Experimental and kinetic modeling study on the low-temperature decomposition and autoignition of 2-Azido-N,N-dimethylethanamine: A promising green mono- and bi-propellant

2-Azido-N,N-Dimethylethanamine (DMAZ) is a promising candidate for mono- and bi- propellant. However, the fundamental gas-phase combustion experiments have not been reported, and its chemical kinetic mechanism is not well understood. Therefore, the ignition delay times (IDTs) of DMAZ were measured utilizing a rapid compression machine and a shock tube, covering a wide temperature range of 570 – 960 K, at 10 and 20 bar with varying equivalence ratios. DMAZ was surprisingly found to undergo decomposition at temperatures as low as 600 K, leading to a pressure rise within the chamber. The low-temperature decomposition characteristics of DMAZ were systematically investigated under various fuel concentrations and pressures. A kinetic model of DMAZ was developed, incorporating quantum chemistry calculations for the thermodynamic data of new species and the rate constants of H-atom abstractions. The newly measured IDTs and characteristic decomposition times (CDTs) were further adopted in the model validation. Results show that DMAZ mainly decomposes through N–N₂ bond fissions, which are also the major reaction pathways during autoignition. O₂ addition to the radicals derived from the decomposition products and subsequent reactions contribute to most of the low-temperature reactivity in DMAZ oxidation. The current kinetic model can reasonably predict the IDTs and CDTs, as well as their dependencies on pressure, equivalence ratio, and fuel concentration.