Walden Product Research Articles

Molar volume, viscosity and conductance studies of sodium bromide in methanol + DMF system

Molar volume, viscosity and conductance of solutions of sodium bromide in different mol percent of methanol in N,N-dimethylformamide have been calculated from density, viscosity and conductance data respectively at temperatures 298.15, 303.15, 308.15 and 313.15 K. The structure breaker behaviour of sodium bromide in 0.1070 mol percent of methanol in N,N-dimethylformamide solutions is inferred from the sign of (∂ 2 Φ 0 v /∂T 2 ) P , dB/dT and temperature coefficient of Walden product i.e. d(Λ 0 m η 0 )/dT values.

Ion−Solvent Interactions of Some Halides of Common Cations with Organic Solvent Mixtures by Conductometric, Volumetric, Viscometric, and Refractometric Techniques

Electrolytic conductivities, densities, viscosities, and refractive indices of some lithium halides (LiCl, LiBr, and LiI) have been studied in mass fraction (0.10, 0.20, and 0.30) of ethylene glycol monomethyl ether + methyl alcohol mixtures at 303.15 K. The limiting molar conductivities (Λ0), association constants (KA), and the distance of closest approach of the ion (R) have been evaluated using the Fuoss conductance equation (1978). The Walden product is obtained and discussed. The limiting apparent molar volumes (ϕV°), experimental slopes (SV*) derived from the Masson equation, and viscosity A and B coefficients using the Jones−Dole equation have been interpreted in terms of ion−ion and ion−solvent interactions, respectively.

Conductance Studies of NaCl, KCl, NaBr, NaI, NaBPh4, and Bu4NI in Water + 2-Ethoxyethanol Mixtures at 298.15 K

The electrical conductances of solutions of sodium chloride (NaCl), potassium chloride (KCl), sodium bromide (NaBr), sodium iodide (NaI), sodium tetraphenylborate (NaBPh4), and tetrabutylammonium iodide (Bu4NI) in water (1) + 2-ethoxyethanol (2) mixtures containing (0.01, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.20) mol fractions of 2-ethoxyethanol have been measured at 298.15 K. The conductance data have been analyzed by the Fuoss−Justice equation. The individual limiting ionic conductivities of Na+, K+, Bu4N+, BPh4−, I−, Cl−, and Br− ions have been determined using the Fuoss−Hirsch assumption. The dependencies of the limiting molar conductances, Λo, and Walden products, Λoη, versus mixed solvent composition have been discussed.

Effect of hydrogen bond, relative permittivity and temperature on the transport properties and the association behavior of some 1:1 electrolytes in some binary mixed solvents

Effect of hydrogen bond, relative permittivity and temperature on the transport properties and the association behavior was studied through the measurements of the specific conductance of sodium acetate, sodium propionate and sodium salicylate in 10%, 20% and 30% (w/w) methanol–water (MeOH–H 2O), ethanol–water (EtOH–H 2O) and glycerol–water (GlyOH–H 2O) mixtures at different temperatures (293, 298, 303 and 308 K). The conductivity data have been analyzed using the Lee–Wheaton conductivity equation. The molar conductance ( Λ), limiting molar conductance ( Λ 0), association constants ( K A), Walden product ( Λ 0 η 0), hydrodynamic radii ( R H), fluidity ratio( R), the activation energy of the transport process ( E a) and standard thermodynamic parameters of association (∆ G A, ∆ H A and ∆ S A) were calculated and discussed. The results show that, the molar conductance values were decreased as the relative permittivity of the solvent decreased while, the association constant increased. Also the results show that the molar conductance and the association constant values were increased as the temperature increased indicate that the association process is endothermic one. The association of the studied electrolytes was also found to affect with the hydrogen bond formation.

Molar volume, viscosity and conductance studies of some alkali metal chlorides in aqueous ascorbic acid

Molar volume, viscosity and conductance of lithium chloride (LiCl), sodium chloride (NaCl) and potassium chloride (KCl) in 0.01 m aqueous ascorbic acid have been calculated from density, viscosity and conductance data at temperatures 303.15, 308.15, 313.15 and 318.15 K. The solute–solvent interactions for LiCl, NaCl and KCl have been inferred from ϕ v o, B-coefficient of Jones–Dole equation and Λ m o values. The structure making/breaking behavior of LiCl, NaCl and KCl is inferred from the sign of [∂ 2 ϕ v o/∂T 2] p, d B/dT and temperature coefficient of Walden product i.e. d( Λ m o η o)/dT values. It has been found from molar volume, viscosity and conductance studies that LiCl, NaCl and KCl behaves as structure-breaker in 0.01 m aqueous ascorbic acid solution. The energy of activation for LiCl, NaCl and KCl is calculated from conductance and viscosity data and it has found that E Λ is less than E η .

Influence of Anion Structure on Transport Properties of Perfluorosulfonylamide Ionic Liquids

We studied transport properties, i.e., viscosity (η), conductivity (σ), and cation and anion self-diffusion coefficients (Dcation, Danion), for C2mim-ILs, N122.1O2-ILs, and N1224-ILs, where C2mim+ is 1-ethyl-3-methylimidazolium, N122.1O2+ is N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium, and N1224+ is N-butyl-N,N-diethyl-N-methylammonium, composed of perfluorosulfonylamide anions. Ten perfluorosulfonylamide anions, i.e., C0C0 (FSA, FSI), C0C1 (FTA), C1C1 (TFSA, TFSI), C1C2, C2C2 (BETA, BETI), C1C4, C4C4, CTFSA, C3FSA, and TSAC, were used in this work. Walden product and "ionicity" quantity were determined from the transport property data. It became apparent that there was high correlation between the Walden product and the "ionicity" quantity for the ILs. The results of the Walden product and the "ionicity" quantity indicated that by comparison with the N122.1O2-ILs and the N1224-ILs the ion dissociation of the C2mim-ILs was large and hardly changed with the amide anion structures.

Conductance studies of NaCl, KCl, NaBr, NaI, NaBPh 4, Bu 4NI and NaClO 4 in water + 2-methoxyethanol mixtures at 298.15 K

The electrical conductances of the solutions of sodium chloride (NaCl), potassium chloride (KCl), sodium bromide (NaBr), sodium iodide (NaI), sodium tetraphenylborate (NaBPh 4), tetrabutylammonium iodide (Bu 4NI) and sodium perchlorate (NaClO 4) in water (1) + 2-methoxyethanol (2) mixtures containing 0.01, 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20 mol fractions of 2-methoxyethanol have been reported at 298.15 K. The conductance data have been analyzed by the Fuoss–Justice equation. The individual limiting ionic conductivities of Na +, K +, Bu 4N +, BPh 4 −, I −, Cl −, and Br − ions have been determined using the Fuoss–Hirsch assumption. The dependencies of the limiting molar conductances, Λ o, and Walden products, Λ o η, versus mixed solvent composition have been discussed.

Volumetric and conductometric studies on the interactions of dipeptides with sodium acetate and sodium butyrate in aqueous solutions at T = 298.15 K

Densities and conductivity data for the sodium carboxylate (sodium acetate and sodium butyrate)–dipeptides {(glycyl- l-glutamine and l-alanyl- l-glutamine) + water} systems were determined at T = 298.15 K. The apparent molar volumes of the peptides and the molar conductivity ( Λ) of sodium acetate and sodium butyrate have been calculated. These data have been utilized to deduce the standard partial molar volumes ( V 2 , Φ ∘ ), standard partial molar volumes of transfer for dipeptide from water to aqueous sodium carboxylate solutions (Δ t V °), volumetric interaction coefficient, the limiting molar conductivity ( Λ °), and Walden product ( Λ ° η). Both V 2 , Φ ∘ and Δ t V ° for the dipeptides increase with increasing concentration of sodium carboxylate. The interpretation is that this result arises from the dominant interactions of the sodium carboxylate with the charged group and polar groups of peptides. The decrease in Λ ° of sodium carboxylate with increasing dipeptide concentration and nonconstant Walden product are attributed to the interactions of sodium carboxylate with peptide and friction resistance of the solvent medium.

Conductivities of CuSO4 and CdSO4 in Sucrose/Trehalose−Water Systems at 298.15 K

The conductivities of CuSO4 and CdSO4 in aqueous disaccharide (sucrose and trehalose) solutions were measured together with the densities, viscosities, and relative dielectric constants of the aqueous disaccharide solutions at 298.15 K. The limiting molar conductivities (Λ0) and association constants (KA) were derived from the Lee−Wheaton conductivity equation. From the obtained conductivity data, the values of the Walden product (Λ0η0) were also calculated. The ion−ion and ion−solvent interactions are discussed.

CONDUCTOMETRIC INVESTIGATION OF MAGNESIUM (II), CALCIUM (II) AND BARIUM (II) COMPLEXES IN AQUEOUS SOLUTION

The ionic association constants, KA, of Mg, Ca and Ba metal ions with succinate, malate and tartrate ligands were conductometrically determined in water at 25–40oC. The conductometric data were analysed by the Shedlovsky extrapolation method. The KA values tend to decrease with the cation size in the order Ca > Ba for all the salts under study with the exception of Mg salts, whereas the KA values for the ligands increase in the order succinate < malate < tartrate. For the salts under study, standard thermodynamic functions, Ho and So for the association were evaluated and discussed. The positive values of both Ho and So in all the systems indicate the ionic association processes are the reactions of unfavorable enthalpy and favorable entropy changes in aqueous solution. The thermodynamic metal gradient, , was evaluated and its significance of ion association of all salts under investigation was discussed. On the other hand, the results of limiting molar conductance, o, are discussed on the light of Walden product.

Conductometric study of some alkali metal halides in (dimethyl sulfoxide + acetonitrile) at T = 298.15 K

Electrolytic conductivities of some alkali metal halides, MX (M + = Li +, Na +, and K +; X − = Cl −, Br −, and I −), NaBPh 4 and Bu 4NBr have been investigated in (20, 40, and 60) mass% {dimethyl sulfoxide (DMSO) in DMSO + acetonitrile} at T = 298.15 K. The conductance results have been analyzed by the Fuoss-conductance-concentration equation in terms of the limiting molar conductance Λ° the association constant K A and the association diameter R. The ionic contributions to the limiting molar conductance have been estimated using Bu 4NBPh 4 as the “reference electrolyte”. The association constant K A tends to increase in the order mass percent 20 < 40 < 60 DMSO in (DMSO + acetonitrile) which is explained by the thermodynamic parameter Δ G° and Walden product Λ° η. The results have been interpreted in terms of ion–solvent interactions and structural changes in the mixed solvents.

Study on ion–solvent interactions of alkali metal salts in pure methanol and its binary mixtures with ethane-1,2-diol by a conductometric technique

Electrolytic conductivities of some sodium salts (NaI, NaSCN, CH 3COONa) have been studied in 0, 25, 50 and 75 mass% ethane-1,2-diol + methyl alcohol mixtures at 293.15, 298.15 and 303.15 K. The limiting molar conductivity ( Λ°), the association constant ( K A ) and the distance of closest approach of ion ( R) have been evaluated using the Fuoss conductance equation (1978). The association constant ( K A ) decreases with temperature while it tends to decrease in the order: 0 mass% > 25 mass% > 50 mass% > 75 mass% ethane-1,2-diol + methyl alcohol mixtures. Thermodynamic parameters Δ H°, Δ G° and Δ S° along with the Walden products ( Λ° η) are obtained and discussed. The results have been interpreted in terms of ion–solvent interactions and structural changes in the mixed solvents.

Solvent effects and ion-solvent interactions from the studies of the solubility and dissociation constants of oxalic acid in aquo + 2-propanol mixtures and determination of single-ion Gibbs energies of transfer from water to 2-propanol + H2O mixtures

The solvent effects on the dissociation of the simplest dibasic organic acid were examined from the determination of the first and second dissociation constants ot oxalic acid conductometrically ana pH-metrically in water + 2-propanol mixtures (0-87 wt% of 2-propanol). The solubility values of oxalic acid and potassium hydrogen oxalate were also determined. The dissociation constants and the solubility values were used to calculate the Gibbs energies of transfer ΔG 0 t of oxalic acid (H 2 OX), bioxalate (HOX-), oxalate (OX 2- ) and potassium (K + ) ions from water to aquo-propanolic mixtures. These represent the 'medium effects' or quantitative measures of solute or ion-solvent interactions of the respective species in going from water to 2-propanol + water mixtures. pK 1 , pK 2 and the solubility values of oxalic acid increase continuously with increase in organic co-solvent. AG 0 t (H 2 OX) and AG 0 t (H + ) are negative i.e. favourable but AG 0 t (H 2 OX), ΔG 0 t (OX 2- ) and AG 0 t (K + ) are in general positive and hence unfavourable for the dissociation processes. The increase in basicity facilitated the dissociation processes but decrease in dielectric constant and H-bonding capability enhances the association processes as the organic co-solvent increases. The pK-values can be suitably utilised to prepare buffer solutions in 2-propanol + water mixtures. The solvent effect and solvation phenomena can be better understood from the collection of single-ion values of transfer. These may be utilised to calculate the solubilities of electrolytes in 2-propanol + water mixtures. Attempts have been made to understand the solvation processes in terms of the structure of the aquo-organic mixtures and Walden products.

Molar volume, viscosity and conductance studies of ascorbic acid in water, 0.01 M aqueous sodium chloride and dextrose + 0.01 M aqueous sodium chloride

Molar volume, viscosity and conductance of ascorbic acid in water, 0.01 m aqueous sodium chloride and 2, 4 and 6 wt. % of dextrose in 0.01 m aqueous sodium chloride solutions have been evaluated from density, viscosity and conductance data respectively at temperatures 303.15, 308.15, 313.15 and 318.15 K. The solute-solvent interactions for ascorbic acid in water, 0.01 m aqueous sodium chloride and 2, 4 and 6 wt. % of dextrose in 0.01 m aqueous sodium chloride have been inferred from φ o v , B-coefficient of Jones-Dole equation and ∧ o m values. The structure making/ breaking behaviour of ascorbic acid is inferred from the sign of [∂ 2 φ o v /∂T 2 ] p ,dB/dT, transition state theory i.e. free energy contribution per mole of solute (Δμ 2 ) and free energy contribution per mole of solvent (Δμ 1 ) values and temperature coefficient of Walden product i.e. d(Λ o m η 0 )/dT. It has been found from viscosity and conductance studies that ascorbic acid behaves as structure-breaker in water, 0.01 m aqueous sodium chloride and 2, 4 and 6 wt. % of dextrose in 0.01 m aqueous sodium chloride solutions. The energy of activation for ascorbic acid in different systems has also been calculated from conductance and viscosity data.

Studies of ion solvation and ion association of n-tetrabutylammonium hexafluorophosphate and n-tetrabutylammonium tetraphenylborate in various solvents

Conductometric investigation of n-tetrabutylammonium hexafluorophosphate (NBu 4PF 6) was performed in methanol (MeOH), ethanol (EtOH), 2-propanol (2-PrOH), acetone (ACE), 3-pentanone (PEN), tetrahydrofurane (THF), dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), dichloromethane (DCM), acetonitrile (ACN) and N-methylformamide (NMF) at 298.15 K. The limiting molar conductivities ( Λ o ) and the association constants ( K A ) were derived from the Lee–Wheaton conductivity equation. The limiting ion conductivities ( λ ± o ) were evaluated using n-tetrabutylammonium tetraphenylborate (NBu 4BPh 4) as a “reference” electrolyte according to the method of Krumgalz. The Stokes’ radii ( r St ) of PF 6 − anion were estimated and used for the calculation of its solvation numbers ( S n ) in investigated solvent media. The mobility of ions was found to be completely controlled by the bulk viscosity ( η) and consequently the Walden product ( W = ηΛ o ) was found to be almost constant. Slight ionic association was found for NBu 4PF 6 in solvent media with dielectric constant ɛ > 16 while the association becomes more significant in THF which has the lowest dielectric constant ( ɛ = 7.5). The S n values indicate weak interactions between PF 6 − and solvent molecules. The only exception was found in the case of MeOH, in which the great S n value can be attributed to a hydrogen bond formation between the fluor atoms of PF 6 − and hydrogen of MeOH molecules.

Volumetric Properties and Conductivities of 1-Butyl-3-methylimidazolium Tetrafluoroborate + Sucrose + Water Mixtures

Densities, limiting molar conductivities (Λ0), and Walden products (Λ0η) for 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4])−sucrose−water solutions were determined at 298.15 K. The measured densities were used to calculate the apparent molar volumes of sucrose (VΦ,S) and [Bmim][BF4] (VΦ,IL) in the studied solutions. Infinite dilution apparent molar volumes, VΦ,S∞ and VΦ,IL∞, have been evaluated, together with the standard transfer volumes of the sucrose (ΔtVS∞) from water to aqueous solutions of [Bmim][BF4] and those of [Bmim][BF4] (ΔtVIL∞) from water to aqueous sucrose solution. It was shown that the ΔtVS∞ and ΔtVIL∞ values are positive and increase with increasing molalities of [Bmim][BF4] and sucrose, respectively. The volumetric interaction parameters for [Bmim][BF4]−sucrose pairs in water were also obtained and interpreted by the structural interactions model. Additionally, the Λ0 values for [Bmim][BF4] decrease with the molality of sucrose (mS), as well as Walden products (Λ0η), due to ...

Electrical Behaviour of Association Phenomena of Tetra aqua-1,10-phenanthroline Iron (II) Chloride in Methanol-Water Mixtures at Different Temperatures

The electrical behaviour of mixed ligand complex of Fe(II) in different percentage of binary mixture of methanol and water at different temperatures can give information about ion-ion and ion-solvent interaction in solution so the limiting molar conductance , KA the association constant and (R) the main distance between ions in solution as a results of those interaction can be calculated. Thermodynamics parameters (H, G, S) of the association processes and the coulombic forces which play an important role in the association process also have been studied, Walden product also calculated for solvent composition which indicate the tendency of the association of the ions in different percentages.

Association of the picrate ion with cations of various nature in solvents of medium and low relative permittivity. An UV/Vis spectroscopic and conductometric study

The behavior of tetra- n-butylammonium picrate, TBAPic, in acetone– n-butyl acetate (AC–BA) solvent system, with the relative permittivity changing gradually from ε r = 20.56 to 5.10, was studied at 25.0 °C using UV/Vis spectroscopy and conductometry. Interactions of the Pic − anion with the TBA + cation in solution result in changes in its electronic absorption spectrum, though not so markedly as in the case of its association with metal ions, such as Li +, Na +, Mg 2+, La 3+, etc. The association constants (TBA + + Pic −⇄ ion pair, K A) and the limiting molar conductivities were determined using the Lee–Wheaton equation. The literature K A value in pure AC is refined. The state of TBAPic, an electrolyte with relatively poor solvated cations and anions, in solvents of medium and low polarity is discussed. At an AC content of 25 mass % and less, the 1:1 association model is unable to satisfactorily describe the conductance data. Hojo's method, modified to some extent by us, was used to fit the phoreograms by taking into consideration symmetrical ion triplets and quadruples, with equilibrium constants K T and K Q, respectively. Our approach presumes also the possible extrapolation of the plots of the Walden product logarithm, log( Λ o η), as well as that of log K A vs. ε r − 1 to required low ε r value. This allows to refine the Λ o value for pure BA and to verify the K A value estimated by Hojo's procedure in this solvent.

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.

Conductometric and thermodynamic studies on the ionic association of HCOONH 4, phCOONH 4, HCOONa and phCOONa in aqueous–organic solvents

The specific conductance of ammonium formate, ammonium benzoate, sodium formate and sodium benzoate in (10%, 20% and 30% (W/W)) methanol–water, ethanol–water and glycerol–water mixtures at different temperatures (293, 298, 303 and 308 K) was measured. The molar conductance ( Λ), limiting molar conductance ( Λ 0), limiting ionic conductance ( λ 0), association constants ( K A), the activation energy of the transport process ( E a), Walden product ( Λ 0 η 0), hydrodynamic radii (1/ r s + + 1/ r s −) − 1 , transfer numbers of the studied ions ( t), standard thermodynamic parameters of association (Δ G A, Δ H A and Δ S A) were calculated and discussed. The results show that, the molar conductance and the limiting molar conductance values were decreased as the relative permittivity of the solvent decreased while, the association constant increased. Also the results show that the molar conductance, the limiting molar conductance and the association constant values were increased as the temperature increased indicating that the association process is an endothermic one.