Vapour-liquid equilibrium of acetone-CO2 mixtures of different compositions at the vicinity of the critical point

The vapour-liquid equilibrium of acetone-CO2 mixtures is studied by computer simulation at 11 different compositions, ranging from neat CO2 to neat acetone, in a 50-100 K wide range of temperatures at the vicinity of the critical point. The composition dependence of the critical parameters is determined, for the first time, in the entire composition range. It is found that while the critical temperature changes monotonically with the composition, the critical pressure goes through a maximum around the acetone mole fraction value of 0.3, and the critical density might also exhibit a maximum in the acetone mole fraction range of 0-0.2. Temperature dependence of the surface tension is also determined in the entire composition range. The obtained results agree, in general, well with experimental data; their deviation remains below the range within which different experimental data sets deviate from each other. Since experimental data in this respect exist, unfortunately, only in limited ranges of compositions (at low acetone mole fractions) and temperatures (data above about 335 K are scarce), the present study largely extends the range of thermodynamic conditions in which we have reliable information on the liquid-vapour equilibrium and critical conditions of acetone-CO2 mixtures.