Thermal hazard evaluation of tert-butylperoxy-2-ethylhexanoate mixed with H₂O and NaOH solution

Tert-butylperoxy-2-ethylhexanoate (TBEC)—an easily decomposable organic peroxide—is widely used as a polymerization initiator in industrial production. Sodium hydroxide solution and water are common impurities in the polymerization process. In this study, exothermic onset temperature (T₀) and heat of decomposition (ΔH) of TBEC with impurities were obtained through differential scanning calorimetry. In addition, maximum pressure (P_max), maximum temperature (T_max), and adiabatic temperature rise (ΔT_ad) were obtained through accelerated rate calorimetry (ARC). Apparent activation energy (E_a) scores for pure TBEC and TBEC mixed with water (TBEC/H₂O) and sodium hydroxide (TBEC/NaOH) were calculated. Subsequently, based on experimental data obtained through ARC, the self-accelerating decomposition temperature and temperature at the time to maximum rate under adiabatic conditions were calculated for 24 h (T_D24) and 8 h (T_D8). The experimental results indicated that H₂O negligibly affected T₀ but decreased ΔH, P_max, T_max, and ΔT_ad. Moreover, addition of H₂O increased the T_D24 and T_D8 of TBEC. Thus, the thermal hazard of TBEC was reduced by addition of H₂O. Addition of NaOH solution increased the complexity of the reaction because the initial decomposition temperature and activation energy were negatively correlated to the content of NaOH in the solution.