Recrystallization of AP by Supercritical CO_ 2 as Anti-Solvent Method

The recrystallization of AP was carried out using supercritical CO_2 as the anti-solvent and acetone as the organic solvent for AP. The effects of the main parameters including temaperatu re,initial concentration of the solution, the final pressure and hold time after the pressurization on thegas anti-solvent(GAS) recrystallization process were studied. AP particles (30-40 nm) with narrow size distribution are obtained a t 10 MPa,40 ℃and 35 kg·h -1. The results show that the intensity of liqu id onflow have a great influence on AP average size and morphological characters in GAS,and AP crystals develope from the nuclei to sphericity, polyhedron,needles,and whiskers in GAS.