Octane aqueous solution data

Sodium acetate reacts with carbon dioxide in aqueous solution to produce acetic anhydride and sodium bicarbonate (49). Under suitable conditions, the sodium bicarbonate precipitates and can be removed by centrifugal separation. Presumably, the cold water solution can be extracted with an organic solvent, eg, chloroform or ethyl acetate, to furnish acetic anhydride. The half-life of aqueous acetic anhydride at 19°C is said to be no more than 1 h (2) and some other data suggests a 6 min half-life at 20°C (50). The free energy of acetic anhydride hydrolysis is given as —65.7 kJ/mol (—15.7 kcal/mol) (51) in water. In wet chloroform, an extractant for anhydride, the free energy of hydrolysis is strangely much lower, —50.0 kJ/mol (—12.0 kcal/mol) (51). Half-life of anhydride in moist chloroform maybe as much as 120 min. Ethyl acetate, chloroform, isooctane, and / -octane may have promise for extraction of acetic anhydride. Benzene extracts acetic anhydride from acetic acid—water solutions (52). 

More complex with respect to molecular interaction is the case of formation of non-aqueous films on the surface of aqueous solutions from non-ionic surfactants [528], Films from octane were obtained by adsorption from drops of octane/non-adsorbing diluent (squalane) mixture. Occasionally the spreading of alkanes on aqueous surfactant solution gives stable thin oil films (e.g. on solutions of the anionic surfactants Aerosol OT) [529,530], Some evidence about the stability of asymmetric films can be derived from the data about the surface pressure and spreading coefficients of liquids on water surface. These data are known for many organic liquids [531,532], It should be also noted that the techniques for determination of the spreading coefficients have improved considerably [533,534]. Most precise values were obtained by measuring the surface pressure of a monolayer with a special substance introduced as an indicator [533]. 

Figure 6 Dependence of y-glutamyl transferase activity on IVq in an AOT-octane-water microemulsion. The figure gives activity data for three reactions catalyzed by the enzyme transpeptidation (top), autotranspeptidation (middle), and hydrolysis (bottom). Values of catalytic activity of the enzyme in aqueous solution, measured under conditions of pH optima, are shown by the dashed lines. A scale of droplet radii corresponding to the Wq scale as well as indications of the radii of the light (L) and heavy (H) subunits and of the heterodimer (L+H) are given on the upper extension line. (From Ref 39.)...

The view that the monomers are confined to the reverse micellar pseudophase is supported by interfacial tension data (67), which demonstrate that in a two-phase octane/water system, partially hydrolyzed TEOS species partition preferentially into the aqueous phase. The interfacial tension determined at the octane/water interface for samples prepared with precursor ethanolic solutions of different water-to-TEOS molar ratios (h - 0, 0.29, and 0.55) are presented in Figure 2.2.14 (67). As can be seen, for TEOS concentrations below about 4 X 10- 1 M, the octane/water interfacial tension is independent of the concentration of TEOS species in the organic phase... 

Figure 4 Comparison of diffusion coefficient data obtained by CV (+), RDV (Af and QELS (O)-The microemulsion comprised CTAB 2 wt Mi, butanol (4 wt Mi), aqueous NaBr (2 wt%) solution, and octane. (From Ref. 51.)...

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