Study on 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) decomposition using online photoionization mass spectrometry and theoretical simulations

Abstract

5-Nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) is a representative and insensitive energetic compound mainly used as a component of low vulnerable ammunition, but its decomposition process is not clear up to date. Herein, online photoionization mass spectrometry combined with theoretical simulations was employed to shed light on the thermal decomposition mechanism of NTO. The experimental and calculated results provide evidences for the thermal decomposition of NTO through direct ring rupture and intermolecular hydrogen transfer pathways. The initial decomposition step of NTO single molecule is direct ring rupture, followed by NO2 removal. The remaining structure undergoes C-N bond cleavage leading to HN2 dissociation, the CONCH finally decomposes into CO and HCN. The major products of NTO decomposition include N2, CO2, H2N2, NH3, and the minor products are HN2, H3N3, H2O, which is basically consistent with experiments. The formation mechanism of decomposition products is also discussed in detail and the total decomposition pathways are constructed.

Keywords

• Physical chemistry
• Thermal decomposition mechanism of NTO
• Molecular dynamics
• TG-PI-TOF-MS
• SPI-TOF-MS