Thermal decomposition kinetics of Hexanitrohexaazaisowurtzitane by mass spectrometry

Thermal decomposition of hexanitrohexaazaisowurtzitane (HNIW) was studied by mass spectroscopy (MS) with low impacting electron energy. Non-isothermal kinetics treating method for ion curves in mass spectroscopy was established. The mechanism of HNIW thermal decomposition was analyzed according to the Arrhenius curves of ion products. The results showed that the apparent activation energy of the HNIW thermal decomposition was 145.1 kJ· mol^-1. Between 130 and 150 ° C, ion products are mainly produced by electron impact, and activation energy is between 28 and 41 kJ· mol^-1. Between 213 and 228 ° C, ion products are mainly produced by thermal decomposition, and activation energy is between 143 and 179 kJ· mol^-1. The kinetic compensation effect occurs in thermal decomposition of HNIW between 213 and 228 ° C, and the compensation effect equation is lnA=0.252E_a-0.645. The main reactions of HNIW thermal decomposition are as HNIW.438→6NO₂+2HCN+HNIW.108, HNIW.438→6NO₂+3HCN+HNIW.81, HNIW.438→6NO₂+4HCN+HNIW.54.