Molar excess volumes of 1,4-dioxane+ acetonitrile,n-butylamine+acetonitrile andn-butylamine+1,4-dioxane at different temperatures

Molar excess volumes and partial molar volumes are reported for binary mixtures of 1,4-dioxane + acetonitrile, n-butylamine + acetonitrile and n-butylamine + 1,4-dioxane at five different temperatures and over the complete concentration range. The Prigogine-Flory-Patterson model of solution thermodynamics has been used to predict the excess molar volumes. This work shows the importance of the three contributions: interactional, internal pressure and free volume, to the excess volume.     

Excess Molar Volumes and Thermal Expansivities of Aqueous Solutions of Dimethylsulfoxide,Tetrahydrofuran and 1,4-Dioxane

Densities, , of the systems water (W) + dimethylsulfoxide (DMSO), W + tetrahydrofuran (THF) and W + 1,4-dioxane (DO) have been determined in the temperature range 303.15-323.15 K. Excess molar volumes, $V_m^E $ , have been found to be negative and large in magnitude. Thermal expansivities, f , and excess thermal expansivities, f E , have been calculated. Densities, excess molar volumes, thermal expansivities and excess thermal expansivities have been plotted against mole fraction of solutes. All these properties have been expressed satisfactorily by appropriate polynomials. Attempt has been made to explain $V_m^E$ in terms of hydrophobic hydration and hydrophilic effect of the solutes.     

Volumetric Properties of the Ternary System 1,4-Dioxane + Butyl Acrylate + Ethyl Acrylate and Its Binary Butyl Acrylate + Ethyl Acrylate at 298.15 K

Densities of the ternary system 1,4-dioxane + butyl acrylate + ethyl acrylate and its binary butyl acrylate + ethyl acrylate have been measured in the whole composition range, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess molar volumes of the binary system are positive and were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. Several models were used to correlate the ternary behavior from the excess molar volume data of their constituent binaries and were found equally good to fit the data. The best fit was based on a direct approach, without information on the component binary systems.     

Excess Molar Volumes of Binary Mixtures of Acetonitrile with n-Alkanols at 25°C

Molar excess volumes of acetonitrile with ten n-alkanols (from methanol to decanol) were determined from density measurements at 25°C and normal atmospheric pressure, using a vibrating-tube densimeter. V ^E for acetonitrile + methanol mixtures are negative over the entire range of mole fractions. The ethanol and propanol mixtures exhibit sigmoidal curves and positive values are obtained for all remaining mixtures. The results for V ^E were compared with those obtained using several theoretical models.     

Excess enthalpies of water+1,4-dioxane at 278.15, 298.15, 318.15 and 338.15 K

The excess molar enthalpies of (1–x)water+x1,4-dioxane have been measured at four different temperatures. All the mixtures showed negative enthalpies in the range of low mole fraction but positive ones in the range of high mole fraction of 1,4-dioxane. Excess enthalpies were increased with increasing temperature except those of at 278.15 K. Partial molar enthalpies have maximum around x=0.13 and minimum around x=0.75. Three different behaviors for the concentration dependence of partial molar enthalpies were observed for all temperature. Theoretical calculations of molecular interactions of three characteristic concentrations were carried out using the molecular orbital method.     

Excess Molar Volumes and Partial Molar Volumes for Binary Mixtures of Water With 1,2-Ethanediol, 1,2-Propanediol,and 1,2-Butanediol at 293.15, 303.15 and 313.15 K

Abstract

From dilatometric method at 293.15,303,15, and 313.15K for binary mixtures of water and 1,2-alkane diols, the excess molar volumes, V^E and the partial molar volumes, V _i of both components at 293.15 K have been obtained as a function of mixtures composition. Excess molar volumes were calculated and correlated by a Redlich-Kister type function in terms of mole fraction. The partial molar volumes have been extrapolated to zero concentration to obtain the limiting values at infinite dilution, V ⁰ _i . All mixtures showed negative values and decreases with the chain length of diols. The values become less negative with increasing temperature. The results are explained in terms of dissociation of the self-associated diol molecules and the formation of aggregates between unlike molecules.     

Excess Molar Volumes of Binary Mixtures of Propyl Ethanoate with some n-Alkanes at 298.15 K and 308.15 K

Abstract

Excess molar volumes v^E have been measured for the binary liquid mixtures of propyl ethanoate with five n-alkanes (n-hexane, n-heptane, n-octane, n-nonane and n-decane) at 298.15 and 308.15 K, using an Anton Paar densimeter. All the mixtures studied present positive v^E values that increase with the length of the chain of the alkane and with the temperature. The experimental results are compared with the predictions of the Nitta—Chao model.     

Excess molar volumes of methyl tert-butyl ether with chloroalkanes at 30°C

Excess molar volumes are reported for binary mixtures of methyl tert-butyl ether with trichloromethane, tetrachloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane, or 1,1,1,2,2-pentachloroethane at 30°C over the entire composition range of the mixtures. Excess volumes for all the mixtures are found to be negative. A qualitative interpretation of the results in terms of O–H–C and Cl–O interactions is presented. The Prigogine-Flory-Patterson theory has been used to analyze the results.     

Viscosities of Aqueous Solutions of Dimethylsulfoxide, 1,4-Dioxane and Tetrahydrofuran

Abstract

Viscosities of the systems, water(W) + dimethylsulfoxide(DMSO), W + 1,4-dioxane (DXN) and W + tetrahydrofuran(THF), are measured at temperatures ranging from 303.15–323.15K. Viscosities and excess viscosities are plotted against the mole fraction of the organic solutes. On addition of solutes to water, viscosities first increase rapidly, pass through maxima and then decline continuously until the pure state of solutes is reached. Excess viscosities are found to be positive and large in magnitude and their curves are similar to those of the viscosity curves. The ascending part of the viscosity curves in the water-rich region is accounted for by both the hydrophobic effect of forming cage structures around solutes and the hydrophilic effect forming H-bonds between water and organic solutes. The descending part of the viscosity curves is explained by the continuous destruction of cages formed. The maxima are thought to be due to competing processes of formation and destruction of cage structures.     

Topological Investigations of Some Cyclic Ether-Water-Alkanol Ternary Mixtures: Molar Excess Volumes

Molar excess volumes, V_ijk^E, of 1,3-dioxolane or 1,4-dioxane (i) + water (j) + propan-1-ol or + propan-2-ol (k) ternary mixtures have been determined dilatometrically over the entire composition range at 308.15 K. The resulting data have been analyzed in terms of (1) the graph theoretical approach (which involves the topology of the mixture constituents), (2) the Sanchez and Locombe theory and (3) the Flory theory. It was observed that V_ijk^Evalues predicted by the graph theory compare reasonably well with their corresponding experimental values. However, although V_ijk^E values calculated by the Sanchez and Lacombe and Flory theories are of same sign and magnitude, the qualitative agreement is poor.     

氯仿与邻二甲苯、间二甲苯、对二甲苯和乙苯的过量体积

在298．15K下用振动管密度计在全浓度范围内测量了氯仿分别与邻二甲苯、间二甲苯、对二甲苯和乙苯构成二元混合物的过量摩尔体积V^E。这四个二元系的过量摩尔体积V^E值均为正值,其大小顺序为：间二甲苯＞对二甲苯＞邻二甲苯＞乙苯。     

Liquid Densities and Excess Molar Volumes for Binary Systems (Ionic Liquids + Methanol or Water) at 298.15, 303.15 and 313.15 K,and at Atmospheric Pressure

Binary excess molar volumes, V _m ^E, have been evaluated from density measurements, using a vibrating tube densimeter over the entire composition range for binary liquid mixtures of ionic liquids 1-ethyl-3-methyl-imidazolium diethyleneglycol monomethylethersulphate [EMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻ or 1-butyl-3-methyl-imidazolium diethyleneglycol monomethylethersulphate [BMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻ or 1-methyl-3-octyl-imidazolium diethyleneglycol monomethylethersulphate [MOIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻+methanol and [EMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻+water at 298.15, 303.15 and 313.15 K. The V _m ^E values were found to be negative for all systems studied. The V _m ^E results are explained in terms of intermolecular interactions and packing effects. The experimental data were fitted by the Redlich-Kister polynomial.     

Excess Molar Enthalpies and Excess Molar Volumes of Binary Mixtures of Benzene and Alkanols with Quinoline

Molar excess enthalpies H _m ^E have been determined over the whole composition range for mixtures of benzene, methanol, ethanol, 1-propanol, 2-propanol and 1-butanol with quinoline at 298.15 K using a Thermometric flow calorimeter. The results reflect a strong H-bond association between an alkanol and quinoline which decreases with increasing length of the alkanol chain. The small H _m ^E for (benzene+quinoline) reflects the similarity of the two molecules. This revised version was published online in August 2006 with corrections to the Cover Date.     

Excess Molar Volumes of Binary Mixtures of 1-Heptanol or 1-Nonanol with n-Polyethers at 25°C

Excess molar volumes V ^E _m at 25°C and atmospheric pressure over the entirecomposition range for binary mixtures of 1-heptanol with 2,5-dioxahexane, 2,5,8-trioxanonane,5,8,11-trioxapentadecane, 2,5,8,11-tetraoxadodecane,or 2,5,8,11,14-pentaoxapentadecane, and mixtures of 1-nonanol with 2,5-dioxahexane,3,6-dioxaoctane, 2,5,8-trioxanonane, 3,6,9-trioxaundecane, 5,8,11-trioxapentadecane,2,5,8,11-tetraoxadodecane, or 2,5,8,11,14-pentaoxapentadecane are reportedfrom densities measured with a vibrating-tube densimeter.V ^E _m curves are nearlysymmetrical at about 0.5 mole fraction. Excess molar volumes are usually positive,indicating predominance of positive contributions to V ^E _m from the disruption ofH bonds of alcohols and from physical interactions. When chain lengths ofboth components of the mixture are increased, the contribution from interstitialaccommodation appears to be sufficiently negative, such that V ^E _m becomes negative(e.g., l-nonanol + 5,8,11-tetraoxapentadecane).     

Molar and Partial Molar Excess Volumes of Benzene in Methyl Ester Solutions at 25°C

Molar and partial molar excess volumes of mixtures of benzene with several methyl esters (from methanoate to decanoate) were determined, over the whole concentration range, at 25°C and atmospheric pressure from experimental densities and correlated by a suitable equation. The applicability of the Flory and Priggogine–Flory–Pattersort models for predicting molar excess volumes is tested. The calculated values with Flory and Priggogine–Flory–Patterson are similar and agree poorly with the experimental data.     

Excess Molar Volumes for (Binary Mixtures of 1-Alkanol and 1-Alkene). I. The System 1-Alkanol + 1-Octene at 25°C

Excess volumes measured at 25°C are reported for binary mixtures of the C₃, C₄, C₆, C₈, and C₁₀ 1-alkanols with 1-octene. In this series of mixtures, the excess-volume curves change from positive values over the whole concentration range for short-chain alkanols C₃ and C₄, to sigmoid for longer-chain alkanols (with positive values in the alkanol-rich region). The positive region decreases with increasing chain length of the 1-alkanol. Excess partial molar volumes of the components are calculated. The results are compared with those for mixtures of 1-alkanols with n-octane. The model of associated mixtures proposed by Treszczanowicz and Benson³ describes very well the size and shape of the excess volume for the class of systems considered.     

Measurements of the Molar Heat Capacities and Excess Molar Heat Capacities for Acetonitrile + Diethylamine or sec-Butylamine Mixtures at Various Temperatures and Atmospheric Pressure

As a continuation of our studies of the excess functions of binary systems containing acetonitrile (1−x)–amines (x) mixtures, the molar heat capacity, Cp, and excess molar heat capacity, Cp ^E, of acetonitrile + diethylamine or sec-butylamine mixtures have been determined as a function of composition at 288.15, 293.15, 298.15 and 303.15 K at atmospheric pressure using a modified 1455 PARR solution calorimeter. The excess heat capacity data are positive for both systems over the whole composition range. The experimental data on the excess molar heat capacity are discussed in terms of the influence of the magnitude of the experimental excess molar enthalpy, H ^E, over the curve shaped for the experimental Cp ^E data, molecular interactions in the mixtures, isomeric effect of the amines and modeling of Cp ^E data.     

Refractive Indices, Densities and Excess Molar Volumes of Monoalcohols + Water

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.     

Excess molar volumes and viscosities of the ternary systemn-butylamine + 1,4-dioxane + acetonitrile at 25°C

Densities and viscosities for the n-butylamine + 1,4-dioxane + acetonitrile system were determined at 25°C and molar excess volumes and excess viscosities were calculated. Of the different expressions existing in the literature that predict these excess properties for ternary mixtures from data for the binary mixtures, the empirical correlation of Singh et al. is the best for this system.     

Apparent Molar Heat Capacities and Apparent Molar Volumes of Aqueous Nicotinamide at Different Temperatures

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, (²C_p,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.