Effect of a Third Component

Effect of a Third Component. Liquid-liquid equilibria in ternary systems have been investigated most frequently at normal or low pressure, but for high pressures experimental data are very scarce. 

Experiments under high pressure have shown that there are evident analogies between the influence of pressure and of the amount of a third component added 

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Effect of a third component on the interactions in a binary mixture determined from the fluctuation theory... 

Equations for the KBIs in ternary mixtures are available in matrix form [2]. Explicit equations are obtained here which will allow us to analyze interesting features of ternary mixtures, such as the effect of a third component on the phase behavior of a binary mixture and the effect of a cosolvent (entrainer) on supercritical binary mixtures. Only the former problem is examined in the present paper. The calculations will he carried out for an interesting ternary mixture, namely AA -dimethylformamide-methanol-water, in order to extract information about the intermolecular interactions. In the next section explicit equations for the KB integrals will he derived and applied to the above ternary mixture. Finally, the results obtained will be used to shed some light on the local structure and the intermolecular interactions in the above mixture. 

Ruckenstein, E. Shulgin, I. Effect of a third component on the interactions in a binary mixture determined from the fluctuation theory of solutions. Fluid Phase Equilib. 2001, 180, 281-297. 

In a binary mixture equilibrium stage, the vapor and liquid compositions are a function of only distribution coefficients and hence a function of only temperature if the pressure is held fixed (Equations 3.3 and 3.4). Thus, in a binary system, the phase compositions are independent of feed composition. If a third component is added to the mixture, the equilibrium vapor and liquid compositions are influenced by the amount and identity of the third component. This phenomenon is the basis of absorption and stripping processes. The following is a simple mathematical analysis of the effect of a third component on phase distribution. 

A striking example of the effects of a third component on the diffusive rate of a species is shown in Fig. 2.3-2 in which the acceleration or the flux of sodium sulfate in aqueous solution owing to the presence of acetone is shown. Soma of the most dramatic examples of malticomponent effects in diffusion occur in budt natural and synthetic membranes. 

Xu QW, Man HC, Lau WS. The effect of a third component on the morphology and mechanical properties of Uquid-crystalline polymer and polypropylene in situ composites. Compos Sci Tech 1999 59 291-6. 

The effectiveness of a third component in raising the yield of PA film with the Nd... 

In the previous sections, we indicated how, under certain conditions, pressure may be used to induce immiscibility in liquid and gaseous binary mixtures which at normal pressures are completely miscible. We now want to consider how the introduction of a third component can bring about immiscibility in a binary liquid that is completely miscible in the absence of the third component. Specifically, we are concerned with the case where the added component is a gas in this case, elevated pressures are required in order to dissolve an appreciable amount of the added component in the binary liquid solvent. For the situation to be discussed, it should be clear that phase instability is not a consequence of the effect of pressure on the chemical potentials, as was the case in the previous sections, but results instead from the presence of an additional component which affects the chemical potentials of the components to be separated. High pressure enters into our discussion only indirectly, because we want to use a highly volatile substance for the additional component. 

In 1962, Higuchi and Misra examined the quantitative aspects of the rate of growth of the large droplets and the rate of dissolution of the small droplets in emulsion for the case in which the process is diffusion controlled in the continuous phase [4]. It was proposed that unstable emulsions may be stabilized with respect to the Ostwald ripening process by the addition of small amounts of a third component, which must distribute preferentially in the dispersed phase [4]. The obtained stability in miniemulsions is said in the literature to be metastable or fully stable. The stabilization effect by adding a third component was recently theoretically described by Webster and Cates [5]. The authors considered an emulsion whose droplets contain a trapped species, which is insoluble in the continuous phase, and studied the emulsion s stability via the Lifshitz-Slyozov dynamics (Ostwald ripening). 

Beall, F.A., Taylor, M.J., Thome, C.B. (1962). Rapid lethal effect in rats of a third component found upon fractionating the toxin of Bacillus anthracis. J. Bacterial. 83 1274-80. 

The larger the dipole moment of the additive, the lower the mobility and the steeper its field dependence becomes. The literature has many examples of the effect of polar third components [55g, 56a-f]. If the dominant polar component is a holetransporting CTM itself, the mobility largely correlates with its dipole moment, even across various chemical families (Figure 37) [56g-m]. 

The promoting effect of the third component is also compared with the case of Pt and Pt-Ru catalysts dispersed in PAni. During the oxidation of methanol, the production of carbon dioxide (final product) is observed at a potential as low as 350 mV versus RHE on PAni/Pt-Ru-Mo. Concerning the case of CO adsorption from gaseous CO, formation of CO2 is observed at 250 mV versus RHE, indicating clearly that Pt-Ru-Mo is less poisoned by CO ads in comparison with Pt-Ru and Pt (the formation of CO2 occurring, respectively, at 400 mV and 750 mV versus RHE). 

Furthermore, in many cases the effect of the third component, namely the solvent, is decisive. For example, the measured Henry s law constant for the system aromatic substance-HCl, only reflects the difference between the chemical potential of HCl in solution, and in the vapour phase, p% (Kortiim and Vogel, 1955). The values obtained therefore do not permit a quantitative interpretation and only give qualitatively the relative order of the basicity of unsaturated compounds. This is also true for partition measurements between an acid and an organic phase, if in such a case the necessary thermodynamic assumptions have not been tested or established by separate investigations. 

The experimental systems described above consisted of the minimal number of components proton emitter and detector. If one wishes to probe a specific site on a protein, he should consider the presence of a third component—the other proton-binding site on the protein. Any species with which the proton may react, referred to here as buffer, will modify the progress of the reaction and perturb the shape of the observed parameter. As the general strategy is to extract the partial rate constant out of the macroscopic ones, we have to retrace the effect of the partial... 

Data on the aqueous solubility of PAHs in the presence of a third component, such as an electrolyte, are also very important. The practical implications are that the presence of this third component may substantially change the solubility, an example being the salting-out effect of sodium chloride and other salts present in seawater (7). 

As a first approximation, the experimental results support the theory in so far as the viscous resistance of the thinning gap is concerned. The effect of a third soluble component on the kinetics of thinning was also at least qualitatively in accordance with expectation for a diffusion model, but quantitatively it was not possible to overcome the mathematical difficulties associated with surface motion caused by surface tension gradients. The fact that such a gradient is present was confirmed by microscopic observation of dust particles at the droplet interface. 

Conversely, interaction with the poison H s causes disruption of the Cu particles leaving the Cu-0 structure apparently unperturbed. There is a significant effect of the third component (alumina) on the reduction temperature required, suggesting some proximity of copper and aluminium in the calcined ternary catalyst. Reduction is then effected at the higher temperature of 533K. Again this appears to form small fee copper particles in addition to a component of copper with Cu-0 bonds. After extended use as a... 

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