Effect of Temperature on the Volumetric Properties of [Difurylmethane+(C<Subscript>2</Subscript>–C<Subscript>6</Subscript>) Alkan-1-ol] Binary Systems: Analyses of New and Literature Density Data in the Temperature Range 288.15–308.15 K

Densities, ρ, of the binary systems {difurylmethane + (ethanol or propan-1-ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire composition range at 288.15 and 308.15 K and atmospheric pressure. The measured and literature densities of [difurylmethane + n-alkanol] binary systems have been used to check the validity of the relationship describing the dependence of density on composition. This relation is useful for obtaining interpolated ρ values corresponding to the experimental data. Excess molar volumes (V _m^E) of each mixture, limiting (V _m,i ^E,∞) and excess partial (V _m,i ^E) molar volumes and the limiting partial molar expansion (E _p,i ^∞) of both components of each binary system have been examined to provide insight into the temperature variations of the intermolecular interactions and molecular packing efficiencies. The results have been discussed in terms of specific intermolecular interactions and structural effects.     

Conductance of Some 1:1 Electrolytes in N,N-Dimethylacetamide at 25°C

Precise conductance measurements of solutions of lithium chloride, lithium bromide, lithium iodide, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, tetrabutylammonium bromide, and tetrabutylammonium tetraphenylborate in N,N-dimethylacetamide are reported at 25°C in the concentration range 0.005–0.015 mol-dm^–3. The conductance data have been analyzed by the 1978 Fuoss conductance equation in terms of the limiting molar conductance (⁰), the association constant (K _a), and the association diameter (R). The limiting ionic conductances have been estimated from an appropriate division of the limiting molar conductivity of the reference electrolyte Bu₄NBPh₄. Slight ionic association was found for all these salts in this solvent medium. The results further indicate significant solvation of Li⁺ion, while the other ions are found to be unsolvated in N,N-dimethylacetamide.     

Conductivity Studies of <Emphasis Type="Italic">n</Emphasis>-Tetrabutylammonium Tetraphenylborate in 3-Pentanone in the Temperature Range from 283.15 to 329.15 K

The molar conductivities (Λ) of solutions of n-tetrabutylammonium tetraphenylborate (NBu₄BPh₄) in 3-pentanone have been measured in the temperature range from 283.15 to 329.15 K. The conductance data have been analyzed using the Lee-Wheaton conductivity equation with the distance parameter (a) set at Bjerrum’s pairing distance, and the limiting molar conductivities (Λ_o) and the association equilibrium constants (K _A) have been derived. The limiting ion conductivities (λ_±^o) have been evaluated according to the method of Krumgalz. The λ₊ ^o values have been compared with λ₊ ^o values calculated from the empirical equation of Gill. The thermodynamic functions, Gibbs energy (Δ G _A ^o), enthalpy (Δ H _A ^o) and entropy (Δ S _A ^o) for the process of ion-pair formation as well as the activation energy of the ionic movement (ΔH ^∗) have been evaluated. The obtained results are discussed in terms of ion-ion and ion-solvent interactions.     

Electrical Conductance of Some Symmetrical Tetraalkylammonium and Alkali Salts in N,N-Dimethylacetamide at 25°C

Precise measurements of electrical conductances of solutions of tetraethylammonium bromide, tetrapropylammonium bromide, tetrapentylammonium bromide, tetrahexylammonium bromide, tetraheptylammonium bromide, tetraocytylammonium bromide, sodium tetraphenylborate, and potassium tetraphenylborate in N,N-dimethylacetamide at 25^°C are reported for the concentration range 0.005-0.015 mol-dm^–3. The conductance data have been analyzed by the 1978 Fuoss conductance-concentration equation in terms of the limiting molar conductance, the association constant, and the association diameter. The limiting ionic conductances have been estimated from the appropriate division of the limiting molar conductivity value of the reference electrolyte Bu₄NBPh₄. Slight ionic association was found for all these salts in this solvent medium. Tetraalkylammonium ions are found to be unsolvated in N,N-dimethylacetamide, whereas significant solvation has been noticed for sodium and potassium ions.     

Excess Molar Volumes and Excess Partial Molar Volumes of Triethylene Glycol Monomethyl Ether–n-Alcohol Mixtures at 25°C

The excess molar volumes V ^E have been measured for binary mixtures of triethylene glycol monomethyl ether with methanol, ethanol, 1-propanol, 1-pentanol, and 1-hexanol as a function of composition using a continuous–dilution dilatometer at 25°C at atmosphere pressure. V ^E are negative over the entire range of composition for the systems triethylene glycol monomethyl ether + methanol, + ethanol, and + 1-propanol, and positive for the remaining systems, containing 1-pentanol and + 1-hexanol. V ^E increases in a positive direction with increasing carbon chain length of the n-alcohol. The excess partial molar volumes V _i ^E of the components were evaluated from the V ^E results. The behavior of V ^E and V _i ^E with composition and the number of carbon atoms in the alcohol molecule is discussed.     

Tetraalkylammonium Ions in Aqueous and Non-aqueous Solutions

Property data for tetraalkylammonium cations, [H(CH₂) _n ]₄N⁺, are reviewed. They pertain to the isolated cations and their transfer from the gas phase into aqueous solutions. Various properties of these cations in aqueous and non-aqueous solutions and data for their transfer between these are also reviewed. Emphasis is placed on the dependence of data on the length n of the alkyl chains rather than on the absolute values. Most of the data are available only for the first four members of the series. The properties of the isolated ions increase linearly with the chain length. Molar enthalpies of formation of the gaseous and aqueous cations, and absolute standard molar enthalpies of hydration, are derived. Standard molar entropies of dissolution of several salts in water are obtained from their solubilities and enthalpies of solution. The molar entropies of the crystalline iodides of the first four members of the series then give the standard partial molar entropies of the aqueous cations and their molar entropies of hydration. The standard partial molar volumes in aqueous and non-aqueous solutions are quite linear with n and in non-aqueous solutions the molar volume hardly depends on the nature of the solvent. On transfer from water to non-aqueous solvents the volume of Me₄N⁺ suffers some shrinkage, that of Et₄N⁺ appears to be unaffected, but from Pr₄N⁺ onwards an increasing expansion takes place. This unexpected result is tentatively explained by hydrophobic intra-molecular association of pairs of alkyl chains in aqueous solutions, resulting in a tightening of the structure. The transfer of the R₄N⁺ cations from water into non-aqueous solvents is governed by a large positive entropy change, outweighing the smaller positive enthalpy change. The transport properties of the aqueous R₄N⁺ cations are non-linear with n. A major impediment to movement is thus the sticking of the water molecules to the ice-like hydrophobic hydration sheaths of the larger cations. The number of water molecules affected by the hydrophobic cations is open to widely differing estimates resulting from various approaches, and constitute an open issue.     

Partial molar volumes and partial molar adiabatic compressibilities of bipyridine and phenanthroline complexes with Fe(II), Co(II), Ni(II), and Cu(II) and chlorides of these metals

Densities and ultrasonic velocities were measured at 25°C for aqueous solutions of bipyridine and phenanthroline complexes [M(bpy)₃]Cl₂ and [M(phen)₃]Cl₂ (M=Fe, Co, Ni, and Cu, bpy=2,2-bipyridine, and phen=1,10-phenanthroline), and chlorides of these metals. The partial molar volumes V ₂ ^o and partial molar adiabatic compressibilities K _s ^o were calculated. For the complex ions, [M(bpy)₃]²⁺ and [M(phen)₃]²⁺, electrostatic interactions with the solvent are not nearly as important as effects due to the hydrophobic ligands bpy and phen. The relationship between V ₂ ^o and K _s ^o of the complex ions and common metal ions are examined.     

New bifunctional N-thiophosphorylated thiourea and 2,5-dithiobiurea derivatives. Crystal structures of R[C(S)NHP(S)(OiPr)2]2 (R = –N(Ph)CH2CH2N(Ph)– and –NHNH–)

A new bifunctional N-thiophosphorylated thiourea and 2,5-dithiobiurea of the common formula R[C(S)NHP(S)(OiPr)₂]₂ [R = –N(Ph)CH₂CH₂N(Ph)– (H₂L^a); –NHNH– (H₂L^b)] have been synthesized and characterized by IR, ¹H, ³¹P spectroscopy and the single crystal X-ray diffraction method. The structure of the latter compound in CDCl₃ and acetone-d₆ solutions has been discussed in comparison with the monofunctional thiosemicarbazide PhNHNHC(S)NHP(S)(OiPr)₂ (HL^c).     

Excess Molar Volumes and Partial Molar Volumes of Binary Mixtures Containing Diethylcarbonate with Benzene and Substituted Benzenes at 293.15 K

Densities of the binary mixtures of diethylcarbonate with benzene and substituted benzenes, namely toluene, bromobenzene, chlorobenzene and nitrobenzene have been measured as a function of the composition, at 293.15 K and atmospheric pressure using a bicapillary pycnometer with an accuracy of 4 parts in 10⁴.The calculated excess molar volumes, V ^E were correlated with Redlich-Kister equation. The excess molar volumes are negative over the entire range of composition for the systems diethylcarbonate with benzene, toluene, bromobenzene and nitrobenzene. An inversion of the sign of V ^E is observed over some concentration for mixtures of diethylcarbonate with chlorobenzene. Partial molar volumes, V_i are also evaluated and their values have been extrapolated to zero concentration to obtain the limiting value at infinite dilution, V^o _i . The numerical values of the excess molar volumes for binary mixtures decrease in the order: chlorobenzene > benzene > bromobenzene ≈ toluene > nitrobenzene. The results are explained in terms of dissociation of the self-associated solute molecules and the formation of aggregates between unlike molecules.     

Thermodynamic Properties of Peptide Solutions. Part 17. Partial Molar Volumes and Heat Capacities of the Tripeptides GlyAspGly and GlyGluGly,and Their Salts K[GlyAspGly] and Na[GlyGluGly] in Aqueous Solution at 25 °C

The partial molar volumes, V^o₂, and partial molar heat capacities, C_p,2^o, at infinite dilution have been determined for the two tripeptides glycylaspartylglycine (glyaspgly) and glycylglutamylglycine (glyglugly), and also for their salts K[glyaspgly] and Na[glyglugly], in aqueous solution at 25 °C. The ionization constants at 25 °C for the aspartyl and glutamyl side-chains have also been determined. These new thermodynamic results have been combined with literature data for electrolytes to obtain the volume and heat capacity changes upon ionization of the acidic side-chains of the peptides. The results are compared with those for other carboxylic acid systems. The partial molar heat capacities and volumes have also been used to calculate the contributions of the acidic amino acid side-chains to the thermodynamic properties.     

Salt Effects on Volumetric Properties of Some n-Alkoxyethanols (C1Em, m = 1, 2, and 3) in Aqueous Solutions at 298.15 K

Accurate density measurements over the whole composition range were made at a temperature of 298.15 K under ambient pressure for the mixtures of ethylene glycol monomethyl ether (2-methoxyethanol, C₃H₇O₂; C₁E₁), or diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol, C₅H₁₂O₃; C₁E₂), or triethylene glycol monomethyl ether [2-{2-(2-methoxyethoxy)ethoxy}ethanol, C₇H₁₆O₄; C₁E₃) in aqueous salt solutions having a common anion with a view to examining the cationic effect on the volumetric properties. To gain insight into the mixing behavior, results of the density measurements were used to estimate excess molar volumes, V_m^E, apparent molar volumes, V_{, i}, partial molar volumes, , excess partial molar volumes, V_m,i^E, and their limiting values at infinite dilution, V_{, i}, V_m,i, and V_m,i^E,, respectively. Aqueous solutions of the chlorides of lithium, sodium, potassium, and calcium in a concentration range to ca. 1 mol-kg^–1 were chosen for investigation as this concentration is used most frequently in applied chemistry. All mixtures except that containing lithium chloride show a decrease in the magnitude of V_m^E with the addition of a salt when compared to salt-free mixtures. Comparison of the derived volumes at infinite dilution suggested modification of the water structure as well as an electrostatic interaction between the ionic species and an alkoxyethanol molecule.     

Topological and thermodynamic investigations of binary mixtures: Molar excess volumes, molar excess enthalpies and isentropic compressibility changes of mixing

Molar excess volumes, V^E, molar excess enthalpies, H^E, and speeds of sound, u, of o-toluidine (i) + cyclohexane or n-hexane or n-heptane (j) binary mixtures have been determined over entire range of composition at 308.15 K. Speeds of sound data have been utilized to predict isentropic compressibility changes of mixing, of (i + j) mixtures. The observed V^E, H^E and data have been analyzed in terms of Graph theory. The analysis of V^E data by Graph theory reveals that o-toluidine exists as an associated molecular entity and (i + j) mixtures contain 1:1 molecular complex. It has been observed that V^E, H^E and values calculated by Graph theory compare well with their corresponding experimental values. The observed data have also been analyzed in term of Flory theory.     

Excess Molar Volumes and Excess Partial Molar Volumes of Triethylene Glycol Monoethyl Ether–n-Alcohol Mixtures at 25°C

We have measured excess molar volumes V^E _m of binary mixtures of triethylene glycol monoethyl ether with methanol, ethanol, 1-propanol, 1-pentanol, and 1-hexanol over the full range of compositions at 25°C. The measurements were carried out with a continuous-dilution dilatometer. The excess molar volumes V^E _m are negative over the entire range of composition for the systems triethylene glycol monoethyl ether + methanol, + ethanol, and + 1-propanol and positive for the remaining systems, triethylene glycol monoethyl ether + 1-pentanol, and + 1-hexanol. The excess V^E _m increases in the positive direction with increasing chain length of the n-alcohol. The measured excess volumes have been compared to our previous published data with an effort to assess the effects of replacing methyl by ethyl groups and of inserting oxyethylene groups. The results have been used to estimate the excess partial molar volumes V^E _m,i of the components. The behavior of V^E _m and V^E _m,i with composition and the number of carbon atoms in the alcohol molecule is discussed.     

Volumetic Properties of Glycerol with N,N-Dimethylformamide and with Water at 25 and 35°C

Densities of glycerol + N,N-Dimethylformamide (DMF) and glycerol + water mixtures have been measured over the full range of compositions at 25 and 35°C. Excess molar volumes and excess partial molar volumes, of each system have been calculated. All mixtures show negative values of the excess molar volume due to increased interactions between unlike molecules.     

Limiting partial molar volumes of tetra-n-alkylammonium perchlorates inN,N- dimethylacetamide,triethylphosphate and dimethyl sulfoxide atT = 298.15 K

The densities of tetraalkylammonium perchlorates R₄NClO₄(R  =  methyl, or ethyl, or propyl, or butyl) and ammonium perchlorate solutions in N, N - dimethylacetamide, dimethyl sulfoxide, and triethylphosphate have been measured over the whole composition range atT =  298.15 K. From these densities, apparent and limiting partial molar volumes of the electrolytes and ions have been evaluated and used to obtain the partial molar volume for theClO₄ ⁻  anion.     

Kinetische und thermodynamische Untersuchungen im System AgCl-LiCl-NaCl

In the ternary system silver chloride-lithium chloride-sodium chloride the kinetics of the galvanic deposition of silver on graphite electrodes was investigated as well as its dissolution without current in the molten salt saturated with chlorine gas.In addition the emf-values were measured in the temperature range between 923 K and 1,173 K by means of, the formation cell graphite/Ag(s)/AgCl(l)–LiCl(l)–NaCl(l)/Cl₂ graphite From these data the partial molar free excessGibbs energies were calculated. Using the equation for a multicomponent system as suggested byRedlich-Kister ¹ G _AgCl ^E values were obtained by a non-linear fitting process, where the fit was performed for all investigated temperatures and over the entire concentration range in the ternary system. With the parameters obtained the partial and integral excess valuesG _i ^E ,G ^E ,H _i ^E ,H ^E ,S _i ^E andS ^E were calculated.

     

Excess Molar Volumes and Partial Molar Volumes for Binary Mixtures of Water With 1,2-Ethanediol, 1,2-Propanediol,and 1,2-Butanediol at 293.15, 303.15 and 313.15 K

Abstract

From dilatometric method at 293.15,303,15, and 313.15K for binary mixtures of water and 1,2-alkane diols, the excess molar volumes, V^E and the partial molar volumes, V _i of both components at 293.15 K have been obtained as a function of mixtures composition. Excess molar volumes were calculated and correlated by a Redlich-Kister type function in terms of mole fraction. The partial molar volumes have been extrapolated to zero concentration to obtain the limiting values at infinite dilution, V ⁰ _i . All mixtures showed negative values and decreases with the chain length of diols. The values become less negative with increasing temperature. The results are explained in terms of dissociation of the self-associated diol molecules and the formation of aggregates between unlike molecules.     

Liquid Solution Densities of Ternary-Pseudobinary Mixtures of (Benzene + Cyclohexane) in the Presence of Tetrachloromethane or <Emphasis Type="Italic">n</Emphasis>-Hexane

Densities have been obtained as a function of composition for ternary-pseudobinary mixtures of [(benzene + tetrachloromethane or n-hexane) + (cyclohexane + tetrachloromethane or n-hexane)] at atmospheric pressure and the temperature 298.15 K, by means of a vibrating-tube densimeter. Excess molar volumes, V_m^E, partial molar volumes and excess partial molar volumes were calculated from the density data. The values of V_m^E have been correlated using the Redlich–Kister equation and the coefficients and standard errors were estimated. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show that the third component, CCl₄ or n-C₆H₁₄, have quite different influences on the volumetric properties of binary liquid mixtures of benzene with cyclohexane.     

Partial Molar Volumes of Transfer of Some Amino Acids from Water to Aqueous Glycerol Solutions at 25°C

Apparent molar volumes of glycine, DL--alanine, L-valine, L-leucine, and L-phenylalanine in 0.5, 1.0, 2.0, 3.5, and 5.0 m _B (mol-kg^–1) aqueous solutions of glycerol have been obtained from solution densities at 25°C using precise vibrating-tube digital densimeter. The estimated partial molar volumes at infinite dilution V ^o ₂ have been used to obtain the corresponding transfer volumes _tr V ₂ ^o from water to different glycerol–water mixtures. The transfer volumes are positive for glycine and DL--alanine, and both positive and negative for the other amino acids over the concentration range studied. Interaction coefficients have been obtained from McMillan–Mayer approach and the data have been interpreted in terms of solute–cosolute interactions.