Phase equilibria of mixtures

Spyriouni, T. Economou, I. G. Theodorou, D. N., Phase equilibria of mixtures containing chain molecules predicted through a novel simulation scheme, Macromolecules 1998, 31, 1430-1431... 

This definition cannot be applied directly to mixtures, as phase equilibria of mixtures can be very complex. Nevertheless, the term supercritical is widely accepted because of its practicable use in certain applications [6]. Some properties of SCFs can be simply tuned by changing the pressure and temperature. In particular, density and viscosity change drastically under conditions close to the critical point. It is well known that the density-dependent properties of an SCF (e.g., solubihty, diffusivity, viscosity, and heat capacity) can be manipulated by relatively small changes in temperature and pressure (Sect. 2.1). 

In this volume, we will apply the principles developed in Principles and Applications to the description of topics of interest to chemists, such as effects of surfaces and gravitational and centrifugal fields phase equilibria of pure substances (first order and continuous transitions) (vapor + liquid), (liquid 4-liquid), (solid + liquid), and (fluid -f fluid) phase equilibria of mixtures chemical equilibria and properties of both nonelectrolyte and electrolyte mixtures. But do not expect a detailed survey of these topics. This, of course, would require a volume of immense breadth and depth. Instead, representative examples are presented to develop general principles that can then be applied to a wide variety of systems. 

Continuous mixtures Phase equilibria of mixtures Polar and associating liquids Electrolyte solutions... 

Sako, T., Wu, A.H. and Prausnitz, J.M., A cubic equation of state for high-pressure phase equilibria of mixtures containing polymers and volatile fluids, J. Appl. Polym. Sci., 38, 1839, 1989. Kontogeorgis, G.M. et al.. Application of the van der Waals equation of state to polymers. I. Correlation, Fluid Phase Equilibria, 96, 65-92, 1994. 

F1N Finck, U., Wohlfarth, Ch., and Hener, T., Calcnlation of high pressure phase equilibria of mixtures of etlylene, viityl acetate and an (ethylene-vinyl acetate) copolymer, Ber. Bunsenges. Phys. Chem., 96, 179, 1992. 

Abdullayev E, Joshi A, Wei W, Zhao Y, Lvov Y (2012) Enlargement of halloysite clay nanotube lumen by selective etehing of aluminum oxide. ACS Nano 6(8) 7216-7226 Alexandre M, Dubois P (2000) Polymer-layered silicate nanocomposites preparation, properties and uses of a new class of materials. Mater Sci Eng R Rep 28(1-2) 1-63 Aice A, Earle MJ, Katdare SP, Rodriguez H, Seddon KR (2007) Phase equilibria of mixtures of mutually immiscible ionie liquids. Fluid Phase Equilib 261(l-2) 427 33 Azizi Samir MAS, Alloin F, Dufresne A (2005) Review of recent research into cellulosic whiskers, their properties and their application in nanocomposite field. Biomacromolecules 6(2) 612-626... 

The development of appropriate thermodynamie models to represent or even prediet solubility and phase equilibria of mixtures is still a ehallenging task. Knowledge of solubilities and equilibrium eompositions are essential for evaluating the feasibility of separation pro-eess. The progress of these models allows the development of eomputer aided tools for the design, simulation, and optimization of viable separation proeesses. 

So far, we have described the effect of pressure and temperature on the phase equilibria of a pure substance. We now want to describe phase equilibrium for mixtures. Composition, usually expressed as mole fraction x or j, now becomes a variable, and the effect of composition on phase equilibrium in mixtures becomes of interest and importance. 

I. F. Holscher, G. M. Schneider and J. B. Ott, "Liquid-Liquid Phase Equilibria of Binary Mixtures of Methanol with Hexane, Nonane, and Decane at Pressures up to 150 MPa", Fluid Phase Equilib., 27, 153-169 (1986). 

Chapters 7 to 9 apply the thermodynamic relationships to mixtures, to phase equilibria, and to chemical equilibrium. In Chapter 7, both nonelectrolyte and electrolyte solutions are described, including the properties of ideal mixtures. The Debye-Hiickel theory is developed and applied to the electrolyte solutions. Thermal properties and osmotic pressure are also described. In Chapter 8, the principles of phase equilibria of pure substances and of mixtures are presented. The phase rule, Clapeyron equation, and phase diagrams are used extensively in the description of representative systems. Chapter 9 uses thermodynamics to describe chemical equilibrium. The equilibrium constant and its relationship to pressure, temperature, and activity is developed, as are the basic equations that apply to electrochemical cells. Examples are given that demonstrate the use of thermodynamics in predicting equilibrium conditions and cell voltages. 

Winsor [15] classified the phase equilibria of microemulsions into four types, now called Winsor I-IV microemulsions, illustrated in Fig. 15.5. Types I and II are two-phase systems where a surfactant rich phase, the microemulsion, is in equilibrium with an excess organic or aqueous phase, respectively. Type III is a three-phase system in which a W/O or an O/W microemulsion is in equilibrium with an excess of both the aqueous and the organic phase. Finally, type IV is a single isotropic phase. In many cases, the properties of the system components require the presence of a surfactant and a cosurfactant in the organic phase in order to achieve the formation of reverse micelles one example is the mixture of sodium dodecylsulfate and pentanol. 

Mehta, A.P. Sloan, E.D. Jr. (1993). Structure H Hydrate Phase Equilibria of Methane + Liquid Hydrocarbon Mixtures. J. Chem. Eng. Data, 38, 580-582. 

Nagata, L, On the thermodynamics of alcohol solutions. Phase equilibria of binary and ternary mixtures containing any number of alcohols. Fluid Phase Equilib., 19,153, 1985. 

G. M. Schneider in "Phase equilibria of liquid and gaseous mixtures at high pressures", B. LeNeindre and B. Vodar eds., Butterworth, London, vol 2., 1975, 787. 

Although a typical natural gas is mainly comprised of the first three normal paraffins, the phase equilibria of each component with water will differ from that of a natural gas with water. However, a comparison of predictions with data for methane, ethane, and propane simple gas hydrates is given as a basis for understanding the phase equilibria of water with binary and ternary mixtures of those gases. 

To evaluate the phase equilibria of binary gas mixtures in contact with water, consider phase diagrams showing pressure versus pseudo-binary hydrocarbon composition. Water is present in excess throughout the phase diagrams and so the compositions of each phase is relative only to the hydrocarbon content. This type of analysis is particularly useful for hydrate phase equilibria since the distribution of the guests is of most importance. This section will discuss one diagram of each binary hydrate mixture of methane, ethane, and propane at a temperature of 277.6 K. 

The methane+ethane+propane+water system is the simplest approximation of a natural gas mixture. As shown in Figure 5.20, the phase equilibria of such a simple mixture is quite complicated at pressures above incipient hydrate formation conditions. One of the most interesting phenomenon is the coexistence of si and sll hydrates which occurs in the interior of some pseudo-ternary phase diagrams. 

The expressions derived for the EOS and the chemical potential of component i in a binary mixture were used to model the phase equilibria of binary mixtures. A set of non-linear equations was obtained and solved by the use of a Newton s method. 

McHugh, M.A. Mallett, M.W. Kohn, J.P. "High Pressure Fluid Phase Equilibria of Alcohol - Water - Supercritical Solvent Mixtures", paper presented at the 1981 annual AIChE meeting, New Orleans, Louisiana, Nov. 9, 1981. 

Predictive Quasilattice Equation of State for Unified High Pressure Phase Equilibria of Pure Fluids and Mixtures... 

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