The thermal decomposition of azidopyridines
The thermal decomposition of new heteroaromatic polyazides 2,6-diazido-3,5-dicyanopyridine, 2,4,6-triazido-3,5-dicyanopyridine, and 2,3,4,5-tetraazido-6-cyanopyridine was studied by thermogravimetry, volumetry, mass-spectrometry, and IR spectroscopy. Reaction kinetic parameters were determined. The only gaseous product of the thermal decomposition of all the azides studied was nitrogen, its degree of purity was 99.0–99.8 vol %. 2,6-Diazido-3,5-dicyanopyridine and 2,4,6-triazido-3,5-dicyanopyridine had thermal stability and thermal decomposition parameters close to those of the majority of aromatic azides. The mechanism of thermal decomposition of these azides includes the splitting off of the nitrogen molecule at the initial limiting process stage. Subsequent intermolecular reactions with the participation of nitrenes result in the formation of an amorphous substance containing polyconjugated fragments with sp 2 hybridization, which form planar two-dimensional networks. 2,3,4,5-Tetraazido-6-cyanopyridine has very low thermal stability; the rate of nitrogen release during its decomposition is almost 1000 times higher than with 2,6-diazido-3,5-dicyanopyridine and 2,4,6-triazido-3,5-dicyanopyridine at comparable temperatures. This was explained by the presence of the ortho azido group (there is no ortho arrangement of azido groups in 2,6-diazido-3,5-dicyanopyridine and 2,4,6-triazido-3,5-dicyanopyridine).
Keywordsazidopyridines thermal decomposition
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