Pyrolysis mechanism of palmityl alcohol: combined with experiments, reaction molecular dynamics, and density functional theory simulation

Abstract

Long-chain fatty alcohols (LCFAs) are often utilized as sustainable organic phase change materials in thermal energy storage systems, owing to their excellent biodegradability. However, in the medium and high temperature energy storage systems, these materials may undergo thermal decomposition at high temperatures, which challenges their safe application in high-temperature energy storage systems. In this study, the pyrolysis behavior of palmityl alcohol was investigated using thermal analysis experiments, DFT calculation, and ReaxFF-MD simulation. The experimental results revealed that the kinetic model of palmityl alcohol pyrolysis was governed by a three-dimensional phase boundary, with an average apparent activation energy of 105 kJ/mol. The main products of palm alcohol pyrolysis include C₂H₄, CH₄, H₂, C₂H₂, CO₂, and H₂O. The simulation results showed that the thermal decomposition of palmityl alcohol initiated with the dissociation of C-C bonds and the dehydration condensation of terminal hydroxyl groups. Furthermore, the hydrogen extraction reaction was enhanced by the formation of stable products such as methane and hydrogen, generated through the interaction of carbonyl oxygen radicals and propenyl radicals from the rearrangement of CO bonds. This study provides theoretical support for the safe application of LCFA in high-temperature environments.