Thermal behavior and decomposition mechanism of azobenzene by using kinetic calculation method and molecular dynamics simulation method

Abstract

In the work, both elevated thermal and isothermal experiments of azobenzene were carried out by using SENSYS Evolution DSC. Kinetic parameters and decomposition mechanism were figured out by using Kinetic Calculation (KC) method and Molecular Dynamics Simulation (MDS) method. The results show that a first endothermic and following exothermic behavior appears distinctly in the thermal decomposition process of azobenzene; the apparent activation energy keeps approximately constant at the stage of 0.1 ≤ α ≤ 0.4, and then reduces gradually as the reaction goes on; the thermal decomposition behavior of azobenzene can be described by Sestak-Berggren mechanism on here; The step without adequate free radicals and the step with exponential growth of free radicals dominate respectively the stable decomposition process at initial stage and the self-accelerating decomposition process at autocatalytic stage; Based on Semenov model, the calculated SADT of azobenzene is 380.5 ℃, when packed in 25 kg standard package.