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Abstract : Excess Molar Volume of Binary Mixtures of Tetrachloroethylene + Acetylacetone, + Acrylonitrile, + Anisole and + Tetrahydrofuran at 303.15 K
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Abstract: Excess molar volumes have been measured by means of a dilatometer for tetrachloroethylene (TCE) +acetyl acetone, + acrylonitrile, +anisole and+ tetrahydrofuran at 303.15 K. VEm values are positive over the entire range of composition for TCE- anisole and TCE – acetyl acetone and negative for TCE- Tetrahydrofuran. For TCE – acrylontrile, VEm has been found to be negative up to x = 0.8379 and positive onward. Values of VmE for the various systems have been fitted by the method of least squares with smoothing equation, and have been discussed from the viewpoint of the existence of specific interactions between the components. Keywords: Tetrachloroethylene, dilatometer, excess volume, specific interaction.Download Full Article |
Abstract : Azeotropy Breaking in Refrigerant Blends with Ionic Liquids
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Abstract: The principal aim of this work is to study azeotropy breaking in the refrigerant blends with ionic liquids (IL). The global phase diagram approach is applied to correlate azeotropic data for binary mixtures based only on critical properties and acentric factor of the individual components in mixtures. Analytical expressions to predict azeotropy phenomena in terms of critical parameters of pure components and binary interaction parameters are given. The eventual azeotropy appearance in the refrigerant – IL blends is discussed and conclusion about highly improbable azeotropic blend formation for these systems is given. Global phase behavior of ionic liquid – industrial refrigerant blends is analyzed and possible III, IV and/or V types according to the classification scheme of Scott and van Konynenburg[1] are established. The azeotropy breaking in binary refrigerant mixtures with ionic liquid adding is predicted. Keywords: Phase equilibria, azeotropy breaking, ionic liquids, refrigerant blends.Download Full Article |
Abstract : Anisotropic Properties of Mesogenic Surfactants with Ionic Liquid Core
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Abstract: Ionic mesogens (HI-n), constructed from imidazolium-functionalized azobenzenes with differential flexible spacers and a nitro polar terminal group, were synthesized. Their potential thermotropic liquid crystal properties were investigated bypolarizing optical microscopy (POM), differential scanning calorimetry (DSC) and temperature variable X-ray diffraction measurements. HI-n exhibited a smectic A fluid (SmA) phase by anisotropy through interactions between azobenzene units and ionic interactions. This SmA formation was observed by POM and DSC. In the SmA phase, focal conic fan textures were observed by POM under the crossed-Nicols. The perpendicular structure (homeotropic alignment) formed spontaneously in the SmA phase through physical adsorption of imidazolium ionic units upon a glass plate. In the SmA phase, HI-n exhibited the X-ray diffraction patterns consisting of sharp inner reflections, corresponding to the layer distance, and a broad outer reflection exhibiting a short range order within the smectic layer. It is expected that the SmA layer consists of the hydrophilic and hydrophobic sublayers. The hydrophilic sublayer was formed by an ionic aggregation of imidazolium and iodide ions. On the other hand, the hydrophobic sublayer was obtained by segregation from the hydrophilic sublayer. It can be considered that HI-n are an anisotropic ionic liquid because the SmA state has a fluidity such as an ionic liquid. The ionic material shows the strong temperature dependence of an ionic interaction. The ionic interactions in the liquid crystal phase became weak gradually with increasing temperature, and the fluidity of the liquid crystal phase increase. HI-n dissolved in water. The HI-n water solution revealed a lyotropic smectic A anisotropic fluid. Keywords: Anisotropic Fluid, Ionic Liquid Core, Ionic Liquid Crystal, Thermal Property, X-ray diffraction.Download Full Article |
Abstract : ‘Meyer-Neldel Rule’: True History of its Development and its Intimate Connection to Classical Thermodynamics
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Abstract: The history of the Meyer-Neldel rule’s development and the initial collective efforts toward its comprehension have been described here. The whole story gives a nice occasion to trigger thorough analysis of the basic thermodynamic laws and looking for the true sense of the entropy notion. Keywords: Entropy, Enthalpy, Compensation, Thermodynamics, Nanoscale.Download Full Article |
