Octan phases

A necessary condition for this measurement is the presence of the enzymes and substrates in the aqueous phase and a charge acceptor in the octane phase [22]. 

We want to mention parenthetically that the characteristic shape of the one-phase region of the lamellar phase in the Cio E5-water-octane phase diagram can also be understood from a calculation based on an interfacial model of membranes [174]. In this model, the undulation modes are responsible for the swelling of the lamellar phase a disordered phase (which is modeled as a dilute droplet phase for simplicity) competes with the symmetric lamellar phase in the lower part of the phase triangle. 

Isolated oligoenzyne complexes of the respiratory chain of mitochondria - cytochrome oxidase, succinate-cytochrome c reductase, and NADH-CoQ reductase -catalyze the transfer of charges between water and octane that can be recorded from the change in the potential shift at the octane/water phase separation boundary by the vibrating plate method. A necessary condition for the appearance of this effect has proved [18,62] to be the presence of the corresponding enzymes in the oxidation substrates in the aqueous phase and also the presence of a charge acceptor in the octane phase [10, 18, 59]. 

Figure 15 shows the results of analogous experiments performed with the isolated sucdnate-cytochrome c reductase complex of mitochondria. It can be seen from Fig. 15 that inclusion of the cytochrome c reductase reaction with rising concentrations of sucdnate in the aqueous phase is accompanied by a displacement of the potential jump at the water/octane boundary of separation with an increase in the negative charge of the octane phase. Half-saturation of the system with the oxidation substrate is achieved at a concentration of succinate of approximately 2 mM. As in the experiments with cytochrome oxidase, the transfer of negative charges into the octane phase by cytochrome c reductase is achieved only when MNQ is present in the system. Nevertheless, the presence in the aqueous phase of a natural electron acceptor -cytochrome c - was necessary to achieve the effect. 

The half-saturation of the system with cytochrome c was achieved at a concentration of about 10 M (Fig. 15a, b). In all cases, the effect was reversed and prevented by antimycin - an inhibitor of the succinate-cytochrome c reductase activity of this enzyme complex - but was not suppressed by cyanide. In concluding this series of experiments, we investigated the isolated NADH-CoQ reductase complex of the respiratory chain of mitochondria. As can be seen from the results given in Fig. 16, an increase in the concentration of the enzyme complex was accompanied by an increase in the negative charge of the octane phase. 

As can be seen from Fig. 17, the semimaximum suppression of the process of charging the octane phase was reached at a rotenone concentration of 2 pM. 

As in the preceding experiments (Figs. 15-17), in the presence of the proton acceptor 2,4-dinitrophenol (DNP) instead of MNQ, the positive shift of the Volta potential is characterized by saturation curves with the semimaximum values reached at a concentration of DNP of 70 M (Fig. 18) and a concentration of NADH of 22 M (Fig. 19). In contrast to the system in which MNQ was used as the electron acceptor, the charging of the octane phase accompanied by the reduction of ferricyanide proved to be insensitive to rotenone. Rotenone also did not suppress the NADH-ferricyanide activity of the enzyme complex measured in an aqueous medium. 

Mersalyl - a reagent that blocks SH groups - proved to be an effective charge into the octane phase. 

The transfer of charges into octane catalyzed by the NADH-CoQ reductase complex requires special consideration. When a lipophilic electron acceptor (MNQ) is present in the octane, this complex catalyzes the transfer of an electron into the octane by a route sensitive to rotenone. In addition to this, the possibility is created for the transfer of protons into the octane which appears as a suppression of the negative charge of the octane phase in the presence of a hpophilic proton acceptor - DNP. The latter process becomes the only possible one when cyanide is used as the electron acceptor in the aqueous phase and DNP as the proton acceptor in the octane phase. 

The increase in the positive charge in the octane phase cannot be explained simply by a shift in the pH value of the aqueous phase at the boundary of separation during the enzymatic reaction, since the magnitude and the kinetic characteristics of the effect did not change with a rise in the concentration of tn s-buffer in the aqueous phase from 3 to 50 mM. It may be assumed that the phenomenon of the transfer of ions into octane... 

Experimental synthesis of ATP at the octane/water interface was carried out [11, 12, 20]. The proton flow through the ATP-synthetase complex from octane to water was provided by creating an excess (relative to equilibrium) concentration of undissociated (or Lewis) acid in the octane phase (Fig. 37). This was achieved in three ways by direct addition of add-pentachlorphenol to octane, by the action of NADH-ferricyanidreductase of the respiratory chain of submitochondrial particles, and also through the action of the H -pump of bacteriorhodopsin sheets from Halobacterium halobium. 

The octane number is a measure of a fuel s ability to resist auto-ignition during the compression phase prior to ignition. 

Catalyst recovery is a major operational problem because rhodium is a cosdy noble metal and every trace must be recovered for an economic process. Several methods have been patented (44—46). The catalyst is often reactivated by heating in the presence of an alcohol. In another technique, water is added to the homogeneous catalyst solution so that the rhodium compounds precipitate. Another way to separate rhodium involves a two-phase Hquid such as the immiscible mixture of octane or cyclohexane and aliphatic alcohols having 4—8 carbon atoms. In a typical instance, the carbonylation reactor is operated so the desired products and other low boiling materials are flash-distilled. The reacting mixture itself may be boiled, or a sidestream can be distilled, returning the heavy ends to the reactor. In either case, the heavier materials tend to accumulate. A part of these materials is separated, then concentrated to leave only the heaviest residues, and treated with the immiscible Hquid pair. The rhodium precipitates and is taken up in anhydride for recycling. 

The physical properties of polyurethane adhesives result from a special form of phase separation which occurs in the cross-linked polyurethane stmcture. The urethane portions of polyurethanes tend to separate from the polyol portion of the resin, providing good shear strength, good low temperature flexibiUty, and high peel strength. Catalysts such as dibutyltin dilaurate [77-58-7], stannous octoate [1912-83-0], l,4-diazabicyclo[2.2.2]octane... 

All of the benzoic acid producers in the United States employ the Hquid-phase toluene air oxidation process. As toluene becomes more important in the gasoline pool as an octane booster, the benzoic acid producers have to compete with gasoline marketers for the available toluene. If the attractiveness of toluene as an octane booster continues, the cost of producing benzoic acid will most likely increase. 

The illustrated unit can be used to study vapor-phase reforming of kerosene fractions to high octane gasoline, or hydrogenation of benzene, neat or in gasoline mixtures to cyclohexane and methylcyclopentane. In liquid phase experiments hydrotreating of distillate fractions can be studied. The so-called Solvent Methanol Process was studied in the liquid phase, where the liquid feed was a solvent only, a white oil fraction. 

Alhedai et al also examined the exclusion properties of a reversed phase material The stationary phase chosen was a Cg hydrocarbon bonded to the silica, and the mobile phase chosen was 2-octane. As the solutes, solvent and stationary phase were all dispersive (hydrophobic in character) and both the stationary phase and the mobile phase contained Cg interacting moieties, the solute would experience the same interactions in both phases. Thus, any differential retention would be solely due to exclusion and not due to molecular interactions. This could be confirmed by carrying out the experiments at two different temperatures. If any interactive mechanism was present that caused retention, then different retention volumes would be obtained for the same solute at different temperatures. Solutes ranging from n-hexane to n hexatriacontane were chromatographed at 30°C and 50°C respectively. The results obtained are shown in Figure 8. 

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... 

FIG. 34 Phase equilibrium of sodium octane 1-sulfonate/1-decanol/water. 

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