Isentropic and Excess Isentropic Compressibilities of Binary Mixtures Containing Cyclic Ethers and Chloroalkanes

Isentropic and excess isentropic compressibilities of binary mixtures formed by tetrahydrofuran or tetrahydropyran and isomeric chlorobutanes at 298.15 and 313.15 K have been calculated from experimental measurements of densities and speeds of sounds. Excess isentropic compressibilities are negative for all the mixtures except for the mixtures containing 1-chlorobutane at 298.15 K at very low concentrations of cyclic ether. Isentropic compressibilities and speeds of sound have been estimated using the Prigogine-Flory-Patterson theory and satisfactorily compared with the experimental values.     

Ultrasonic Studies of Binary Mixtures of p-Chlorotoluene with l-Alcohols at 303.15 K

Abstract

Ultrasonic sound velocities and densities were measured for the binary mixtures of p-chlorotoluene with l-alcohols. The alcohols included: l-propanol, l-butanol, l-pentanol, l-hexanol and l-heptanol. Isentropic compressibilities, k_s and deviation in isentropic compressibility, K_s from ideal behaviour have been calculated from the results. The deviation in isentropic compressibility has been ascribed to competition between structure-breaking and structural effects to different extents.     

Densities and speeds of sound for binary mixtures of (1,3-dioxolane or 1,4-dioxane) with (2-methyl-1-propanol or 2-methyl-2-propanol) at the temperatures (298.15 and 313.15) K

This paper reports densities and speeds of sound for the binary mixtures of (1,3-dioxolane or 1,4-dioxane) with (2-methyl-1-propanol or 2-methyl-2-propanol) at the temperatures (298.15 and 313.15) K. Excess volumes and excess isentropic compressibility coefficients have been calculated from experimental data and fitted by means of a Redlich-Kister type equation. The ERAS model has been used to calculate the excess volumes of the four systems at both temperatures.     

Densities and Volumetric Properties of Binary Mixtures of Formamide with 1-Butanol, 2-Butanol, 1,3-Butanediol and 1,4-Butanediol at Temperatures between 293.15 and 318.15 K

The densities of binary mixtures of formamide (FA) with 1-butanol, 2-butanol, 1,3-butanediol, and 1,4-butanediol, including those of the pure liquids, over the entire composition range were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V _m ^E, partial molar volumes, and , at infinite dilution, and excess partial molar volumes, and , at infinite dilution were calculated. The variation of these parameters with composition and temperature of the mixtures are discussed in terms of molecular interactions in these mixtures. The partial molar expansivities, and , at infinite dilution and excess partial molar expansivities, and , at infinite dilution were also calculated. The V _m ^E values were found to be positive for all the mixtures at each temperature studied, except for FA + 1-butanol which exhibits a sigmoid trend wherein V _m ^E values change sign from positive to negative as the concentration of FA in the mixture is increased. The V _m ^E values for these mixtures follow the order: 1-butanol < 2-butanol < 1,3-butanediol < 1,4-butanediol. It is observed that the V _m ^E values depend upon the number and position of hydroxyl groups in these alkanol molecules.     

Study of Densities, Viscosities and Ultrasonic Speeds of Binary Mixtures Containing 1,2-Dimethoxyethane and an Alkan-l-ol at 298.15 K

The viscosity deviation (Δη), the excess molar volume (V ^E) and the ultrasonic speed (u) have been investigated from viscosity (η) and density (ρ ) measurements of binary liquid mixtures of 1,2-dimethyoxyethane with methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol or octan-1-ol over the entire range of composition at 298.15 K. The excess volumes are negative over the entire range of composition for all of the mixtures with the exception of hexan-1-ol and octan-1-ol. The excess isentropic compressibilities (K _S ^E) and viscosity deviations are negative for all of the mixtures. The magnitudes of the negative values of V ^E decrease with the number of carbon atoms of the alkan-1-ol. The trend of increasing K _S ^E values with the chain length of the alkanol is similar to that observed in the case of V ^E. Graphs of V ^E, Δ η, K _S ^E, Δ u, L _f ^E and Z ^E against composition are presented as a basis for a qualitative discussion of the results.     

Excess and deviation properties for the binary mixtures of methylcyclohexane with benzene, toluene, p-xylene, mesitylene, and anisole at T = (298.15, 303.15, and 308.15) K

Experimental data on density, viscosity, and refractive index at T = (298.15, 303.15, and 308.15) K, while speed of sound values at T = 298.15 K are presented for the binary mixtures of (methylcyclohexane + benzene), methylbenzene (toluene), 1,4-dimethylbenzene (p-xylene), 1,3,5-trimethylbenzene (mesitylene), and methoxybenzene (anisole). From these data of density, viscosity, and refractive index, the excess molar volume, the deviations in viscosity, molar refraction, speed of sound, and isentropic compressibility have been calculated. The computed values have been fitted to Redlich-Kister polynomial equation to derive the coefficients and estimate the standard errors. Variations in the calculated excess quantities for these mixtures have been studied in terms of molecular interactions between the component liquids and the effects of methyl and methoxy group substitution on benzene ring.     

293.15K时咪唑醋酸盐-乙醇二元体系的体积性质及分子间相互作用简

用比重瓶法测定了293.15 K时1-甲基咪唑醋酸盐([Mim]Ac)/1,3-二甲基咪唑醋酸盐([Mmim]Ac)/1-乙基-3-甲基咪唑醋酸盐([Emim]Ac)-乙醇(EtOH)二元体系在全组成范围内的密度. 计算出[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH的表观摩尔体积和体系的超额摩尔体积. 用三参数多项式关联拟合了表观摩尔体积与摩尔分数的关系,外推出组分的极限偏摩尔体积和摩尔体积. [Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH的摩尔体积的外推值与实验值分别在±0.07和±0.04 cm3/mol范围内相一致. 计算出了[Mim]Ac/[Mmim]Ac/[Emim]Ac和EtOH分别在无限稀溶液中的溶剂化系数. 用Redlich-Kister 方程关联拟合了超额摩尔体积与摩尔分数的关系. 分别根据极限偏摩尔体积、摩尔体积与极限偏摩尔体积的差值、溶剂化系数和超额摩尔体积对照讨论了分子间相互作用的强弱. 结果显示,在[Mim]Ac/[Mmim]Ac/[Emim]Ac的浓度无限稀溶液中,[Mim]Ac/[Mmim]Ac/[Emim]Ac-EtOH分子对间相互作用的强弱顺序为[Mim]Ac-EtOH>[Mmim]Ac-EtOH >[Emim]Ac-EtOH;在EtOH的浓度无限稀溶液中,以及体系中[Mim]Ac/[Mmim]Ac/[Emim]Ac的摩尔分数在0.15～0.95间时,[Mim]Ac/[Mmim]Ac/[Emim]Ac-EtOH分子对间相互作用的强弱顺序都为[Emim]Ac-EtOH>[Mmim]Ac-EtOH>[Mim]Ac-EtOH.     

Ultrasonic Studies in Binary Mixtures of 1-2-Dibromoethane with Alcohols at 303.15 K

Abstract

Isentropic compressibility data, K_S of 1,2-Dibromoethane + Propan-1-ol, + butan-1-ol, + pentan-1-ol, hexan-1-ol, heptan-1-ol and octan-1-ol at 303.15 K are reported. Deviations in isentropic compressibility, K_S values are found to be negative for mixtures of 1,2-dibromoethane with propan-1-ol over the entire range of composition and while in butan-1-ol the δK_S values are negative at lower molefractions and positive at higher molefractions. Therefore as the chain length increases it is showing the positive deviations. The data are interpreted in terms of specific interactions between the components.     

Densities and Volumetric Properties of Binary Mixtures of Tetrahydrofuran with Some Aromatic Hydrocarbons at Temperatures from 278.15 to 318.15 K

The densities, ρ, of binary mixtures of tetrahydrofuran (THF) with benzene, toluene, o-xylene, m-xylene, p-xylene and mesitylene, including those of the pure liquids, were measured over the entire composition range at the temperatures (278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, V _m ^E, partial molar volumes, _m,1 ^∘ and _m,2 ^∘, and excess partial molar volumes, _m,1 ^∘E and _m,2 ^∘E, at infinite dilution were calculated. The V _m ^E values were found to be negative over the whole composition range for all of the mixtures and at each temperature studied, except for THF + mesitylene, which exhibits a sigmoid trend wherein V _m ^E changes sign from negative to positive as the concentration of THF in the mixture is increased, indicating the presence of specific interactions between THF and aromatic hydrocarbon molecules. The extent of negative deviations in the V _m ^E values follows the order: benzene > toluene > p-xylene > m-xylene > o-xylene > mesitylene. It is observed that the V _m ^E values depend upon the number and position of the methyl groups in these aromatic hydrocarbons.     

Measurement and Prediction on the Surface Properties of Dimethyl Sulfoxide/Water Mixtures

Pendent drop method was adopted to measure the surface tension of dimethyl sulfoxide(DMSO)/water mixtures. A new pendent drop apparatus was built up and checked with water, and a good agreement of our data with literature could be found. With the new apparatus, the surface tensions of nine DMSO/water mixtures with mass fractions of water from 0.1 to 0.9 were investigated in a temperature range of 298-338 K. The expanded uncertainty for surface tension measurement was estimated to be 0.5% at a confidence level of 95%(k=2) in the whole temperature range. A thermodynamic-based relation was used to predict the surface properties of DMSO/water mixtures. Based on the relation and Gibbs adsorption theory, a prediction model was proposed for the calculation of surface relative excess and the thickness of the surface molecule layer.     

Direct Evaluation of Partial Molar Volumes of Binary Solutions of Dimethyl Sulfoxide with Ethyl Acrylate,Butyl Acrylate,Methyl Methacrylate and Styrene

The Tikhonov regularization is applied to convert specific molar volume data of binary solutions of dimethyl sulfoxide with a number of acrylates and with styrene into their second- and first-partial derivatives with respect to mole fraction under constant temperature and pressure. Generalized Cross Validation is used to guide the selection of the regularization parameter that keeps noise amplification under control. The resulting first derivative is then used to compute the partial molar volumes. These are compared against that obtained by the traditional method of least-squares fitting of excess molar volumes. Some of the advantages of the current approach and possible extension to other partial molar quantities are briefly discussed.     

Physical Properties of the Ternary Mixture Ethanol+Water+1-Butyl-3-Methylimidazolium Chloride at 298.15 K

In this work densities, refractive indices, speeds of sound and isentropic compressibilities of the ternary mixture ethanol+water+1-butyl-3-methylimidazolium chloride ([C₄mim][Cl]), and of the binary subsystems containing the ionic liquid, have been measured at 298.15 K and atmospheric pressure.     

二元体系C6H6-DMF在293.15 K下的体积性质

利用Anton Paar DMA4500振动管密度计, 测量了293.15 K时二元体系C6H6-DMF(苯-N,N-二甲基甲酰胺)溶液的密度, 利用最小二乘法确立了溶液密度与组成的函数关系. 利用密度数据分别计算了二元体系中C6H6和DMF的表观摩尔体积, 并利用非线性最小二乘拟合法, 分别拟合得到了优化的C6H6和DMF的表观摩尔体积和摩尔分数的函数关系, 以及C6H6和DMF的表观摩尔体积和质量分数的函数关系. 通过对函数关系的极限运算得到了C6H6和DMF的标准偏摩尔体积和摩尔体积. 此外, 还计算了不同组分下体系的超额摩尔体积, 数据可用四参数Redlich-Kister方程很好地关联拟合, 得到方程系数及体系的超额摩尔体积极值位置.     

温度对二甲基亚砜水溶液的结构和热力学性质的影响

应用参考作用格位模型理论计算了二甲基亚砜(DMSO)摩尔分数为0.002时不同温度下溶液的微观结构和热力学性质. 计算结果表明, DMSO加入到水中能够增强溶液的分子网络结构. 温度升高, 配位数减小, 溶液中分子排布趋向无序. 平均力势的波动增大表明分子间的诱导力表现为斥力. 计算得到的各种热力学性质显示: 温度升高, 溶液的熵和溶剂化自由能增加, 相互作用能和过剩化学位也增加, 即高温下溶液越来越偏离理想溶液; 空位形成能降低表明溶液分子结构在高温下更容易重组.     

Excess Volumes of Binary Mixtures of Benzene + 1-Alkanols at 303.15 K

Abstract

Excess molar volumes V^E of binary mixtures of benzene + 1-propanol, + 1-butanol, + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-nonanol and 1-decanol were measured at 303.15 K. The V^E values are positive over the entire range of composition for these mixtures. The results are discussed in terms of intermolecular interactions.     

Densities and Viscosities for the Binary Mixtures (2-Methyl-1-Chloropropane + Isomeric Butanol) at 298.15 and 313.15 K

Abstract

This paper reports excess volumes, V^E , and viscosity deviations, Δ\eta, for binary mixtures of 2-methyl-1-chloropropane with an isomer of butanol at the temperatures 298.15 K and 313.15 K. These properties were obtained from density and viscosity measurements. The results are correlated by means of a Redlich-Kister type equation, and interpreted in terms of molecular interactions. The systems show positive values of V^E except in a short range of compositions for mixtures containing primary butanols (1-butanol at both temperatures and 2-methyl-1-propanol at 298.15 K), whereas Δ\eta presents negative values at both temperatures over the whole composition range.     

Experimental Densities, Speeds of Sound, Isentropic Compressibilties and Shear Relaxation Times of CaSO4·2H2O + CaCl2 + H2O and CaSO4·2H2O + NaCl + H2O Systems at Temperatures 30 and 35 °C

Speeds of sound, u, have been measured as a function of concentration for the systems, CaSO₄·2H₂O +CaCl₂ + H₂O and CaSO₄·2H₂O + NaCl + H₂O, at temperatures of 30 and 35 °C. Derived parameters such as the isentropic compressibility, κ _S , and the shear relaxation time,τ,were calculated using the experimental speed of sound data in combination with viscosity values from our earlier work. Results have been compared with those of the CaCl₂+ H₂Oand NaCl + H₂O systems reported in literature,to examine the effect of adding CaSO₄·2H₂O(s).Values of κ _S for the system,CaSO₄·2H₂O + CaCl₂+H₂O,are smaller compared with those for the CaCl₂+ H₂O system.Values of τ are lower at lower concentrations and then cross over in a narrow concentration region.Values of κ _S for the system,CaSO₄·2H₂O+NaCl+H₂O, are also smaller when compared with those forthe NaCl +H₂O system.For this system the τ values are higher. These τ values reach a minimum at a certain concentration of NaCl in the solution and then increase with further increases in concentration.The influenceof solvent-separated and/or solvent-shared ion pairs plays a dominant role at higher concentrations for both systems.Results have been interpreted and discussed in terms of the expansion and contraction of the primary hydration shell of the ionic species present in the studied systems.     

FT IR ATR Study of Molecular Interactions in the Urea/Dimethyl Sulfoxide and Urea/Diethyl Sulfoxide Binary Systems

FT IR ATR spectra of urea/dimethyl sulfoxide and urea/diethyl sulfoxide mixtures in the S=O and N—H stretching vibration regions at different molar ratios have been measured. On the basis of the band deconvolution data, various types of intermolecular associated forms, including dimers and hydrogen-bonded urea–sulfoxide complexes, have been revealed. The latter has been confirmed also by ab initio calculations.