Two-Dimensional Burn Velocity and Analysis of Burn Products of Nitromethane at High Pressure

The burn velocity of nitromethane (NM) at high pressure in a diamond anvil cell (DAC) has been studied using imaging with ICCD cameras and the burn products have been measured using Raman spectroscopy. The use of ICCD cameras allows for the measurement of the deflagration velocity in two dimensions, in contrast with previous one-dimensional streak camera measurements, providing the ability to observe anisotropic deflagration behavior. A change in the burn product chemistry is observed when the NM is ignited above 25 GPa. In the region above 25 GPa, the burn products are transparent (consistent with earlier reports) and contain ammonium carbonate and nitrogen. The transparent phase remains when decompressed. When burned below 25 GPa, the burn products consist of, at least, carbonaceous soot. Changes in the pressure of the DAC after the burns were also observed. Deuterated NM and isotopically labeled (15N and 13C) NM were also studied and compared against the unlabeled sample.