Experimental determination and calculation of the critical curves for the binary systems of CO2 containing ketone, alkane, ester and alcohol, respectively

A set of variable-volume autoclave with a quartz window was used for the experimental determination of the high-pressure phase equilibria and critical curves. The critical temperatures, pressures, densities and mole volumes in the region near the critical point of CO2 were examined for eleven binary systems of supercritical CO2 (SC CO2) with different kinds of substances (ketone, alkane, ester and alcohol), respectively. The critical curves of the above binary systems were also calculated using an equation of state. The equation consists of a hard body repulsion term and an additive perturbation term, which takes care of the attractive molecular interaction. The calculated data were compared with the experimental data, and yielded good agreements. At the same time, the values of the adjustable parameters, λ, kσ and kɛ were obtained. The critical curves of the above eleven binary systems at higher temperatures and pressures all belong to type I.

► Critical properties of eleven CO2 binary systems are determined and calculated.
► The calculated results show good agreements compared with the experimental data.
► The adjustable parameters λ, kσ and kɛ were obtained.
► The critical curves all belong to type I at higher temperatures and pressures.