Influence of Salts on the Solubility of Carbon Dioxide in (Water + Methanol). Part 1: Sodium Chloride

The influence of strong electrolytes on the solubility of gases in aqueous/organic solutions has to be known in many industrial applications. In particular, thermodynamic models for correlating and predicting that influence have to be developed and tested. Progress in that area is rather limited, as reliable experimental data are scarcely found in the literature. Here, new experimental results are presented for the total pressure above liquid mixtures of (H2O + CH3OH + CO2 + NaCl) at temperatures of about (313.7, 354.4, and 395) K, total pressures up to ~10 MPa, mole fractions of methanol in the binary solvent mixture (water + methanol) up to ~0.75, and salt molalities up to 2 moles per kilogram of (water + methanol) but always well below the solubility limit of the salt in the gas-free solvent mixture. The new results are used to further test a recently developed extension of Pitzerʹs molality-scale-based model for the Gibbs excess energy of aqueous electrolyte solutions to mixed-solvent electrolyte- and gas-containing systems.