unsymmetrical electrolytes of the type 3:1, 1:3, 3:2, 4:1, 1:4, 4:2, 2:4, 1:5 1:6 and 6:1 are reexamined in the framework of the Quint-Viallard conductivity equations, in order to obtain a uniform representation of their conductivities. The molar and equivalent limiting conductances were evaluated with ion association constants, which were treated as adjustable parameters. The derived values were compared with corresponding results from the literature. The following electrolytes are considered: rare earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er) halides, perchlorides, nitrates and sulfates; hexamminecobalt and tris-ethylenediaminecobalt halides, perchlorides, nitrates and sulfates; [Ni₂(trien)₃]Cl₄, [Pt(pn)₃]Cl₄, [Co₂(trien)₃]Cl₆; cyanides K₃[Fe(CN)₆], K₃[Co(CN)₆], M₃[W(CN)₈] with M=Na, K, Rb, Cs; Ca₂[Fe(CN)₆], K₄[Fe(CN)₆], K₄[Mo(CN)₈], K₄[W(CN)₈], K₄[Ru(CN)₈], (Me₄N)₄[Fe(CN)₆], (Pr₄N)₄[Fe(CN)₆], K₄[Mo(CN)₈], (Me₄N)₄[Mo(CN)₈], (Et₄N)₄[Mo(CN)₈] and (Pr₄N)₄[Mo(CN)₈]; phosphates Na₄P₂O₇, Na₄P₄O₁₂, Na₅P₃O₁₀, Na₆P₆O₁₈ and (Me₄N)₄P₄O₁₂.     

Ion Association and Solvation Behavior of Some 1-1 Electrolytes in 2-Ethoxyethanol Probed by a Conductometric Study

Precise measurements of the electrical conductances of solutions of potassium thiocyanate (KCNS), ammonium thiocyanate (NH₄CNS), sodium nitrate (NaNO₃) and ammonium nitrate (NH₄NO₃) in 2-ethoxyethanol (EE) at temperatures 35, 40, 45 and 50,^∘C are reported. The conductance data have been analyzed by the 1978 Fuoss conductance equation. A thermodynamic analysis of the ionic association processes has also been made and the Coulombic forces are found to play a major role in the association processes. The ionic contributions to the limiting equivalent conductances have been determined using the reference electrolyte method. Strong association was found for all these electrolytes in this solvent medium. The cations are found to be substantially solvated in 2-ethoxyethanol, whereas the anions appear to have only weak interaction with the solvent molecules.     

Conductances and solubilities of uni-univalent electrolytes in 2-cyanopyridine at 30°C

Conductance measurements for twenty-five uni-univalent electrolytes in 2-cyanopyridine at 30°C (dielectric constant=93.8) were made over the concentration range of 1.4-100×10^–4 mol-dm^–3. All conductance data were evaluated by the Lee-Wheaton equation. The results indicate only slight association for most of the salts but Et₂H₂NBr and Et₃HNBr are quite strongly associated while ammonium picrate, AgNO₃ and LiClO₄ show less, but significant, association. Picric acid was found to be a weak acid in 2-cyanopyridine. Ionic limiting equivalent conductances were evaluated using (i-Pent)₃BuNPh₄ as a reference electrolyte. Anions appear tobe poorly solvated while cations show some evidence of ion-solvent interaction. Solubilities were determined for eight salts of moderate-to-low solubility in 2-cyanopyridine. Single ion free energies of transfer from water to 2-cyanopyridine were estimated for ions from these salts using the AsPh₄NBPh₄ approximation. The results indicate that 2-cyanopyridine is not a particularly good solvating medium for most common inorganic salts.This study was presented, in part,at the Fifth International Conference on Non-Aqueous Solutions, University of Leeds, England, July 1976.     

The Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint–Viallard Conductivity Equation

Electrical conductivities of dilute aqueous solutions of aluminum sulfate were determined and analyzed in terms of a strongly associated electrolyte of the 3:2 type. The conductivities reported here were determined from 15 to 35 °C. Representation of conductances, in the framework of the ion association model, was performed using the Quint–Viallard conductivity equations for highly charged electrolytes and the Debye–Hückel expression for activity coefficients. Determined apparent association constants K _a(T) were considered as adjustable parameters. The determined limiting conductances of the trivalent aluminum ion λ⁰((1/3)Al³⁺) are considerably higher than those reported in the literature. Available specific conductivities in concentrated aqueous solutions of aluminum sulfate were fitted by a new empirical equation with only three adjustable parameters.     

Modeling of Aqueous 3–1 Rare Earth Electrolytes and Their Mixtures to Very High Concentrations

A simple modification to the Pitzer ion–interaction model has been presented for osmotic and activity coefficients of aqueous solutions of highly soluble and highly unsymmetrical electrolytes and their mixtures. The equations extending to the C⁽³⁾ parameter enable the literature osmotic and activity coefficients of aqueous rare earth nitrates, perchlorates and chlorides at 298.15 K to be represented accurately from infinite dilution to maximum saturation or supersaturation concentrations available. The ionic interactions have also been investigated from the isopiestic measurements on aqueous mixtures Y(NO₃)₃–La(NO₃)₃, Y(NO₃)₃–Pr(NO₃)₃, Y(NO₃)₃–Nd(NO₃)₃, La(NO₃)₃–Pr(NO₃)₃, La(NO₃)₃–Nd(NO₃)₃ and Pr(NO₃)₃–Nd(NO₃)₃ at 298.15 K to near saturation, and the simple modification can represent the new measurements within experimental uncertainty over the full concentration range. In addition, the Zdanovskii-Stokes-Robinson model or partial ideal solution model is obeyed by all the mixtures within isopiestic accuracy, which is consistent with the nature of rare earth elements.     

NaCl(或KCl)-CH3OH-H2O体系的摩尔电导

CHaOH－HzO体系具有非常特殊的性质，同时在工业生产及临床治疗方面有着十分广泛的应用，文献中有大量地从不同角度就这类体系进行研究的报道．然而，就N3CI及KCI－CH30H－H20体系的电导研究而言，文献中仅有关干KCI－CH30H－H20（间隔20％CH30H）的部分研究工作．作为全面、系     

Influence of alkoxyethanols on the mixed micelle formation by hexadecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide surfactant mixtures

 The conductances of hexadecyltrimethylammonium bromide (HTAB) and tetradecyltrimethylammonium bromide (TTAB) mixtures over the entire mole fraction range of HTAB were measured in aqueous binary mixtures of ethylene glycol monomethyl ether, monoethyl ether, and monobutyl ether, and of diethylene glycol monomethyl ether and monoethyl ether containing 10–30 wt% additive in their respective binary mixtures at 30 °C. Each conductivity curve showed a single break over the whole mole fraction range of HTAB–TTAB mixtures. From the break in the conductivity curve, various micellar parameters were calculated and the results were discussed with respect to the alkoxyethanol's additive effect on the mixed micelle formation. The micellar parameters of HTAB, TTAB, and of their mixtures showed a strong dependence both on the amount as well as on the number of repeating units in the presence of ethylene glycol derivatives, whereas a significant dependence only on the amount of additive was observed in aqueous diethylene glycol derivatives. The results in the former case were attributed to the hydrophobic hydration of the mixed micelles by the ethylene glycol derivatives, which showed a large dependence on the increase in the alkyl chain length of the additive. The hydrophobic hydration was considerably reduced in the case of diethylene glycol derivatives owing to the presence of an extra ether oxygen. An evaluation of the nonideality in the HTAB–TTAB mixtures revealed that in spite of the strong hydrophobic hydration of the HTAB–TTAB mixtures by the alkoxyethanols, the mixed micelles remain almost free from the additive molecules. Received: 11 January 2000/Accepted: 14 April 2000     

Electrical conductances of tetrabutylammonium bromide and tetrapentylammonium bromide in 2-ethoxyethanol + water mixtures at 308.15, 313.15, 318.15 and 323.15 K

The electrical conductances of the solutions of tetrabutylammonium bromide (Bu₄NBr), and tetrapentylammonium bromide (Pen₄NBr) in 2-ethoxyethanol (1) + water (2) mixed solvent media containing 0.25, 50 and 0.75 mass fractions of 2-ethoxyethanol (w ₁) have been reported at 308.15, 313.15, 318.15 and 323.15 K. The conductance data have been analyzed by the 1978 Fuoss conductance–concentration equation in terms of the limiting molar conductance (Λ⁰), the association constant (K _A) and the association diameter (R). These two electrolytes are found to exist essentially as free ions in the solvent mixtures with w ₁ = 0.25 and 0.50 over the entire temperature range; however, slight ionic association was observed in the mixed solvent medium richest in 2-ethoxyethanol. The electrostatic ion–solvent interaction is found to be very weak for the tetraalkylammonium ions in the aqueous 2-ethoxyethanol mixtures investigated.     

Ion-Solvent Interaction of Biunivalent Electrolytes in Dioxane-Water Mixtures from Conductivity Data at Different Temperatures

This paper presents the conductivity measurements for some alkaline earth metal salts MgCl₂, MgBr₂, Mg(NO₃)₂, CaCl₂, CaBr₂ and Ca(NO₃)₂ by which the ion-solvent interactions are reported in the concentration range in dioxane-water mixtures at mass fraction of 0, 3, 10, 20 and 30% at 30°, 35°, 40° and 45°C ± 0.01. The conductance data were analyzed for the limiting molar conductivity, A_o, by the Fuoss-Edelson conductivity equation for the 2:1 unsymmetrical electrolytes. The results were discussed in terms of the solute-solvent interaction from the temperature coefficient of Walden product, Λ_oη of the electrolyte solutions. Moreover, Λ_oη was found to exhibit a linear relationship with the dielectric constant, ?, of the dioxane-water mixtures. The study gives information regarding the ion-solvent interactions from the mobilities and Walden product of the ions in the solvent. The ions appear to interact appreciably and the ion-solvent interaction tends to increase in the order Ca > Mg for the same anion while for the anions, the trend decreases in the order Cl^? < Br^? < No^?₃.     

Effect of pressure and temperature on electrolyte conductance in 2-propanol

Equivalent conductances for tetrabutylammonium chloride, bromide, iodide, and perchlorate and lithium chloride were determined in 2-propanol at 10, 25, and 40°C over the pressure range 1 to 3,000 kg-cm^?2. The data are analyzed with the 1975 Fuoss-Onsager equation. The limiting equivalent conductances and association constants show the same level of precision as generally obtained in high precision conductance measurements at 1 atmosphere. The unusual association pattern observed for electrolytes in alcohols persisted up to the highest pressures used in this study.     

Effect of tetrahydrofuran on the conductance and ion-pairing of hydrogen chloride in wet and dry methanol mixtures

The molar conductance of dilute solutions of HCl in wet (68.5% methanol + 31.5% tetrahydrofurane mixtures at 25°C have been measured. The data were analyzed using the Fuoss-Hsia equation to calculate the infinite dilution molar conductances and association constants. The trend of the limiting conductances in these mixtures as a function of the water content shows, once more, the peculiar minimum due to the anomalous proton conductance mechanism. From these data the limiting molar conductance in the anhydrous binary solvent system was evaluated. The percentage excess proton mobility with respect to potassium ion has also been determined. All these data are compared to those found in a binary isodielectric methanol mixture containing as cosolvent 1,4-dioxane. This comparison shows that proton mobilities are very similar in both solvent mixtures. The dielectric constants, refractive indices, viscosities and densities of the methanol-tetrahydrofuran mixtures in the whole mole fraction range have been measured and are reported. An analysis of the excess molar volumes and viscosities shows a slight deviation of this system from ideality.     

Electrical Conductances of Tetrabutylammonium and Decamethylferrocenium Hexafluorophosphate in Organic Solvents

The electrical conductances of tetrabutylammonium hexafluorophosphate in acetone and of decamethylferrocenium hexafluorophosphate in acetone, acetonitrile 1,2-dichloroethane, and dichloromethane have been measured at 25^°C. The Walden product of the Bu₄N⁺ cation and the PF₆^- anion in acetone and other solvents is discussed in relation to the dielectric friction. The electric conductance at infinite dilution and the association constant of decamethylferrocenium hexafluorophosphate were determined in the four solvents investigated. The association constant of this electrolyte increases with decreasing reduced temperature, as expected in the framework of the association theory, within the primitive model of electrolytes.     

Interactions and Transport in Highly Concentrated LiTFSI-based Electrolytes

To elucidate what properties control and practically limit ion transport in highly concentrated electrolytes (HCEs), the viscosity, ionic conductivity, ionicity, and transport numbers were studied for nine model electrolytes and connected to the rate capability in Li-ion battery (LIB) cells. The electrolytes employed the LiTFSI salt in three molar ratio concentrations; 1 : 2, 1 : 4, and 1 : 16 (LiTFSI:X) vs. solvents (X) with different permittivities; tert-butyl methyl ether (MTBE), tetrahydrofuran (THF) and propylene carbonate (PC). While the low polarity MTBE creates liquid electrolytes, ion-pairing limits the ionic conductivity despite extremely low viscosities. For the less concentrated 1 : 16 LiTFSI:MTBE and 1 : 16 LiTFSI:THF electrolytes the ionic diffusivities decrease with increased temperature, a sign of aggregation, but still their ionic conductivities and LIB performance increase. In general, the low ionic conductivity and high viscosity both limit the use of HCEs in LIBs, and no compensating mechanism seems to be present.     

Conductance behavior of 1:1 electrolytes in 3-methyl-2-oxazolidone at 25°C

The conductance behavior of twenty-five 1∶1 electrolytes has been investigated in 3-methyl-2-oxazolidone (3Me20x) at 25°C. Conductance data were analyzed by the Lee-Wheaton equation, and all salts studied were found to be only slightly associated. Ionic limiting equivalent conductances were obtained using tris(iso-pentyl)butylammonium tetraphenylborate as a reference electrolyte. The relative values of the ionic limiting molar conductance are generally similar to those for other dipolar aprotic solvents. However, the order $$\lambda _0 (i - Pent_3 BuN^ + ) > \lambda _0 (Pent_4 N^ + )and\lambda _0 (Br^ - ) > \lambda _0 (ClO_4^ - )$$ is opposite to that found previously in the similar solvent 3-tert-bytyl-2-oxazolidone.     

Conductance of electrolytes in dipolar aprotic solvent mixtures. I. Conductance of lithium chloride in mixtures of methylethylketone and acetone with N,N-dimethylformamide at 25°C

The conductances of LiCl in acetone-N,N-dimethylformamide (AC-DMF) and methylethylketone-N,N-dimethylformamide (MEK-DMF) binary mixtures have been measured at 25°C. The data were fitted to the 1978 Fuoss equation to obtain ion association constants K_A and limiting molar conductances ₀. The Bjerrum ion association theory modified by Fernandez-Prini and Prue was also used for evaluation of K_A and a, the contact ion-pair distance. LiCl is more associated in AC-DMF mixtures than in the MEK-DMF system. Addition of DMF to either AC or MEK decreases K_A and ₀ as expected from the increase in the dielectric constant and the viscosity. The distance parameter a is almost constant and equal to 2.6 A in these mixed solvent systems. The Walden products pass through minima in both ketone-rich regions.