Production of High Bulk Density Nitroguanidine(HBNQ) in Laboratory Scale

Nitroguanidine is an important constituent in certain explosive compositions particularly in propellants and for some of these compositions it is desirable to be able to manufacture nitroguanidine of very small particle size and a high bulk density and also in a form in which the crystals have better flowing and handing properties. The crystallization of nitroguanidine has been studied for many years and it is known that it is possible to prepare high bulk density nitroguanidine (HBNQ). HBNQ has been prepared in organic and aqueous solvents or combination of these solvents. Organic solvents are volatile, flammable and toxic, thus scaling up processes based on these solvents is difficult and uneconomical. However, aqueous solvent dont have these problems. In this research project, we used a process through which crystals of nitroguanidine were produced in a relatively spherical form and with a high bulk density. Methylcellulose and poly(vinyl alcohol) were used as additives(crystal habit modifier) and the effects of these additives and other parameters such as cooling rate, nitroguanidine concentration, stirring on bulk density, and crystal size distribution were studied.