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 62 毫秒
1.
Abstract

Densities and viscosities of the ternary mixture (benzene + 1-propanol + ethyl acetate) and the corresponding binary mixtures (benzene + 1-propanol, benzene + ethyl acetate and 1-propanol + ethyl acetate) have been measured at the temperature 298.15 K. From these measurements excess volumes, VE , excess viscosities, ηE, and excess Gibbs energies of activation for viscous flow, G*E , have been determined. The equation of Redlich-Kister has been used for fitting the excess properties of binary mixtures. The excess properties of the ternary system were fitted to Cibulka's equation.  相似文献   

2.
Speeds of sound, uijk, of 1,3-dioxolane or 1,4-dioxane (i) + water (j) + formamide or dimethylformamide (k) ternary mixtures and of their binary subsystems, uij, of 1,3-dioxolane or 1,4-dioxane (i) + formamide or dimethylformamide (j), and water (i) + formamide or dimethylformamide (j) have been measured over the entire composition range at 308.15 K. The experimental data have been used to evaluate the excess isentropic compressibilities of binary (κsE)ij and ternary (κsE)ijk mixtures using their densities calculated from molar excess volume data. The Moelwyn-Huggins concept [M. L. Huggins, Polymer 12, 389 (1971)] of interaction between the surfaces of components of a binary mixture has been employed to evaluate the excess isentropic compressibilities (using the concept of connectivity parameter of third degree of a molecule, 3ξ, which in turn depends on its topology) of binary mixtures, and this method has been extended to predict excess compressibilities of ternary mixtures. Values of (κsE)ij and (κsE)ijk have also been calculated by the Flory theory. It was observed that (κsE)ij and (κsE)ijk predicted by the Moelwyn-Huggins approach compare well with calculated and experimental values.  相似文献   

3.
Summary Experimental excess molar enthalpies and densities have been measured for the ternary mixture x1MTBE+x21-propanol+(1-x1-x2)octane and the involved binary mixtures at 298.15 K and atmospheric pressure. In addition, excess molar volumes were determined from the densities of the pure liquids and mixtures. A standard Calvet microcalorimeter was employed to determine the excess molar enthalpies. Densities were measured using a DMA 4500 Anton Paar densimeter. The UNIFAC group contribution model (in the versions of Larsen et al., and Gmehling et al.) has been used to estimate excess enthalpies values. Experimental data were also used to test several empirical expressions for estimating ternary properties from experimental binary results.  相似文献   

4.
Abstract

The excess volume VE of the ternary water + diacetone alcohol (or DAA) + 2-propanol and of the three binaries water + DAA, water + 2-propanol and DAA + 2-propanol was evaluated from experimental density data (2772 values) as a function of the pressure P (between 0.1 MPa and 65 MPa), the temperature T (303.15K, 323.15K and 343.15K) and the composition. Various representative models are discussed. It is possible to account for the values of the density with an average absolute deviation of about 0.06% in the experimental P-T domain.  相似文献   

5.
The excess molar volumes, V mE, viscosity deviations, Δη, and excess Gibbs energies of activation, ΔG *E, of viscous flow have been investigated from density and viscosity measurements for two ternary mixtures, 1-butanol + triethylamine + cyclohexane and 1-pentanol + triethylamine + cyclohexane, and corresponding binaries at 303.15 K and atmospheric pressure over the entire range of composition. The empirical equations due to Redlich-Kister, Kohler, Rastogi et al., Jacob-Fitzner, Tsao-Smith, Lark et al., Heric-Brewer, and Singh et al. have been employed to correlate V mE, Δη and ΔG *E of the ternary mixtures with their corresponding binary parameters. The results are discussed in terms of the molecular interactions between the components of the mixture. Further, the Extended Real Associated Solution, ERAS, model has been applied to V mE for the present binary and ternary mixtures, and the results are compared with experimental data.  相似文献   

6.
Experimental excess molar enthalpies and excess molar volumes of the ternary system x1MTBE+x21-propanol+(1-x1-x2) hexane and the involved binary mixtures have been determined at 298.15 K and atmospheric pressure. Excess molar enthalpies were measured using a standard Calvet microcalorimeter, and excess molar volumes were determined from the densities of the pure liquids and mixtures, using a DMA 4500 Anton Paar densimeter. The UNIFAC group contribution model (in the versions of Larsen et al., and Gmehling et al.) has been employed to estimate excess enthalpies values. Several empirical expressions for estimating ternary properties from experimental binary results were applied.  相似文献   

7.
《Fluid Phase Equilibria》1998,153(2):293-315
Vapour–liquid equilibrium (VLE) for the ternary system ethanol (EtOH)+N,N-dimethylformamide (DMF)+cyclohexane (Cy) and for the relevant binary mixtures containing DMF have been determined at 298.15 K by headspace gas chromatographic analysis of the vapour phase directly withdrawn from an equilibrium apparatus. Measurements of liquid–liquid equilibria in both binary DMF+Cy and ternary mixtures have been also carried out. The binary VLE data have been described with different correlation equations. The capabilities of different models of either predicting or reproducing the ternary data have been compared. Excess Gibbs energies GE as well as activity coefficients γi of components have been obtained and briefly discussed. While EtOH+DMF behaves almost ideally with slightly negative GE-values, both EtOH+Cy and DMF+Cy exhibit large positive deviations. The GEs of the ternary system are positive with the exception of a narrow region in dilute Cy. The excess entropy and the temperature dependence of GE and γi have been calculated in the whole ternary domain from the known excess enthalpy and heat capacity. The predictions by different equations of the effect of temperature on the mutual solubilities of DMF and Cy as well as on the binodal curve of EtOH+DMF+Cy have been compared with experiment.  相似文献   

8.
Abstract

Densities of the systems, 1-Propanol(P)+aniline(A), 1-Propanol(P)+N-Methylaniline (NMA) and 1-Propanol(P)+N,N-Dimethylaniline(DMA) have been measured from 21°C to 50°C at an interval of 5°C. The excess molar volumes, V E, of the systems, P+A and P +NMA have been found to be negative for the whole range of composition. VE of the system P+DMA has also been found to be negative, except in DMA-rich region where small positive excess volume is observed. The negative excess volume has been explained primarily in terms of strong specific interaction and size difference of unlike molecules. The magnitude of the negative excess volumes of these systems is of the order, P+A > P + NMA > P + DMA, which has been strongly influenced by steric effect due to CH3 group attached to N-atom of NMA and DMA. In the highly rich region of DMA in P+DMA system the small positive excess volume is accounted for by the steric effect and breaking up of H-bond of 1-Propanol.  相似文献   

9.
Abstract

Molar excess volumes (VE ) and partial molar excess volumes ( VE ) are reported for non-electrolyte binary mixtures of n-pentanol + cumene, n-pentanol + 1,4-dioxane and cumene + 1,4-dioxane at four temperatures and over the whole concentration range. In these systems, the n-pentanol is a highly polar molecule with association in its pure state, while the others two show little polarity without association in their pure states. The results of VE are discussed in terms of the interactions between components. The Prigogine–Flory–Patterson model of solution thermodynamics has been used to predict VE . This work shows the importance of the three contributions δV int, δV p? and δVF to VE .  相似文献   

10.
Excess molar volumes, VE123V^{\mathrm{E}}_{123} of 1,3-dioxolane or 1,4-dioxane (1) + benzene or toluene (2) + formamide or + N,N-dimethylformamide (3) ternary mixtures at 308.15 K and at atmospheric pressure have been determined dilatometrically over the entire composition range. The excess molar volumes data of these ternary systems were fitted to the Redlich–Kister equation. The data have been analyzed in terms of Graph theory (model) to understand the nature and strength of molecular interactions existing in these mixtures. It has been observed that VE123V^{\mathrm{E}}_{123} values predicted by Graph theory compare well with their corresponding experimental values.  相似文献   

11.
Speed of sound data, uijk, of 1,3-dioxolane or 1,4-dioxane(i) + water(j) + propan-1-ol or propan-2-ol(k) ternary mixtures and their sub-binary mixtures, uij, of 1,3-dioxolane or 1,4-dioxane(i) + water or propan-1-ol or propan-2-ol(j) and water(i) + propan-1-ol or propan-2-ol(j) mixtures have been measured over the entire composition range at 308.15 K. Isentropic compressibility changes of mixing, (κsE)ij and (κsE) ijk, for the binary and ternary mixtures have been determined by employing the observed speeds of sound data and densities (calculated from their molar excess volumes data). The (κsE) ij and (κsE) ijk values have also been predicated by the graph theoretical approach and the Flory theory. It has been observed that (κsE) ij and (κsE) ijk predicted by the graph theoretical approach compare well with their corresponding experimental values.  相似文献   

12.
Phase separation temperatures of the ternary system polystyrene (PS) (Mw = 1.67 × 104)/poly(α-methyl styrene) (PαMS) (Mw = 9.0 × 104)/cyclopentane with a blend ratio PS/PαMS = 55/45 have been determined over the polymer concentration range 0.02 ≤ ψPS + PαMS ≤ 0.52, where ψ PS + PαMS is the segment fraction of polymer in ternary system. Phase separation temperatures for the upper critical separation in the ternary system decrease with increasing ψ PS + PαMS over the range 0.1 ≤ ψ PS + PαMS ≤ 0.52. The vapor—liquid equilibrium in this system with a blend ratio PS/PαMS=50/50 has been determined over the concentration range 0.925 ≤ ψPS + PαMS < 0.995 and the temperature range 60–100°C by the piezoelectric vapor sorption method. The polymer—polymer interaction parameters χ′12 determined are positive except at 100°C and increase with increasing ψ PS + PαMS. Values of χ′12 extrapolated to zero solvent concentration are positive (0.0–1.3) over the temperature range measured. Phase separation behavior is discussed in terms of phase separation temperature in a ternary system and the polymer–polymer interaction parameter.  相似文献   

13.
Abstract

Molar excess enthalpies, H E m, at 298.15K and atmospheric pressure have been determined for three binary liquid mixtures [x{1,3-dichloropropane or 1,4-dichlorobutane and 1,6-dichlorohexane} + (1 - x) tetrachloromethane]. These experimental results along with the data available in the literature on molar excess Gibbs energies, G E m, activity coefficients at infinite dilution, In γ i , and molar excess enthalpies, H E m, for α,ω-dihaloalkanes + benzene or + tetrachloromethane mixtures are examined on the basis of the DISQUAC group contribution model.  相似文献   

14.
Speeds of sound of the ternary mixtures cyclohexane+1,3-dioxolane+2-butanol and n-hexane+1,3-dioxolane+2-butanol have been measured at the temperatures of 298.15 and 313.15 K. Isentropic compressibilities and excess isentropic compressibilities have been calculated from experimental data. We have also compared the experimental isentropic compressibilities with calculated values from the free length theory and the collision factor theory. Experimental results show positive values of excess isentropic compressibilities in almost the whole composition range for the ternary mixture containing cyclohexane, meanwhile they are negative for the mixture containing n-hexane. Such different behaviour of these systems is related to the large free volume shown by n-hexane. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
Abstract

Liquid-liquid equilibria, distribution coefficients, and selectivities of ternary systems of the type: (water + K + nitromethane), where Kis 1-propanol, acetone, or p-dioxane, have been determined at (303.15 ± 0.05) K, in order to evaluate the suitability of nitromethane for extracting preferentially the second components from their aqueous solutions. The line data were satisfactorily correlated by the Othmer and obias method, and the plait point coordinates for the three systems were estimated. The experimental data were compared with values calculated using the NRTL and UNIQUAC models, and with those predicted by the UNIFAC group contribution method. This last method predicts qualitative and quantitative behaviour which are in disagreement with experimental results, while the values calculated using the other two models are in agreement but only when the concentration of component K is low. The three ternary systems studied have distribution coefficients higher than unity, and high selectivities. Therefore, nitromethane could be considered as a potential solvent for the extraction of K from its aqueous solutions  相似文献   

16.
The density of the 2-chloroethanol (CE) + 2-methoxyethanol (ME) + 1,2-dimethoxye- thane (DME) ternary mixtures has been measured at different temperatures ranging from –10 to 80°C, and over the entire composition range. The experimental data have been used to check the validity of some relationships accounting for the dependence of the density on temperature and composition domains. Starting from the primary data, some derived quantities, such as excess molar volumes V E, partial molar volumes and partial excess molar volumes , have been obtained. In these mixtures, V E is always positive for the [CE(1) + ME(2)] binaries, while it is generally negative at all other experimental conditions, showing the greatest deviations along the binary axes corresponding to the binary subsystems in the sequence [CE(1) + DME(2)] < [CE(1) + ME(2)] < [ME(1) + DME(2)]. The results are compared and discussed to in terms of changes in molecular association and structural effects in these solvent systems.  相似文献   

17.
The kinetics of the title reactions have been studied using the discharge-flow mass spectrometic method at 296 K and 1 torr of helium. The rate constant obtained for the forward reaction Br+IBr→I+Br2 (1), using three different experimental approaches (kinetics of Br consumption in excess of IBr, IBr consumption in excess of Br, and I formation), is: k1=(2.7±0.4)×10−11 cm3 molecule−1s−1. The rate constant of the reverse reaction: I+Br2→Br+IBr (−1) has been obtained from the Br2 consumption rate (with an excess of I atoms) and the IBr formation rate: k−1=(1.65±0.2)×10−13 cm3molecule−1s−1. The equilibrium constant for the reactions (1,−1), resulting from these direct determinations of k1 and k−1 and, also, from the measurements of the equilibrium concentrations of Br, IBr, I, and Br2, is: K1=k1/k−1=161.2±19.7. These data have been used to determine the enthalpy of reaction (1), ΔH298°=−(3.6±0.1) kcal mol−1 and the heat of formation of the IBr molecule, ΔHf,298°(IBr)=(9.8±0.1) kcal mol−1. © 1998 John Wiley & sons, Inc. Int J Chem Kinet 30: 933–940, 1998  相似文献   

18.
Abstract

The ultrasonic velocity, u, viscosity, η, and density, ρ of dimethylsulphoxide (DMSO), 1-butanol, 1-hexanol, 1-octanol, and of their binary mixtures, where DMSO is common component, have been measured at 303.15 K. From the experimental data, excess isentropic compressibility, K E s, excess intermolecular free length, LE f, excess velocity, u E, excess acoustic impedance, Z E, excess viscosity, ηE, excess free energy of activation of viscous flow, G?E, and excess rheochore, [R E] have been calculated. The behaviours of excess functions with composition of the mixtures suggest that the structure-breaking effect dominates over the interaction effect between the component molecules. Furthermore, the experimental values of u and η were fitted by empirical equations stating their dependence on composition of the mixtures. The experimental values of u have been compared with those calculated by using Nomoto and Van Dael relations.  相似文献   

19.
Densities at 298.15 K and atmospheric pressure have been measured, using a DMA 4500 Anton Paar densimeter, for the ternary mixture methyl tert-butyl ether (MTBE)+1-pentanol+nonane and for the involved binary mixture 1-pentanol+nonane. In addition, excess molar volumes were determined from the densities of the pure liquids and mixtures. Suitable fitting equations have been used in order to correlate adequately the excess molar volumes. Experimental data were also used to test several empirical expressions for estimating ternary properties from experimental binary results.  相似文献   

20.
The density and speed of sound of the ternary mixture (diethyl carbonate + p-xylene + octane) have been measured at atmospheric pressure and in the temperature range T = (288.15 to 308.15) K. Besides, surface tension has been also determined for the same mixture at T = 298.15 K. The experimental measurements have allowed the calculation of the corresponding derived properties: excess molar volumes, excess isentropic compressibilities, and surface tension deviations. Excess properties have been correlated using Nagata and Tamura equation and correlation for the surface tension deviation has been done with the Cibulka equation. Good accuracy has been obtained. Based on the variations of the derived properties values with composition, a qualitative discussion about the intermolecular interactions was drawn.  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