Molecular Dynamics Simulation Study on High Temperature Oxidation Mechanism of n-Propylbenzene

n-Propylbenzene is a typical aromatic substitute component of Jet A, Jet A-1 and RP-3 aviation kerosene. In this work, the main oxidation reaction networks and the product distributions of n-propylbenzene at different temperatures, densities and equivalence ratios were investigated by ReaxFF based on reactive molecular dynamics simulation. The reaction kinetics theory was also employed to calculate the rate constants of n-propylbenzene oxidation. The results show that the consumption of n-propylbenzene mainly occurs in the alkyl side chain including six C-C and C-H bond fissions of unimolecular reactions and three H-abstraction reactions by O-2 and other small radicals. Due to the lowest bond dissociation energy, the C-C bond fission adjacent to benzyl radical is the most important consumption channel but the contributions of all H-abstraction reactions are similar. The simulated temperature and density/pressure are positively correlated with the oxidation rate of n-propylbenzene, while the effect of equivalence ratio is heavily dependent on the system temperature. Additionally, the calculated apparent activation energies and pre-exponential factors are acceptable compared to the reported experimental results.