Thermal hazard and reaction mechanism for the preparation of epoxidized soybean oil from hydrogen peroxide

Epoxidized soybean oil (ESO) is a sustainable alternative that reduces emissions of volatile organic compounds, enhances coating and adhesion properties, and has a wide range of applications in bio-based composites. However, the industrial-scale production of ESO through the Prilezhaev reaction presents challenges in terms of temperature regulation and the potential for uncontrolled thermal reactions. This study aimed to investigate the thermal hazards associated with ESO production using hydrogen peroxide. We analyzed the reaction mechanism and exothermic behavior using dynamic differential scanning calorimetry (DSC), accelerated calorimetry (ARC), reaction calorimetry (RClmx), and in situ Fourier transform infrared spectroscopy (FTIR). Our findings demonstrated that the addition of sulfuric acid and formic acid raised the onset decomposition temperature of hydrogen peroxide. We also identified two exothermic phases (epoxidation of the double bond and degradation of the organic matter) and observed a rapid increase in temperature and pressure, posing a safety risk. Formic acid formation and epoxidation of the double bond were the main steps of the reaction mechanism, and the exothermic behavior stems mainly from the latter. We assessed the thermal hazard level using a risk matrix and the Stoessel criterion, which highlighted the high risk of thermal runaway without proper cooling and temperature control. This paper offers practical guidance for mitigating these risks in the industry.