RECRYSTALLIZATION OF MICRO- AND SUBMICRO-PARTICLES USING SUPERCRITICAL CO2

Abstract

Fine particles formation processes using supercritical CO2 are attractive technologies for the production of small, uniform and solvent-free particles. The most important techniques are the rapid expansion of supercritical solutions process (RESS), the supercritical antisolvent recrystallization process (SAS), and the particles from gas-saturated solutions process (PGSS). In this study, anthracene was micronized via the RESS process, and poly-L-lactic acid (L-PLA) was the SAS process. Experiments were conducted to investigate the effects of extraction pressure (150 ~ 250 bar), extraction temperature (50 ~ 70°C), and pre-expansion temperature (70 ~ 300°C) on the particle size and distribution of the precipitated anthracene. In case of L-PLA, they were performed with changing process variables such as the pressure (60 ~ 150bar) and temperature (25 ~ 45°C) of precipitator, concentration of liquid solution (0.5 ~ 2wt%), and flow rate of CO2 (1.5 ~ 6SLPM) and liquid solution (0.5 ~ 2 ml/min). To obtain the fine particles, 100, 200, and 300 µm nozzles were used in both processes.