Liquid equilibrium data, isobaric

Application of the algorithm for analysis of vapor-liquid equilibrium data can be illustrated with the isobaric data of 0th-mer (1928) for the system acetone(1)-methanol(2). For simplicity, the van Laar equations are used here to express the activity coefficients. 

Table I. Isobaric Vapor—Liquid Equilibrium Data for the Potassium Bromide—Ethanol—Water System at x = 0.206 0.001 (760 5 Torr)...

Related Calculations. When vapor-liquid equilibrium data are taken under isobaric rather than isothermal conditions, as is often the case, the right-hand side of the preceding Gibbs-Duhem equation cannot as readily be taken to approximate zero. Instead, the equation should be taken as... 

So that an azeotrope with acetone does not form, the alcohol used must have a high enough boiling point. This requirement is reliably established only if vapor-liquid equilibrium data for at least two, preferably three, of the members of the series with acetone are known. The Pierotti-Deal-Derr method (4) (discussed later) or the Tassios-Van Winkle method (5) can be used in this case. In the latter method a log-log plot of y°i vs. P°i should yield a straight line. Figure 1 presents results for n-alco-hols and benzene from the isobaric (760 mm Hg) data of Wehe and Coates (6). Reliable infinite dilution activity coefficients are established for the other n-alcohols from data for at least two, and preferably three, of them. These y° values are used with equations like those of Van Laar or Wilson (7) to generate activity coefficients at intermediate compositions and to check for an existing azeotrope or a difficult separation (x-y curve close to the 45° line). 

Prediction of Isobaric Vapor-Liquid Equilibrium Data for Mixtures of Water and Simple Alcohols... 

The Non-Random, Two Liquid Equation was used in an attempt to develop a method for predicting isobaric vapor-liquid equilibrium data for multicomponent systems of water and simple alcohols—i.e., ethanol, 1-propanol, 2-methyl-l-propanol (2-butanol), and 3-methyl-l-butanol (isoamyl alcohol). Methods were developed to obtain binary equilibrium data indirectly from boiling point measurements. The binary data were used in the Non-Random, Two Liquid Equation to predict vapor-liquid equilibrium data for the ternary mixtures, water-ethanol-l-propanol, water-ethanol-2-methyl-1-propanol, and water-ethanol-3-methyl-l-butanol. Equilibrium data for these systems are reported. 

Isobaric vapor-liquid equilibrium data at atmospheric pressure are reported for the four systems of the present investigation in Tables I-VI. Salt concentrations are reported as mole fraction salt in the solution, while mixed-solvent compositions are given on a salt-free basis. A single fixed-liquid composition was used for potassium iodide and sodium acetate potassium acetate used three—all chosen from the region of ethanol-water composition where relative volatility is highest. In the... 

Table III. Isobaric Vapory-Liquid Equilibrium Data for the Sodium Acetate—Ethanol—Water System at x = 0.309 0.001 (758 3 torr)...

FIG. 13-9 Isobaric vapor-liquid equilibrium data for benzene-toluence. Brian, Staged Cascades in Chemical Processing, Prentice-Hall, Englewood Cliffy, NJ, 1972.)... 

The present Landolt-Bomstein volume provides numerieal vapor-liquid equilibrium data for 3316 binary systems of noneleetrolytes. The physical quantities involved are the pressure P, the temperature T, and the mole fraction compositions of the liquid and vapor yi. Seventeen Property Types are distinguished depending on whether none, one, or several among the physical quantities P, T, X] or yi is kept constant in the particular data file isobaric (constant P), isothermal (constant 7), isoplethal (constantxi oryi) (Chap. 2.1.1). 

Dominguez, M. Martin, S. Artigas, H. Lopez, M. C. Royo, F. M. Isobaric vapor-liquid equilibrium data for the binary mixtures (2-butanol n-hexane) and (2-butanol + 1-butylamine) and for the ternary system (2-butanol -1- n-hexane -1-1-butylamine) at 101.3 kPa J. Chem. Eng. Data 2002,47, 405-410... 

Ortega, J. Espiau, F. Dieppa, R. Measurement and correlation of isobaric vapour-liquid equilibrium data and excess properties of ethyl methanoate with alkanes (hexane to decane) Fluid Phase Equilib. 2004,215, 175-186... 

Cabezas, J. L. Beltran, S. Coca, J. Isobaric vapor-liquid equilibrium data for furfural with chlorinated hydrocaibons Fluid... 

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