THE THERMAL-DECOMPOSITION OF AMINOTETRAZOLES .2. 1-METHYL-5-AMINOTETRAZOLE AND 1,5-DIAMINOTETRAZOLE

The thermal decompositions of 1-methyl-5-aminotetrazole and of 1,5-diaminotetrazole have been studied using thermogravimetry, differential scanning calorimetry and thermal volumetric analysis. The solid residues, and the high boiling point and gaseous products of the decompositions have been collected and identified using IR spectroscopy and mass spectrometry. Both aminotetrazoles start to decompose just after melting: 1-methyl-5-aminotetrazole at 495 K and 1,5-diaminotetrazole at 460 K. The decomposition is accompanied by elimination of gaseous and high boiling point products, partial evaporation of the original substances and formation of thermally stable residues. Both 1-methyl-5-aminotetrazole and 1,5-diaminotetrazole, in the solid state and probably in the melt, coexist in amino and imino tautomeric forms. Therefore, two competing mechanisms of tetrazole ring-breaking, with elimination of respectively nitrogen or hydrogen azide molecule, are proposed.