A new correlation of second virial coefficients of both polar and nonpolar systems is presented. It uses the Pitzer‐Curl correlation for nonpolar compounds, but in a modified form. The second virial coefficient of nonhydrogen bonding compounds (ketones, acetaldehyde, acetonitrile, ethers) and weakly hydrogen bonding compounds (phenol) is fitted satisfactorily with only one additional parameter per compound, which is shown to be a strong function of the reduced dipole moment. Two parameters are needed for hydrogen bonding compounds (alcohols, water), but for alcohols, one parameter has been kept constant and the other expressed as a function of the reduced dipole moment. The extension of the correlation to mixtures is satisfactory, direct, and involves only one coefficient per binary.

The mutual solubilities at the three-phase equilibrium pressure of three C6 hydrocarbons (benzene, cyclohexane and n-hexane) and water have been experimentally investigated up to 482 K. A thermodynamic analysis of these new measurements and of critically selected literature data has been carried out up to the three-phase critical end point. Information is also provided on the two-phase critical locus, The solubility of hydrocarbons in water has been used to calculate Henry's constants, while the solubility of water in the hydrocarbons has been correlated with a modified version of the Redlich-Kwong equation of state. Consideration is also given to the effect of pressure on the mutual solubilities. CONSTANTINE TSONOPOULOS SCOPEKnowledge of the hydrocarbon/water mutual solubilities is frequently of importance to the design and operation of process equipment in refineries and petrochemical plants. Hydrocarbons, like other pollutants, must be removed from refinery and petrochemical plant wastewater streams. Accordingly, the solubility and volatility of the hydrocarbons are needed to trace their phase distribution through the entire process sequence and to design separation equipment (such as sour water strippers) for their removal.If the water present in a hydrocarbon mixture exceeds its solubility limit, a second liquid phase will form, the "free" water phase, that can affect product specifications and equipment operation. Perhaps the most common adverse process effect is corrosion. Even when a free-water phase does not form, the solubility of water in hydrocarbons at 470 K and above is so high that the phase distribution of water can affect both the operation of the equipment, say, a distillation tower, and the product quality. Sometimes, however, a water-rich phase is formed intentionally, for example, to remove salts that would otherwise deposit out. This case also requires the accurate prediction of the solubility limits.The maximum temperature of interest in water pollution abatement is about 420 K, or even 470 K in certain cases, which can be reached in sour water strippers. On the hydrocarbon-rich side, the maximum temperature of interest can be much higher. Generally, it is the maximum temperature at which the hydrocarbon-rich liquid phase can exist. This is somewhat below the critical temperature of the hydrocarbon.The process conditions at which hydrocarbon streams are contacted with water and lead to the formation of a second liquid phase need to be predicted reliably. The solution of water in hydrocarbons can be predicted accurately with an equation of state, using only a temperature-independent binary interaction parameter. The same procedure can then be used to predict the distribution of water between the vapor and hydrocarbonrich liquid phases. On the other hand, the solubility of hydrocarbons in water is not predictable by such a procedure, unless the binary interaction parameter is made a strong function of temperature. The solubility of hydrocarbons in water is so low, however, that Henry's law i...

This is part 2 of a series of contributions by the critical properties group of the IUPAC Commission 1.2 on Thermodynamics, Subcommittee on Thermodynamic Data. It presents all known experimental data for the critical constants of normal alkanes, the most extensively investigated class of organic compounds. Data are presented up to C24, and recommendations are given along with uncertainties. Such uncertainties are relatively small for the first 10 normal alkanes, which are stable at the critical point, but are larger for the progressively more unstable Cu-C24 compounds. The critical temperatures have been convertedto

No abstract

In Part I (Tsonopoulos and Wilson, 1983), the mutual solubilities of three Ca hydrocarbons (benzene, cyclohexane, n-hexane) and water were experimentally investigated and, together with critically selected literature data, were correlated up to the three-phase critical end point. The present paper extends this analysis to the mutual solubilities of three Cs hydrocarbons (ethylbenzene, ethylcyclohexane, n-octane) and water, which have been measured at the threephase equilibrium pressure up to the critical temperatures (568,561 and 539 K, respectively), A thermodynamic analysis of these new measurements and of available literature data has been performed up to the three-phase critical end point. Information is also provided on vapor-phase equilibrium compositions. The solubility of hydrocarbons in water has been used to calculate Henry's constants, while the solubility and volatility of water in hydrocarbons has been successfully correlated with several modifications of the Redlich-Kwong equation of state. SCOPEThe importance of hydrocarbon/water mutual solubilities to the design and operation of process equipment in refineries and petrochemical pIants was discussed by Tsonopoulos and Wilson (1983) [this reference will be cited as TW (1983)J The same reference also discussed the correlation and prediction of mutual solubilities, Henry's constants for hydrocarbons in water, and the use of equations of slate. All these were applied to Ce hydrocarbons, for which much more is known than for other hydrocarbons.Our work continues with CS hydrocarbons to study the effect of carbon number on mutual solubilities. But we have also expanded the scope of our study by including experimental data for the vapor composition and the three-phase critical end point, the highest temperature at which the vapor and the two liquid phases coexist.

No abstract

This is part 3 of a series of contributions by the critical properties group of the IUPAC Commission 1.2 on Thermodynamics, Subcommittee on Thermodynamic Data. It presents all known experimental data for the critical constants of aromatic hydrocarbons, which have been divided into four families: normal alkylbenzenes (5 compounds, Ce-Cio); other alkylbenzenes (13 compounds, Cg-C12); polyphenyls (5 compounds, C12-C18); and condensed polycyclics (7 compounds, C9-C14). Recommendations are given together with uncertainties. Critical temperatures have been converted to ITS-90.The aromatic hydrocarbons have been divided into four families: (A) normal alkylbenzenes; (B) other alkylbenzenes; (C) polyphenyls; and (D) condensed polycyclics.Except for benzene, there are relatively few experimental data available for aromatic hydrocarbons, and some of these data, especially for the terphenyls, may be unreliable.The presentation and evaluation of the experimental data follow the guidelines of Ambrose et al. in parts 1 and

No abstract