The next phase of our current study is to use the parameters obtained from pure-component systems in a transferable manner to represent the corresponding mixtures. Mixtures of n-alkanes and H2O have been studied previously with SAFT-γ SW [82]. In general it is well known that the extreme nature of the phase separation [150] makes it challenging to model mixtures of H2O with non-polar compounds. Because of the large differences in the dielectric constant of the two phases as well as in the dipole moment of H2O and the hydrophobic molecules, it especially difficult to obtain phase-independent unlike interaction parameters [112] and thus to model simultaneously the equilibrium phases. In previous work [82], emphasis was placed on obtaining an accurate description of the alkane-rich phases (both liquid and vapour), while small absolute (but not relative) deviations for the aqueous phase composition were achieved. The systems of interest in our current work are typically aqueous mixtures containing a high proportion of H2O, alkylamine, and CO2. Consequently, in order to provide an improved overall description of the fluid-phase equilibria at the conditions of interest, refinements have been made to the unlike parameters presented in the previous study [129] relating to the interactions between H2O and the alkyl groups, CH3 and CH2, namely ϵCH3,H2O, ϵCH2,H2O and λCH3,H2O, λCH2,H2O.
