An empirical method to evaluate the solubility of several gases in polar and non-polar solvents

Abstract

A predictive method, based on the application of the NRTL equation, is proposed to evaluate the solubility of gases in polar and non-polar solvents. The method relies on two main hypotheses: (i) the symmetrical convention can be assumed for the activity coefficients of supercritical components also according to a procedure previously proposed by the author; (ii) the NRTL binary constants can be evaluated through simple generalized correlations which link these parameters to the pure components properties expressed by the Hildebrand solubility parameter and the molar volume. The solubilities of ten gases (H 2, O 2, N 2, CH 4, C 2H 4, C 2H 6, C 3H 8, CO, CO 2, H 2S) in both non-polar and polar solvents are examined. Usually, each gas requires two “ad hoc” procedures for polar and non-polar solvents, respectively. The proposed method is applied to more than 100 literature systems which cover a wide range of experimental conditions. The reliability of the predictions is expressed by the percent deviations of calculated pressures and vapor compositions from the experimental data. A comparison is also made with two literature methods.