Polar + nonpolar mixtures, thermodynamic properties

C02 Binaries. The final group of binaries that will be examined is that of C02 with nonpolar and polar compounds. The thermodynamic properties of C02 differ significantly from those of similar nonpolar compounds, and this is the result of its very strong quadrupole moment. This effect is seen more clearly in the behavior of C02 in mixtures. King and his students have reported By data for several C02 binaries the resulting ky s have been in Table V. 

The problems associated with new synthesis gas processes are far greater than problems associated with gas processing plants or refineries because of water, salt, sludge, ammonia, and cresols present in the process streams. This paper attempts to identify the magnitude of the problems and methods for solving these problems. The problem of predicting the thermodynamic properties of nonpolar-polar mixtures by means of equations of state is also identified as an area needing study. 

In Chapter 4, methods based on equations of state were presented for predicting thermodynamic properties of vapor and liquid mixtures. Alternatively, as developed in this chapter, predictions of liquid properties can be based on correlations for liquid-phase activity coefficients. Regular solution theory, which can be applied to mixtures of nonpolar compounds using only properties of the pure components, is the first type of correlation presented. This presentation is followed by a discussion of several correlations that can be applied to mixtures containing polar compounds, provided that experimental data are available to determine the binary interaction parameters contained in the correlations. If not, group-contribution methods, which have recently undergone extensive development, can be used to make estimates. All the correlations discussed can be applied to predict vapor-liquid phase equilibria and some, as discussed in the final section of this chapter, can estimate liquid-liquid equilibria. 

Initial works on the phase equilibrium of polymer solutions were concerned with nonpolar solutions using carefully prepared quasi-monodisperse polymer fractions [78]. The theory and practice was later extended to molecularly heterogeneous polymers [84], multicomponent solutions (ternary mixtures) such as polymer/solvent mixture [16, 85] and polymer mixture/solvent [86], and polymer blends [79, 80], among others [87]. Improvements on predicting thermodynamic properties were particularly proposed for polymer solutions of industrial importance, including those having polar and hydrogen-bonded components [16]. 

From R. Nakamura, G.J.F. Breedveld, J.M. Prausnitz, "Thermodynamic Properties of Gas Mixtures Containing Common Polar and Nonpolar Components", Ind. Eng. Chem. Process Des. Dev., vl5, 4, pp557-564 (1976)... 

The phase behaviours of binary and ternary ionic liquid mixtures with carbon dioxide,organics " and water " have been determined using COSMO-RS. In the COSMO-RS framework, ionic liquids are considered to be completely dissociated into cations and anions. Ionic liquids are thus taken as an equimolar mixture of two distinct ions, which contribute as two different compounds. Because ionic liquids only dissociate in the presence of strongly polar substances, the COSMO-RS prediction of the phase behaviour of ionic liquid systems with polar compounds (water and alcohols) is more accurate than that of ionic liquid systems with nonpolar compounds (carbon dioxide and organics). Especially the COSMO-RS prediciton of the solubility of (relatively nonpolar) carbon dioxide in ionic liquids shows considerable deviations ( 15 %) from experimental values. lUPAC Technical Reports document the measurements of the thermodynamic and thermophysical properties of l-hexyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]amide and the recommended values. ... 

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