Water quaternary phase diagram

In the quaternary phase diagrams of the systems water-n-undecane-C 2-i4 all l polyglycol ether for alkyl polyglycol ether concentrations c.v<10 wt%, a three-phase area is found that is surrounded by two-phase regions. As is characteristic for systems with surfactant mixtures, the three-phase area is shifted toward higher temperatures for low surfactant concentrations and high oil concentrations. The same trends are described in Ref. 21. For surfactant concentrations Cs>20 wt%, the lamellar La phase is formed. 

The above calculations were obtained using a W/0 microemulsion of water/ xylene/sodium dodecyl benzene sulphonate (NaDBS)/hexanol [11]. The microemulsion region was established using the quaternary phase diagram. The 0 microemulsions were produced at various water volume fractions, using increasing amounts of NaDBS (5, 10.9,15 and 20%). 

Figure 16.6 illustrates the analogous (to Fig. 16.3) quaternary amphiphile-oU-water-electrolyte phase diagram, including a representative tietriangle, the S-shaped curve of T, M, and B compositions, the lower and upper critical end points (R and Q, respectively), and the lower (PR) and upper (QS) critical tielines (37). For clarity, the two-phase regions... 

Relatively few four-component systems have been studied in any detail. Fig. 2.24a shows diagrammatically the way in which the quaternary phase diagram for the system phosphated nonyl phenolethoxylate (PNE)-phosphated fatty alcohol ethoxylate (PFE)-n-hexane-water (Fig. 2.24b) is built up [42]. 

Figure 2.24(a) Diagrammatic representation of the effect of progressively adding water to a mixture of PNE, PFE and n-hexane. L, liquid Gg, gel E, emulsion Mj, middle phase liquid crystal G, neat phase liquid crystal, (b) Diagrammatic quaternary phase diagram for the system PNE-PFE-water-n-hexane at 25° C. From Groves et al [42] with permission. 

An example for a partially known ternary phase diagram is the sodium octane 1 -sulfonate/ 1-decanol/water system [61]. Figure 34 shows the isotropic areas L, and L2 for the water-rich surfactant phase with solubilized alcohol and for the solvent-rich surfactant phase with solubilized water, respectively. Furthermore, the lamellar neat phase D and the anisotropic hexagonal middle phase E are indicated (for systematics, cf. Ref. 62). For the quaternary sodium octane 1-sulfonate (A)/l-butanol (B)/n-tetradecane (0)/water (W) system, the tricritical point which characterizes the transition of three coexisting phases into one liquid phase is at 40.1°C A, 0.042 (mass parts) B, 0.958 (A + B = 56 wt %) O, 0.54 W, 0.46 [63]. For both the binary phase equilibrium dodecane... 

SLE of quaternary ammonium ILs in alcohols, hydrocarbons, and water have been measured for many salts. Systematic studies of SLE phase diagrams for quaternary ammonium salts [(Cj)2C2HOC2N]Br, [(Ci)2C3HOC2N]Br, [(Cj)2C4HOC2N]Br, and [(Ci)2CgHOC2N]Br in water and alcohols have been published [52,79]. Other anions including [BFJ, [PFg], [dca] , and [TfjN] have also been investigated [53]. 

The phase diagram of the quaternary system, n-tetradecane, water, A-B-A block copol3nner (where A Is poly— (12-hydroxystearlc acid) and B Is poly(ethylene oxide)) and n-butanol was Investigated at 7, 23 and 47 C. Two A-B-A polymer concentrations of 10 and 20Z were used. 

Figure 1 Phase diagrams for the quaternary system tetradecane, butan-l-ol, water, B246 at 7°C (a), 23°C (b) and 40°C (c). Total concentration of B246 is 10%.

The phase behavior observed in the quaternary systems A and B is also evidenced in ternary systems. Figure 4 shows the phase diagrams for systems made of AOT-water and two different oils. The phase diagram with decane was established by Assih (14) and that with isooctane has been established in our laboratory. At 25°C the isooctane system does not present a critical point and the inverse micellar phase is bounded by a two-phase domain where the inverse micellar phase is in equilibrium with a liquid crystalline phase, as for system B or system A when the W/S ratio is below 1.1. In the case of decane, a critical point has been evidenced by light scattering (15). Assih and al. have observed around the critical point a two-phase region where two microemulsions are in equilibrium. A three-phase equilibrium connects the liquid crystalline phase and this last region. 

Most work has been done with monoalkyl quaternaries, and the conclusions extended to the dialkyl cationic surfactants. This process is incorrect since the monoalkyl derivatives are much more water soluble than the corresponding dialkyl derivatives and they behave differently. Only a few studies have been carried out on DHTDMAC. They are discussed by Crutzen [102], A very different approach was that of Kunieda and Shinoda [88] and Laughlin and co-workers [89,103,104] who studied the phase diagram of dioctadecyldimethylammonium chloride as a model for DHTDMAC deposition. 

Very early, the Swedish school attempted to determine the extent and shape of the region of existence of microemulsions in quaternary systems [76-78]. By examination of sections of the phase diagram at several levels of oil, Friberg and coworkers established a direct connection between the microemulsion areas and the inverse micellar solutions described by Ekwall [1]. Thus, prior to describing the phase diagrams of the quaternary systems, those of ternary systems made of water, sodium dodecylsulfate (SDS), and an alcohol are first presented here. 

The phase diagrams of two quaternary mixtures made of sodium dodecylsulfate (SDS)-water-dodecane and hexanol (system A) or pentanol (system B) have been investigated in detail [22,23]. In both cases, sections of the three-dimensional diagram with constant water/surfactant ratio have been examined. These cuts were chosen because they allow a good description of the oil region and also because the water/SDS ratio, termed X in the following, fixes the size of the droplets in the inverse microemulsion phase and the thickness of the bilayers in the oil-rich lamellar phase. In the description of the quaternary mixtures, we emphasize the details of the evolution of the phase equilibria as X is varied. We have focused our attention not only on the characterization and the location of the boundaries of the various phases but also on the equilibria between the phases. 

In the quaternary system water-dodecane-pentanol-SDS, the critical behavior is much more complex. As mentioned in Sec. II. B, at fixed temperature T = 21°C, this quaternary mixture presents a line of critical points that extends in the phase diagram between a critical point belonging to the ternary mixture water-SDS-pentanol and a critical endpoint P . located in the oil-rich part of the diagram. The X values (expressed in weight) corresponding to P p and P are 0.95 and 6.6, respectively. 

Figure 1 Pseudo ternary phase diagrams at room temperature of (a) quaternary systems containing lecithin, butanol, isopropyl myristate, and water or (b) a 10 wt% aqueous solution of sodium salicylate, at a lecithin/butanol ratio of 1 1. (Adapted from Ref. 9.)...

The phase behavior of ternary and quaternary systems of the type water-oil-surfactant-cosurfactant is affected strongly by the addition of other components. Therefore, it is questioned how the solubilization of soil during the use of microemulsions as cleaning media in the washing process influences their existence region in the phase diagram and their solubilization power. To test this effect, the temperature dependence of the phase behavior of samples 10-28 (see Table 2) after their use in model... 

Figure 2.17 Mass phase diagram of the quaternary liquid system made of CTAB/butariol (1/1 in mass) as the surface active mixture (surfactant + cosurfactant), heptane and water (NaCl O.IM). This system presents a continuous change from the LI structure to the L2 structure (see Figure 2.14). The dotted area corresponds to viscous milky compositions, redrawn from [31].

Fig. 5. Stable phase diagram of the quaternary system (NaCl - KCl - Na2B4C>7 - K2B4O7 - H2O) at 298.15 K. (a), dry-salt phase diagram (b), water-phase diagram.

As with azeotropes, eutectics maybe ternary, quaternary, and so on, but their phase diagrams get very complex very quickly. A few important eutectics have an impact on ordinary life. Ordinary solder is a eutectic of tin and lead (63% and 37%, respectively) that melts at 183 C, whereas the melting points of tin and lead are 232 C and 327 C. Wood s metal is an alloy of bismuth, lead, tin, and cadmium (50 25 12.5 12.5) that melts at 70 C (lower than the boiling point of water ) that can be used in overhead fire sprinkler systems. NaCl and H2O make a eutectic that melts at — 21 C, which should be of some interest to communities that use salt on icy roads in the winter. (The composition of this eutectic is about 23 weight percent NaCl.) An unusual eutectic exists for cesium and potassium. In a 77 23 ratio, this eutectic melts at —48 C This eutectic would be a liquid metal at most terrestrial temperatures (and be very reactive toward water). 

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