Advanced technology of thermal decomposition for AMBN and ABVN by DSC and VSP2

In addition to organic peroxides, azo compounds are important basic initiators applied in chemical plants. In general, these compounds decompose at lower temperatures than aldehydes, ketones, and ethers, some of which decompose unimolecularly at higher temperatures so that the first products are not as stable due to the bivalent -N=N- composition, which has very active characteristics. In this study, thermal stability tests of two azo compounds, 2,2'-azobis (2-methylbutyronitrile) and 2,2'-azobis-(2-4-dimethylvaleronitrile), were evaluated via differential scanning calorimetry to determine the apparent exothermic onset temperature (T (0)), heat of decomposition (Delta H (d)), and apparent exothermic peak temperature (T (p)) for intrinsic thermal safety analysis. Following the dynamic tests, vent sizing package 2 (VSP2) was employed to determine the maximum pressure (P (max)), maximum temperature (T (max)), maximum self-heating rate [(dT/dt)(max)], maximum pressure rise rate [(dP/dt)(max)], and adiabatic time to maximum rate [(TMR)(ad)] under a credible case. Finally, we attempted to obtain the apparent activation energy (E (a)) and pre-exponential factor (A) during decomposition via a non-isothermal approach through Flynn-Wall-Ozawa equation and the approximate solution for the design of safer reaction conditions with greater efficiency when azo compounds are used as initiators. As a whole, a prudent approach for the integration of thermal hazard data was developed that is necessary and useful for determining a proactive emergency response procedure associated with industrial applications on azo compounds during thermal upsets.