Science and Technology of Energetic Materials

Vol.79, No.3 (2018)

Research paper

Initial decomposition pathways of guanidium nitrate studied by quantum chemistry calculation
Yu-ichiro Izato and Atsumi Miyake


The decomposition mechanism of guanidium nitrate (GN) was investigated by quantum chemistry calculations. Optimized structures of reactants, products, and transition states were obtained at the ωB97X-D/6-311++G(d,p)/SCRF = (solvent = water) level of theory and the total electron energies and free energies of these structures were calculated at the CBS-QB3 level of theory. In the initial decomposition pathway of GN, two mechanisms occur in parallel: CN3H5 decomposition and the interaction between CN3H5 and HNO3. The former mechanism has three pathways and each of these schemes provided the same global reaction: CN3H5→ HNCNH + NH3. Pathways for neutral monomolecular decomposition, neutral-neutral bimolecular decomposition (CN3H5 + CN3H5), and cation-neutral bimolecular reaction (CN3H6+ + CN3H5) were developed. The latter reaction has four pathways and each of these schemes provided the same global reaction: CN3H5 + HNO3 → HNCNH + N2O + 2H2O. These schemes can be divided according to the combination of oxidizers (HNO3 or N2O5) and reductants (CN3H5 or CN3H6+). Based on the energy-barrier results, HNO3-catalyzed monomolecular decomposition in CN3H5 decomposition and N2O5/CN3H5 schemes in the interaction between CN3H5 and HNO3 are the most plausible mechanisms.

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guanidine nitrate, gas-generation agent, decomposition, liquid-phase reaction, ab initio calculation

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