APPLICATION OF ISOTHERMAL CALORIMETRY AND UV SPECTROSCOPY FOR STABILITY MONITORING OF PENTAERYTHRITOL TETRANITRATE

Thermal stabilities for three pentaerythritol tetranitrate (PETN) samples with variable surface areas were monitored by isothermal calorimetry and UV spectroscopy over the range 363-408 K. Isothermal induction times measured with constant volume calorimetry under an air atmosphere, and NO evolution rates monitored by UV absorbance at 213 nm under vacuum correlated with the PETN surface area at temperatures equal or exceeding 383 K. Rate data measured at 383 K are in accord with predictions based on detailed kinetic modeling. Below 383 K, NO evolution data suggested that additional geometric factors may be significant in controlling PETN stability. Mechanisms for the influence of surface area upon the rate-determining step are addressed.