Azeotropic mixtures homogenous

Fig. 13. Schematic isobatic phase diagrams for binary azeotropic mixtures (az). (a) Homogeneous azeotrope (b) heterogeneous azeotrope.

FIG. 13-57 (Continued) Schematic isoharic-phase diagrams for binary azeotropic mixtures, (b) Homogeneous maximum-boiling azeotrope. 

Obviously, the use of a nonvolatile ionic liquid simplifies the distillative workup of volatile products, especially in comparison with the use of low-boiling solvents, where it may save the distillation of the solvent during product isolation. Moreover, common problems related to the formation of azeotropic mixtures of the volatile solvents and the product/by-products formed are avoided by use of a nonvolatile ionic liquid. In the Rh-catalyzed hydroformylation of 3-pentenoic acid methyl ester it was even found that the addition of ionic liquid was able to stabilize the homogeneous catalyst during the thermal stress of product distillation (Figure 5.2-1) [21]. This option may be especially attractive technically, due to the fact that the stabilizing effects could already be observed even with quite small amounts of added ionic liquid. 

Figure 13.28. Vapor-liquid equilibria of some azeotropic and partially miscible liquids, (a) Effect of pressure on vapor-liquid equilibria of a typical homogeneous azeotropic mixture, acetone and water, (b) Uncommon behavior of the partially miscible system of methylethylketone and water whose two-phase boundary does not extend byond the y = x line, (c) x-y diagram of a partially miscible system represented by the Margules equation with the given parameters and vapor pressures Pj = 3, = 1 atm the broken line is not physically significant but is...

Allyl alcohol forms an azeotropic mixture with water, and the mixture is a homogeneous liquid. Therefore, to obtain dry allyl alcohol, ternary azeotropic distillation and dehydration are required. 

J.-U. Repke, F. Fomer, A Klein, 2006, Separation of Homogeneous Azeotropic Mixtures by Pressure Swing Distillation - Analysis of the Operation Performanee, Chem. Eng. Techn., vol. 28, 1151-1557. 

Kossack, S., Kramer, K., Marquardt, W. Efflcient optimization based design of distillation columns for homogenous azeotropic mixtures. Ind. Eng. Chem. Res. 45(24), 8492-8502 (2006)... 

Pervapor- ation Asymmetric membrane with homogeneous skin and microporous substructure. Partial vapor pressure gradient 0.001 to 1 bar Solution-diffusion mechanism, solubility and diffus-ivity of individual components in the polymer matrix determine separation characteristics. Separation of organic solutions such as ethanol, butanol, acetic acid, etc. from aqueous solutions, especially separation of azeotropic mixtures. 

The condensate that collects on the cold surface is usually a completely homogeneous, or miscible, mixture of components. In general, the relative composition of the liquid components in the condensate is different from the composition in the vapor phase (except for an azeotropic mixture, where the condensate has the same exact molar concentration ratio as the vapor phase) [194]. The film that forms is not necessarily smooth but may show the appearance of streamers (or rivulets), waves, or droplets, depending on the particular mixture and its surface tension (which depends on the local wall temperature) [25,195,196]. If the condensate mixture is heterogeneous, or immiscible (as can occur when one component, for example, is aqueous and the other is organic), the pattern can be quite complex, looking somewhat like dropwise condensation [25,193,197]. These different condensate patterns affect the resulting fluid flow and heat transfer. 

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