Thermal decomposition mechanism and hazard assessment of di-tert-butyl azodicarboxylate (DBAD)

In this work, we used C80 Micro-calorimeter and STA-FTIR-MS instrument to analyze decomposition mechanism of DBAD and evaluated the thermal hazard by the key index on self-accelerating decomposition temperature (SADT). Based on C80 data, the heat release per unit mass of DBAD is 699.85 ± 52.88 kJ kg −1 , and the activation energy calculated by Friedman method ranges from 28.58 to 52.03 kJ mol −1 . Besides, the thermal decomposition reaction of DBAD can be described by Zhuralev-Lesokin-Tempelman equation. In summary, the decomposition mechanism of DBAD is as follows: the C–O bond cracks firstly, separating ·C(CH 3 ) 3 out, then the C–C bond cracks, separating ·CH 3 out; the N=N double bond, C–N bond and C–O bond crack subsequently, separating: N–CO, ·O–CO–N:, HO–CO–N: and ·N=N–CO out, and these radical groups gradually decompose or oxidize into ·CH=CHCH 3 , ·O–CO/CO 2 , ·COOH, etc.; finally, all these radical groups dissociate and oxidize into H 2 O, CO 2 and N 2 . The SADT calculated by Semenov model of DBAD under 25 kg standard package is 63.95 °C.