<p>2,4-Toluene diisocyanate (2,4-TDI) is a key industrial chemical widely used in polyurethane synthesis, although the high reactivity of its functional groups introduces thermal safety risk. In this manuscript, the exothermic behavior of 2,4-TDI was investigated under dynamic, adiabatic, and isothermal conditions using differential scanning calorimetry (DSC) and adiabatic accelerating calorimetry (ARC). A comprehensive assessment of its thermodynamic characteristics and thermal hazards was conducted. Under both dynamic and adiabatic conditions, 2,4-TDI exhibited a single exothermic peak within the experimental temperature range, accompanied by the release of non-condensable gases, indicating a significant thermal hazard and a potential risk of thermal explosion. Kinetic analysis via the Kissinger and Starink methods at heating rates of 2, 4, 6, 8, and 10&#xa0;°C min⁻¹ yielded activation energies of 99.94 kJ mol⁻¹ and 101.02 kJ mol⁻¹, respectively. Both methods showed strong linear correlations (<i>R</i>² &gt; 0.99), confirming methodological reliability. The isothermal heat flow curve indicates that the reaction follows an n-order kinetic model with a reaction order of <i>n</i> = 0.63. Gas chromatography analysis of the non-condensable gases generated under adiabatic conditions identified nitrogen, carbon dioxide, benzene, and toluene as the main components, indicating that the exothermic process under adiabatic conditions corresponds to thermal decomposition. An assessment of the thermal hazard was conducted via the determination of three critical thermal stability parameters: TD₂₄(164.62&#xa0;°C), TCL₌₁(172.73&#xa0;°C), and SADT(171.71&#xa0;°C). These quantitative indicators provide essential reference data for evaluating and optimizing the thermal safety of 2,4-TDI throughout its production, storage, transportation, and application.</p> Graphical abstract <p></p>