Iranian Scientific Association of Energetic Materials

In the synthesis of hexamethylenetetranitramine (HMX) by Bachmann method, the morphology of crude HMX products are needle-like with alpha polymorph. This quality of materials leads to separation of α-HMX from final suspension to be time-consuming and difficult. On the other hands, crude product of α-HMX are the more sensitive and unsafe than β-HMX. Herein, a seeding strategy was developed in the synthesis of HMX by hexamine and 1,5-dinitroendomethylene-1,3,5,7-tetraazacyclooctane (DPT) as raw materials, to control the polymorphism of the crude products from a to b type, and their morphology from needle-like to spherical shape. Therefore, the microparticles of β-HMX, as micro-seeds, were added to the nitrator in the various steps of production process from hexamine and DPT reactants, then the yield of process was determined and  morphology of products were characterized using X-ray diffraction spectroscopy (X-ray) and optical microscopy. The results show that this interesting technique can control the polymorphism and structure of crude HMX from a to b type, improving the safety of crude product and its filtration time. Also, micro-seeding provides a useful conditions to the preparation and crystallization of β-HMX.