Effects of incompatible substances on thermal stability of dimethyl 2,2′-azobis(2-methylpropionate) (AIBME) in the application process

Dimethyl 2,2′-azobis (2-methylpropionate) (AIBME) is an oil-soluble azo initiator whose nature is unstable. In the chemical process, acids, alkalines or catalysts are often added to catalyze reactions. However, the decomposition process of the azo compounds may change when it is in contact with incompatible substances. In order to investigate the effects of common substances (hydrochloric acid (HCl), sodium hydroxide (NaOH), iron oxide (Fe₂O₃)) on the thermal stability of AIBME, differential scanning calorimetry (DSC) was utilized to obtain thermodynamic parameters. The dynamic calculations were carried out by Kissinger and Ozawa method. Meanwhile, adiabatic calorimeter Phi-TEC II was used to simulate the occurrence of thermal runaway of AIBME mixed with three incompatible substances under adiabatic conditions. Based on the adiabatic kinetic analysis, temperature at the time to maximum rate for 8 h (T_D8) and 24 h (T_D24) were obtained. Self-accelerating decomposition temperature (SADT) was calculated by the Semenov thermal spontaneous combustion theory. Non-isothermal experimental results showed that HCl reduced the activation energy of AIBME and increased its potential risk, while NaOH and Fe₂O₃ had inverse effect. In the adiabatic decomposition process, HCl and NaOH decreased the adiabatic temperature rise (ΔT_ad) of AIBME, but Fe₂O₃ had less influence. In addition, calculations for SADT of mixtures indicated that a low temperature environment should be provided for storage and transportation.