Sodium octanoate

Measured ernes range from large concentrations, such as approximately 0.6 M for sodium octanoate, to... 

Figure C2.3.7. Snapshot of micelle of sodium octanoate obtained during molecular dynamics simulation. The darkest shading is for sodium counter-ions, the lightest shading is for oxygens and the medium shading is for carbon atoms. Reproduced by pennission from figure 2 of [36].

Sodium octanoate (NaO) forms reversed micelles not only in hydrocarbons but also in 1-hexanol/water. The hydration of the ionogenic NaO headgroups plays an important role in this case too. For this reason Fujii et al. 64) studied the dynamic behaviour of these headgroups and the influence of hydration-water with l3C and 23Na NMR measurements. Below w0 = [H20]/[NaO] 6 the 23Na line-width... 

Capillary tube isotachophoresis using a potential gradient detector is another technique that has been applied to the analysis of alcohol sulfates, such as sodium and lithium alcohol sulfates [303]. The leading electrolyte solution is a mixture of methyl cyanate and aqueous histidine buffer containing calcium chloride. The terminating electrolyte solution is an aqueous solution of sodium octanoate. 

Figure 13 The HOESY two-dimensional spectrum of micellized sodium octanoate in aqueous solution. Besides one-bond carbon-proton correlations, remote correlations are observed (marked by an arrow).

P. oleovorans R. eutropha phaCAB Blend of P(3HB) and P(3HB-co-3-HO) Sodium octanoate 102,103... 

Figure 3.11. Upper diagram micelle of sodium octanoate in water lower diagram micelle of 2 1 clay (the center gray layer is an aluminum octahedral sheet the upper and lower are silicon tetrahedral sheets).

Ducis I, Norenberg L-OB, Norenberg MD. 1990. Effect of phenol and sodium octanoate on the astrocyte benzodiazepine receptor. Brain Res 514 349-351. 

Addition of the dicarboxylic acid to a water/ detergent combination prevents (B) the gelling caused by a model dirt (octanol, CgOH) below the cmc (A). A The model dirt octanol (CgOH) forms a liquid crystalline phase with water and sodium octanoiate (CgOOH at pH 10) in area 3 and 4 Partial substitution of the sodium octanoate with the diacid soap (pH 10) leads to an increase of solubilization of the octanol (B). 1 aqueous... 

The host liquid crystalline matrix was composed of water, sodium octanoate and octanol. This combination was chosen in order to create an environment as closely matching the specific requirements of the problem as possible. In the first instance, the surfactant was Identical to the one used for the solubilization determinations (12) and the alcohol was present in order to resemble actual laundering conditions with "oily dirt" molecules present (12). 

The conformational distinction which was sought was the location of the middle carboxylic group relative to the Interface. If the middle carboxylic group were found at the Interface, the Interlayer spacing as influenced by the dicarboxylic acid would be comparable to the one from sodium octanoate. A straight conformation of the dlacid, on the other hand, would give an increment to the Interlayer spacing similar to the one from sodium oleate. 

In recent studies, Friberg and co-workers (J, 2) showed that the 21 carbon dicarboxylic acid 5(6)-carboxyl-4-hexyl-2-cyclohexene-1-yl octanoic acid (C21-DA, see Figure 1) exhibited hydrotropic or solubilizing properties in the multicomponent system(s) sodium octanoate (decanoate)/n-octanol/C2i-DA aqueous disodium salt solutions. Hydrotropic action was observed in dilute solutions even at concentrations below the critical micelle concentration (CMC) of the alkanoate. Such action was also observed in concentrates containing pure nonionic and anionic surfactants and C21-DA salt. The function of the hydrotrope was to retard formation of a more ordered structure or mesophase (liquid crystalline phase). 

Figure 8. Schematic of mesomorphous structures in phase E, D, and F in the three-component system sodium octanoate-decanol-water (1)...

Figure 9. Phase diagram for the three-component system sodium octanoate-n-decanol-water at 20°C (1). Concentrations expressed as weight percent.

To characterize the mesophases thermodynamically, it is desirable to have detailed knowledge of the regions in which phases B and C exist in the model system sodium octanoate-decanol-water. The heats at which the mesophases are formed are somewhat easier to obtain than the chemical potentials. Table I gives some examples of the few calorimetric values available (14, 15). 

Table I. Apparent Heats of Aggregation in Micellar Solutions and Mesomorphic Phases in the System Sodium Octanoate—ft-Pentanol—Water (14,15)...

Figure 10. The activity of n-pentanol in micellar solutions of sodium octanoate with solubilized pentanol and in equilibrium with the lamellar mesophase D. The abscissa indicates the mole fraction of sodium octanoate in the system (15).

Figure 11. 23Na chemical shifts (in ppm) for isotropic solutions of sodium octanoate (X) and sodium octylsul-fate (O) as a function of the inverse soap concentration. 

For a mesophase composed of sodium octanoate, decanol, and heavy water such double quantum transitions for 23Na are easily observed, as shown in Figure 5. This figure shows that at low rf field amplitudes a typical 23Na powder spectrum is obtained, but at high rf field strengths new peaks arise in the spectrum. 

Figure 5. 23Na NMR spectra of a lamellar mesophase sample of the system sodium octanoate-decanol-water. The rf field amplitude was increased in the order a,b,c,dt Peaks arising from double quantum transitions are clearly shown (cf. Figure 1).

Van Hoogdalem, E.J., et al. 1989. Rate-controlled rectal absorption enhancement of cefoxitin by coadministeration of sodium salicylate or sodium octanoate in healthy volunteers. Br J Clin Pharmacol 27 75. 

Sodium octanoate is the water soluble sodium salt of octanoic (caprylic) acid, but it has no antibacterial or antifungal activity as tested by the same procedures described above, and the results are reported in Table 4.12. 

Table 4.12 Antifungal activity of caprylic acid and sodium octanoate...

Note 1 10 pi of each material above, except sodium octanoate, NaCA 1, as pipetted onto a 6 mm paper disc. For NaCA 1, a small amount of the powder was placed directly onto the agar... 

J. Wilf and A. Ben-Naim, Solubilization of paraffin gases in aqueous solutions of sodium octanoate, J. Solution Chem. 12... 

Partial or total fluorination has striking effects on the CMC. Thus while perfluorinated compounds have much lower CMCs than the corresponding hydrocarbon surfactants (as an example the CMC is 0.030 M for sodium perfluorooctanoate and 0.38 M for sodium octanoate), partial fluorination increases the CMC. The strong deviation from an ideal behavior is illustrated in Fig. 2.425. A markedly nonideal behavior is also found in mixtures of hydrocarbon and fluorocarbon surfactants26. ... 

Fig. 2.12. The partial excess free energy, gf, the partial excess enthalpy, h2, and the partial excess entropy times temperature, Tsf, for aqueous solutions of sodium octanoate. (From Ref.38))...

---