(468b) Criticality Reduction through Alternative Nitration Conditions

Development of  novel explosives always poses challenges to safe scaleup. Nitrations can result in unstable reaction mixtures with resulting high criticality classes. Nalas Engineering evaluated potential processing options to produce 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) from 2,6-dimethoxy-pyrazine (DMP).

Previous investigations by Nalas revealed a strong decomposition of the desired intermediate 2,6-dimethoxy-3,5-dinitropyrazine (DMDNP) in the reaction mixture over time. This instability was evident and prevented further scale-up. Identification of process conditions that reduced the criticality class or afforded alternative manufacturing conditions suitable to produce DMDNP were investigated to include continuous processing options.

The objective of this effort was to compare the time to maximum rate (TMR) and thermal stability of the reaction mixture (TD₂₄) as a function of nitric acid stoichiometry as well alternative nitrating media.  This information afforded a reduced criticality class and higher level of overall safety for the nitration.