Thermal Stabilities of Polyazido Substituted N,N'-azo-1,2,4-triazoles: Experimental and Theoretical Study

摘要

3-azido-4,4'-azo-l,2,4-triazole (1), 3,3'-di(azido)-4,4'-azo-l,2,4-triazole (2), 3,3',5-tri(azido)- 4,4'-azo-l,2,4-triazole (3) and 3,3',5,5'-tetra(azido)-4,4'-azo-l,2,4-triazole (4) with N,N'-azo linkage were synthesized, and their thermal stabilities were studied by differential scanning calorimetry (DSC). Theoretical method was used to investigate the substituent effects on the stability of N,N'-azo linkage, and the decomposition mechanism were also analyzed. The results of DSC test and bond dissociation energy calculation indicates that the introduction of azido groups reduce the stability of N,N'-azo linkage. The decomposition mechanism changes, as the number of the azido group increases. Both the rupture of the N-N single bond of the N,N'-a.zo linkage and the decomposition of the azido group are probably the initial decomposition step for mono- and di(azido)-4,4'-azo-triazoles, while the rupture of the N-N single bond trigger the decomposition of tri- and tetra(azido)-4,4'-azo-triazoles.