Micronization of CL-20 using supercritical and liquefied gases

Abstract

Liquid and supercritical CO₂ and TFE have been systematically studied as media for CL-20 recrystallization to estimate their potential for the selective preparation of ultrafine particles. It has been found that the polymorphic composition of produced microcrystals can be efficiently controlled by the alteration of the solvent system and the micronization method used. Thus, the application of CO₂ as an anti-solvent in both SAS and GAS methods results in the formation of α-CL-20–CO₂ solvates, regardless of the process conditions. The use of TFE as an active medium for the GAS and RESS methods allows for selective preparation of uniform ultrafine β- or ε-CL-20 particles under mild conditions. The developed ε-CL-20 production method favorably differs from the known analogues by its tolerance to the quality of the initial substrate (crude CL-20), increased environmental and industrial safety, ease of product isolation, and the ability to control the particle morphology and crystalline phase.