Phase pseudoternary

Fig. 2-30. Pseudoternary phase diagram of mixtures of a synthetic oil with carbon dioxide. The oil is represented as a mixture of methane and ethane plus. (Data from Leach and Yellig, Trans., AIME, 271, 89.)...

A novel approach to reduce the experimental effort associated with constructing pseudoternary phase diagrams is by using expert systems to predict the phase behavior of multicomponent ME-forming systems. Artificial neural networks have been investigated and were shown to be promising in phase behavior studies [17,35,36] as well as in the process of ingredient selection [37]. 

Alany, R. G, Davies, N. M., Tucker, I. G, and Rades, T. (2001), Characterising colloidal structures of pseudoternary phase diagrams formed by oil/water/amphiphile systems, Drug Dev. Ind. Pharm., 27(1), 33-41. 

Previously (11-12), we had contacted water and water in oil (W/0) microemulsion and found that transient lamellar liquid crystals (11) were formed even though these were not located in the pseudoternary phase diagram. The interesting feature was that these phases could be precipitated either in the oil phase or in the water phase, although the controlling factors could not be established. Because of its considerable significance in oil recovery (4) the mechanism of... 

Complex carbides containing boron, occurring frequently in boron-alloyed steels and superalloys, are also named carboborides. Metal borocarbides (see Table 1) are synthesized by powder metallurgical methods or are extracted from a metal matrix. There are pseudoternary or -quaternary borocarbides, such as Mn23(B, C) or (Cr, Mn, Fe)23 (B, C)g (t phases) although boron-carbon substitution in borocarbides is less pronounced than nitrogen-carbon substitution in metal carbonitrides. 

FIGURE 23.9 Vertical cross-sectional diagram including 123 and 211 compounds in pseudoternary phase diagram. (From Osamura, K., et al., Z. Metllkd., 84, 408, 1991.)... 

Pseudoternary phase diagrams of the water-dodecane-SDS-pentanol and water-dodecane-SDS-hexanol systems have been investigated in detail. A great variety of new domains has been evidenced in the oil rich part of these diagrams including, one-, two-, three- and four-phase liquid regions. An interpretation of these diagrams is proposed it is shown that interactions between water domains play an important role in microemulsion stability. 

Figure 3. W/S pseudoternary diagrams at T = 21.5 °C ( in volume) of the water-dodecane-SDS-pentanol system. Top W/S = 1 bottom W/S = 1.4. L, Lg, and L designate respectively an isotropic phase, a birefringent phase and a flow birefringent liquid phase.

The demixing curves in the W/S pseudoternary diagrams for the hexanol and pentanol systems have been calculated according to the above theoretical treatment. These lines have been determined in the following way. The calculation of the state equation is applied to a dilution line along such a line the inverse micelles have a constant radius R. The micelles contain the whole water (volume Vw), the surfactant (volume V ) and a part of the alcohol V. The rest of alcohol is in the oil continuous phase. We suppose that the alcohol-oil ratio in the continuous phase is constant and is equal to k. Besides, in the calculation of the micellar radius R one assumes that the surfactant and the alcohol molecules which are situated at the interface have a constant area per chain s. In mos of the previous studies s has been found constant and equal to 25 A2. This value is taken equal for the alcohol and surfactant chains. Consequently ... 

In our model a critical radius Rc appears its value is 52 A in the pentanol system. Then in each W/S plane a critical dilution line corresponding to such a radius is obtained. Its location depends on the W/S ratio. As this ratio decreases, the critical line lies at a lower alcohol content. In the case, where the critical dilution line is below the "lamellar" demixing line, the phase diagram is expected to be similar to that observed with the hexanol system for which the interactions are not predominant. This is the case of the pseudoternary sections defined by a W/S ratio less than 1.1. Besides this provides an explanation for the simultaneous disappearance of the regions X, V, XI, XII. 

The theory of diffusion paths, extended to allow for diffusion in a two-phase dispersion, was used to solve the diffusion equations for a model, pseudoternary system. Predicted diffusion paths were... 

Theoretical diffusion path studies were made with a model system for comparison to the experimentally observed phenomena. A pseudoternary representation was chosen for modeling the phase behavior, and brine and oil were chosen as the independent diffusing species. For simplicity and because their exact positions and shapes were not known, phase boundaries in the liquid crystal region were represented as straight lines. Actually, studies indicate a rather complex transition from liquid crystal to microemulsions as system oil content is increased, especially near optimum salinity (15-16). A modified Hand scheme was used to model the equilibria of binodal lobes (14,17). Other assumptions are described in detail elsewhere (13). 

At low salinities, the pseudoternary phase behavior is like that shown in Figure 19. Tie lines indicate a preferential solubility of the surfactant-alcohol mixture in brine. Also, the initial aqueous structure at composition D is a dilute dispersion of liquid crystal in an isotropic aqueous solution. The calculated... 

The multicontact miscibility development by a vaporizing mechanism is illustrated in Fig. 1. The pseudoternary diagram shows light (L) components (CO2, CH4), intermediate (I) gases (C2-C5) and heavy (H) components (Ce+j in the vertices. The critical point on the two-phase diagram is denoted by C. Oil and solvent compositions are denoted by O and S, respectively. As oil and solvent mix at oil-solvent front, two phases form, as shown by LI and Gl. The gas moves ahead being less viscous and mixes with original oil. This produces a two-phase mixture that forms compositions shown by L2 and G2. G2 moves ahead and mixes with oil. This process repeats itself and the... 

Figure 1 Pseudoternary phase diagram (Base - AI2O3- Si02) showing spherical temperature (ST) contours. See text for discussion of points connected by arrow and inset.

Extrapolation of Equation 1 to Vni=100 corresponds to T=1360°C for the liquidus. Extrapolation of Equation 3 to Vm=0 yields T=1119°C for the disappearance of liquid, the solidus temperature. This is a complex system for which complete phase diagrams are not available pseudoternary diagrams such as those presented by Grove et a l. (2) for similar compositions are generally applicable to this composition. 

Figure 14.5 Pseudoternary phase diagram of water/SDS/hexanol/dodecane with SDS hexanol ratio ofl 1.76. Solid and dashed lines indicate the emulsification paths followed starting from both 0/W (W ) and W/O (O ) microemulsion domains.

Figure 14.8 Pseudoternary phase diagram at 25 °C of the system water-C 2 04-hexadecane.

Figure 15.5 Schematic representation of the pseudoternary phase diagram of oil/water/ surfactant/cosurfactant.

FIGURE 9.12 High-salinity diffusion path for contact of composition D with oil (O) indicating an intermediate brine phase (b) and spontaneous emulsification in the oil phase (s.e.). Ic and w/o denote the lamellar liquid crystalline phase and a water in oil microemulsion, respectively. S/A denotes the surfactant/alcohol mixture in this pseudoternary diagram. (From Raney, K.H. and Miller, C.A., AIChE J., 33, 1791, 1987. With permission.)... 

Figure 8.6 Pseudoternary phase diagram of a system containing 20 wt.% emulsifier (Cs/io-APG, Q2/14-APG and GMO), 20 wt.% perfume oil, 0.6 wt.% oil (dicapryl ether, octyldodecanol) and 59.4 wt.% water at 25°C. The formation of microemulsions was studied as a function of the emulsifier s composition. The dotted lines separate the o/w- from the w/o-region. ME indicates a one-phase microemulsion. (From Ref. [39], reprinted with permission of Elsevier.)...

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