Crystallization of HMX-particles by using the gas anti-solvent-process

A ternary system consisting of cylcotetramethylene tetranitramine (octogen, HMX) as the solute, acetone respectively g‐butyrolactone as solvents and carbon dioxide as the anti‐solvent was used to investigate the formation of fine particles with the GAS‐process as well as the influence of the solvents upon the particle morphology under the same operating conditions. The precipitated particles were examined by infrared radiation spectroscopy (IR), laser light diffraction and light‐optical microscopy. The results show that octogen with a narrow particle size distribution was obtained. The crystals are of the same modification as the raw material and of hight purity. The modification and the particle size are influenced by the solvent used for the recrystallization.