首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The mole fraction solubility of phenacetin (PNC) in methanol + water binary solvent mixtures at 298.15 K was determined along with density of the saturated solutions. All these solubility values were correlated with the Jouyban–Acree model. Preferential solvation parameters of PNC by methanol (δx1,3) were derived from their thermodynamic solution properties using the inverse Kirkwood–Buff integrals (IKBI) method. δx1,3 values are negative in water-rich mixtures but positive in methanol mole fraction of >0.32. It is conjecturable that in the former case the hydrophobic hydration around non-polar groups of PNC plays a relevant role in the solvation. The higher solvation by methanol in mixtures of similar cosolvent compositions and methanol-rich mixtures could be explained in terms of the higher basic behaviour of methanol.  相似文献   

2.
A thermochemical study of the processes of L-proline dissolution in aqueous solutions of acetonitrile, 1,4-dioxane, acetone, dimethyl sulfoxide, nitromethane and tetrahydrofuran at Т = 298.15 K in the range of organic solvent concentrations x2 = 0–0.25 mole fractions is performed. Standard values of the enthalpies of solution and transfer of L-proline from water to mixed solvent, and the enthalpy coefficients of pairwise interactions between L-proline and molecules of organic solvents, are calculated. The effect the composition of a water–organic mixture and the structure of organic solvents have on the enthalpy characteristics of L-proline dissolution and transfer is examined. The effect the energy properties of intermolecular interactions between components of a mixed solvent has on the intermolecular interactions between L-proline and molecules of cosolvent is estimated. The correlation between the enthalpy characteristics of L-proline dissolution and electron-donor properties of organic cosolvent in aqueous solutions is determined.  相似文献   

3.
The solubility data of tetranitroglycoluril in acetone, methanol, ethanol, ethyl acetate, nitromethane and chloroform at temperatures ranging from 295–318 K were measured by gravimetric method. The solubility data of tetranitroglycoluril were fitted with Apelblat semiempirical equation. The dissolution enthalpy, entropy and Gibbs energy of tetranitroglycoluril were calculated using the Van’t Hoff and Gibbs equations. The results showed that the Apelblat semiempirical equation was significantly correlated with solubility data. The dissolving process was endothermic, entropy-driven, and nonspontaneous.  相似文献   

4.
The study of physical properties of binary liquid mixtures is of great importance for understanding and characterisation of molecular interactions. In the same way, some models attempt to correlate viscosity in liquid mixtures to release eventual interactions, structures’ change and peculiar behaviours. Grunberg–Nissan (GN) parameters for viscosity (η) in 1,4-dioxane?+?water mixtures over the entire range of mole fractions under atmospheric pressure and from 293.15?K to 320.15?K were calculated from experimental dynamic viscosities presented in previous works. Many experimenters investigate physicochemical properties using numerous models to derive some interpretations and conclusions. The present work comes within the framework of correlating different used equations to restrict investigations with an optimal of number of these models. Relationship between the GN, Arrhenius and Jouyban–Acree parameters for viscosity is shown in one binary mixture which dielectric constants of their pure components are very distinct.  相似文献   

5.
The solubility of phthalic anhydride was measured at 283–313 K under atmospheric pressure in ethyl acetate, n-propyl acetate, methyl acetate, acetone, 1,4-dioxane, n-hexane, n-butyl acetate, cyclohexane, and dichloromethane. The solubility of phthalic anhydride in all solvents increased with the increasing temperature. The Van’t Hoff equation, modified Apelblat equation, λh equation, and Wilson model were used to correlate the experimental solubility data. The standard dissolution enthalpy, the standard entropy, and the standard Gibbs energy were evaluated based on the Van’t Hoff analysis. The experimental data and model parameters would be useful for optimizing of the separation processes involving phthalic anhydride.  相似文献   

6.
The tables of recommended numerical values for the water solubility of helium at gas partial pressures of 0.1–100 MPa within a temperature range of 278.15–353.15 K are given. The thermodynamic characteristics of dissolution of helium in water at the mentioned parameters of state have been calculated. The independence of the dissolution enthalpy on the pressure has been recognized and explained.  相似文献   

7.
8.
9.
《Fluid Phase Equilibria》1999,157(1):41-51
Isothermal vapour–liquid equilibrium data are reported for binary mixtures of propan-2-one with 1,1,2,2-tetrachloroethane (I) and 1,4-dichlorobutane (II) within the 298.15–313.15 K temperature range. Total vapour pressures were measured by a static method, the mixtures beeing prepared by weight and degased directly into the working cell. The experimental data were correlated by Barker's method and different expressions for excess Gibbs energy were tested. The results indicate negative deviation from ideality for mixture (I), while mixture (II) behaves almost ideally, with slightly positive deviations.  相似文献   

10.
The solubilities of budesonide (BDS) in binary aqueous mixtures of N-methyl-2-pyrrolidone at temperatures ranging from 293.2 to 313.2 K were determined and mathematically correlated by three cosolvency models, i.e. Jouyban–Acree model, Jouyban–Acree–van’t Hoff model and modified Wilson model. The solubilities were measured using the shake-flask method and the models wereused to fit the solubility data of BDS in the solvent mixtures. The obtained mean relative deviations (MRDs %) for cosolvency models trained using whole data points varied between 5.0% and 31.0%. Solubilities were also predicted by the generally trained version of the Jouyban–Acree model with the MRD of 37.0%. Furthermore, the apparent thermodynamic properties of dissolution process of BDS in all the mixed solvents were calculated according to van’t Hoff and Gibbs equations. Dissolution of BDS in these mixed solvents is an endothermic process.  相似文献   

11.
Calculation of excess properties in N,N-dimethylacetamide + 2-ethoxyethanol binary mixtures at (298.15, 308.15 and 318.15) K from experimental density, viscosity and sound velocity values were presented in previous work. Applications of these experimental values to test different correlation equations as well as their corresponding relative functions were also reported. Considering the quasi-equality between the Arrhenius activation energy Ea and the enthalpy of activation of viscous flow ?H*, here we can define partial molar activation energy Ea1 and Ea2 for N,N-dimethylacetamide and 2-ethoxyethanol, respectively, along with their individual contribution separately. Correlation between the two Arrhenius parameters of viscosity in all the domains of composition shows the existence of two main distinct behaviours separated by a stabilised structure in a short range of mole fraction in N,N-dimethylacetamide from 0.14 to 0.45. We add that correlation reveals interesting Arrhenius temperature, which is closely related to the vaporisation temperature in the liquid vapour equilibrium.  相似文献   

12.
Excess molar volumes and viscosity deviations in N,N-dimethylacetamide?+?dimethylformamide binary mixtures at 298.15, 308.15 and 318.15?K were calculated from experimental density and viscosity data presented in the previous work. Here these experimental values were used to test the applicability of the correlative reduced RedlichKister equation and the recently proposed Herráez equation. Their correlation ability at different temperatures, and the use of different number of parameters, is discussed for the case of limited experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Limiting excess partial molar volumes at infinite dilution were deduced from different methods, parameters of molar Gibbs energy of activation of viscous flow against compositions were investigated. The results of these observations have been interpreted in terms of structural effects of the solvents. 1H-NMR studies of these mixtures are also reported.  相似文献   

13.
We show that zinc oxide can be dissolved in the protic ionic liquid 1-methylimidazolium trifluoromethylsulfonate, [MIm]TfO at quite a high concentration (~ 2.5 mol/L). FTIR and Raman spectra revealed the association of zinc ions with 1-methylimidazole. The ZnO/[MIm]TfO solutions and their mixtures with water were employed as electrolytes for the electrodeposition of zinc. High current density electrodeposition of zinc can be achieved in the employed electrolytes. Spongy-like zinc structures with a high porosity were obtained in ZnO/[MIm]TfO and the formation of Au1.2Zn8.8 alloy was observed. Compact and hexagonal zinc deposits were found in the presence of water. The present results show the potential of ionic liquids as electrolytes for rechargeable zinc–air batteries.  相似文献   

14.
Journal of Thermal Analysis and Calorimetry - 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexazisowurtzitane (HNIW)·1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) co-crystal in a 2:1 molar ratio was...  相似文献   

15.
16.
Knowledge and prediction of physicochemical properties of binary mixtures is of great importance for understanding intermolecular interactions. The literature shows that most such systems exhibit non-linear behaviour. Excess molar volumes, viscosity deviations and isentropic compressibility changes in N,N-dimethylacetamide?+?2-methoxyethanol binary mixtures at 298.15, 308.15 and 318.15?K were calculated from experimental density, viscosity and sound velocity data presented in previous work. Here these experimental values were used to test the applicability of the correlative reduced Redlich–Kister equation and the recently proposed Herráez equation as well as their corresponding relative functions. Their correlation ability at different temperatures, and the use of different numbers of parameters, is discussed for the case of limited experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Limiting excess partial molar volume at infinite dilution were deduced from different methods, activation parameters and partial molar Gibbs energy of activation of viscous flow against compositions were investigated. The results of these observations have been interpreted in terms of structural effects of the solvents. In this frame, a correlating equation is recently proposed by Belda and in order to assess the validity of the proposed equation, it has also been applied to the present system for molar volume properties.  相似文献   

17.
《Fluid Phase Equilibria》2004,220(1):21-35
An equation of state that can be used for phase equilibrium and other thermodynamic property calculations at high pressures is developed for systems that contain aqueous solutions of strong electrolytes and molecular species. The proposed equation of state is based upon contributions to the Helmholtz free energy from a non-electrolyte term and three electrolyte terms. The non-electrolyte term comes from the Trebble–Bishnoi equation of state and the electrolyte terms consist of a Born energy term, a mean spherical approximation term and a newly developed hydration term. The application of the proposed equation of state to aqueous systems containing mixed salts and mixed solvents is illustrated by calculating the vapour–liquid equilibrium (VLE) and solid (Clathrate hydrate)–vapour–liquid equilibrium (SVLE) conditions for several systems. The solubility of CO2 in salt water systems is examined at elevated pressures. As well, the new equation of state is used in conjunction with the model of van der Waals and Platteeuw to predict the SVLE conditions for gas hydrate forming systems in the presence of single salts, mixed salts and a mixture of aqueous salts and methanol. It is found that the new equation of state is able to accurately represent the experimental data over a wide range of pressure, temperature and salt concentration.  相似文献   

18.
The solubility of nitrogen and argon in aqueous solutions of dodecyltrimethylammonium bromide (DTAB) were measured, using the drop pressure method, at temperatures between (283.15 and 298.15) K and partial pressure of 101325 Pa of gas in an instrument specially developed for this purpose. The gas solubility was calculated as Henry’s constant. The solubilities of argon and of nitrogen increase linearly with DTAB concentration and decrease as the temperature increases. Experimental results show that the increase in the solubility of argon and nitrogen in the DTAB micelles is between 59.0 and 83.5 higher than the solubility in pure water, reflecting the ability of DTAB micelles to increase the solubility of non-polar gases in water.  相似文献   

19.
Activity coefficients of rubidium chloride and cesium chloride in methanol–water mixed solvent systems were determined by electromotive force (EMF) measurements at 298.15 K, in the range 0–40% (wt.%) methanol. For our work, the cells:
Rb-ISE | RbCl (m), methanol (Y), water (1 − Y) | Cl-ISE;  Cs-ISE | CsCl (m), methanol (Y), water (1 − Y) | Cl-ISE
were used to obtain the emf data. The rubidium and cesium ion-selective electrodes were prepared by ourselves, and they exhibited reasonably good Nernst response. Then the experimental data were calculated by both Pitzer and Pitzer–Simonson–Clegg models. We got the corresponding parameters of two models, the standard potentials and the activity coefficients of rubidium chloride and cesium chloride. Moreover, the standard Gibbs free energies of transference of RbCl or CsCl from water to methanol–water mixtures had been discussed as well. After the comparative study, it was found that the Pitzer–Simonson–Clegg model was superior in this work.  相似文献   

20.
The solubility of budesonide (BDS) in binary mixtures of ethanol and water at T = (293.2–313.2) K is determined and mathematically represented using two cosolvency models, i.e. Jouyban–Acree model and Jouyban–Acree–van’t Hoff model. The mean relative deviations for fitting the solubility data of BDS in binary mixtures of ethanol + water are 6.6% and 6.5%, respectively. Furthermore, the apparent thermodynamic properties, dissolution enthalpy, dissolution entropy, and Gibbs free energy change of dissolution process of BDS in all the mixed solvents were calculated according to van’t Hoff and Gibbs equations. Dissolution of BDS in these mixed solvents is an endothermic process.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号