Sodium alkanesulfonates

Sodium alkanesulfonates for detergent manufacture can also be produced from the free-radical addition of sodium bisulfite and alpha olefins ... 

Figure 20 shows the plot of the surface tension vs. the logarithm of the concentration (or-lg c-isotherms) of sodium alkanesulfonates C,0-C15 at 45°C. In accordance with the general behavior of surfactants, the interfacial activity increases with growing chain length. The critical micelle concentration (cM) is shifted to lower concentration values. The typical surface tension at cM is between 38 and 33 mN/m. The ammonium alkanesulfonates show similar behavior, though their solubility is much better. The impact of the counterions is twofold First, a more polarizable counterion lowers the cM value (Fig. 21), while the aggregation number of the micelles rises. Second, polarizable and hydrophobic counterions, such as n-propyl- or isopropylammonium and n-butylammonium ions, enhance the interfacial activity as well (Fig. 22). Hydrophilic counterions such as 2-hydroxyethylammonium have the opposite effect. Table 14 summarizes some data for the dodecane 1-sulfonates.

FIG. 23 CT-lg c Isotherms for sodium alkanesulfonates with the functional group in different positions, x, Dodecane 1-sulfonate (45°C) , dodecane 5-sulfonate (25°C) , pentadecane 1-sulfonate (45°C) , pentadecane 8-sulfonate (45°C). 

TABLE 15 Surfactant Properties of Homologous Sodium Alkanesulfonates in Water at 25°C... 

In Fig. 24 the dependence of the surface tension on the concentration is shown for two sodium alkanesulfonates which were purified by exploitation of... 

The poor solubility of higher sodium alkanesulfonates cited above is reflected in the surface tension vs. concentration plots of sodium pentadecane 4-sulfonate (Fig. 26). Because below the critical micelle concentration the solubility limit is reached, a break in the a-c plot occurs. The problem of solubility properties of alkanesulfonates below the point at which the hydrated crystals or solid... 

TABLE 18 Data on the Interface Energetics of Sodium Alkanesulfonates on Tristearin (tristearin/5 x 103 mol 1 alkanesulfonate in distilled water at 50°C)... 

The Krafft point has practical implications for the solubility of surfactants. Only above the Krafft temperature can concentrated surfactant solutions be prepared. Otherwise, on cooling a hot surfactant solution a sudden precipitation may occur. A linear correlation between the Krafft temperature TK (°C) and the carbon number nc of sodium alkanesulfonates C10-C22 is given by the following equation ... 

Column, octadecyl-bonded silica gel, 15 cm x 4.6 mm i.d. eluent, 0.01 M sodium acetate buffer containing 0.4 M copper acetate and 1.0 mM sodium alkanesulfonate (pH 5.6) flow rate, 1 ml min-1 detection, UV 230 nm. Counter-ion C6, sodium hexanesulfonate Cl, sodium heptanesulfonate and C8, sodium octane sulfonate. Compounds Ser, serine Gly, glycine Glu, glutamic acid and Asp, aspartic acid. 

Secondary alkanesulfonates (SAS). The large-scale production of sodium alkanesulfonates (SAS) began in the late 1960s. 

Sodium alkanesulfonates are produced by photochemical sulfoxidation or sulfochlorination of suitable C12-C18 paraffin cuts. SAS can largely be substituted for LAS in formulations because of the similarity in terms of solubility, solubilizing properties, and wetting power [4]. 

Berthold, H., Haase, B., Lipfert, G., Rockstuhl, R., Werner, W. and Wirth, D., Preparation of solid sodium alkanesulfonates from aqueous solutions, German (East) DD 290,775, 1991. 

There have been further reports on the rate enhancement observed when the normal complex [Ni(pada)] is formed in the presence of micelles. These can be very considerable but it has been found that sodium alkanesulfonates are about 25% less effective in this respect than the alkyl sulfates. The effect of various anionic polyelectrolytes on this reaction has also been studied it ranges from an acceleration of about two orders of magnitude in the case of poly(styrene sulfonate) to a retardation by about one order of magnitude for polyphosphate and seems to be dependent on the state of hydration of the Ni ion when condensed in the polyelectrolyte domains. Polyphosphate exerts a similar retardation on the formation of [CoCpada)] " and the effect is attributed to the complete replacement of the coordinating water by the polyelectrolyte. Activation... 

Hicks, J.R., Reinsborough, V.C. Rate enhancement of the nickel(II)-PADA complex formation in sodium alkanesulfonate micellar solutions. Ausf. J. Chem. 1982, 35(1), 15-19. 

The sodium alkanesulfonate mixture (0.5-1.0 g) is slurried in 15 mL of warm aqueous Na2S04 solution (200 g/L). 150 mL 60 40 1-butanol/acetone is then added, slowly and without heating. The solution will first become clear, then cloudy as sodium sulfate decahydrate begins to crystallize. After cooling and filtering off the sodium sulfate, the solution is evaporated to dryness at steam bath temperature, treated three times with acetone, evaporating the acetone off each time, then finally heated in a vacuum oven at 120-C to remove the last traces of moisture and paraffin. The final weight is corrected for the sodium chloride content. 

Recovery of anionic surfactants can be improved by adding an ion pairing reagent to the solvent. For example, tetrabutylammonium bisulfate in methanol effectively removes LAS and sodium alkanesulfonate from sewage sludge (84). 

Takeshita, R., N. Jinnai, H. Yoshida, Detection of sodium alkanesulfonates and alkylbenzene-sulfonates by polyamide TLC, J. Chwmatogr., 1976, 123, 301-307. 

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