A Thermochemical Kinetic-Based Study of Ignition Delays for 2-Azidoethanamine-Red Fuming Nitric Acid Systems: 2 Azido-N-Methylethanamine (MMAZ) Vs. 2 Azido-N,N-Dimethylethanamine (DMAZ)

Abstract : Reaction rate expressions for paths with the potential to be rate-determining steps in the ignition of MMAZ-RFNA systems were estimated on the basis of results obtained from quantum chemistry models and transition state theory. The expressions were added to an existing finite-rate, chemical kinetics mechanism for TMEDA-DMAZ-RFNA systems to produce a TMEDA-DMAZ-MMAZ-RFNA mechanism. Homogeneous reactor simulations produced with the new mechanism predict time-to-ignition values for MMAZ-RFNA systems that are significantly longer than those for comparable DMAZ-RFNA systems. This result is consistent with experimentally measured ignition delays that have been reported for the two systems. An analysis of the computationally based results indicates that the difference in the ignition delays is attributable to differences in the rates of NO2-mediated abstraction of H-atoms from the parent fuels.