Solubility of gases in liquids: a critical review

Abstract

Ab4tLw2;t -Selected theoretical and experimental aspects of vapor-liquid equilibria involving supercritical (noncondensable) components are reviewed. The focus is on the rigorous thermodynamic basis on which high-precision methods for the determination of Henry coefficients have to rest. A condensed outline of current theories and correlations for the prediction of auxiliary quantities, such as virial coefficients and partial molar volumes, is presented. Finally, attention is given to recent work on relatively simple aqueous solutions of nonelectrolytes, which may contribute towards a better understanding of hydrophobic effects.

Solubility of gases in liquids. 22. High-precision determination of Henry’s law constants of oxygen in liquid water fromT=274 K toT=328 K

“…In the absence of theoretically well-founded models of general validity, one has to rely on essentially empirical fitting equations, subject however, to some important thermodynamic constraints. (6,7,32,33) Depending on the choice of variables, that is, T or 1/T , for expanding the partial molar enthalpy change on solution (see below), either the Clarke-Glew equation (34) or the Benson-Krause (BK) equation (4,35) is obtained. On the basis of its ability to fit very accurate H 2,1 (T, p s,1 ) data over large temperature ranges, and its simplicity, the BK power series in 1/T appear to be superior.…”

“…Since the thermodynamic method used for data reduction has been described previously, (5)(6)(7)(10)(11)(12) only a brief summary of its salient features will be given here. For details we refer to the original papers.…”

Solubility of nonpolar gases in 2,6-dimethylcyclohexanone

“…The non-ideality of the gas phase was not considered due to the lack of the necessary data to get the gas virial coefficients for the solvent and the mixture. However, empirical approaches (12,13) were used to estimate the critical data for the solvent and the necessary parameters, and from these the mentioned virial coefficients in the case of the most soluble gases, to give an idea of the error introduced by considering ideal gas phase behaviour. In the least favourable instances, Xe, C2H4, C2H6, and SF6, such estimations led to mole fractions about 1 % , 1 % , 1.5%, and 2.3%, respectively, higher than when ideality is assumed.…”

Solubility of gases in liquids. 21. Solubility of He, Ne, Ar, Kr, N2, O2, CH4, CF4, and SF6in 2,2,4-trimethylpentane atT= 298.15 K

“…Given the limits of experimental precision attainable with this apparatus, to an excellent approximation, the Henry fugacity H 2,1 (T, p s,1 ) at the same temperature and the vapour pressure p s,1 of the pure solvent (which is also known as Henry's law constant) may be obtained (10,(12)(13)(14) according to:…”

“…The critical quantities of 2,2,4-trimethylpentane (i = 1), including the critical molar volume V c,1 , are those recently recommended by Daubert, (23) and the acentric factor ω 1 = 0.303 was taken from Reid et al (24) For T = 298.15 K we obtained B 11 = −3151 cm 3 · mol −1 . For the estimation of second virial cross-coefficients B 12 , it is generally assumed that the same extended corresponding states relation, equation (9), is valid but with characteristic mixture parameters T c,12 , p c,12 , and ω 12 replacing the pure substance quantities. (21,22) Thus, reduced second virial cross-coefficients B 12 (T r,12 ) p c,12 /(RT c,12 ) were obtained at a reduced temperature T r,12 = T /T c,12 with the conventional combination rules:…”