Complex thermal analysis and runaway reaction of 2,2′-azobis (isobutyronitrile) using DSC, STA, VSP2, and GC/MS

Abstract

A severe manufacturing accident involving 2,2′-azobis (isobutyronitrile) (AIBN) occurred in China on April 14, 2011, which created high-pressure gas release killing nine people and severely damaging equipment and buildings. Eliminating chemical catastrophes in the petrochemical industry is a global concern. A new approach, which combines non-isothermal kinetic modeling, runaway reaction, and product analysis, was employed to determine decomposition mechanisms of AIBN by separately using differential scanning calorimetry, simultaneous thermogravimetric analyzer, vent sizing package 2, and gas chromatography/mass spectrometer. The results indicated that azo compound AIBN exhibits higher level of thermal decomposition with a maximum temperature of 294 °C and maximum pressure of 367 psig in comparison to the other azos. Moreover, various critical thermokinetic parameters, such as time to maximum rate, exothermic onset temperature, adiabatic temperature rise, and pressure gradients were obtained. A combination of thermal hazards and reaction pathways was subsequently employed to investigate the thermokinetics and mechanisms of AIBN decomposition.