Evidence for Homolytic Decomposition of Ammonium Nitrate at High Temperature

Article abstract of DOI:10.1021/j100347a033

Rates of decomposition of ammonium nitrate in the liquid and vapor state have been measured at temperatures up to 400 deg C.The evidence indicates that an ionic mechanism operating at temperatures below 290 deg C is overtaken by a homolytic mechanism at higher temperatures.The activation energy increases to 193 kJ/mol, which is nearly equal to the N-O bond energy in HNO3.Water and NH3 strogly inhibit the ionic reaction at low temperature, but the effect fades away at high temperature.There is no primary H/D kinetic isotope effect.The reaction rates of liquid and vapor are nearly the same at high temperature.The rate at high temperature is given by (kT/h)e^4.06e^-23300/T.