Molecular Dynamics Simulation on the Pyrolysis Process of PODE3-5

Abstract

This paper investigates the pyrolysis of PODEn (n = 3, 4, 5) using ReaxFF molecular dynamics simulation. A large-scale model, which contains 2000 PODEn molecules, is simulated at 3000 K. The higher frequencies of the initial PODEn decomposition reaction at α or β C-O bond show that the α or β C-O bond in PODEn is not easy to break, which is approximately half the number of the other type of C-O bond dissociation. Furthermore, the bond dissociation energies (BDEs) are calculated using the ReaxFF method. The BDE of α or β C-O bond is higher than that of the other C-O bond, ~3–11 kcal/mol, indicating that BDE is one of the factors causing the different proportions of bonds broken. The evolution of pyrolysis products is also investigated. The results reveal that long-chain pyrolysis products from the initial PODEn decomposition are prone to further reaction, while a large amount of CH3O and CH3 remains in the system. This helps explain the difficulty in α and β C-O bond dissociation reactions. The results of the pyrolysis products are consistent with the result in further chemical kinetic simulation. The C2 species in pyrolysis products is relatively low, especially for C2H4 and C2H3, which is around zero. This supports the ability of PODEn to reduce soot emission.