Prediction of Excess Volumes and Excess Surface Tensions from Experimental Refractive Indices

Abstract

Refractive indices for the binary liquid mixtures: {hexane or heptane + ethanol}, {o-xylene + benzene} and {cyclohexane + benzene, toluene or hexane} were measured at 298.15 K. Excess refractive indices were calculated and fitted to a Redlich-Kister function. Using some mixture rules (Lorentz-Lorenz, Dale -Gladstone, Eykman, Oster, Arago-Biot and Newton), predictions for v^E have been made and compared with experimental data taken from the literature. Furthermore the Sugden equation has been used in two different ways for predicting excess surface tensions: the first one starting from densities and the other one from refractive indices. Results are plotted together with the literature data.     

Densities,speeds of sound and isentropic compressibilities of binary and ternary mixtures containing benzene,cyclohexane and hexane at 298.15 K

Densities, ϱ, and speeds of sound, u, have been measured for the ternary mixture {benzene + cyclohexane + hexane} and the corresponding binary mixtures {benzene + cyclohexane}, {benzene + hexane} and {cyclohexane + hexane}, at the temperature 298.15 K. Using these results, the isentropic compressibilities, κ_s, the excess isentropic compressibilities, κ_s^E, and the speeds of sound deviations, Δu, have been calculated for both the binary mixtures and the ternary system. Excess isentropic compressibilities, κ_s^E, and the speeds of sound deviations, Δu, have been fitted to the Redlich-Kister equation in the case of binary mixtures, while the equation of Cibulka was used to fit the values relating to the ternary system. The empiric equations of Redlich-Kister, Tsao-Smith, Kohler and Colinet have been applied in order to predict the κ_s^E and Δu of ternary mixtures from the binary contributions.     

Thermodynamic Properties of Multicomponent Liquid Mixtures

Considering a ternary liquid mixture to be made up of three binary mixtures, by means of cell model using Sutherland type potential function for pair interaction between molecules, a statistical theory for binary liquid mixtures has been extended for ternary systems. In the light of above extension, excess volume ( V E ), excess energy ( E E ) and excess entropy ( TS E ) have been computed for three binary (benzene + cyclohexane, benzene + chlorobenzene and cyclohexane + chlorobenzene) and the resultant ternary system (benzene + cyclohexane + chlorobenzene) at 298.15 K. All the above mentioned excess properties have been computed from the data of ultrasonic velocity and density only.     

Surface tension of binary liquid mixtures

Experimental measurements of the liquid-air interfacial tension are reported for the systems benzene + n-hexane at 20°C and acetone + isooctane at 25°C. The excess surface tension for both systems is negative while the surface tension itself for the second system, when plotted against composition, exhibits a flat minimum. An attempt is made to interpret this behavior in terms of basic thermodynamic quantities of the mixtures such as the excess free enthalpy, the heat of mixing, the excess volume, and the isothermal compressibility.     

聚四氟乙烯等温稀释型量热计

过量焓是溶液的基本热力学性质,近廾年来不少学者对它进行了大量的研究,取得了引人注目的成绩。目前应用较多的为等温稀释型及流动型量热计。尽管后者具有速度快、试剂用量省等优点,但前者结构简单、操作方便和实验精度高,因此得到广泛的应用。传统的等温稀释型量热计的本体为玻璃杜瓦瓶,当活塞上下移动时常常引起破裂,另一方面由于使用汞封,使实验物料受到很大限制。为了克服这些缺点,我们用聚四氟乙烯作为量热计本体,取得满意的效     

On the reactivity of recoil tritium with organic compounds

The reactivity of recoil tritium in the T-for-H substitution was studied in mixtures of benzene, hexane, cyclohexane or cyclohexane-d₁₂ with lithium carbonate which were irradiated in a reactor. The relative rates per C–H bond of hexane and cyclohexane to benzene were somewhat less than one third. The H/D isotope effect in cyclohexane was given as 1.14.     

Excess volume of mixing of some polar and nonpolar liquids with propylene carbonate

The excess volume of mixing as a function of composition has been measured at 30°C and 40°C for mixtures of propylene carbonate with nitrobenzene, chlorobenzene, benzene, toluene, cyclohexane, dioxane, carbon tetrachloride, and chloroform. The highly polar nitrobenzene forms an ideal mixture with propylene carbonate. Chloroform, carbon tetrachloride, dioxane, chlorobenzene, benzene, and toluene give negative volume changes on mixing. In mixtures with cyclohexane,V _m ^E is positive at lower mole fractions of cyclohexane but becomes negative as the mole fraction of cyclohexane increases.     

Ultrasonic behaviour of methyl methacrylate+hydrocarbon mixtures at 298.15 and 308.15 K

The excess isentropic compressibilities, K_s^E for seven binary mixtures of methyl methacrylate+benzene, +o-xylene, +m-xylene, +p-xylene, +toluene, +ethylbenzene and +cyclohexane were estimated from the measured densities and speeds of sound at 298.15 and 308.15 K. The K_s^E values were large and positive for MMA+cyclohexane and +m-xylene, while they were negative for other mixtures. A qualitative analysis of K_s^E values was made in terms of molecular interactions. The speeds of sound of all the mixtures were also predicted from the free length theory (FLT) and collision factor theory (CFT).     

Excess molar enthalpy of binary mixtures of hexane+ethyl benzene, <Emphasis Type="Italic">o</Emphasis>-xylene, <Emphasis Type="Italic">m</Emphasis>-xylene and <Emphasis Type="Italic">p</Emphasis>-xylene at 298.15 K

Summary This paper reports excess molar enthalpies of the binary systems hexane+ethyl benzene, hexane+o-xylene, hexane+m-xylene and hexane+p-xylene at 298.15 K and atmospheric pressure, over the whole composition range. The data was measured directly using a Calvet microcalorimeter. The excess magnitude was correlated to a Redlich-Kister type equation for each mixture. Also, we will discuss the results for the four mixtures studied here and by comparison with the same binary systems but containing propyl propanoate as first component. Finally, we will correlate our results with the Nitta-Chao and the three UNIFAC theoretical approximations.     

Viscosities of Binary Liquid Mixtures of Tetrachloroethylene with Some Aliphatic,Alicyclic and Substituted Aromatic Hydrocarbons

Abstract

Viscosities of binary mixtures of tetrachloroethylene with hexane, heptane, cyclohexane, methylcyclohexane, toluene, chlorobenzene, bromobenzene and nitrobenzene were measured at 303.15 K. The values of η^E are negative in all the systems except in tetrachloroethylene + bromobenzene system. An inversion in sign from positive to negative is observed in the system, tetrachloroethylene + bromobenzene. The viscosity data were analysed in terms of absolute reaction rate and free volume theories of liquid viscosity. Further, Grunberg and Nissan Parameter has also been evaluated.     

Mixing cell for indirect measurements of excess volume

A mixing cell suitable for making liquid mixtures of accurately known composition is described and has been tested by measurements of the excess volume of benzene + cyclohexane.     

Viscosity of ternary liquid mixtures

Viscosities of ternary liquid mixtures containing benzene + cyclohexane + carbon tetrachloride and the three possible binary combinations were measured at 25°C, and the excess viscosities were computed. Theoretical expressions for viscosity were developed on the basis of the Flory theory, the significant structure theory and a theory based on a method of estimating the properties of multi-component systems from those of binary systems. Reasonable agreement between experimental and theoretical viscosities is found.     

Thermodynamics of binary mixtures with n-mono and n-dibutyl phosphates

Thermodynamic properties of the binary mixtures of n-monobutyl phosphate and n-dibutyl phosphate with a number of diluents (water, benzene, hexane, cyclohexane, carbon tetrachloride, chloroform and ethanol) are considered. They were evaluated from the total vapour pressure measurements performed in the temperature range, 298.15–318.15 K. Activity coefficients and the excess Gibbs energies of mixing were calculated from the Gibbs-Duhem equation and the results obtained are discussed in terms of intermolecular hydrogen bond formation.     

Densities and Viscosities of the Ternary Mixture (Benzene + 1-Propanol + Ethyl Acetate) at 298.15 K

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, V^E , excess viscosities, η^E, 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.     

Volumetric Properties of Ternary-Pseudobinary Mixtures Containing Benzene and Cyclohexane

Densities have been measured as a function of composition for ternary-pseudobinary mixtures of [(benzene + toluene or methylcyclohexane) + (cyclohexane + toluene or methylcyclohexane)] by means of a vibrating-tube densimeter at atmospheric pressure and the temperature 298.15 K. The excess molar volumes, V_m^E, were calculated from the densities and correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show the third component, toluene and methylcyclohexane, influences the interaction between benzene and cyclohexane.     

Density,partial molar volume,and excess volume of solutions of acrylic acid in acetonitrile, 1,2-dichloroethane,hexane, and benzene at 293 K

Using pycnometric method, we have measured density of the solutions of acrylic acid in acetonitrile, 1,2-dichloroethane, hexane, and benzene at 293 K and atmospheric pressure. The values of the excess molar volume for these systems and the values of the partial molar volumes of components were derived. In the whole concentration range the excess molar volume for binary mixtures of acrylic acid and either 1,2-dichloroethane, or benzene, or hexane has positive values, and in the system of acrylic acid-acetonitrile the value is negative.     

Solubility in Binary Solvent Systems: Comparison of Predictive Equations Derived from the NIBS Model

Abstract

Experimental solubilities are reported for pyrene in binary solvent mixtures containing benzene with n-hexane, cyclohexane, n-heptane, n-octane, cyclooctane and isooctane at 26°C. Results of these measurements, combined with published pyrene and biphenyl solubilities, are used to test predictive expressions derived from the Nearly Ideal Binary Solvent (NIBS) model. The most successful equation in terms of goodness of fit involved a surface fraction average of the excess Gibbs free energy relative to Raoult's law and predicted the experimental solubilities in 17 systems with an average deviation of 2.3% and a maximum deviation of 8.9%. Two expressions approximating weighting factors with molar volumes provided accurate predictions in many systems studied but failed in their ability to predict pyrene solubilities in solvent mixtures containing benzene.     

Speeds of sound and isentropic compressibil- ities of cyclohexane+1,3-dioxolane+2-butanol and n-hexane+1,3-dioxolane+2-butanol

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.     

Thermodynamics of organic mixtures containing amines. X. Phase equilibria for binary systems formed by imidazoles and hydrocarbons: Experimental data and modelling using DISQUAC

(Solid + liquid) equilibrium (SLE) temperatures have been determined using a dynamic method for the systems (1H-imidazole, + benzene, + toluene, + hexane, or + cyclohexane; 1-methylimidazole + benzene, or + toluene, 2-methyl-1H-imidazole + benzene, + toluene, or + cyclohexane, and benzimidazole + benzene). In addition (liquid + liquid) equilibrium (LLE) temperatures have been obtained using a cloud point method for (1H-imidazole, + hexane, or + cyclohexane; 1-methylimidazole + toluene, and 2-methyl-1H-imidazole + cyclohexane). The measured systems show positive deviations from the Raoult’s law, due to strong dipolar interactions between amine molecules related to the high dipole moment of imidazoles. On the other hand, DISQUAC interaction parameters for the contacts present in these solutions and for the amine/hydroxyl contacts in (1H-imidazole + 1-alkanol) mixtures have been determined. The model correctly represents the available data for the examined systems. Deviations between experimental and calculated SLE temperatures are similar to those obtained using the Wilson or NRTL equations, or the UNIQUAC association solution model. The quasichemical interaction parameters are the same for mixtures containing 1H-imidazole, 1-methylimidazole, or 2-methyl-1H-imidazole and hydrocarbons. This may be interpreted assuming that they are members of a homologous series. Benzimidazole behaves differently.