On the Selection of Proper Thermodynamic Conditions for the Gas Antisolvent Process (GAS) at Nearcritical and Supercritical Conditions

In this work the volume expansion for the binary systems of ethanol and toluene, as industrial organic solvents, in the presence of nearcritical and supercritical carbon dioxide, CO2, at a temperature range of 293 to 333 K has been meticulously measured. The effect of the temperature and pressure of binary systems on volume expansion for organic solvents have also been investigated. It can be observed that by increasing the pressure of the system at a constant temperature, the volume of the liquid phase increases smoothly, while at higher pressures a sudden volume expansion can occur. The range of pressure that can lead to a sudden increase in the volume expansion of the liquid phase in each specified temperature can be reported as a proper condition in producing micro and nanoparticles. The experimental data for the volume expansion of organic solvents were modeled using the conventional cubic Peng Robinson equation of state. The Average Absolute Relative Deviation percent (AARD%) for the binary systems of ethanol + CO2 and toluene + CO2 were reported as 14.9% and 15.1%. As inferred, it is vital to develop a thermodynamic model with greater accuracy in order to correlate the volume expansion of the systems studied in this work at various conditions.