Identification of Autocatalysis in Organic Peroxides

Abstract Chemicals containing peroxy functionality, which are known to be thermally unstable but industrially useful, have been associated with several industrial incidents. In this study, the thermal decomposition characteristics and autocatalytic potential of 40 organic peroxides were systematically investigated using differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC). Dynamic DSC and ARC results indicated that most samples presented significant thermal hazards, characterized by low onset temperatures (Tonset), high decomposition enthalpies (ΔH), large adiabatic temperature rise (ΔTad), and short time-to-maximum-rate. Distinctive structure–dependent stability was observed, with peroxy dicarbonates generally exhibiting lower Tonset values, while dialkyl peroxides showed comparatively higher thermal stability. Isothermal DSC identified 18 organic peroxides exhibiting a typical induction–acceleration–decay heat flow profile, indicative of autocatalytic behavior. Autocatalytic manifestation was more frequently observed in diacyl peroxides, peroxy esters, and peroxy dicarbonates, whereas dialkyl peroxides, alkylperoxyl carbonates, and ketone peroxides showed no detectable autocatalytic features. Concentration–gradient experiments further demonstrated that autocatalytic behavior is formulation-dependent and may attenuate upon dilution. These experimental findings provide systematic evidence for structure-hazard correlations and highlight the necessity of individual evaluation of organic peroxide formulations to ensure reliable thermal risk assessment.