Abstract: n-Hexane, 2-methylpentane, 2,3-dimethylbutane, cyclohexane, methylcyclopentane, and 1-hexene were selected as model compounds for the C6 component in gasoline. The ReaxFF-MD method was used to simulate their oxidative cracking process at a temperature of 3000 K and an equivalent ratioof O₂ consumption of 1.0. The changes in the content of reactants, products (H₂O, CO, CO₂), key free radicals, and intermediates (C₂H₄, C₃H₆, .CH₃, CH₂O) in the system over time were statistically analyzed, and sensitivity analysis was conducted on CH₂O and CO. The preliminary reaction pathways for the oxidative cracking of six C₆ components were analyzed, as well as a unified subsequent oxidative cracking reaction pathway. The simulation results indicate that at the beginning of the reaction, all six C₆ components undergo simultaneous cracking and oxidation reactions;but before 200 ps of reaction, all six C₆ components mainly undergo cleavage reactions, and the generated free radicals and intermediates are mainly C₂H₄, C₃H₆, .CH₃; the molecular structure of C₆ component can affect the concentration peak of carbon containing free radicals or intermediates generated by its cracking, but the occurrence time of the same type of free radical or intermediate concentration peak is similar in different systems; as of 2000 ps of reaction, the conversion degree of C element in C₆ component is slightly higher than that of H element. Sensitivity analysis revealed that CH₂O is mainly produced by the dehydrogenation of intermediates CH₃O. and CH₃O₂., and is consumed through the dehydrogenation to form .CHO; CO is mainly produced through .CHO dehydrogenation and consumed through oxidation reactions with .OH and HO₂..

Key words: C6 hydrocarbons, ReaxFF MD, molecular simulation, oxidation and cracking, reaction mechanism