Dodecylsulfate salts

To obtain a true k in MEEKC, it is important to trace the migration of the pseudostationary phase accurately. Sudan III, timepidium bromide, and quine, which have generally been used as tracers for micelles in MEKC, could not be employed as tracers for microemulsions consisting of sodium dodecylsulfate salt (SDS) or cetyltrimethylammonium bromide (CTAB), n-butanol and heptane (12). An iteration method based on a linear relationship between log k and the carbon number for alkylbenzenes (13) seems to provide a reasonable value of the migration time of the microemulsions. Dodecylbenzene shows a migration time larger than the value calculated by the iteration method and those of other hydrophobic compounds, such as phenanthrene, fluoranthrene, and Sudan III (Table 1). Methanol and ethanol were used as tracers for the aqueous phase. 

Micellar catalysis of azo coupling reactions was first studied by Poindexter and McKay (1972). They investigated the reaction of a 4-nitrobenzenediazonium salt with 2-naphthol-6-sulfonic and 2-naphthol-3,6-disulfonic acid in the presence of sodium dodecylsulfate or hexadecyltrimethylammonium bromide. With both the anionic and cationic additives an inhibition (up to 15-fold) was observed. This result was to be expected on the basis of the principles of micellar catalysis, since the charges of the two reacting species are opposite. This is due to the fact that either of the reagents will, for electrostatic reasons, be excluded from the micelle. 

III. The effects of salt on the adsorption of sodium dodecylsulfate. Bull. Chem. Soc. Japan, 44(7), 1767-71. 

Relatively small retardations of the rate of the base catalyzed hydrolysis of methyl-1-naphthoate by sodium dodecylsulfate (NaLS) and hexadecyltrimethylammonium bromide (CTAB) in 50 wt percent dioxane-water have been observed. These effects were attributed to micelle formation in this solvent system since plots of In where 2 and are the second order rate constants in the presence and absence of the organic salts, vs. the concentration of the salts were non-linear... 

Sodium dodecylsulfate. SDS. lauryl sulfate, sodium salt... 

The major subgroups of anionic surfactants include the alkali carboxylates (soaps), sulfates, sulfonates, and to a smaller degree, phosphates. The esterification of alcohol with sulfuric acid yields probably the best-studied surfactant, sodium dodecylsulfate or SDS. SDS, a sulfate ester, is an extremely effective emulsifier because of its high-electrostatic repulsion. Other sulfates are, for example, sulfated esters from fatty acids, sulfated ethers, and sulfated fats and oils. Sulfonates stem from the reaction of sulfonic acid with suitable substrates. Members of the class of sulfonates are, for example, sulfonic acid salts or aliphatic sulfonates. Other anionic surfactants include substances such as carboxylated soaps and esters of phosphoric acid. 

GAF Corp., respectively. These surfactants were used without further purification. Sodium dodecylsulfate (SDS), obtained from Fisher Scientific Co., was purified by recrystallization from an ethanol-water mixture. 4-dodecyl-diethylenetriamine (DDIEN) was purchased from Eastman Kodak Co. Metal ion salts were all reagent grade. Standard pH buffers (Fisher Scientific Co.) and Hepes buffers (Sigma Chemical Co.) were used as provided. 

Let us describe the mechanism of two-phase titration in some detail, using the titration of sodium dodecylsulfate (SDS) with Hyamine 1622 in the presence of mixed dye indicator as an example. At the beginning of the titration, when only SDS is present in aqueous solution, dimidium bromide reacts with it to form a salt that is insoluble in water, but... 

Synonyms cas 151-21-3 aquarexmethyl dodecyl alcohol, hydrogen sulfate, sodium salt dodecyl SODIUM sulfate DODECYLSULFATE sodium salt DREFT LAURYL SODIUM SULFATE SODIUM MONODECYL SULFATE SULFURIC ACID, MONODECYL ESTER, SODIUM SALT... 

Fig. 9 Decay lengths of the exponentially decaying component versus one over the square root of the salt concentration. The dashed line corresponds to the calculated Debye length. The figure summarizes results of measurements with hydrophilic and hydrophobic silica microspheres in solutions with different concentrations of SDS (sodium dodecylsulfate) or DTAB (from Ref [143]).

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