Thermal Decomposition of Energetic Materials. 25. Shifting of the Dominant Decomposition Site by Backbone Substitution of Alkylammonium Nitrate Salts

Article abstract of DOI:10.1021/j100297a039

Exchanging X = -C(NO2)2F for X = -C(NO2)3 causes the dominating fast thermal decomposition site in NO3 salts to shift from largely that of the C-NO2 bond to largely that of the -H⁺...NO3^- portion.This is consistent with an order of thermal stability of the energetic sites in these salts of -C(NO2)2F>-H⁺...NO3^->-C(NO2)3.These conclusions were drawn from the nature of the IR-active gas products that are evolved in real time upon fast thermolysis (>100 K s^-1) and from slow heating of the condensed phase.The O/H ratio of the parent primary ammonium salt appears to be a qualitative indicator of whether NH3(g) will formed under these conditions.Salts with O/H >/= 1 have not been observed to release NH3(g) while those with O/H < 1 do.The salt with X=-C(NO2)2F possesses four polymorphs between 297 K and its two melting points.Only two polymorphs are present when X = -C(NO2)3.