Methanol-water thermodynamic properties

Zhong Y, Warren GL, Patel S (2008) Thermodynamic and structural properties of methanol-water solutions using nonadditive interaction models. J Comput Chem 29(7) 1142-1152... 

Our recent research efforts have been directed to developing an improved and extended set of parameters for the various groups used in the PFGC equation of state (16). We have dubbed our version of this equation the PFGC-MES. A thorough evaluation of the ability of this equation to predict the thermodynamic properties of hydrocarbon systems has been a part of this development process. A companion project has been the extension of the equation to describe the behavior of hydrocarbon-water-alcohol-nonhydrocarbon systems. This paper gives some of the results of our work on hydrocarbon-water-methanol systems. We also report some of our work on extending the SRK equation of state to hydrocarbon water systems. 

The (liquid 4- liquid) equilibria diagram for (cyclohexane + methanol) was taken from D. C. Jones and S. Amstell, The Critical Solution Temperature of the System Methyl Alcohol-Cyclohexane as a Means of Detecting and Estimating Water in Methyl Alcohol , J. Chem. Soc., 1930, 1316-1323 (1930). The G results were calculated from the (vapor 4- liquid) results of K. Strubl, V. Svoboda, R. Holub, and J. Pick, Liquid-Vapour Equilibrium. XIV. Isothermal Equilibrium and Calculation of Excess Functions in the Systems Methanol -Cyclohexane and Cyclohexane-Propanol , Collect. Czech. Chem. Commun., 35, 3004-3019 (1970). The results are from M. Dai and J.-P.Chao, Studies on Thermodynamic Properties of Binary Systems Containing Alcohols. II. Excess Enthalpies of C to C5 Normal Alcohols + 1,4-Dioxane , Fluid Phase Equilib., 23, 321-326 (1985). 

Considerable attention has been devoted to the nature of the solvent effects (as determined in water and in various mixed solvents) on the ionic dissociations (and related thermodynamic quantities) and other acid-base properties of aliphatic zwitterionic compounds. Such investigations include studies of tricine in 50 mass % methanol-water (1), Bes in pure water and in 50 mass % methanol-water 2,3), glycine in 50 mass % monoglyme-water (4), and glycine in pure water and in 50 mass % methanol-water (5,6, 7). The numerous factors (8,9,10) which... 

In Section 13.5.1 we presented the data of Vogelpohl for the distillation of two ternary systems acetone-methanol-water and methanol-2-propanol-water in a bubble cap column. Krishnamurthy and Taylor (1985b) simulated these experiments using a nonequilibrium stage model similar to the one described above. The AIChE correlations were used to calculate the mass transfer coefficients. Thermodynamic properties were calculated with the models described by Prausnitz et al. (1980). 

The bubble point tests conducted in methanol/water mixtures were worked up to show properties of the three-phase interfaces along the complex contact line in SS304 LAD screens. In particular, the variation with F2 of the solid/vapor interfacial tension /sv differed from that of the solid/liquid interface j/sl- The data are consistent with the Langmuir isotherm description of the thermodynamics of adsorption. The result of the analysis is that the co-areas Amin are 0.32 nm /molecule for the SS304— vapor interface and 1.77 nm /molecule for the SS304—solution interface. This implies that that methanol molecules form a dense, liquid-like monolayer at the interface of SS304 with the vapor phase, while the methanol molecules are very dilute in the interface between SS304 and the solution of methanol/water. 

In a later paper Pollard et al discuss the use of the flame ionization detector in the gas chromatography of tetramethyltin, trimethylethyltin, dimethyldiethyltin, methyltriethyltin and tetra-ethyltin. They discuss the unusual sensitivity characteristic of the chromatography of these compounds and present and correlate specific dynamic properties obtained and various thermodynamic properties obtained on columns comprising 15% Silicone oil E301 (mol.wt, 700,000) on Celite (James and Martin ) (treated by dry sieving to mesh 36-60, washing with concentrated hydrochloric acid, methanol and distilled water, followed by drying at 300°C). 

Ortega, J. Vreekamp, R. Penco, E. Marrero, E. (2008). Mixing thermodynamic properties of l-butyl-4-ethylpyridinium tetrafluoroborate [b4mpy][BF4] with water and with an alkan-lol (methanol to pentanol). J.Chem.Thermodynamics 40, 7 0uly 2008) 1087-1094. 

Propylene oxide is a colorless, low hoiling (34.2°C) liquid. Table 1 lists general physical properties Table 2 provides equations for temperature variation on some thermodynamic functions. Vapor—liquid equilibrium data for binary mixtures of propylene oxide and other chemicals of commercial importance ate available. References for binary mixtures include 1,2-propanediol (14), water (7,8,15), 1,2-dichloropropane [78-87-5] (16), 2-propanol [67-63-0] (17), 2-methyl-2-pentene [625-27-4] (18), methyl formate [107-31-3] (19), acetaldehyde [75-07-0] (17), methanol [67-56-1] (20), ptopanal [123-38-6] (16), 1-phenylethanol [60-12-8] (21), and / /f-butanol [75-65-0] (22,23). 

Example 5.15 Retrofits of distillation columns by thermodynamic analysis The synthesis of methanol takes place in a tube reactor in section 3 in the methanol plant shown in Figure 5.7. The reactor outlet is flashed at 45°C and 75 bar, and the liquid product (stream 407) containing 73.45 mol% of methanol is fed into the separation section (see Figure 5.8), where the methanol is purified. Stream 407 and the makeup water are the feed streams to the section. Table 5.2 shows the properties and compositions of the streams in section 3. The converged simulations are obtained from the Redlich-Kwong-Soave method to estimate the vapor properties, while the activity coefficient... 

FIG. 4-4 Property changes of mixing at 50 C for six binary liquid systems (a) chloroform(l)/n-heptane(2) (b) acetone(l)/ methanol(2)( (c) acetone(l)/chloroform(2)( (d) ethanol(l)/n-heptane(2) (e) ethanol(l)/chloroform(2) (/) ethanol(l)/water(2). [SmitK YanNesSy and Abbott, Introduction to Chemical Engineering Thermodynamics, 7thed.,p. 455, McGraw-Hill, New Yorb (2005).]... 

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