Ternary systems surfactant

Reversible transitions in ternary systems (surfactant-water-organic solvent), for instance, from a micellar to a liquid-crystalline state (including the macroheterogeneous state, when surfactant and enzyme are located in the condensed phase, while the reaction product is situated in the organic solvent), may also be considered as a general separation technique. This approach (see, e.g., [30]) seems extremely prospective for the purposes of organic synthesis. 

Porte G, Gomati R, Elhaitamy O, AppeU J, Marignan J (1986) Morphological transformations of the primary surfactant structures in brine-rich mixtures of ternary-systems (surfactant alcohol brine). J Phys Chem 90(22) 5746-5751... 

FIG. 1 Self-assembled structures in amphiphilic systems micellar structures (a) and (b) exist in aqueous solution as well as in ternary oil/water/amphiphile mixtures. In the latter case, they are swollen by the oil on the hydrophobic (tail) side. Monolayers (c) separate water from oil domains in ternary systems. Lipids in water tend to form bilayers (d) rather than micelles, since their hydrophobic block (two chains) is so compact and bulky, compared to the head group, that they cannot easily pack into a sphere [4]. At small concentrations, bilayers often close up to form vesicles (e). Some surfactants also form cyhndrical (wormlike) micelles (not shown). 

Like other surfactants, alkanesulfonates generate lyotropic liquid-crystalline phases. But the phase equilibria can only be inadequately described because of the enormous experimental difficulties in, for instance, establishing an appropriate equilibrium. Nevertheless, for simple ternary systems the modeling of surfactant-containing liquid-liquid equilibria has been successfully demonstrated [60],... 

Figure 4.23 Synthesis space diagram for a ternary system composed of tetraethylorthosilicate (TEOS), cetyltrimethylammonium bromide (CTAB), and sodium hydroxide (H, hexagonal phase [MCM-41] C, cubic phase [MCM-48] L, lamellar phase [MCM-50] H20/Si02 = 100, reaction temperature 100°C, reaction time 10 days). (Reprinted from Science, Vol. 267, A. Firouzi, D. Kumar, L.M. Bull, T. Besier, R Sieger, Q. Huo, S.A. Walker, J.A. Zasadzinski, C. Glinka, J. Nicol, D.l. Margolese, G.D. Stucky, B.F. Chmelka, Cooperative Organization of Inorganic-Surfactant and Biomimetic Assemblies, pp. 1138-1143. Copyright 1995. With permission of AAAS.)...

This problem was resolved by Nakae et al. [7] using non-polar octadecylsilica as the stationary phase and a solution of 0.1 M of sodium perchlorate in methanol/water (80 20) as the mobile phase. The ternary system (water-alcohol-salt), previously used by Fudano and Konishi [8] as an eluent for the separation of ionic surfactants at higher concentrations, induced the so-called salting out effect . The addition of the organic solvent to the water modified the polarity of the eluent and produced a good separation within a short period of time [9]. It also has the function of dissociating the surfactant micelles in individual molecules that are dissolved in the eluent [8], The presence of the salt (NaC104) in the mobile phase has a considerable influence on... 

The low interfacial tensions between two liquids have been measured for different systems by using the pendant drop method. In the case of the quaternary system Ci2ll25S 3 tNa+H20+n-Butanol+Toluene, the interfacial data as measured by pendant drop method are compared with reported literature data, using other methods (with varying NaCl concentration). In order to understand the role of co-surfactant, ternary systems were also investigated. The pendant drop method was also used for measuring the interfacial tension between surfactant-H20/n-alcohol (with number of carbon atoms in alcohol varying from 4-10). The interfacial tension variation was dependent on both the surfactant and alcohol. 

W.D. Bancroft The Theory of Emulsification, V. J. Phys. Chem. 17, 501 (1913). K. Shinoda and H. Saito The Effect of Temperature on the Phase Equilibrium and the Types of Dispersions of the Ternary System Composed of Water, Cyclohexane and Nonionic Surfactant. J. Colloid Interface Sci. 26, 70 (1968). 

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. 

Figure 7 indicates the phase behavior of SOW systems containing ternary nonionic surfactant mixtures that in turn contain a very hydrophilic surfactant (Tween 60 Sorbitan -i- 20 EO stearate), a very hpophihc surfactant (Span 20 Sorbitan monolaurate), and an intermediate (Tween 85 Sorbitan 20 EO trioleate or Nonylphenol with an average of 5 EO groups). The two intermediate surfactants correspond exactly to an optimum formulation in the physicochemical conditions, i.e., they exhibit three-phase behavior with the system 1 wt. % NaCl brine-heptane-2-butanol. As the intermediate hy-drophihcity surfactant is replaced by an equivalent mixture of the extreme ... 

Bourrel M, Chambu C (1983) The Rules for Achieving High Solubilization of Brine and OU by AmphiphUic Molecules. Soc Petrol Eng J 23 327-338 Kunieda H, Shinoda K (1985) Evaluation of the hydrophile-lipophile balance (HLB) of nonionic surfactants I. Multisurfactant systems. J Colloid Interface Sci 107 107-121 Kahlweit M, Strey R, Eirman P (1986) Search for tricritical points in ternary systems Water-oil-nonionic amphiphile. J Phys Chem 90 671... 

Raney K, Benton W, Miller CA (1987) Optimum detergency conditions with nonionic sm-factants I. Ternary water-surfactant-hydrocarbon system. J Colloid Interface Sci 117 282-290... 

These fluorescent probes have been successful in reporting the structural parameters of surfactant assemblies such as micelles [103], reverse micelles [104], ternary systems [105], swollen micelles [106], microemulsion [107], vesicles [108], liposomes [109], hemimicelles [110], monolayers [111] and bilayers [111]. 

Fontell K, Khan A, Lindstrom B, Maciejewska D, Puangngern S (1991) Phase-Equilibria and Structures in Ternary-Systems of a Cationic Surfactant (C16tabr or (C16ta)2so4), Alcohol, and Water. Colloid Polym Sci 269 727-742 Israelachvili JN, Mitchell DJ, Ninham BW (1977) Theory of Self-Assembly of Lipid Bilayers and Vesicles. Biochim Biophys Acta 470 185-201... 

Yoon MS, Chung YB, Han K. A study of gel structure in the nonionic surfactant/cetos-tearyl alcohol/water ternary systems by differential scanning calorimetry. J Disp Sci Tech 1999 20 1695-1713. 

Ternary systems of surfactant, slightly polar additives and water are particularly interesting. A typical example is the classical model system... 

CMC determinations as a function of temperature utilizing the change of the amount of solubilized water are inaccurate. This procedure has been frequently applied. In this way, for example, the effect of the temperature on the CMC of hexa-oxyethylene dodecylether in cyclohexane183) was determined. The CMC loses its well defined meaning in a ternary system, viz. to represent a thermodynamic property of the particular surfactant/solvent system (see Paragraph 2.2). 

A correlation of the detergency performance and the equilibrium phase behavior of such ternary systems is expected, based on the results presented by Miller et al. (3,6). The phase behavior of surfactant - oil - water (brine) systems, particularly with regard to the formation of so-called "middle" or "microemulsion" phases, has been shown by Kahlweit et al. (7,8) to be understandable in teims of the... 

Figure 3.22 (right) represents the three-phase temperature intervals for Q2E4 and Q2E5 vs the number n of carbon atoms of n-alkanes (for the phase behaviour of ternary systems see Section 3.4.2, Figure 3.26). The left part of Figure 3.22 shows the detergency of these surfactants for hexadecane. Both parts of Figure 3.22 indicate that the maximum oil removal is in the three-phase interval of the oil used (n-hexadecane) [22]. This means that not only the solubilisation capacity of the concentrated surfactant phase, but probably also the minimum interfacial tension existing in the range of the three-phase body is responsible for the maximum oil removal. Further details about the influence of the polarity of the oil, the type of surfactant and the addition of salt are summarised in the review of Miller and Raney [23].

There is a common rule, called Bancroft s rule, that is well known to people doing practical work with emulsions if they want to prepare an O/W emulsion they have to choose a hydrophilic emulsifier which is preferably soluble in water. If a W/O emulsion is to be produced, a more hydrophobic emulsifier predominantly soluble in oil has to be selected. This means that the emulsifier has to be soluble to a higher extent in the continuous phase. This rule often holds but there are restrictions and limitations since the solubilities in the ternary system may differ from the binary system surfactant/oil or surfactant/water. Further determining variables on the emulsion type are the ratios of the two phases, the electrolyte concentration or the temperature. 

The Kahlweit fish, however, is only a special case for a fixed water/oil ratio of an even more complex phase behaviour of the ternary system water/oil/surfactant. The more general... 

Figure 3.26 Schematic phase diagram of a ternary system consisting of water, oil and ethoxy-lated non-ionic surfactant.

A Monolayer Stmcture. One of Ae auAors (DMA) has proposed another structure of quite a different nature for a cubic phase occuring in ternary systems involving quaternary ammonium surfactants (16). and this cubic phase is Ae focus of much of... 

Solubilization can be defined as the preparation of a thermodynamically stable isotropic solution of a substance normally insoluble or very slightly soluble in a given solvent by the introduction of an additional amphiphilic component or components. The amphiphilic components (surfactants) must be introduced at a concentration at or above their critical micelle concentrations. Simple micellar systems (and reverse micellar) as well as liquid crystalline phases and vesicles referred to above are all capable of solubilization. In liquid crystalline phases and vesicles, a ternary system is formed on incorporation of the solubilizate and thus these anisotropic systems are not strictly in accordance with the definition given above. 

The rigidity and strength of networks prepared with cetostearyl alcohol and alkyltrimethyl-ammonium bromides (Cj2-Cjg) increase as the alkyl chain length increases. The rheological stability of ternary systems is markedly dependent on the alcohol chain length networks prepared with ionic or nonionic surfactants and pure cetyl or pure stearyl alcohol are weaker than those prepared with cetostearyl alcohol. In particular, emulsions prepared with stearyl alcohol are mobile and eventually separate. 

The extraction method using 8-hydroxyquinoline is not very sensitive, but it is highly selective. The really sensitive methods for spectrophotometric determination of aluminium are based on ternary systems, including triphenylmethane reagents (mainly Chrome Azurol S and Eriochrome Cyanine R) and some surfactants. 

Other cationic surfactants, cetylpyridinium bromide (CP) [27], and Zephiramine [26] have been recommended for determining Ga in a ternary system with ECR. 

Since methods for determining indium are rather unselective, the separation methods are very important. The spectrophotometric method involving 4-(2-pyridylazo)resorcinol (PAR), and the much more sensitive method based on the ternary system with Eriochrome Cyanine R and CTA (cationic surfactant) are discussed below in detail. 

The optimum pH for formation of a ternary compound Fe(III)-ECR-CTA, suitable for Fe determinations, is 4.5 0.5. Maximal and stable absorbances (at 610 nm) are obtained when suitable (sufficiently large) concentrations of chromogenic reagent and cationic surfactant (see Procedure) are present in the sample solutions. In the ternary system a large bathochromic shift and hyperchromic effect are observed in comparison with the binary system (without CTA). 

The reaction of Bromopyrogallol Red (BPR) (formula 4.21) with Mo(Vl) is not suitable for analytical use because the absorption maxima of the binary complex and of the reagent itself are too close. However, in the presence of cationic surfactants, bathochromic and hyperchromic effects are observed. These ternary systems allow a sensitive determination of molybdenum the absorbance of the reagent at the absorbance maximum of the ternary complex is insignificant [63-65]. The best results are obtained with the use of CTA ions. 

A considerable increase in the sensitivity of methods for palladium determination has been found with triphenylmethane reagents in ternary systems that include cationic surfactants, e.g., Eriochrome Cyanine R with CP [79], Chromal Blue G with CTA (e = 1.0-10 ) [80], Chrome Azurol S-CTA (or -CP) [81], Eriochrome Azurol B-CTA (e = 1.15-10 ) [82], and Eriochrome Azurol G-CTA [83]. 

In a type 111 system, a left lobe or right lobe microemulsion cannot coexist with the middle-phase microemulsion. The total composition determines the existence of a lobe or the middle-phase microemulsion. Gary A. Pope (Personal communication on Febraary 17, 2009) pointed out that, as a practical matter, we rarely measure a sufficient number of points in the ternary system to clearly define two-phase and three-phase regions. When cosolvent and/or Ca is used, or when soap forms, a ternary diagram does not accurately represent the phase behavior. When typical salinity scans at WOR = 1 and a low surfactant concentration are performed, almost aU the cases in a type III environment will be three phases. So there is little, if any, practical issue involved in a typical phase behavior experiment. 

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