Molecular dynamic simulation study on pyrolytic behaviour of xylan

Xylan is the most relevant component in hemicellulose, and in order to understand the mechanism of thermal decomposition of hemicellulose, the pyrolysis process of xylan as a hemicellulose model compound has been simulated by molecular dynamics method. The simulation results show that the pyrolysis process of xylan can mostly be divided into three stages: low, intermediate and high temperature pyrolysis stage. The hydroxyl bonds begin to break down when temperature rises to about 400 K. The glycosidic bonds on side groups begin to break down at about 550 K, and those on main chain begin to break down at about 600 K. Thus, the whole molecule depolymerises and all kinds of fragments are formed. Based on the related experimental results in references, the possible formation pathways of major products have been analysed.