Phase sulfonate surfactant

The interfacial tension behavior between a crude oil (as opposed to pure hydrocarbon) and an aqueous surfactant phase as a function of temperature has not been extensively studied. Burkowsky and Marx T181 observed interfacial tension minima at temperatures between 50 and 80°C for crude oils with some surfactant formulations, whereas interfacial tensions for other formulations were not affected by temperature changes. Handy et al. [191 observed little or no temperature dependence (25-180°C) for interfacial tensions between California crude and aqueous petroleum sulfonate surfactants at various NaCI concentrations. In contrast, for a pure hydrocarbon or mineral oil and the same surfactant systems, an abrupt decrease in interfacial tension was observed at temperatures in excess of 120°C 1 20]. Non ionic surfactants showed sharp minima of interfacial tension for crude... 

It has also been shown [254] that a commercial petroleum sulfonate surfactant which consists of a diverse admixture of monomers does not exhibit behavior typically associated with micelle formation (i.e., a sharp inflection of solvent properties as the concentration of surfactant reaches CMC). These surfactants exhibit gradual change in solvent behavior with added surfactant. This gradual solubility enhancement indicates that micelle formation is a gradual process instead of a single event (i. e., CMC does not exist as a unique point, rather it is a continuous function of molecular properties). This type of surfactant can represent humic material in water, and may indicate that DHS form molecular aggregates in solution, which comprise an important third phase in the aqueous environment. This phase can affect an increase in the apparent solubility of very hydrophobic chemicals. 

Alkyl sulfates and sulfonates Two-phase or surfactant-electrode monitored titration... 

Figure 3. Effect of oil phase and number of ethoxy groups on foam volume produced by sulfonate surfactants.

The next system studied was novel in that the lower phase was a homogeneous lamellar liquid crystal containing a synthetic sulfonate surfactant in equilibrium with an excess oil phase. No previous observations of liquid crystalline flow through porous media have been reported. The initial viscosity of the liquid crystalIjiie phase was a relatively low 10 cp at a shear rate of 4.5 s -. The interfacial tension between liquid crystal and oleic phase was 0.018 dyne/cm (14). 

Table 1 Gradient Elution Program for Reversed-Phase HPLC of Alkyl Ether Sulfate Synthetic and Petroleum Sulfonate Surfactants...

The lET between the polymer-rich phase and surfactant-rich phase in an oil-free case could be very low, sometimes as low as 10 to 10 mN/m (Szabo, 1979). These low values of IFT indicate that the trapping of sulfonate, as discussed by Trushenski (1977), relates more to the difference in mobilities of the separated phases than to capillary force (IFT). 

Phase Behavior of a Pure Alkyl Aryl Sulfonate Surfactant... 

Few studies of pure alkyl aryl sulfonate surfactants have appeared (8,11c,12). The interpretation of phase behavior and interfacial tension data for pure, single surfactants and well-defined surfactant mixtures is expected to be easier than for complex and poorly-defined mixtures. Fundamental studies on pure surfactants will shed light on the behavior of practically important surfactant systems which are impure. 

Upon contacting of Salem Crude with the sulfonate system a mutual dissolution of the phases (oil, surfactant, co-surfactant and water) takes place. The phase which contains the mutually dissolved (or dispersed) components of the system does not possess the same phase contrast between it and the aqueous phase as between the crude oil and the aqueous phase as seen from Figure 1A. 

Figure 11.12. Effect of surfactant concentration on the inlerfacial tension (IFT) of TRS 10-410 (a petroleum sulfonate surfactant) -F isobutyl alcohol (IBA) in 1.5% NaCl with dodecane. An ultralow IFT can occur at low or high surfactant concentrations , interfacial tension of o/w micro emulsion A, interfacial tension of w/o micro emulsion. A three-phase system (oil-continuous, water-continuous and middle-phase regions) exists where the ( ) and (A) data overlap...

FIGURE 4.24 Phase behavior as a function of the salinity for a system containing a petroleum sulfonate surfactant, a short-chain alcohol, and approximately equal volumes of oil and brine. 

Interfacial coacervation has been successfully used for many types of microcapsules. Stabilization of the emulsion phase with surfactant is an important step in this process. The surfactants used have included lignin sulfonates, other sulfonated polymeric surfactants, and vinylpyrrolidone co-and terpolymers. Increased photo stabilization of the AI, apparently due to light-absorbing properties of the polymers used, has been an added benefit observed for some encapsulated formulations. 

Vasquez, in "Phase Behavior and Interfacial Tension of Sulfonated Surfactants," Master s Thesis, The University of Texas at Austin (1978). 

For a further separation of the sulfonated surfactants the latter are heated for 4 h with 2 N HCl. The methyl ester sulfonates are split into methanol and a-sulfo fatty acids, which form disodium salts after neutralization with NaOH. The product mixture from acid hydrolysis can be separated by extraction with petroleum ether. For example, the fatty alcohols formed from fatty alcohol sulfoacetates are soluble in the petroleum ether phase whereas the disalts of the ester sulfonates remain in the water phase. The saponification of the a-sulfo fatty acid esters with 2 N alcoholic potash lye leads to an extensive decomposition of the fatty acids [113]. 

The same catalyst showed higher ee values approaching 90% in the hydrogenation of acetamidocinnamic and methylenesuccinic acids in aqueous solutions, which is still somewhat less than those obtained with standard BINAP [163]. A new approach to the immobilization of the catalyst utilized a technique similar to the supported aqueous phase method. Sulfonate surfactant residues were tailored to the surface of silica, thus providing a layer capable... 

This parameter is also called neutral oil, or, in the case of higher molecular weight materials, wax. The determination is most often performed by extraction from water with a nonpolar solvent, such as petroleum ether. The nonpolar hydrocarbon will be extracted, while the surfactant and salts remain in the aqueous phase. Sulfones, if present, are included with the neutral oil. Some surfactants are not amenable to analysis by extraction because of emulsion formation. These are analyzed by ion exchange or adsorption chromatography procedures. The chromatography methods are more amenable to automation. 

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... 

The HLB numbers decrease with increasing chain length, e.g., from 13.25 for sodium decane 1-sulfonate to 9.45 for the C18 homolog [72]. Typical HLB numbers for positional isomers range from 12.3 for sodium dodecane 1-sulfonate to 13.2 for the more hydrophilic 6 isomer [73]. The HLB numbers of alkanesulfonates are less influenced by the isomeric position of the functional group and by substituents than the cM values [68]. HLB numbers can be correlated with partition coefficients for the distribution of a surfactant between the aqueous and oily phases, which emphasizes that the partition coefficient is dependent on the carbon number [68]. 

Entry Surfactant Di mono sulfonate Aqueous phase Oil phase IFT (dynes/cm)... 

Baviere et al. [41] determined the adsorption of C18 AOS onto kaolinite by agitating tubes containing 2 g of kaolinite per 10 g of surfactant solution for 4 h in a thermostat. Solids were separated from the liquid phase by centrifugation and the supernatant liquid titrated for sulfonate. The amount of AOS adsorbed is the difference between initial solution concentration and supernatant solution concentration at equilibrium. 

The phase behavior of a-ester sulfonates has been studied in detail with methyl laurate and methyl palmitate [58]. In both cases, at higher temperatures, as the surfactant concentration increases, there is a transition from an isotropic solution to a hexagonal liquid crystalline phase and finally, at high surfactant concentrations, to a lamellar liquid crystal (Fig. 4). The crystal/liquid-crys-tal phase transition occurs at even higher temperatures as the chain length increases. On the other hand, chain length has practically no influence on the... 

Fatty alcohol- (or alkyl-)ethoxylates, CoE, are considered to be better candidates for LLE based on their ability to induce rapid phase separation for Winsor II and III systems. (Winsor III systems consist of excess aqueous and organic phases, and a middle phase containing bicontinuous microemulsions.) However, C,E,-type surfactants alone cannot extract biomolecules, presumably because they have no net negative charge, in contrast to sorbitan esters [24,26,30,31]. But, when combined with an additional anionic surfactant such as AOT or sodium benzene dodecyl sulfonate (SDBS), or affinity surfactant, extraction readily occurs [30,31]. The second surfactant must be present beyond a minimum threshold value so that its interfacial concentration is sufficiently large to be seen by... 

The sulfonate content was determined either by the well-known technique of two-phase titration with hyamine or by liquid chromatography (HPCL). Nonionic surfactants were analyzed by HPLC (16) in the reverse or normal phase mode depending on whether the aim was to determine their content in effluents or to compare their ethylene oxide distribution. 

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