Study on the effect of low molecular hydrocarbon compounds on coal spontaneous combustion

• Pentane reacts with oxygen by breaking old chemical bonds and forming new chemical bonds. • Active sites of pentane are C1, C5, C8, C11 and C14 atoms. • Priority order is Path 6 > Path 5 > Path 1 > Path 3 > Path 7 > Path 4 > Path 2. The molecular structure of coal is composed of macromolecules and low molecules, of which low molecules account for 20%. Low molecules have a great influence on the coal spontaneous combustion, but there are few studies on the influence of low molecule on the coal spontaneous combustion. Therefore, it is of great significance to study the mechanism of low molecule spontaneous combustion in coal. Because there are many kinds of low molecular compound, the low molecular hydrocarbon pentane was chosen as the research object. Gaussian03 software was used to simulate and analyze the molecular level by using the B3LYP/6-311G method of quantum chemical density functional theory (DFT). Following conclusions were drawn: active sites of pentane in the process of spontaneous combustion are C1, C5, C8, C11 and C14 atoms. The reaction mechanism of pentane with oxygen during coal spontaneous combustion is the process of breaking old chemical bonds and forming new chemical bonds. The priority order of each reaction channel is Path 6 > Path 5 > Path 1 > Path 3 > Path 7 > Path 4 > Path 2.