The Effect of Parameters on Recrystallization of AP by Supercritical CO_2 as Anti-solvent

Basing on the Vapor-liquid equilibria in the CO_2-acetone and CO_2-ethanol calculated with Peng-Robinson equation(PR).The recrystallization of AP was carried out using supercritical supercritical CO_2 as the antisolvent,acetone and ethanol as the organic solvents for AP.The range of operating conditions for GAS recrystallization were 25—40℃ for temperatures,6—9MPa for pressure and 0.38—1.8g/100ml for the concentration of AP.After recrystallization AP micropraticles were produced with size of 60nm and 100nm at 25℃,9MPa,1% solution of AP in ethanol and 40℃,9MPa,1% solution of AP in acetone respectively.Compared with acetone,the average size of recrystallization AP with ethanol as solvent is much smaller and the causes was explained theoretically with partial molar volume(PMV).TEM was used to examine particle size and morphological character.The effect of some factors,such as temperature 、 pressure 、initial concentration,etc.,on particle size and particle size distribution was analyzed.The results show:(1) The intensity of liquid onflow have a great impact on AP average size and morphological characters in GAS.(2) In GAS,the interaction between the solvent and antisolvent is of greater importance on the size and shape of AP microparticles.