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1.
The apparent molar volumes, Vφ of tetramethylammonium, tetraethylammonium, tetrabutylammonium, butyltriethylammonium, dibutyldiethylammonium, and tributylethylammonium
bromides have been measured at 298.15K in the concentration range from 0.01 to 0.04mol⋅kg−1. The concentration dependence of Vφ is given using the Redlich and Meyer relation. The apparent molar volume at infinite dilution, V∘_φ, and the empirical constant, BV, have been calculated. The CH2-group contribution has been obtained by the additivity rule. The results were interpreted in terms of solute–solvent interactions. 相似文献
2.
Cveto Klofutar Jaka Horvat Darja Rudan-Tasic 《Monatshefte für Chemie / Chemical Monthly》2006,35(3):1151-1162
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. 相似文献
3.
Cveto Klofutar Jaka Horvat Darja Rudan-Tasic 《Monatshefte für Chemie / Chemical Monthly》2006,137(9):1151-1162
Summary. 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. 相似文献
4.
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. 相似文献
5.
Specific heat capacities and apparent molar heat capacities of aqueous nicotinamide have been determined from 25.0 to 55.0°C using microdifferential scanning calorimetry in the molality range of 0.07433 to 1.50124 mol-kg–1. Densities and apparent molar volumes have also been determined for aqueous nicotinamide from 10.30 to 34.98°C using a digital densimeter in the molality range 0.07804–2.02435 mol-kg–1. The results of these measurements have been used to calculate the following partial molar quantities and temperature derivatives for aqueous nicotinamide as a function of temperature: C
p,2,m
o, (C
p,2,m
o/T)p, (2Cp,2,m
o/T
2)p, V
2,m
o, ( V
2,m
o/T)p, and (2
V
2,m
2/T
2)p. The results are discussed in terms of the changes in the packing of nicotinamide molecules in the crystal, interactions in the aqueous form, and its structure-promoting ability with rise in temperature. 相似文献
6.
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. 相似文献
7.
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. 相似文献
8.
Specific heats and apparent molar heat capacities of aqueous 1,1,1,3,3,3-hexafluoroiso- proanol (HFIP) have been determined at temperatures from 20.0 to 45.0°C using micro differential scanning calorimetry in the molality range of 0.06741 to 1.24053 mol-kg– 1. Densities and apparent molar volumes have also been determined for aqueous HFIP at temperatures from 10.3 to 30.0°C using digital densimetry in the molality range of 0.04009 to 0.67427 mol-kg– 1. The results of these measurements have been used to calculate the following partial molar quantities and temperature derivatives for aqueous HFIP as a function of temperature: Cp,2,m°, (Cp,2,m°/T)p, (2Cp,2,m°/T2)p, V2,m° and (V2,m°/T)p. The contribution of the — F atom to the partial molar heat capacity and volume has been calculated. The results have been explained in terms of structural changes in water in aqueous HFIP solution. The results obtained in this work contain essential information needed for the development of an equation of state for this system, when used in combination with other thermodynamic properties of aqueous HFIP. 相似文献
9.
The paper is dedicated to determining the partial and apparent molar volumes of aqueous electrolytes in a wide concentration range where formulas are commonly employed that are applicable only for very low concentrations. 相似文献
10.
S. Vani Latha G. Little Flower K. Rayapa Reddy C. V. Nageswara Rao A. Ratnakar 《Journal of solution chemistry》2017,46(2):305-330
Organic esters of carbonic acid {dimethyl carbonate (DMC)/diethyl carbonate (DEC)/propylene carbonate (PC)}, in combination with a lactate ester {ethyl lactate (EL)}, with green chemistry characteristics were chosen for the present study of molecular interactions in binary liquid mixtures. Densities (ρ) and ultrasonic velocities (U) of the pure solvents and liquid mixtures were measured experimentally over the entire composition range at temperatures (303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. The experimental data was used to calculate thermodynamic and acoustic parameters \( V_{\text{m}}^{\text{E}} \), \( \kappa_{S}^{\text{E}} \), \( L_{\text{f}}^{\text{E}} \), \( \bar{V}_{\text{m,1}}^{{}} \), \( \bar{V}_{\text{m,2}}^{{}} \), \( \bar{V}_{\text{m,1}}^{\text{E}} \), \( \bar{V}_{\text{m,2}}^{\text{E}} \), \( \bar{V}_{ 1}^{\text{E,0}} \) and \( \bar{V}_{ 2}^{\text{E,0}} \) and the excess functions were fitted with the Redlich–Kister polynomial equation to obtain the binary solution coefficients and the standard deviations. It was observed that the values of \( V_{\text{m}}^{\text{E}} \), \( \kappa_{S}^{\text{E}} \) and \( L_{\text{f}}^{\text{E}} \) are positive for the mixtures of (EL + DMC/DEC) and negative for those of (EL + PC) over the entire range of composition and temperature. The positive values of \( V_{\text{m}}^{\text{E}} \), \( \kappa_{S}^{\text{E}} \) and \( L_{\text{f}}^{\text{E}} \) indicate the action of dispersion forces between the component molecules of (EL + DMC/DEC) mixtures whereas negative values for the mixture (EL + PC) suggest the existence of strong specific interactions between the component molecules, probably resulting from chemical and structural contributions. The excess properties have also been analyzed by using the reduced (\( Y^{\text{E}} /x_{1} x_{2} \)) excess function approach and the results are found to be in agreement with those from the corresponding \( Y^{\text{E}} \)(= \( V_{\text{m}}^{\text{E}} \), \( \kappa_{S}^{\text{E}} \) and \( L_{\text{f}}^{\text{E}} \)) values. This is further supported by FTIR spectral analysis. 相似文献
11.
Densities of four aqueous NaNO3 solutions (0.100, 0.303, 0.580, 0.892 mol-kg–1 H2O) have been measured in the liquid phase with a constant-volume piezometer immersed in a precision liquid thermostat. Measurements were made at ten isotherms between 292 and 573 K. The range of pressure was 0.1–30 MPa. The total uncertainty of density, pressure, temperature, and concentration measurements were estimated to be less than 0.06%, 0.05%, 10 mK, and 0.014%, respectively. Values of saturated densities were determined by extrapolating experimental P- data to the vapor pressure at fixed temperature and composition. Apparent molar volumes were derived using measured values of density for the solutions and for pure water. The apparent molar volumes were extrapolated to zero concentration to yield partial molar volumes at infinite dilution. The temperature, pressure, and concentration dependence of partial and apparent molar volumes were studied. The measured values of density and apparent and partial molar volume were compared with data reported in the literature. 相似文献
12.
New experimental data for the density, speed of sound, and refractive index of aqueous solutions of diglycine + NaCl and triglycine + NaCl have been reported. The apparent molar volume and apparent molar isentropic compressibility of these peptides at various NaCl concentrations have been calculated from the measured properties. The results show that both peptides exhibit a positive volume transfer to solutions with higher NaCl concentrations and a negative apparent isentropic compressibility in the presence of NaCl. These effects indicate that the apparent volumes of the peptide molecules are larger in solutions with higher NaCl concentrations and that the water molecules around the peptide molecules are less compressible than the water molecules in the bulk solvent. These effects are attributed to the doubly charged nature of the peptides and the interactions between the charged groups and hydrocarbon backbone of peptides with the ions. 相似文献
13.
Héctor Rodríguez Ana Soto Alberto Arce Mohammad K. Khoshkbarchi 《Journal of solution chemistry》2003,32(1):53-63
New experimental data at 25°C for the density, velocity of sound, refractive index, and viscosity of aqueous solutions of DL-alanine and NaCl are reported. The apparent molar volume and isentropic compressibility of DL-alanine in aqueous electrolyte solutions have been calculated from the measured properties. The results show that DL-alanine exhibits a positive volume transfer to solutions of a higher NaCl concentration and a negative apparent isentropic compressibility for DL-alanine in the presence of NaCl. These effects indicate that the apparent volume of DL-alanine is larger in solutions with higher electrolyte concentration and the water molecules surrounding the DL-alanine molecules are less compressible than the water molecules in the bulk solution. The results also show an increase in the viscosity of the solution with an increase in both DL-alanine and NaCl concentrations. These effects are attributed to the two charged groups of DL-alanine and the interactions between the charged groups and the hydrocarbon backbone of DL-alanine with the ions. A model, consisting of a short-range interaction term represented by a virial expansion and a Debye-Hückel term that considers long-range interactions, has been developed to correlate the measured experimental data. 相似文献
14.
O'Brien RW 《Physical chemistry chemical physics : PCCP》2006,8(43):5115-5123
Porous colloidal particles can dissipate ultrasonic energy at a much greater rate than solid particles of the same size and density. In this paper the mechanism for this extra dissipation is described, and a theoretical formula for the attenuation is derived for particles with interconnected pores. In Part II (William N. Rowlands, James K. Beattie, Alex M. Djerdjev, and Richard W. O'Brien, Phys. Chem. Chem. Phys., 2006, DOI: 10.1039/b605617m) this formula is compared to measurements on some porous particle systems. 相似文献
15.
Data for the apparent molar volumes of aqueous dimethylamine and dimethylammonium chloride have been determined with platinum vibrating tube densimeters at temperatures 283.15 K T 523.15 K and at different pressures. Apparent molar heat capacities were measured with a Picker flow microcalorimeter over the temperature range 283.15 K T 343.15 K at 1 bar. At high temperatures and steam saturation pressures, the standard partial molar volumes
of dimethylamine and dimethylammonium chloride deviate towards positive and negative discontinuities at the critical temperature and pressure, as is typical for many neutral and ionic species. The revised Helgeson-Kirkham-Flowers (HKF) model and fitting equations based on the appropriate derivatives of solvent density have been used to represent the temperature and pressure dependence of the standard partial molar properties. The standard partial molar heat capacities of dimethylamine ionization
, calculated from both models, are consistent with literature data obtained by calorimetric measurements at T 398 K to within experimental error. At temperatures below 523 K, the standard partial molar volumes of dimethylamine ionization
agree with those of morpholine to within 12 cm3-mol-1, suggesting that the ionization of secondary amine groups in each molecule is very similar. The extrapolated value for
of dimethylamine above 523 K is very different from the values measured for morpholine at higher temperature. The difference is undoubtedly due to the lower critical temperature and pressure of (CH3)2NH(aq). 相似文献
16.
B. Tutaj A. González-Pérez J. Czapkiewicz J. L. Del Castillo J. R. Rodriguez 《Journal of solution chemistry》2001,30(12):1101-1109
Apparent molar volumes at infinite dilution of benzyltrimethylammonium bromide and its butyl and hexyl homologs at 15, 25, and 35°C and of dibenzyldimethylammonium bromide at 25°C in aqueous solution were estimated from density measurements. The additivity rule for the contribution of the methylene groups to the apparent molar volumes was found to be obeyed within a broad range of homologs, which covers the parent salt and the dodecyldimethylbenzylammonium bromide. The volumetric contribution of the phenylene (–C6H4–) group was estimated to be 61 cm3-mol–1 at 25°C. A value of –16.9 ± 0.3 cm3-mol–1 was suggested for the volumetric contribution of the N+ fragment to the apparent molar volume of alkylbenzyldimethylammonium salts. 相似文献
17.
Pedro Bernal Albert Bunn Jennifer Logan Jennifer McCluan 《Journal of solution chemistry》2000,29(7):651-665
Apparent molar volumes and adiabatic compressibilities of 18-crown-6,15-crown-5, 12-crown-4, tetraglyme, and triglyme were measured at 15, 25, and40°C. Apparent molar expansibilities andK
o
Tvalues were also determined.The contribution of the -CH2CH2O- group to the limiting partial molar volumesand compressibilities of cyclic and open-chain ethers are compared. It isconcluded, on the basis of the compressibility results, that there is a subtle differencebetween the hydration of the ethene-oxide group in cyclic and open-chain ethers. 相似文献
18.
Densities of NaOH(aq) solutions with molalities between 0.033 and 6.047 mol⋅kg−1 were measured with a vibrating-tube densitometer at temperatures between 373 K and 623 K and pressures from near the saturation vapor pressure of water to 30 MPa. Apparent molar volumes, V
φ, calculated from the measured densities in this work were well represented with the Pitzer ion-interaction treatment up to T = 523 K. Above that temperature the formation of ion pairs must be taken into account to describe correctly the molality dependence of V
φ and for the reliable extrapolation of V
φ to infinite dilution. Standard-state thermodynamic properties for the ion formation reaction were taken from recently published electrical conductivity measurements. A comparison with previous correlations of volumetric properties of NaOH(aq) is presented covering the full range of pressure and temperature. 相似文献
19.
Densities of four (2.124, 2.953, 5.015 and 6.271 mol-kg−1) and viscosities of eight (0.265, 0.503, 0.665, 1.412, 2.106, 2.977, 5.015 and 6.271 mol-kg−1) NaNO3(aq) solutions have been measured with a constant-volume piezometer immersed in a precision liquid thermostat and using capillary flow techniques, respectively. Measurements were made at pressures up to 30 MPa. The temperature range was 298–607 K for the density measurements and 298–576 K for the viscosity measurements. The total uncertainty of density, viscosity, pressure, temperature and composition measurements were estimated to be less than 0.06%, 1.6%, 0.05%, 15 mK and 0.02%, respectively. The temperature, pressure and concentration dependence of density and viscosity of NaNO3(aq) solutions were studied. The measured values of density and viscosity of NaNO3(aq) were compared with data and correlations reported in the literature. Apparent molar volumes were derived using the measured density values. The viscosity data have been interpreted in terms of the extended Jones–Dole equation for strong electrolytes. The values of the viscosity A-, B-, D- and F-coefficients of the extended Jones–Dole equation for the relative viscosity (η/η0) of NaNO3(aq) solutions were evaluated as a function of temperature. The derived values of the viscosity A- and B-coefficients were compared with the results predicted by Falkenhagen–Dole theory of electrolyte solutions and calculated with the ionic B-coefficient data. 相似文献
20.
The refractive index, n
D
, and density, ρ, of binary mixtures of monoalcohols + water, have been measured at a temperature of 298.15,K and atmospheric pressure. The variation of the refractive indices of these solutions has also been determined with temperature in the range T = (278.15 to 338.15) K and atmospheric pressure. A comparative study has been made of the refractive indices obtained experimentally and those calculated by means of the Lorentz-Lorenz [Theory of Electrons, Dover Phoenix (1952)] and Gladstone-Dale relations [Trans. R. Soc. London 148:887–902 (1858)]; in all cases, the Gladstone–Dale equation was seen to afford values similar to those obtained experimentally. Calculations have been made of the excess molar volumes, V
E, and the molar refraction deviations, ΔR, of these mixtures and the differences between the experimental values for refractive index and those obtained by means of the Gladstone–Dale equation. Values of V
E were compared with others in the literature. In all cases the V
E values were negative, and in all cases, except in the methanol + water, ΔR showed a maximum for x = 0.8. 相似文献