Abstract:

At B3LYP/6-31G* and MP2/6-31G* levels, the bond dissociation energies(BDEs) of O—NO2 bond in four nitrates such as n-propyl nitrate(NPN), isopropyl nitrate(IPN), 2-ethylhexyl nitrate(EHN), and tri-ethylene glycol dinitrate(Tri-EGDN) were calculated. The thermal decomposition characteristics of NPN, IPN, EHN, and Tri-EGDN were investigated by means of ambient-pressure DSC and high-pressure DSC. Kinetic parameters of thermal decomposition were obtained. The results show that the thermal decomposition of four nitrates under ambientpressure occurred in gas phase. When the pressure increased up to 2 MPa, their decomposition processes occurred in liquid phase. According to the fact that the calculated results of O—NO2 BDEs of the four nitrates are in good agreement with the experimental results of apparent activation energies obtained from DSC, we deduce that the thermolysis of the four nitrates is only unimolecular homolytic cleavage of the O—NO2 bonds.

Key words: nitrates, density functional theory (DFT), bond dissociation energy (BDE), high-pressure DSC, thermal decomposition, activation energy