The Mixing rules of Modified Huron and Viddal, (MHV1), Wong and Sandler, (W-S), and a new mixing rule based on a combination of W-S and MHV1 using neural networks, called combined mixing rule (CMR) have been revised and extended to applications involving mixtures with non-condensable gases over broader ranges of temperature and pressure. The paper presents the use of Modified UNIFAC (Lyngby) with the equation of state Soave-Redlich-Kwong (SRK) for the prediction of solubility of gases in different mixtures of alkanes and alcohols.