Dodecane-water systems

Moyer, B.A., Caley, C.E. 1988. Hydration and aggregation of monofunctional sulfoxide and other neutral oxygen-donor extractants The di(2-ethylhexyl)sulfoxide, dodecane, water system. Solvent Extr. Ion Exch. 6 (5) 785-817. 

TABLE 1 Molecular Characteristics of the Two PI/PV2P Cl Copolymers, A and B, Used as Emulsifiers of the Dodecane-Water System... 

FIGURE 2.9 Distribution constants of metal(II, III or IV)-acetylacetone complexes in dodecane/water system. The solid line denoted SPT is the predicted KD from the scaled particle theory. Closed circles are data of triflnoroacetylacetone complexes. 

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 phase diagram for the dodecane 1-sulfonic acid/water system was drawn from data obtained by visual inspection, microscopic observations through a... 

As previously mentioned the regression coefficients c, s, a, b and v vary with the parhtioning system inveshgated (e.g. a is 0.034 for octanol-water and -3.45 for dodecane-water as reported by ADME Boxes software version 3.5.), whereas E, S,... 

Octonol is an intermediate for the production of several optically active pharmaceuticals, such as steroids and vitamins. The asymmetric reduction of 2-octanone to (5)-2-octonol by baker s yeast was inhibited severely by substrate and product concentration of 10 him and 6 mM respectively. Whole-cell biotransformation of 2-octanone in a water-ra-dodecane biphasic system yielded a high product concentration of 106him with 89% ee in 96h [37],... 

Erlinger, C., Gazeau, D., Zemb, Th. et al. 1998. Effect of nitric acid extraction on phase behavior, microstructure and interactions between primary aggregates in the system dimethyldibutyl-tetradecylmalonamide (DMDBTDMA)/ -dodecane/water A phase analysis and small-angle X-ray scattering (S AXS) characterization study. Solvent Extr. Ion Exch. 16 707-738. 

Lefrancois, L., Belnet, F., Noel, D., Tondre, C. 1999. An attempt to theoretically predict third-phase formation in the dimethyldibutyltetradecylmalonamide (DMDBTDMA)/ dodecane/water/nitric acid extraction system. Sep. Sci. Technol. 34 (5) 755-770. 

L. Lefrancois, J. J. Delpuech, M. Hebrant, J. Chrisment, and C. Tondre. Aggregation and protonation phenomena in third phase formation An NMR study of the quaternary malon-amide/dodecane/nitric acid/water system. J. Phys. Chem. B, 105(13) 2551-2564, 2001. 

Peters and Luthy (1993, 1994) performed a detailed analysis of the equilibrium behavior of solvent coal tar water mixtures in work that was complementary to column studies performed by Roy, et. al. (1995). Peters and Luthy successfully modeled ternary phase diagrams of coal tar/n-butylamine/water systems. In addition, Peters and Luthy identified n-butylamine as the leading solvent for coal tar extraction. Pennell and Abriola (1993) report the solubilization of residual dodecane in Ottawa sand using a nonionic surfactant, polyoxyethylene sorbitan monooleate, which achieved a 5 order of magnitude increase over the aqueous solubility, but is still 7 times less than the equilibrium batch solubility with the same surfactant system. 

Fig. 13. Single molecule detection of Dil at the dodecane-water interface by fluorescence microscopy (left). Short photon burst in the SDS systems and (right) long burst in the DMPC systems.

The emulsifying properties of lipopeptides were tested in many oil/water systems. The oil was aromatic such as toluene and styrene, paraffinic such as decane and dodecane, or a base product of the cosmetic industry. Lipopeptides give 3 types of emulsions macro-... 

Bicontinuous structures are also present in the well-investigated surfactant system didodecyldimethylammonium bromide (DDABr)-dodecane-water [95,103], where a percolation process occurs that is a function of the water content. Upon an increase in the water concentration, the interconnected water channels originally present (bicontinuous microemulsion) are transformed into globular water droplets (W/O microemulsion), and in this phase region the viscosity is somewhat lower than that of the bicontinuous microemulsion [104],... 

As just stated, the L3 phase resembles structurally a bicontinuous microemulsion, which makes it interesting to compare their rheological properties. Viscosity measurements on an L3 phase [in the system cetylpyridinium chloride-hexanol-brine (0.2 M NaCl)] showed Newtonian flow behavior for the range of shear rates of 0.1-100 s" [113]. The viscosity of this highly interconnected, spongelike system is always very low and close to the solvent viscosity, even for a volume fraction of 0.2 it is less than 10 mPa s. (Similar viscosity values have been observed in the L3 phase of the system tetradecyldimethylamine oxide-hexanol-water [114].) It increases linearly with the volume fraction of the amphiphilic material, where it is interesting to note that extrapolation to zero concentration does not yield the solvent viscosity but a value about three times as high. A similar value for the extrapolated viscosity was also reported more recently for another L3 phase (in the system SDS pentanol-dodecane-water [115]), and it seems that this enhanced viscosity is a universal property connected to the structure of the L3 phase. 

Figure 8 Aggregated microstructure of deformed droplets in the H20- -dodecane-DDAB system at equal volumes of water and oil. Bar = 2000 A. (From Ref 21.)...

The diffusion studies described in the above sections pertain to water-continuous and bicontinuous microemulsions. Chen and Georges [34] were the first to study diffusion in oil-continuous microemulsions using steady-state microelectrode voltammetry. Ferrocene was used to probe diffusion in an SDS-dodecane-1-heptanol-water system. The diffusion coefficient of the hydrophobic probe indicated the microviscosity of the oil rather than the bulk viscosity of the microemulsion. Owlia et al. [36] reported diffusion coefficient measurements of water droplets in an Aerosol OT [AOT, bis(2-ethylhexyl)sulfosuccinate] microemulsion using a microelectrode. Water-soluble cobalt(II) corrin complex (vitamin Bi2r) was used in an oil-continuous microemulsion containing 0.2 M AOT, 4 M water buffered at pH 3, and isooctane. The apparent diffusion coefficient decreased with the probe concentration in accordance with Eq. (13) as shown in Fig. 6 [36]. The water droplet size was... 

Li, X., and Kunieda, H. (2000) Solubilization of micellar cubic phases and their structural relationships in the systems anionic-cationic surfactant-dodecane-water. Langmuir, 16, 10092-10100. 

Somewhat more specific definitions of the above description came from other authors. Thus, Hauser et al. [139] found that in reverse micelles in the system AOT/isooctane/water, thirteen molecules of HjO, divided among the three types of water with differing attractions for AOT-Na, were affected by one AOT molecule two of them were more strongly bonded, while the rest eleven were weakly associated with the surfactant. Kon-No and colleagues [130, 140, 134] studied reverse microemulsions in systems AOT / (heptane / cyclohexane / isooctane /dodecane)/water and BDDAB (butyldodecyldimethylammonium bromide)/ chlorobenzene/water for examining the state of water molecules. They observed that, as discussed above, there were up to three types of water as w was increased ... 

The ability of RS molecules to form self-assembling layers at the interfaces was evaluated by means of surface tension measurements of model systems. The surface tension values determined as a function of the RS concentration at the interface of chloroform-water and dodecane-water are shown in Fig. 2. The significant decrease with increasing RS concentration suggests a surface-active character based on the molecular structure of the interfacial additive. 

The simple but elegant way by which Senatra and coworkers solved the problem of identifying interphasal water in dodecane-containing systems should be noted. Both interphasal water and dodecane melt at about - 10°C, thus leading to overlapping of their fusion peaks. However, the existence of interphasal water may be clearly shown by taking the following into consideration [10] ... 

A similar difference in the appearance of free water was shown for the system AOT-isooctane or dodecane-water [27]. Thus, in the case of dodecane, aU the water except for the last 6.5 water molecules freezes when the AOT reversed micelles are cooled down to 50 C. The same applies to the isooctane microemulsion, where all the water except for the last 4.5 water molecules Ifeezes when the AOT reversed micelles are cooled down to -50°C. It was suggested that this effect is due to diminished penetration of the longer dodecane within the hydrophobic chains of AOT molecules [27]. On a molecular level, this phenomenon may be interpreted in terms of the Hou and Shah mechanism [86-88]. 

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