Sulfate surfactants

Xu Z H, Ducker W and Israelachvili J N 1996 Forces between crystalline alumina (sapphire) surfaces in aqueous sodium dodecyl sulfate surfactant solutions Langmuir 12 2263-70... 

Table 2. Volume, Value, and Growth of U.S. Sulfonated and Sulfated Surfactant Products by Class ...

FIG. 3 Lime soap dispersing power of some alkyl ether carboxylates compared to other surfactants (DIN 53903). AEC, alkyl ether carboxylate AMEC, amidether carboxylate CAPB, cocamidoproplylbetaine OEC, oleyl ether carboxylate SLES, sodium lauryl ether sulfate. % surfactant soap = % surfactant calculated on the soap needed to disperse the lime soap. (From Refs. 61 and 64.)... 

Dodson KS, GF White (1983) Some microbial enzymes involved in the biodegradation of sulfated surfactants. In Topics in Enzyme and Fermentation Technology (Ed A Wiseman), Vol 7, pp. 90-155. Ellis-Horwood, Chichester. 

Ellis AW, SG Hales, NGA Ur-Rehman, GF White (2002) Novel alkylsulfatases required for biodegradation of the branched primary alkyl sulfate surfactant 2-butyloctyl sulfate. Appl Environ Microbiol 68 31-36. 

Choi PK, Funayama K (2007) Multibubble sonoluminescence and Na atom emission in sodium dodecyl sulfate surfactant solutions. Jpn J Appl Phys 46 4768 1770... 

Sulfate-resisting cement, 5 498 Sulfate surfactants, 24 145 Sulfate titanium dioxide production process, 29 388-391 Sulfathiazole, 28 684 Sulfation, 23 513, 514, 536-538 higher aliphatic alcohols, 2 4 in higher olefins, 27 713 Sulfation operations, industrial changes affecting, 23 515-516 Sulfation processes, general overviews of, 23 555... 

Sulfated surfactants (i.e. those for which the hydrophilic group is a sulfate ion)... 

Among the purposes of this paper is to report the results of calorimetric measurements of the heats of micellar mixing in some nonideal surfactant systems. Here, attention is focused on interactions of alkyl ethoxylate nonionics with alkyl sulfate and alkyl ethoxylate sulfate surfactants. The use of calorimetry as an alternative technique for the determination of the cmc s of mixed surfactant systems is also demonstrated. Besides providing a direct measurement of the effect of the surfactant structure on the heats of micellar mixing, calorimetric results can also be compared with nonideal mixing theory. This allows the appropriateness of the regular solution approximation used in models of mixed micellization to be assessed. 

It is clearly seen that the interaction of SDS with C] oE5 is significantly stronger than that of the alkyl ethoxylate sulfate surfactants with C] oE5 In addition, the symmetry in the heat of mixing curves is strikingly different with those for C] 2 2 Cj qEjS showing an asymmetric maximum at about a... 

Calorimetric measurements can be used to obtain heats of mixing between different surfactant components in nonideal mixed micelles and assess the effects of surfactant structure on the thermodynamics of mixed micellization. Calorimetry can also be successfully applied in measuring the erne s of nonideal mixed surfactant systems. The results of such measurements show that alkyl ethoxylate sulfate surfactants exhibit smaller deviations from ideality and interact significantly less strongly with alkyl ethoxylate nonionics than alkyl sulfates. 

Table 3 presents the results for the analysis of the homologue series of the alkyl sulfate surfactants. The maximum adsorption, Poo, increases, together with the increasing munber of carbon atoms in the hydrophobic tail. Consequently, there is an increase in the attraction forces the stronger attractions lead to smaller areas occupied by the surfactant ions. This increases the number of the counterion bindings (except the last homologue-tetradecyl sulfate). The model has not been able to best fit the data for tetradecyl sulfate in the presence as well as in the absence (A/r = 0) of a Stern layer. 

Fig. 9 Dependence of the molecular interaction between adsorbed dodecyl sulfate ions on the concentration of alkali dodecyl sulfate surfactants...

CMC-Values of a Homologous Series of Alkyl Sulfate Surfactants in Distilled Water (Excerpted from Rosen, 1989). 

The self-diffusion of the individual components is strongly affected by the formation of micelles in the solution. This applies to the surfactant, the counterion, the water, and to solubilized molecules. As illustrated in Fig. 2.11 for sodium dodecyl sulfate, surfactant and counterion diffusion are very weakly dependent on concentration below the CMC while a marked decrease in the micellar region is observed for the surfactant and a less marked one for the counterion37. Water diffusion shows a stronger concentration dependence below the CMC than above it. Self-diffusion studies using radioactive tracers have been performed to obtain information on CMC, on counterion binding, on hydration and on intermicellar interactions and shape changes. 

Hong Y, Patri UB, Ramakrishnan S, Roy D, Babu SV. Utility of dodecyl sulfate surfactants as dissolution inhibitors in chemical-mechanical planarization of copper. J Mater Res Soc 2005 20(12) 3413. 

Anionic alkyl ether sulfate surfactants are produced by sulfating nonionic alcohol polyalkyloxylates such as the ethoxylated surfactants discussed earlier. The sul-fated products generally contain variable amounts of unconverted alcohols and inorganic salts as reaction by-products. Determination of the ratio of anionic to nonionic components in surfactant mixtures is desired for quality control and performance evaluation. Separation of the ionic sulfate and nonionic alcohol components is achieved by reversed-phase chromatography. The separation of four alkyl ether sulfate surfactants is shown in Table 3. 

The first component is inorganic salt and it is eluted with 90% water and 10% THF. As the THF concentration increases to 60%, the ionic sulfate surfactant components are eluted. After elution of these ionics, the nonionic components are backflushed with 100% THF. The analysis time is 4 min per sample. 

Table 3 HPLC Analysis of Inorganic Salt, Sulfated Surfactant, and Unreacted Alcohol in Alkyl Ether Sulfate Surfactants...

Surfactant Inorganic salt Sulfated surfactant Unreacted alcohol Surfactant Inorganic salt Sulfated surfactant... 

Synthetic and petroleum sulfonates are analyzed by the same reversed-phase chromatographic system used for the analysis of alkyl ether sulfate surfactants. Similar to alkyl ether sulfates, the sulfonate mixtures are separated into three fractions inorganic salt, sulfonates, and unreacted oil. The analysis of two petroleum sulfonates, NaPS-1 and NaPS-2, is shown in Table 4. Good separation was obtained between the inorganic salt and the sul-fonated components. The oil present in NaPS-1 and NaPS-2 surfactants consisted of low-molecular-weight components, which were totally volatile under the detector operating conditions and, therefore, could not be detected. These two sulfonates are considerably different in molecular structure distribution. However, their elution characteristics were the same as those observed for the synthetic single-component sulfonates. 

Lastly, we would like to point out that the head group of the ionic surfactant have to be hydrated by a minimum amount of water in order to dissolve into a low polarity solvent (e.g. short chain alcohols). In the hydrocarbon oil rich corner of a microemulsion phase diagram, micellization occurs as long as the minimum water required to hydrate the ionic head group is added (5). Hence the minimum water to surfactant molar ratio required for such hydration can be determined by light scattering measurement. The ratio has been found to be 10 for sulfate surfactants in toluene and 8 for carboxy-... 

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