Miscibility ternary systems

A Kirkwood-Buff Integrals in Fully Miscible Ternary Systems Thermodynamic Data, Calculation, Representation, and Interpretation... 

Kirkwood-Buff Integrals in Fully Miscible Ternary Systems... 

It was shown that introduction of various amounts of HEMA into the starting system leads to the formation of a semi-IPN which is characterized by a single temperature transition based on DMA and DSC data [310,353]. The position of this transition depends on the system composition and on the kinetic conditions of the reaction (rates of formation of both components). The kinetic measurements have shown that during reaction in the presence of HEMA no phase separation proceeds, as follows from the hght scattering data. In this case the final system has a one-phase structure due to the formation of a thermodynamically miscible ternary system and to the grafting of PU chains onto PS macromolecules via the third component. The reaction compatibilization was studied more thoroughly for semi-IPN PU/PS in the presence of OUDM [311]. 

In ternary systems, we distinguish between two common types. In type II, two binaries are partially miscible and the third binary is completely miscible in type I, only one binary is partially miscible. (A third type, where all three binaries are only partially miscible, is relatively rare and not considered here.)... 

Using the ternary tie-line data and the binary VLE data for the miscible binary pairs, the optimum binary parameters are obtained for each ternary of the type 1-2-i for i = 3. .. m. This results in multiple sets of the parameters for the 1-2 binary, since this binary occurs in each of the ternaries containing two liquid phases. To determine a single set of parameters to represent the 1-2 binary system, the values obtained from initial data reduction of each of the ternary systems are plotted with their approximate confidence ellipses. We choose a single optimum set from the intersection of the confidence ellipses. Finally, with the parameters for the 1-2 binary set at their optimum value, the parameters are adjusted for the remaining miscible binary in each ternary, i.e. the parameters for the 2-i binary system in each ternary of the type 1-2-i for i = 3. .. m. This adjustment is made, again, using the ternary tie-line data and binary VLE data. 

Selected physical properties of various methacrylate esters, amides, and derivatives are given in Tables 1—4. Tables 3 and 4 describe more commercially available methacrylic acid derivatives. A2eotrope data for MMA are shown in Table 5 (8). The solubiUty of MMA in water at 25°C is 1.5%. Water solubiUty of longer alkyl methacrylates ranges from slight to insoluble. Some functionalized esters such as 2-dimethylaniinoethyl methacrylate are miscible and/or hydrolyze. The solubiUty of 2-hydroxypropyl methacrylate in water at 25°C is 13%. Vapor—Hquid equiUbrium (VLE) data have been pubHshed on methanol, methyl methacrylate, and methacrylic acid pairs (9), as have solubiUty data for this ternary system (10). VLE data are also available for methyl methacrylate, methacrylic acid, methyl a-hydroxyisobutyrate, methanol, and water, which are the critical components obtained in the commercially important acetone cyanohydrin route to methyl methacrylate (11). 

The system H2S-CH4-H20 is an example of a ternary system forming a continuous range of mixed hydrates of Structure I. For this system Noaker and Katz22 studied the H2S/CH4 ratio of the gas in equilibrium with aqueous liquid and hydrate. From the variation of this ratio with total pressure at constant temperature it follows that complete miscibility must occur in the solid phase. 

Emulsions formed from immiscible organic liquids in aqueous peroxide mixtures may behave in the same way as miscible organic liquids, but if the emulsion breaks and separation of the organic phase occurs, passage into an explosive region of the peroxide-water-organic liquid ternary system may occur, and this is potentially very dangerous. 

Ternary Systems with Phases of Differing Miscibility... 

Figure 7.12 shows the liquidus surface of a ternary system with complete miscibility at solid state between components 1-2 and complete immiscibility at solid state between components 1-3 and 2-3. Note also that components 1 and 2 form a lens-shaped two-phase field, indicating ideality in the various aggregation states (Roozeboom type I). 

Figure 7.12 Phase stability relations in a ternary system with complete solid state miscibility of components 1-2 and complete immiscibility at solid state for components 1-3 and 2-3.

The effect of adding a surfactant, (NaDDS), was also investigated. One such case only is shown in Fig. 6 where BE is replaced by a 5 1 mixture of BE-NaDDS. The main effect of NaDDS is to increase the miscibility range of the oil in water. Various ratios of BE-NaDDS were used and, as a first approximation, the change in the phase diagram is directly proportional to the concentration of NaDDS. The addition of a surfactant probably stabilizes the microstructures which were already present in the ternary system BE-DEC-H O and decreases the quantity of BE needed to solubilize DEC. Therefore the presence of a surfactant is useful but not essential to the stability of microemulsions. 

Movements in the plane of the interface result from local variations of interfacial tension during the course of mass transfer. These variations may be produced by local variations of any quantity which affects the interfacial tension. Interfaeial motions have been ascribed to variations in interfacial concentration (H6, P6, S33), temperature (A9, P6), and electrical properties (AlO, B19). In ternary systems, variations in concentration are the major factor causing interfacial motion in partially miscible binary systems, interfacial temperature variations due to heat of solution effects are usually the cause. 

During the 1940s, a large amount of solubility data was obtained by Francis (6, 7), who carried out measurements on hundreds of binary and ternary systems with liquid carbon dioxide just below its critical point. Francis (6, 7) found that liquid carbon dioxide is also an excellent solvent for organic materials and that many of the compounds studied were completely miscible. In 1955, Todd and Elgin (8) reported on phase equilibrium studies with supercritical ethylene and a number of... 

Sulphur, selenium and tellurium exhibit allotropy, and in certain of their crystalline forms the elements are isomorphous. As would be expected from the increased positive character of tellurium, the allotropy of this element is less well defined. In the liquid condition the elements arc miscible with one another and yield mixed crystals the ternary system, S— Sc—Tc, exhibits neither the formation of compounds nor ternary eutectics, but contains two zones of complete miscibility in which there exist mixed crystals of selenium and tellurium with sulphur, and of sulphur and tellurium with selenium.2... 

Figure 14.1. Equilibria in a ternary system, type 1, with one pair of partially miscible liquids A = 1-hexene, B = tetramethylene sulfbne, C = benzene, at 5(TC (JR.M. De Fre, thesis, Gent, 1976). (a) Equilateral triangular plot point P is at 20% A, 10% B, and 70% C. (b) Right triangular plot with delines and tieline locus, the amount of A can be read off along the perpendicular to the hypotenuse or by difference, (c) Rectangular coordinate plot with tieline correlation below, also called Janecke and solvent-free coordinates.

Figure 11-12. a) Gibbs phase diagram for a ternary system with a miscibility gap. Tie lines and reaction path between (A,B) and C are indicated, b) Possible reaction paths near and across the miscibility gap. Starting compositions of the reaction couple are indicated (o) in Figure a. (Stable and unstable morphologies see text.)... 

There is a large body of experimental work on ternary systems of the type salt + water + organic cosolvent. In many cases the binary water + organic solvent subsystems show reentrant phase transitions, which means that there is more than one critical point. Well-known examples are closed miscibility loops that possess both a LCST and a UCST. Addition of salts may lead to an expansion or shrinking of these loops, or may even generate a loop in a completely miscible binary mixture. By judicious choice of the salt concentration, one can then achieve very special critical states, where two or even more critical points coincide [90, 160,161]. This leads to very peculiar critical behavior—for example, a doubling of the critical exponent y. We shall not discuss these aspects here in detail, but refer to a comprehensive review of reentrant phase transitions [90], We note, however, that for reentrant phase transitions one has to redefine the reduced temperature T, because near a given critical point the system s behavior is also affected by the existence of the second critical point. An improper treatment of these issues will obscure results on criticality. 

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