The liquid-liquid phase equilibrium of mixtures of the room temperature ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF 6 ], and three single alkanols (ethanol, 1-propanol, and 1-butanol) was investigated over the entire composition range at ambient pressure. The experiments were conducted from 262 K to the vicinity of the critical solution temperature of the binary mixture (at maximum 362 K) by two different methods, namely, synthetic cloud-point measurements and analytical UV spectroscopy. The cloud-point method was mainly applied for the [bmim][PF 6 ]-rich liquid, whereas UV spectroscopy was used to determine the very small concentrations of [bmim][PF 6 ] in the alkanols, since under these conditions the cloud-point method is no longer applicable. All three systems show an upper critical solution temperature. With increasing chain length of the alcohol, that temperature rises and simultaneously the biphasic region becomes larger. Inspired by recent publications, the liquid-liquid equilibrium of these three binary systems was predicted by applying the COSMO-RS method. Calculations resulted in predictions of a miscibility gap, but the calculated miscibility gap strongly differs from the experimental results. A far better representation of the experimental data was accomplished via a UNIQUAC-based correlation.

A headspace gas chromatography technique was applied to determine the solubility of carbon dioxide in aqueous solutions of 2,2‘-methyliminodiethanol (N-methyldiethanolamine, MDEA) at low gas loadings (at stoichiometric molar ratios of carbon dioxide to MDEA between about 0.003 and 0.8). A temperature range T ≈ 313−393 K was covered. The stoichiometric molality of MDEA in water amounted to about 2, 4, and 8 mol/(kg of water) (mass fraction of MDEA ≈ 0.192, 0.323, and 0.488). The partial pressure of carbon dioxide was between about 0.1 and 70 kPa. A thermodynamic model for describing the vapor−liquid equilibrium (which applies Pitzer's molality-scale-based equation for describing the Gibbs excess energy of the aqueous phase) is revised and extended using the new data.

New experimental results for the solubility of carbon dioxide in solvent mixtures of methanol and water are presented (at solvent mixture methanol mole fractions of (5, 10, 25, 50, 75, 90, 95, and 100) %, at (313.75, 354.35, and 395.0) K, and total pressures up to about 10 MPa). The experimental work is to provide a database for the development of a thermodynamic model to describe the gas solubility in saltfree and salt-containing mixed solvents.

New experimental results are presented for the solubility of carbon dioxide in pure liquid acetone {) 2-propanone, (CH 3 ) 2 CO} and in solvent mixtures of (acetone + water) at gas-free solvent mixture acetone mole fractions of about (0.05, 0.1, 0.25, 0.5, 0.75, 0.9, and 0.95), temperatures of (313.75, 354.35, and 395.0) K, and total pressures up to about 10 MPa. Numerical values are reported for the (molality scale based) Henry's constant of CO 2 in acetone and in (acetone + water) at vanishing amount of the gas in the liquid mixture resulting from the new experimental data by applying the well-known extrapolation procedure. The experimental work is to provide a database for developing and testing thermodynamic models to describe the gas solubility in salt-free and saltcontaining mixed solvents as well as to test screening methods based, for example, on molecular simulation.

A high-pressure view-cell technique based on the synthetic method was used to determine the solubility of ammonia in liquid methanol (total pressure at a preset temperature and liquid-phase composition). The solubility pressure ranges up to about 4.2 MPa. The temperature amounts to (313.75, 354.35, and 395.0) K. The molality of ammonia in methanol (the mole fraction of ammonia in the liquid) ranges up to about 66.4 mol·kg-1 (about 0.68). Furthermore, a high-pressure cell technique based on the analytical method was used to investigate the vapor−liquid equilibrium of that same system (equilibrium pressure as well as liquid- and gas-phase compositions at a preset temperature). The solubility pressure ranges up to about 1.6 MPa. The temperature amounts to (353.1 and 393.1) K. The molality of ammonia in methanol (the mole fraction of ammonia in the liquid) ranges up to 13 mol·kg-1 (about 0.3). The experimental results are used to determine Henry's constant of ammonia in methanol. Furthermore, the experimental data are correlated by applying Pitzer's molality scale based equation for the Gibbs excess energy.