Apparent Molar Volume and Apparent Molar Expansibility of Rubidium, Cesium, and Ammonium Cyclohexylsulfamate in Aqueous Solution

The apparent molar volume of rubidium, caesium, and ammonium cyclohexylsulfamate was determined from the density data of their aqueous solutions at 293.15, 298.15, 303.15, 313.15, 323.15, and 333.15 K. From the apparent molar volume, determined at various temperatures, the apparent molar expansibility was calculated. The limiting apparent molar volume and apparent molar expansibility were evaluated and apportioned into their ionic components. The limiting partial molar ionic volumes and expansibilities are discussed in terms of the various effects of the ion in solution on the structure of water. It was shown that the limiting partial molar ionic expansibilities of the alkali-metal cations increase with their ionic radii. The coefficients of thermal expansion of the investigated solutions at 298.15 K were calculated and are presented graphically together with some alkali-metal cyclohexylsulfamates and tetramethylammonium cyclohexylsulfamate. The densities of the investigated solutions can be adequately represented by an equation derived by Redlich.     

Apparent Molar Volume and Apparent Molar Expansibility of Lithium,Sodium, Potassium,and Tetramethylammonium Cyclohexylsulfamate in Aqueous Solution

Summary. The apparent molar volume of lithium, sodium, potassium, and tetramethylammonium cyclohexylsulfamate was determined from the density data of their aqueous solutions at 293.15, 298.15, 303.15, 313.15, and 323.15 K. The apparent molar expansibility was calculated from the apparent molar volume at various temperatures. The limiting apparent molar volume and apparent molar expansibility were evaluated and divided into their ionic components. The partial molar ionic expansibilities were discussed in terms of the hydration of the ion in solution, as well as in terms of the hydration effects on the solute as a whole. From the partial molar expansibility of the solute at infinite dilution the partial molar expansibility of the hydration shell was deduced. The coefficients of thermal expansion of the investigated solutions at 298.15 K were calculated and are presented graphically. The density of the investigated solutions can be adequately represented by an equation derived by Root.     

Apparent Molar Volume and Apparent Molar Expansibility of Lithium, Sodium, Potassium, and Tetramethylammonium Cyclohexylsulfamate in Aqueous Solution

The apparent molar volume of lithium, sodium, potassium, and tetramethylammonium cyclohexylsulfamate was determined from the density data of their aqueous solutions at 293.15, 298.15, 303.15, 313.15, and 323.15 K. The apparent molar expansibility was calculated from the apparent molar volume at various temperatures. The limiting apparent molar volume and apparent molar expansibility were evaluated and divided into their ionic components. The partial molar ionic expansibilities were discussed in terms of the hydration of the ion in solution, as well as in terms of the hydration effects on the solute as a whole. From the partial molar expansibility of the solute at infinite dilution the partial molar expansibility of the hydration shell was deduced. The coefficients of thermal expansion of the investigated solutions at 298.15 K were calculated and are presented graphically. The density of the investigated solutions can be adequately represented by an equation derived by Root.     

Apparent Molar Volumes of Some Sodium Sulfonamides in Water at Several Molalities and Temperatures

In this article, measured densities of aqueous solutions of sodium sulfadiazine, sodium sulfamerazine and sodium sulfamethazine are reported as a function of molality from 0.0500 to 0.5000 mol?kg^?1 and as a function of temperature at (278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K. The apparent molar volumes, partial molar volumes at infinite dilution and partial molar expansibilities were calculated. The dependence of these properties upon temperature is shown. The results are interpreted in terms of solute-solvent interactions.     

Volumetric Properties of Aqueous Solutions of Cyclohexylsulfamic Acid

The mean apparent molar volume of cyclohexylsulfamic acid has been determined from the density data of aqueous solutions up to a molality of 0.540 mol⋅kg⁻¹ and at 293.15, 298.15, 303.15, 313.15, and 323.15 K. The mean apparent molar volume of the acid was divided into contributing ionic and molecular apparent molar volumes. The limiting apparent molar volume of the molecular acid amounts to (131.69± 0.02) cm³⋅mol⁻¹ and the limiting apparent molar expansibility to (0.130± 0.003) cm³⋅mol⁻¹⋅K⁻¹ at 298.15 K. From the limiting ionic and molecular apparent molar volumes the limiting volume change of ionization of cyclohexylsulfamic acid was calculated. A value of −7.76 cm³⋅mol⁻¹ was evaluated at 298.15 K. The temperature dependence of the volume change of ionization amounts to −(0.018± 0.009) cm³⋅mol⁻¹⋅K⁻¹. From the density data the coefficient of thermal expansion of the investigated solutions was calculated and from this the mean apparent molar expansibility of cyclohexylsulfamic acid was derived.     

Volumetric properties of aqueous solutions of quinic acid and its sodium salt

Abstract  

The apparent molar volume of quinic acid and its sodium salt were determined from the density data of aqueous solutions up to molality of 0.4 mol kg⁻¹ and in the temperature range from 293.15 to 328.15 K. The apparent molar volume of sodium quinate comprises the ionic and the associated ion-pair contributions. From the apparent molar volumes of quinic acid and the quinate ion, the molecular contributions to that of quinic acid are derived. At 298.15 K, the limiting apparent molar volume of quinic acid is 119.8 ± 0.5 cm³ mol⁻¹, and that of the quinic ion is 111.6 ± 0.3 cm³ mol⁻¹. Similarly, at 298.15 K, the limiting apparent molar expansibility of sodium quinate is 0.198 ± 0.003 cm³ mol⁻¹ K⁻¹, and that of quinic acid is 0.142 ± 0.003 cm³ mol⁻¹ K⁻¹. From these limiting ionic and molecular apparent molar volumes, the limiting volume change caused by ionization of quinic acid was calculated as −8.2 cm³ mol⁻¹ at 298.15 K. The coefficients of thermal expansion of these solutions were calculated from the density data, and from these the apparent molar expansibilities of quinic acid and its sodium salt were derived.     

Apparent molar volumes and compressibilities of selected electrolytes in dimethylsulfoxide

Densities at T = (293.15, 298.15, 303.15, 313.15, 323.15, and 333.15) K and sound velocities at T = 298.15 K of tetraphenylphosphonium bromide, sodium tetraphenylborate, sodium bromide, and sodium perchlorate in dimethylsulfoxide have been measured over the composition range from (0 to 0.3) mol · kg⁻¹. From these data, apparent molar volumes and apparent molar isentropic compressibilities at infinite dilution as well as the expansibilities have been evaluated. The results have been discussed in terms of employing tetraphenylphosphonium tetraphenylborate as a reference electrolyte in splitting the limiting apparent molar volumes and apparent molar isentropic compressibilities into ionic contributions.     

Apparent molar volumes and compressibilities of lanthanum,gadolinium and lutetium trifluoromethanesulfonates in dimethylsulfoxide

Temperature dependencies of the densities of dimethylsulfoxide solutions of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been determined over a wide range of concentrations. The apparent molar volumes and partial molar volumes of the salts at infinite dilution, as well as the expansibilities of the salts, have been calculated from density data. Additionally, the apparent molar isentropic compressibilities of lanthanum, gadolinium and lutetium trifluoromethanesulfonates have been calculated from sound velocity data at 298.15 K. The data obtained have been interpreted in terms of ion−solvent interactions.     

Apparent Molar Volume and Viscosity Studies on Some Carbohydrates in Solutions

Summary.  The apparent molar volume (φ_v) and viscosity (η) of L(+)-arabinose, D(+)-galactose, D(−)-fructose, D(+)-glucose, sucrose, lactose, and maltose in water and in 0.1% and 0.3% water-Surf Excel solutions were measured as a function of solute concentrations at 308.15, 313.15, and 323.15 K, respectively. The apparent molar volume (φ_v) of the carbohydrates was found to be a linear function of the concentration. From a φ_v versus molality (b) plot, the apparent molar volume at infinite dilution (), which is practically equal to the partial molar volume at infinite dilutions () of these substances was determined. The viscosity coefficients B and D for the carbohydrates were calculated on the basis of the viscosity of the solutions and the solvent using the Jones-Dole equation. The activation free energy for viscous flow (ΔG ^≠) of the solutions was also calculated using the Eyring equation. The carbohydrates showed structure making behaviour both in water and in water-Surf Excel solutions. When water-Surf Excel solutions and pure water solutions containing carbohydrate molecules are compared, the former were found to be more structured. The behaviour of these solutes in water and in water-Surf Excel solution systems is discussed in the light of solute–solvent interactions. Corresponding author. E-mail: chemistry_ru@yahoo.com Received March 19, 2002; accepted (revised) July 31, 2002 Published online February 24, 2003     

Volumetric and compressibility studies for (L-arginine + D-maltose monohydrate + water) system in the temperature range of (298.15 to 308.15) K

The density and speed of sound of L-arginine (0.025–0.2 mol kg^?1) in aqueous + D-maltose (0–6 mass% of maltose in water) were obtained at temperatures of (298.15, 303.15 and 308.15) K. The apparent molar volume, limiting apparent molar volume, transfer volume, as well as apparent molar compressibility, limiting apparent molar compressibility, transfer compressibility, pair and triple interaction coefficients, partial molar expansibilities, coefficient of thermal expansion and also the hydration number, were calculated using the experimental density and speed of sound values. The results have been discussed in terms of solute–solute and solute–solvent interactions in these systems. Solute–solvent (hydrophilic–ionic group and hydrophilic–hydrophilic group) interactions were found to be dominating over solute–solute (hydrophobic–hydrophilic group) interactions in the solution, which increases with increase in maltose concentration.     

Apparent Molar Volume and Viscosity Studies on Some Carbohydrates in Solutions

 The apparent molar volume (φ_v) and viscosity (η) of L(+)-arabinose, D(+)-galactose, D(−)-fructose, D(+)-glucose, sucrose, lactose, and maltose in water and in 0.1% and 0.3% water-Surf Excel solutions were measured as a function of solute concentrations at 308.15, 313.15, and 323.15 K, respectively. The apparent molar volume (φ_v) of the carbohydrates was found to be a linear function of the concentration. From a φ_v versus molality (b) plot, the apparent molar volume at infinite dilution (), which is practically equal to the partial molar volume at infinite dilutions () of these substances was determined. The viscosity coefficients B and D for the carbohydrates were calculated on the basis of the viscosity of the solutions and the solvent using the Jones-Dole equation. The activation free energy for viscous flow (ΔG ^≠) of the solutions was also calculated using the Eyring equation. The carbohydrates showed structure making behaviour both in water and in water-Surf Excel solutions. When water-Surf Excel solutions and pure water solutions containing carbohydrate molecules are compared, the former were found to be more structured. The behaviour of these solutes in water and in water-Surf Excel solution systems is discussed in the light of solute–solvent interactions.     

Apparent Specific Volume and Apparent Specific Refraction of Some Poly(oxyethylene) Glycols in 1,4-Dioxane and Benzene Solutions at 298.15 K

Summary. The density and refractive index of 1,4-dioxane and benzene solutions of poly(oxyethylene) glycols of the type HO–(CH₂CH₂O)_n–H (n varying from 4 to 36) were measured at 298.15K. From the experimental data the apparent specific volume and the apparent specific refraction at infinite dilution were calculated. The limiting apparent specific volume and the limiting apparent specific refraction were found to be inversely proportional to the number average molecular weight of solute. From the limiting apparent specific values at the infinite degree of polymerization, the partial molar volume and partial molar refraction of the monomeric unit were calculated. The partial molar volume as well as the partial molar refraction of the investigated compounds at infinite dilution are additive and depend linearly on the number of oxyethylene groups. The volumetric data were analyzed in terms of the intrinsic volume of solute molecules and by a void partial molar volume. The packing density of the investigated compounds approaches a uniform value as the size of the molecules increases and in both solvents limiting values are reached.     

Volumetric properties of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B1) in dilute HCl and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K

Apparent molar volumes and apparent molar isentropic compressibilities of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B₁) were determined from accurately measured density and sound velocity data in water and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K. These volume and compressibility data were extrapolated to zero concentration using suitable empirical or theoretical equations to determine the corresponding infinite dilution values. Apparent molar expansibilities at infinite dilution were determined from slopes of apparent molar volume vs. temperature plots. Ionization of both ascorbic acid and thiamine hydrochloride were suppressed using sufficiently acidic solutions. Apparent molar volumes at infinite dilution for ascorbic acid and thiamine hydrochloride were found to increase with temperature in acidic solutions and in the presence of co-solute, NaCl. Apparent molar expansibility at infinite dilution were found to be constant over the temperature range studied and were all positive, indicating the hydrophilic character of the two vitamins studied in water and in the presence of co-solute, NaCl. Apparent molar isentropic compressibilities of ascorbic acid at infinite dilution were positive in water and in the presence of co-solute, NaCl, at low molalities. Those of thiamine hydrochloride at infinitive dilution were all negative, consistent with its ionic nature. Transfer apparent molar volumes of vitamins at infinite dilution from water solutions to NaCl solutions at various temperatures were determined. The results were interpreted in terms of complex vitamin-water-co-solute (NaCl) interactions.     

Apparent molar volumes and expansibilities of 1-octanol, 1-nonanol,and 1-decanol in dilute cyclohexane solutions

The densities of solutions of 1-octanol, 1-nonanol, and 1-decanol in cyclohexane up to concentrations of 1.56 mol kg^–1 were measured at temperatures between 20 and 60°C. The apparent molar volumes and expansibilities were found to be linearly dependent on solute concentration. The excess molar volume and the excess thermal expansion coefficient of the solute were derived from the partial molar volume of the solute at infinite dilution and the solute densities. In addition, the limiting partial molar volume of the solute is discussed in terms of the scaled particle theory.     

Effect of Amino Acids and Sodium Chloride on <Emphasis Type="SmallCaps">d</Emphasis>-Sorbitol in Aqueous Solutions at Different Temperatures: Volumetric and Acoustic Approach

Apparent molar volumes and apparent molar compressibilities for d-sorbitol in (0.05, 0.1, 0.2 and 0.3) mol·kg^?1 aqueous solutions of l-alanine, l-cysteine and l-histidine and NaCl have been determined from measurements of solution density at T?=?(288.15, 298.15, 308.15 and 318.15) K and sound velocity at T?=?298.15 K, as a function of the concentration of the sugar alcohol. The data were used to obtain the limiting apparent molar volumes, limiting apparent molar compressibilities and the corresponding transfer parameters. Limiting apparent molar expansibilities and their second order derivatives and volume interaction coefficients were also estimated. These parameters are discussed in terms of d-sorbitol and co-solute (amino acid or sodium chloride) interactions in aqueous solutions.     

氨基酸-醇-水体系的密度与表观摩尔体积

用DMA602/60型震动管数字密度计测定了298.15 K下甘氨酸、丙氨酸分别在纯水和四个不同浓度甲醇、乙醇和丙醇水溶液中的密度, 计算了相应的表观摩尔体积, 用最小二乘法拟合了氨基酸在醇水溶液中的标准偏摩尔体积. 根据McMillan-Mayer理论拟合了水溶液中氨基酸分别与醇相互作用的对相互作用参数Vab和三相互作用参数Vabb, Vaab. 结果表明甘氨酸、丙氨酸在醇水溶液中的表观摩尔体积都随醇浓度的增加而增加, 都属亲水破坏性溶质; 其自相互作用参数和三相互作用参数均为正值, 对相互作用参数Vab均为负值且随烃基链的延长, 负值依次增大. 分别根据极性分子的相互作用模型、结构水化模型和溶剂分离缔合模型进行了讨论.     

Apparent Molar Volumes and Solvation Coefficients in Ternary-pseudo-binary Mixtures [（Styrene＋Ethyl Acetate or Benzene）＋（N-Methyl-2-pyrrolidone＋Ethyl Acetate or Benzene）]

Over the full range of compositions,in the ternary-pseudo-binary mixtures of x[(1-y)C6H5CH=CH2+ yCH3COOC2H5(or C6H6)]+(1-x)[(1-y)NMP+yCH3COOC2H5(or C6H6)],the apparent molar volumes of each pseudo-pure component at different y values were calculated from the density data at 298.15 K and atmospheric pressure.The results show that the four parameters cubic polynomial can correlate the apparent molar volume with the molar fraction well over the full molar fraction range.The limiting partial molar volumes and the molar volumes of each pseudo-pure component were evaluated with different methods.Based on the limiting partial molar volume and molar volume at a certain y value,a new universal coefficient termed as solvation coefficient γ was defined to describe quantitatively the solvation degree of pseudo-pure solute and the interactions of solute-solvent molecules from the macroscopical thermodynamics viewpoint.The results demonstrate the solvation coefficients decrease with the amount of the third component increasing for each pseudo-pure solute,irrespective of the pseudo-pure solvent.Then the solvation degrees of each pseudo-pure component,the specific interactions between the solute molecule and the solvent one were discussed in terms of the solvation coefficient.     

Determination of the Apparent Molar Refraction and Partial Molar Volume at Infinite Dilution of Thiophene-, Pyrrole- and Furan-2-Carboxaldehyde Phenylhydrazone Derivatives in Acetonitrile at 293.15 K

High-precision densitometry and high-accuracy refractometry measurements of extremely dilute solutions of the thiophene-2- (TCPH), pyrrole-2- (PCPH) and furan-2-carboxaldehyde-phenylhydrazone (FCPH) compounds in acetonitrile have been obtained at 293.15 K. The partial molar volumes V ₂^∞ of each compound at infinite dilution were determined. The apparent molar refraction of these solutes at infinite dilution at 293.15 K has been experimentally determined within the Kohner-Geffcken-Grunwald-Haley approximation. The volumetric and refractometric results were interpreted in terms of the Pauling electronegativity and intrinsic molar volume of the heteroatom, and the aromaticity of the heterocyclic rings. The experimental results indicate that solute-solute interactions are negligible within the concentration range studied. Theoretical calculations at the DFT-B3LYP/6−311++G(3d,3p) level of molecular volumes support the interpretation that the volumetric contribution from the solute-solvent interactions to the limiting partial molar volumes of solutes are very small and thus solute molecules are isolated in this medium.     

Effect of dipotassium hydrogen phosphate on thermodynamic properties of glycine and l-alanine in aqueous solutions at different temperatures

Densities, ρ, speed of sound, u for glycine, l-alanine have been measured in aqueous solutions of dipotassium hydrogen phosphate (DKHP) ranging from 0.2, 0.4, 0.6 and 0.8 mol·kg⁻¹ at temperatures T = (288.15, 298.15, 308.15 and 318.15) K. The different parameters such as apparent molar volume, limiting apparent molar volume, transfer volume, partial molar expansibility have been derived from density data. Experimental speeds of sound data were used to estimate apparent molar adiabatic compressibility, limiting apparent molar adiabatic compressibility, transfer parameter and hydration number. These parameters have been discussed in the light of ion-ion and ion-solvent interactions.     

Partial molar volumes of tetraalkylammonium hydroxides in aqueous solution at 25°C

The densities of aqueous solutions of tetramethylammonium, tetraethylammonium, tetra-n-propylammonium and tetra-n-butylammonium hydroxide have been measured at 25°C in the concentration range 0.1–1.0 mol-kg^-1 . The apparent and partial molar volumes are calculated from the density measurements. The apparent molar volumes of the solutes show considerable deviation from the Debye-Hülckel limiting law, even at high dilution. The relation for the concentration dependence of the apparent molar volume is given in an analytical form. The limiting apparent molar volumes of the solutes are split into their ionic components by an extrathermodynamic approach and are discussed in terms of ion-solvent interactions. In this way, the limiting partial molar ionic volume for the hydroxide ion is found to be 2 cm³-mol^-1.