THERMAL HAZARDS - CALCULATING ADIABATIC BEHAVIOR FROM DIFFERENTIAL SCANNING CALORIMETRY (DSC) DATA

Temperature-time data under adiabatic conditions is required for the safe use of substances which decompose exothermically. Such data can be measured directly by adiabatic calorimetry but not by DSC. However, here it is shown that the kinetic and thermodynamic data from a carefully designed DSC experiment (using high pressures or pressure-tight pans to minimise vaporisation) can be transformed using simple physical chemistry to predict the course which the reaction would follow under adiabatic conditions. The procedure is illustrated for the decomposition of di-tert-butyl peroxide and tert-butyl peroxybenzoate, and the predictions are compared with data from an adiabatic calorimeter.