2-Propanol binary azeotropes

Binary System. The first task is to examine the characteristics of the 2-propanol—water-phase equilibria (VLE, LLE, SLE) to determine the compositions of interest and any critical features. 2-Propanol forms a minimum boiling azeotrope with water (80.4°C at 101.3 kPa (760 torr), 68 mol % 2-propanol). The azeotrope is between the feed and the IPA product and is a distillation boundary, thus it is impossible to obtain both desired products from any single-feed... 

Figure 3.9 highlights the key feature of a RCM by means of the mixture isopropanol, n-propanol, water, in which two binary azeotropes of water-alcohol occur ... 

Water is the most common azeotropic component In the bible of azeotropic information, the reference given in Ref. 3, Appendix 2, there are 64 pages devoted to lists of binary azeotropes with water Each page has approximately 50 entries of different azeotropes with water as one component. For comparison, there are 30, 35, 10, and 13 pages for methanol, ethanol, n-propanol, and isopropanol, respectively... 

Solution To determine the location of the azeotrope for a specified pressure, the liquid composition has to be varied and a bubble-point calculation performed at each liquid composition until a composition is identified, whereby X = y,-. Alternatively, the vapor composition could be varied and a dew-point calculation performed at each vapor composition. Either way, this requires iteration. Figure 4.5 shows the x—y diagram for the 2-propanol-water system. This was obtained by carrying out a bubble-point calculation at different values of the liquid composition. The point where the x—y plot crosses the diagonal line gives the azeotropic composition. A more direct search for the azeotropic composition can be carried out for such a binary system in a spreadsheet by varying T and x simultaneously and by solving the objective function (see Section 3.9) ... 

Thus, if the saturated vapor pressure is known at the azeotropic composition, the activity coefficient can be calculated. If the composition of the azeotrope is known, then the compositions and activity of the coefficients at the azeotrope can be substituted into the Wilson equation to determine the interaction parameters. For the 2-propanol-water system, the azeotropic composition of 2-propanol can be assumed to be at a mole fraction of 0.69 and temperature of 353.4 K at 1 atm. By combining Equation 4.93 with the Wilson equation for a binary system, set up two simultaneous equations and solve Au and A21. Vapor pressure data can be taken from Table 4.11 and the universal gas constant can be taken to be 8.3145 kJ-kmol 1-K 1. Then, using the values of molar volume in Table 4.12, calculate the interaction parameters for the Wilson equation and compare with the values in Table 4.12. 

At atmospheric pressure, the n-butanol-water system exhibits a minimum boiling azeotrope and partial miscibility, and hence a binary heterogeneous azeotrope. Figure 1.8 shows the Tyx and Pyx phase diagrams for l-propanol(l)-water(2) azeotropic mixture obtained from the Aspen Plus simulator using the NRTL activity coefficient model. 

Isopropyl alcohol [67-63-0] (2-propanol, isopropanol) is a colorless liquid that is miscible in all proportions with water and with commonly used organic solvents. It forms binary and ternary azeotropes with water and many organic solvents. 

Critical Azeotropy. Systems with critical azeotropy form azeotropes up to the critical region. The type shown in Figure 3a corresponds to a positive azeotrope and has been found e.g. for binary mixtures of H2O (component II) with ethanol, 1-propanol, or acetone (component I).t Severalp(x) isotherms are schematically represented for this type in Figure 3b, the cusp-like isotherm for T = const. = T% being especially interesting since here the limits of material and mechanical stability coincide. ... 

Dejoz, A. Gonzalez-Alfaro, V. Llopis, F. J.> Vazquez, M. I. Phase equilibria and variation of the azeotropic composition with pressure for binary mixtures of 1-propanol cWorobenzene and 1-butanol -l- chlorobenzene Fluid Phase Equilib. 1998,145, 287-299... 

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