ReaxFF molecular dynamics study on the pyrolysis process of cyclohexanone

Thermal fragmentation of carbonyl compounds is important in bio-oil pyrolysis and combustion. This paper presents pyrolysis simulations of cyclohexanone with ReaxFF-MD. Annealing simulations were performed using LAMMPS and reactions analyses were carried out by ChemTrayzer code. The results showed that consumption of cyclohexanone was mainly through ring opening, mostly by alpha-cleavage. Other possible paths involve isomerization to enol and H-abstraction from ring. The main findings include: (a) reaction paths indicated experimentally were confirmed by simulations, mainly leading to the formation of ethene and ethenone; (b) new reaction channels were predicted, enclosing new biradicals, which can contribute to photoionization mass spectra interpretation; (c) multimolecular mechanistic details were proposed, adding new features to unimolecular mechanism presented previously in literature. These results can help to explain thermolysis of carbonyl compounds and may be extended hereafter to thermochemistry of other compounds.